# EDGAR Filing Document

**Accession Number:** 0001724979
**File Stem:** 0001558370-23-003331
**Filing Date:** 2023-3
**Character Count:** 488733
**Document Hash:** d03a0244eee72a04c071dfd7cb6d325d
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001558370-23-003331.hdr.sgml**: 20230309

**ACCESSION NUMBER**: 0001558370-23-003331

**CONFORMED SUBMISSION TYPE**: 10-K

**PUBLIC DOCUMENT COUNT**: 83

**CONFORMED PERIOD OF REPORT**: 20221231

**FILED AS OF DATE**: 20230309

**DATE AS OF CHANGE**: 20230309

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Rain Oncology Inc.
- **CENTRAL INDEX KEY:** 0001724979
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **IRS NUMBER:** 821130967
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 10-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40356
- **FILM NUMBER:** 23720173

**BUSINESS ADDRESS:**
- **STREET 1:** 8000 JARVIS AVENUE
- **STREET 2:** SUITE 204
- **CITY:** NEWARK
- **STATE:** CA
- **ZIP:** 94560
- **BUSINESS PHONE:** (510) 953-5559

**MAIL ADDRESS:**
- **STREET 1:** 8000 JARVIS AVENUE
- **STREET 2:** SUITE 204
- **CITY:** NEWARK
- **STATE:** CA
- **ZIP:** 94560

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Rain Therapeutics Inc.
- **DATE OF NAME CHANGE:** 20171211

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**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**FORM 10-K**

**(Mark One)**

**☒** **ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934** 

**For the fiscal year ended December 31, 2022**

**OR**

**☐** **TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; TO &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**

**Commission File Number 001-40356**

**Rain Oncology Inc.**

**(Exact name of Registrant as specified in its Charter)**

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| | |
|:---|:---|
| **Delaware** | **82-1130967** |
| **(State or other jurisdiction of**<br>**incorporation or organization)** | **(I.R.S. Employer**<br>**Identification No.)** |
| **8000 Jarvis Avenue, Suite 204**<br>**Newark, CA** | **94560** |
| **(Address of principal executive offices)** | **(Zip Code)** |

---

**Registrant's telephone number, including area code: (510) 953-5559**

**Former name, former address and former fiscal year, if changed since last report: Rain Therapeutics Inc.**

Securities registered pursuant to Section 12(b) of the Act:

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| | | |
|:---|:---|:---|
| **Title of each class** | **Trading Symbol(s)** | **Name of each exchange on which registered** |
| Common Stock, par value $0.001 per share | RAIN | The Nasdaq Global Select Market |

---

Securities registered pursuant to Section 12(g) of the Act: **None**

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐ No ☒

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ☐ No ☒

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

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| | | | |
|:---|:---|:---|:---|
| Large accelerated filer | ☐ | Accelerated filer | ☐ |
| Non-accelerated filer | ☒ | Smaller reporting company | ☒ |
| Emerging growth company | ☒ |  |  |

---

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the Registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the Registrant's executive oﬃcers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). YES ☐ NO ☒

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrant as of June 30, 2022, the last business day of the Registrant's most recently completed second fiscal quarter, was approximately $43,929,838, based on the closing price of the shares of common stock on The Nasdaq Global Select Market reported for such date. Shares of common stock held by each officer and director and by each person who is known to own 10% or more of the outstanding common stock have been excluded in that such persons may be deemed to be affiliates of the Registrant. This determination of affiliate status is not necessarily a conclusive determination for other purposes.

As of February 28, 2023, the registrant had 36,356,233 shares of common stock, $0.001 par value per share, outstanding, comprised of 26,513,513 shares of common stock, $0.001 par value per share, and 9,842,720 shares non-voting common stock, $0.001 par value per share.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant's definitive proxy statement relating to its 2023 Annual Meeting of Stockholders to be filed with the Securities and Exchange Commission within 120 days after the end of the fiscal year ended December 31, 2022 are incorporated herein by reference in Part III of this Annual Report on Form 10-K where indicated.

------

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**Table of Contents**

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| | | |
|:---|:---|:---|
|  |  | **Page** |
| [**PART I**](#PARTI_965648) |  |  |
| &nbsp;&nbsp;[Item 1.](#ITEM1BUSINESS_663032) | [Business](#ITEM1BUSINESS_663032) | 1 |
| &nbsp;&nbsp;[Item 1A.](#Item1ARISKFACTORS_690588) | [Risk Factors](#Item1ARISKFACTORS_690588) | 36 |
| &nbsp;&nbsp;[Item 1B.](#Item1BUNRESOLVEDSTAFFCOMMENTS_262929) | [Unresolved Staff Comments](#Item1BUNRESOLVEDSTAFFCOMMENTS_262929) | 60 |
| &nbsp;&nbsp;[Item 2.](#Item2PROPERTIES_613552) | [Properties](#Item2PROPERTIES_613552) | 60 |
| &nbsp;&nbsp;[Item 3.](#Item3LEGALPROCEEDINGS_885337) | [Legal Proceedings](#Item3LEGALPROCEEDINGS_885337) | 61 |
| &nbsp;&nbsp;[Item 4.](#Item4MINESAFETYDISCLOSURES_26723) | [Mine Safety Disclosures](#Item4MINESAFETYDISCLOSURES_26723) | 61 |
| [**PART II**](#PARTII_532282) |  |  |
| &nbsp;&nbsp;[Item 5.](#Item5MARKETFORREGISTRANTSCOMMONEQUITYREL) | [Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities](#Item5MARKETFORREGISTRANTSCOMMONEQUITYREL) | 62 |
| &nbsp;&nbsp;[Item 6.](#Item6Reserved_199591) | [Reserved](#Item6Reserved_199591) | 63 |
| &nbsp;&nbsp;[Item 7.](#Item7MANAGEMENTSDISCUSSIONANDANALYSISOFF) | [Management's Discussion and Analysis of Financial Condition and Results of Operations](#Item7MANAGEMENTSDISCUSSIONANDANALYSISOFF) | 64 |
| &nbsp;&nbsp;[Item 7A.](#Item7AQUANTITATIVEANDQUALITATIVEDISCLOSU) | [Quantitative and Qualitative Disclosures About Market Risk](#Item7AQUANTITATIVEANDQUALITATIVEDISCLOSU) | 74 |
| &nbsp;&nbsp;[Item 8.](#Item8FINANCIALSTATEMENTSANDSUPPLEMENTARY) | [Financial Statements and Supplementary Data](#Item8FINANCIALSTATEMENTSANDSUPPLEMENTARY) | 75 |
| &nbsp;&nbsp;[Item 9.](#Item9CHANGESINANDDISAGREEMENTSWITHACCOUN) | [Changes in and Disagreements With Accountants on Accounting and Financial Disclosure](#Item9CHANGESINANDDISAGREEMENTSWITHACCOUN) | 104 |
| &nbsp;&nbsp;[Item 9A.](#Item9ACONTROLSANDPROCEDURES_778059) | [Controls and Procedures](#Item9ACONTROLSANDPROCEDURES_778059) | 104 |
| &nbsp;&nbsp;[Item 9B.](#Item9BOTHERINFORMATION_752854) | [Other Information](#Item9BOTHERINFORMATION_752854) | 105 |
| &nbsp;&nbsp;[Item 9C.](#Item9CDISCLOSUREREGARDINGFOREIGNJURISDIC) | [Disclosure Regarding Foreign Jurisdictions that Prevent Inspections](#Item9CDISCLOSUREREGARDINGFOREIGNJURISDIC) | 105 |
| [**PART III**](#PARTIII_953370) |  |  |
| &nbsp;&nbsp;[Item 10.](#Item10DIRECTORSEXECUTIVEOFFICERSANDCORPO) | [Directors, Executive Officers and Corporate Governance](#Item10DIRECTORSEXECUTIVEOFFICERSANDCORPO) | 106 |
| &nbsp;&nbsp;[Item 11.](#Item11EXECUTIVECOMPENSATION_133745) | [Executive Compensation](#Item11EXECUTIVECOMPENSATION_133745) | 106 |
| &nbsp;&nbsp;[Item 12.](#Item12SECURITYOWNERSHIPOFCERTAINBENEFICI) | [Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters](#Item12SECURITYOWNERSHIPOFCERTAINBENEFICI) | 106 |
| &nbsp;&nbsp;[Item 13.](#Item13CERTAINRELATIONSHIPSANDRELATEDTRAN) | [Certain Relationships and Related Transactions, and Director Independence](#Item13CERTAINRELATIONSHIPSANDRELATEDTRAN) | 106 |
| &nbsp;&nbsp;[Item 14.](#Item14PRINCIPALACCOUNTANTFEESANDSERVICES) | [Principal Accountant Fees and Services](#Item14PRINCIPALACCOUNTANTFEESANDSERVICES) | 106 |
| [**PART IV**](#PARTIV_406211) |  |  |
| &nbsp;&nbsp;[Item 15.](#Item15EXHIBITSFINANCIALSTATEMENTSCHEDULE) | [Exhibits, Financial Statement Schedules](#Item15EXHIBITSFINANCIALSTATEMENTSCHEDULE) | 107 |
| &nbsp;&nbsp;[Item 16.](#Item16FORM10KSUMMARY_612849) | [Form 10-K Summary](#Item16FORM10KSUMMARY_612849) | 110 |

---

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#### NOTE REGARDING FORWARD-LOOKING STATEMENTS
This Annual Report on Form 10-K includes "forward-looking statements" within the meaning of the federal securities laws, which statements are subject to substantial risks and uncertainties and are based on estimates and assumptions. All statements, other than statements of historical facts included in this Annual Report on Form 10-K, including statements concerning our plans, objectives, goals, strategies, future events, future revenues or performance, financing needs, plans or intentions relating to product candidates and markets and business trends and other information referred to under the sections titled "Business," "Risk Factors," and "Management's Discussion and Analysis of Financial Condition and Results of Operations" are forward-looking statements. In some cases, you can identify forward looking statements by terms such as "may," "might," "will," "objective," "intend," "should," "could," "can," "would," "expect," "believe,", "design," "estimate," "predict," "potential," "plan" or the negative of these terms and similar expressions intended to identify forward-looking statements. Forward-looking statements are not historical facts and reflect our current views with respect to future events. Given the significant uncertainties, you should not place undue reliance on these forward-looking statements.

There are a number of risks, uncertainties and other factors that could cause our actual results to differ materially from the forward-looking statements expressed or implied in this Annual Report on Form 10-K. Such risks, uncertainties and other factors include, among others, the risks, uncertainties and factors set forth in "Risk Factors," and the following risks, uncertainties and factors:

● the ability of our clinical trials to demonstrate safety and efficacy of our product candidates and other positive results;

● the timing and focus of our ongoing and future preclinical studies and clinical trials and the reporting of data from those studies and trials;

● our plans relating to commercializing our product candidates, if approved, including the geographic areas of focus and sales strategy;

● the size of the market opportunity for our product candidates, including our estimates of the number of patients who suffer from the diseases we are targeting;

● our expectations regarding the approval and use of our product candidates as first, second or subsequent lines of therapy or in combination with other drugs;

● the success of competing therapies that are or may become available;

● our estimates of the number of patients that we will enroll in our clinical trials;

● the beneficial characteristics, safety, efficacy and therapeutic effects of our product candidates;

● the timing or likelihood of regulatory filings and approvals, including our expectation to seek an accelerated approval pathway and special designations, such as orphan drug designation, for our product candidates for various diseases;

● our ability to obtain and maintain regulatory approval of our product candidates;

● our plans relating to the further development of our product candidates, including additional indications we may pursue;

● existing regulations and regulatory developments in the United States, Europe and other jurisdictions;

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● our plans and ability to obtain or protect intellectual property rights, including extensions of existing patent terms where available;

● our continued reliance on third parties to conduct additional clinical trials of our product candidates and for the manufacture of our product candidates for preclinical studies and clinical trials;

● our plans regarding, and our ability to obtain, and negotiate favorable terms of, any collaboration, licensing or other arrangements that may be necessary or desirable to develop, manufacture or commercialize our product candidates;

● our plans to develop our product candidates in combination with other therapies;

● the need to hire additional personnel and our ability to attract and retain such personnel;

● our estimates regarding expenses, future revenue, capital requirements and needs for additional financing;

● our financial performance;

● the period over which we estimate our existing cash and cash equivalents will be sufficient to fund our future operating expenses and capital expenditure requirements; and

● our expectations regarding the period during which we will qualify as an emerging growth company under the JOBS Act.

There may be other factors that may cause our actual results to differ materially from the forward-looking statements, including factors disclosed in "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations." You should evaluate all forward-looking statements made in this Annual Report on Form 10-K in the context of these risks and uncertainties.

We caution you that the risks, uncertainties and other factors referred to above may not contain all of the risks, uncertainties and other factors that are important to you. In addition, we cannot assure you that we will realize the results, benefits or developments that we expect or anticipate or, even if substantially realized, that they will result in the consequences or affect us or our business in the way expected. All forward-looking statements in this Annual Report on Form 10-K apply only as of the date made and are expressly qualified in their entirety by the cautionary statements included in this Annual Report on Form 10-K. We undertake no obligation to publicly update or revise any forward-looking statements to reflect subsequent events or circumstances.

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#### PART I

#### ITEM 1. BUSINESS.

#### Company Overview
We are a late-stage precision oncology company developing therapies that target oncogenic drivers to genetically select patients we believe will most likely benefit. This approach includes using a tumor-agnostic strategy to select patients based on their tumors' underlying genetics rather than histology. We have in-licensed product candidates, each with a differentiated profile relative to available therapies, and we intend to continue strengthening our pipeline through focused business development and internal research efforts.

Our lead product candidate, milademetan (also known as RAIN-32) is an oral, small molecule inhibitor of the p53-mouse double minute 2 (p53-MDM2) complex that reactivates p53. We in-licensed milademetan from Daiichi Sankyo Company, Limited (Daiichi Sankyo) in September 2020 based on the results of a Phase 1 clinical trial, which demonstrated meaningful antitumor activity in an MDM2-amplified subtype of liposarcoma (LPS) and other solid tumors. Data from de-differentiated liposarcoma (DDLPS) patients in the Phase 1 clinical trial of milademetan demonstrated median progression-free survival (mPFS) of approximately seven to eight months. Importantly, this result was accomplished with a rationally designed dosing schedule designed to mitigate safety concerns and widen the therapeutic window of MDM2 inhibition unlocking the potential for milademetan in a broad range of MDM2-dependent cancers. Based on these data, we commenced a pivotal Phase 3 trial in LPS (MANTRA) in July 2021. We expect to report topline data from our MANTRA trial in the second quarter of 2023. We also commenced a Phase 2 tumor-agnostic basket trial in certain solid tumors (MANTRA-2) in November 2021. We anticipate commencing a Phase 1/2 basket trial to evaluate the safety, tolerability and efficacy of milademetan in combination with atezolizumab in patients with loss of cyclin-dependent kinase inhibitor 2A (CDKN2A) and wildtype p53 advanced solid tumors (MANTRA-4) in mid-2023.

#### Our Strategy
Our vision is to be a leading precision oncology company that develops and commercializes small molecule therapeutics through leveraging both an acquisition-based business model and internal research efforts. Our strategy to achieve this vision is as follows:

● Rapidly advance our lead product candidate, milademetan, through clinical development toward approval in LPS and subsequently expand across a multitude of MDM2-dependent tumors. As the trials progress, we plan to accelerate efforts to engage with the regulatory authorities and, upon potential receipt of the requisite approvals, will initiate efforts to manufacture and commercially launch milademetan.

● Increase probability of a clinically meaningful benefit for patients for our pipeline programs by utilizing biomarker driven patient selection. We employ widely available, comprehensive next generation sequencing (NGS) diagnostic tests and partner with industry-leading assay developers to identify patients for our clinical trials based on molecular biomarkers indicating oncogene addiction and dependency on specific cellular signaling networks. This pre-selection of patients is designed to target patients most likely to benefit from our therapies.

● Maximize opportunity of commercial success for our pipeline programs by focusing on tumor-agnostic clinical trials. Through our MANTRA-2 open-label basket trial for milademetan, we are employing a tumor-agnostic development approach to the essential biological pathways and molecular machinery of cancer. This strategy leverages existing comprehensive next generation tumor sequencing in cancer patients and we believe will allow for rapid patient enrollment and subsequent collection of data and, as a result, the potential acceleration of clinical trial timelines.

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We believe our continued focus on this approach will maximize our total addressable patient population and the overall commercial opportunities for our pipeline programs.

● Leverage our business development expertise to expand our pipeline of precision oncology candidates by identifying genetically or biologically defined subsets across solid tumors and hematologic malignancies in patients with limited treatment options. Our team has a diversity of backgrounds from academia and drug research and development to biopharma industry experience. Our expansive networks in the biopharma landscape coupled with our analytical approach to business development allows us to screen and identify drug candidates and programs with potentially significant commercial opportunities. We are exploring pipeline programs in the following three categories: (1) small molecule programs focusing on novel oncogenic drivers, and with mechanisms of action that are distinct from existing and upcoming therapeutics; (2) programs that improve upon existing therapies with validated oncology targets and clinical efficacy, but which lack clinical utility due to a narrow therapeutic window; and (3) programs targeting emerging classes and/or biological targets of precision oncology, such as synthetic lethality.

● Pursue global clinical and regulatory strategies enabling us to commercialize pipeline programs worldwide. We will pursue a global regulatory approach and take into consideration the differing requirements and criteria of the Food and Drug Administration (FDA), European Medicines Agency (EMA) and other regulatory agencies as our pipeline programs progress in their respective clinical trials. We plan to retain significant economic and commercial rights to our portfolio in the United States and certain other regions. We will evaluate partnership opportunities in regions in which we are unlikely to pursue commercialization on our own.

● Pursue collaborations with leading academic clinical investigators to evaluate new therapeutic indications and combinations of pipeline programs. In addition to building a pipeline of therapies through internal research and business development efforts, we expect to continue to partner with academic and research institutions to expand the scope of our data.

#### Overview of Precision Oncology and Our Approach
Precision oncology broadly refers to the strategy of harnessing tumor biology to design drugs and clinical trial strategies to treat cancer more effectively in patients. Recent companion diagnostic approvals and reimbursement for multi-gene NGS assays have made it easier to translate and distil cancer biology into tenable biomarkers that can then be readily identified in tumor or blood samples from patients. This approach has accelerated over the last decade and has resulted in numerous targeted therapies for previously difficult to treat cancers such as lung adenocarcinoma, bladder cancer, and cholangiocarcinoma, among others. A recent development within the precision oncology strategy is the strategy of seeking regulatory approval of cancer drugs based solely on tumor biology and biomarkers across cancer types, rather than tumor histology or organ site-specific approvals. Successful examples of this strategy include larotrectinib, developed by Loxo Oncology, Inc., and entrectinib, developed by Ignyta, Inc., both for tumors harboring NTRK gene fusions, and pembrolizumab, developed by Merck, for microsatellite instability-high tumors. As a result, a new era of cancer drug development has emerged, demonstrating an unprecedented degree of insight into the critical drivers of cancer, tumorigenesis and its associated signaling networks.

With a biology-based approach that views a tumor's biological driver as more important than tumor type for selecting treatment modalities, we believe that understanding the molecular machinery employed by a tumor is paramount to developing cancer therapeutics. We intend to pursue therapeutics that target genetic alterations in cell-signaling pathways that may be oncogenic, including synthetic lethal interactions. By understanding these biological dependencies in cancer cells, we hope to identify new therapies to meaningfully extend patients' lives.

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We seek to build a pipeline of precision oncology therapeutics for genetically-defined patients by discovering or licensing programs in three categories:

● programs focusing on novel oncogenic drivers and small molecules with mechanisms of action that are distinct from existing and upcoming therapeutics;

● programs that improve upon existing therapies with validated oncology targets and clinical efficacy, but which lack clinical utility due to a narrow therapeutic window; and

● programs targeting emerging classes and/or biological targets of precision oncology, such as synthetic lethality.

Programs that capitalize on rational tumor targets are required to exhibit appropriate selectivity with a high degree of target engagement. We view the three key pillars of any successful program as:

● targeting a tumor with unambiguous oncogenic addiction;

● achieving sufficient exposure of therapeutics in plasma and the tumor; and

● strong target engagement during the dosing window.

Our approach leverages currently available tumor genetic testing strategies to enroll and treat patients with advanced cancer. We employ companion diagnostics and partnerships with industry-leading assay developers to identify patients based on molecular biomarkers indicating oncogene addiction and dependency on specific cellular signaling networks. In our MANTRA-2 basket trial of milademetan, we are enrolling patients with advanced or metastatic cancer based on MDM2 gene amplification and p53 mutation status, both of which are widely available on existing commercial NGS assays. The significant expansion of the FDA-approved targeted therapies in non-small cell lung cancer (NSCLC), breast cancer, bladder cancer, melanoma, cholangiocarcinoma and tumor-agnostic indications has led to increasing adoption of multi-gene NGS assays to determine patient eligibility for an ever-expanding number of targeted therapies.

#### Our Development Pipeline
Our development pipeline is unified by a strategy to target oncogenic drivers through differentiated therapies for which we are able to genetically select the patients we believe will be most likely to benefit from treatment. We currently retain global development and commercialization rights to all of our product candidates.

![Graphic](rain-20221231x10k006.jpg)

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#### Our Lead Product Candidate, Milademetan

#### Milademetan Overview
Our lead product candidate, milademetan, is a small molecule, oral inhibitor of MDM2 and is being developed in patients with MDM2-dependent cancers. Historically, MDM2 inhibition has presented treatment challenges due to dose-limiting, on-target hematologic toxicities. We believe an MDM2-targeted therapy must possess certain pharmacological characteristics related to potency and pharmacokinetics to allow for the design of an optimized dosing schedule. An optimized dosing schedule is intended to improve peak drug exposure leading to apoptosis and cell cycle arrest during the dosing period, while permitting hematopoietic precursor cell recovery during the dosing break, thereby minimizing hematologic toxicity. Milademetan's differentiated profile, as a potent MDM2 inhibitor has enabled a rationally designed dosing schedule that we believe has the potential to reduce toxicities while preserving activity. We anticipate that this dosing schedule may also be applicable to other MDM2-dependent cancer populations across solid and hematologic tumor types.

***Overview of p53 and MDM2***

Milademetan reactivates p53, known as the "guardian of the genome," by inhibiting MDM2. p53 is present in every cell and acts as a key regulator of a variety of cellular processes including cell cycle, DNA repair and apoptosis. In a normal cell, the activity of p53 is controlled and regulated by the inhibitory protein MDM2. MDM2 binds to p53, thereby inducing degradation and allowing normal cells to function properly. In response to cell damage and other stress conditions, p53 is activated and prevents the formation of cancerous cells by inducing apoptosis.

In contrast to normal cells, in tumor cells, the two primary mechanisms by which p53 can be inactivated in tumor cells are mutations in p53 and activation or overexpression of MDM2. Approximately half of all tumors are characterized by mutations of the p53 gene. The remaining cancer patients have a p53 gene that is not mutated, and is otherwise known as WT p53, but can be functionally suppressed through the activation or overexpression of MDM2. We have identified MDM2 dependence in several solid tumors. This dependence is caused by overexpression of MDM2 through gene amplification or other mechanisms, loss of a negative regulator of MDM2 or other causes. Overexpression of MDM2 promotes the degradation of p53 and also eliminates p53's ability to activate transcription. Milademetan, by binding MDM2 at the p53 interaction site, prevents the formation of the MDM2-p53 complex, allowing p53 reactivation and subsequent transcription of genes that trigger cancer cell cycle arrest (e.g., p21) or apoptosis (e.g., PUMA) and can be readily measured by increases in the pharmacodynamic marker MIC-1 (GDF15) in the blood.

#### Phase 1 Clinical Data
Milademetan has been evaluated by Daiichi Sankyo in various solid tumors, including DDLPS, in a Phase 1 trial (U101) for initial assessment of safety, tolerability and preliminary efficacy. The largest population enrolled in the trial were DDLPS patients (approximately 50% of the total patients enrolled). DDLPS tumors have nearly universal MDM2 gene amplification and WT p53, and hence are nearly universally MDM2-dependent. Therefore, we believe these LPS patients represent an appropriate population for MDM2 inhibition therapy. In October 2020, Daiichi Sankyo reported comprehensive results from this Phase 1 trial covering 107 patients. Milademetan has demonstrated meaningful antitumor activity in an MDM2-amplified subtype of LPS and other solid tumors in a Phase 1 clinical trial, validating a rationally-designed dosing schedule to potentially mitigate safety concerns and widen the therapeutic window of MDM2 inhibition.

#### Clinical Observations to Support Pursuing Milademetan as a Treatment in LPS Patients
Historically, LPS treatment rarely produces tumor responses, regardless of therapy and line of treatment. As a result, efficacy in LPS has been assessed with an endpoint of PFS, and we are using PFS as

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the primary endpoint in our MANTRA Phase 3 LPS trial. Notwithstanding, tumor responses to milademetan were observed in the Phase 1 trial. Of the 53 patients with DDLPS who received one or more doses of milademetan, two (3.8%) achieved partial response and 34 (64.2%) achieved stable disease.

The trial also identified the disease control rate (DCR) for the LPS population enrolled in the trial, which consisted primarily of patients with MDM2-amplified tumors, as compared to an unselected non-LPS population. The DCR in the LPS population was nearly double the DCR in the non-LPS population, 58.5% versus 32.4%, respectively, supporting our plan to select patients with MDM2 amplification in future clinical trials.

In July 2021, we provided an update on patients who received milademetan monotherapy from the concluded Phase 1 dose escalation and expansion study. As of July 1, 2021, three DDLPS patients received therapy with milademetan monotherapy for greater than 51 months. Two of these patients received therapy with durations of 51 and 57 months without disease progression, and an additional patient received therapy for greater than 59 months before discontinuation in the second quarter of 2021. We believe this highlights the potential for milademetan to have a favorable long-term tolerability and safety profile.

Based on the Phase 1 data, we initiated a pivotal Phase 3 trial in DDLPS patients (MANTRA) in July 2021.

#### Clinical Observations in Non-LPS Patients to Support Pursuing Milademetan as a Tumor-agnostic Treatment for Patients with MDM2-amplified Tumors
In contrast to LPS patients who rarely have tumor responses to treatment, certain non-LPS patients enrolled in the Phase 1 trial exhibited tumor responses when treated with milademetan. Of the ten non-LPS patients receiving milademetan in Schedule D of the completed Phase 1 clinical trial, three patients were characterized for MDM2 gene amplification. Patients characterized for MDM2 gene amplification included patients with breast cancer, synovial sarcoma and small cell lung cancer (SCLC). The first patient exhibited a confirmed tumor volume reduction. The latter two patients exhibited partial responses, one of which was a confirmed partial response.

Based on the available data from patients with non-LPS MDM2-amplified tumors, we initiated a Phase 2 tumor agnostic basket clinical trial (MANTRA-2) in November 2021.

#### Clinical Development Plan
*Phase 3 Trial in DDLPS Patients (MANTRA)*

In July 2021, we initiated a randomized, multicenter, open-label, Phase 3 registrational trial (MANTRA) for patients with unresectable or metastatic DDLPS component that has progressed on one or more prior systemic therapies, including at least one anthracycline-based therapy. This trial is an open label, 1:1 randomized trial comparing milademetan to trabectedin, an SOC therapeutic, in approximately 160 DDLPS patients with at least one prior anthracycline-based therapy. The dosing schedule for the Phase 3 trial will be identical to the Schedule D dose of 260 mg (qd 3/14x2) employed in the Phase 1 trial. The primary objective of the trial is to compare PFS evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) criteria in blinded independent review between the milademetan treatment arm and the trabectedin control arm. Secondary endpoints include overall survival, PFS by investigator assessment, objective response rate, duration of response, disease control rate, safety and patient reported outcomes. Our commencement of a Phase 3 trial following the Phase 1 trial referenced above is based on the data observed in the Phase 1 trial and FDA feedback with respect to our development plan.

The PFS assumptions for statistical powering are based on a PFS assumption for the control arm of 3.0 months and 6.0 months for milademetan. The doubling of PFS corresponds to a hazard ratio of 0.5.

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In August 2022, we announced the completion of enrollment into our MANTRA Phase 3 trial of milademetan, and we expect to report topline data from our MANTRA trial in the second quarter of 2023. Subject to supportive clinical data, we anticipate filing regulatory applications in the United States and Europe thereafter.

*Phase 2 MDM2-amplified Tumor-agnostic Basket Trial (MANTRA-2)*

In November 2021, the first patient was dosed in the multicenter, single arm, open-label, Phase 2 basket trial evaluating Milademetan for the treatment of MDM2-amplified advanced solid (MANTRA-2). The MANTRA-2 trial is designed to evaluate the safety and efficacy of milademetan in patients with advanced or metastatic solid tumors refractory or intolerant to standard-of-care therapy and that exhibit wild-type p53 and a prespecified minimum MDM2 gene copy number. Approximately 65 patients are anticipated to be enrolled to receive milademetan. The primary endpoint of the trial is objective response rate as measured by RECIST criteria. Secondary endpoints include duration of response, disease control rate progression-free survival by investigator assessment, overall survival, and growth modulation index.

We are enrolling patients that have received and progressed on standard of care (SOC) therapy and will be unlikely to tolerate or derive clinically meaningful benefit from SOC therapy. Patients with MDM2 amplification will be selected using local tumor testing, such as a commercially-available NGS-based diagnostic assay. Milademetan will be administered in doses of 260 mg using the Schedule D dosing schedule from the Phase 1 trial (qd 3/14x2). The primary endpoint of this trial will be ORR by RECIST, with secondary endpoints of PFS, Duration of Response (DOR), OS and growth-modulation index (GMI). We believe the basket trial is supported by data in the Phase 1 clinical trial, in which non-LPS patients with MDM2-amplified tumors exhibited tumor volume reductions and confirmed partial responses under RECIST criteria.

In November 2022, we announced preliminary data in our MANTRA-2 trial. As of the latest data cutoff on October 26, 2022, 17 patients had been enrolled, 15 of whom had been dosed with milademetan. There were 10 efficacy-evaluable patients with CN greater than or equal to 8 by central testing. We observed two unconfirmed partial responses with tumor regression of 34% and 30% (pancreatic and lung cancer, respectively). Two patients exhibited promising activity with tumor regression of 29% and 27% (biliary tract and breast cancer, respectively). In addition, we observed anti-tumor effect of milademetan in heavily pretreated, refractory patients, with a median of four prior therapies. The safety profile as of the data cutoff was preliminarily consistent with our prior Phase 1 trial of milademetan.

*Phase 2 Trial for Milademetan in Merkel Cell Carcinoma (MANTRA-3)*

We are deprioritizing the Phase 2 MANTRA-3 trial in Merkel cell carcinoma as an area of focus due to our continued effort to rationalize use of capital in the current market environment.

*Phase 1/2 Trial for Milademetan in Combination with Atezolizumab in Patients with CDKN2A Loss and Wildtype p53 advanced solid tumors (MANTRA-4)*

Cyclin-dependent kinase inhibitor 2A (CDKN2A) encodes for the tumor suppressor p14ARF, an inhibitor of MDM2, and the loss of CDKN2A may lead to MDM2-dependent cancers. This concept of MDM2 dependency is supported by nonclinical data demonstrating *in vitro* sensitivity to milademetan of cancer cell lines harboring CDKN2A loss and WT p53 as well as several in vivo models with CDKN2A loss showing anti-tumor activity of milademetan. Loss of p53 activity via MDM2 and/or CDKN2A loss has also been associated with poor clinical outcomes for patients treated with immune checkpoint inhibitors (ICI). Nonclinical data in an immune competent mouse model of colorectal cancer with CDKN2A loss demonstrated enhanced combinatorial activity of milademetan plus an anti-PD1 antibody compared to either agent alone.

In January 2022, we announced a clinical supply agreement with Roche for the supply of the anti-Programmed Death Ligand-1 (PD-L1) monoclonal antibody, atezolizumab. Clinical trials are planned to

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evaluate milademetan in combination with atezolizumab for the treatment of patients in genetically selected populations. Under this agreement, we are the sponsor of the anticipated clinical trials, and Roche will supply atezolizumab.

An initial Phase 1/2 basket trial is planned to evaluate the safety, tolerability and efficacy of milademetan in combination with atezolizumab in patients with loss of CDKN2A and wildtype p53 advanced solid tumors who have previously progressed on ICI. We anticipate the start of the Phase 1/2 basket trial in mid-2023. Subsequent Phase 2 clinical trials evaluating the combination of milademetan and atezolizumab may span various additional tumor types.

#### Preclinical RAD52 Program
In February 2023, we decided to discontinue further development of our preclinical program focused on targeting RAD52 in the DNA damage repair pathway.

#### Collaboration and License Agreements

#### Daiichi Sankyo License Agreement
On September 2, 2020, we entered into a license agreement with Daiichi Sankyo, a Japanese corporation (the Daiichi Sankyo License Agreement). Pursuant to the Daiichi Sankyo License Agreement, we obtained a worldwide, sublicensable (through multiple tiers), royalty-bearing, exclusive right and license under Daiichi Sankyo's know how and seven families of patents and patent applications to make, have made, use, import and export milademetan (also known as RAIN-32) (the Licensed Compound) for all human prophylactic or therapeutic uses that derive therapeutic effect by binding to MDM2 for the prevention and treatment of any indication for the purpose of making, having made, using, offering for sale, selling, marketing, distributing, importing, and exporting products containing milademetan as an active pharmaceutical ingredient (the Products). See the section titled "Intellectual Property."

While we are solely responsible under the Daiichi Sankyo License Agreement for the research, development and registration of the Licensed Compound and Products, Daiichi Sankyo will continue to conduct three ongoing clinical trials and prepare final reports with respect to these clinical trials. We have agreed to reimburse Daiichi Sankyo certain third-party expenses incurred by Daiichi Sankyo while conducting such trials.

We are obligated to use commercially reasonable efforts to develop, commercialize and manufacture the Products and to commercially launch the Products as soon as reasonably practicable after receiving the requisite marketing approvals from the authorities in any given country. We are also obligated to use commercially reasonable efforts to receive at least three full approvals for use in each of the following countries: France, Germany, Italy, Spain, the United Kingdom, the United States and one country outside of the United States and the European Union.

In accordance with the terms of the Daiichi Sankyo License Agreement, we paid Daiichi Sankyo an initial upfront payment of $5.0 million in September 2020. We are required to make aggregate future milestone payments of up to $223.5 million, contingent on the attainment of certain development, regulatory and sales milestones. On July 20, 2021, we announced that the first patient has been randomized in the multicenter, open-label, Phase 3 registrational trial (MANTRA) evaluating milademetan for the treatment of de-differentiated liposarcoma. Accordingly, pursuant to the Daiichi Sankyo License Agreement, we recorded $5.5 million in milestone fees as research and development expense in the consolidated statement of operations and comprehensive loss during the year ended December 31, 2021. Of the $5.5 million milestone fees, $2.5 million was paid in the third quarter of 2021 and $3.0 million was accrued as part of accrued research and development in the consolidated balance sheet as of December 31, 2021. On June 29, 2022, we entered into an amendment to the Daiichi Sankyo License Agreement with Daiichi Sankyo. The amendment reduced the $3.0 million milestone fee liability associated with previously achieved milestone to

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$2.0 million and accordingly reduced research and development expense on the consolidated statements of operations and comprehensive loss by $1.0 million for the year ended December 31, 2022. The amendment also extended the due date of the milestone fee payment to June 30, 2023. During the year ended December 31, 2022, we incurred no milestone research and development expense under the Daiichi Sankyo License Agreement.

On March 3, 2022, we entered into a Memorandum of Understanding with Daiichi Sankyo (the "Memorandum of Understanding"), which provides that Daiichi Sankyo will terminate its U105 study, and we will reimburse a total of $2.0 million to Daiichi Sankyo for expenses related to such study in four installments of $0.5 million each until December 31, 2022. As of December 31, 2022, we paid total installments of $1.5 million and the remaining $0.5 million installment as of December 31, 2022 has been paid in full in the first quarter of 2023. Under the Daiichi Sankyo License Agreement, we made other clinical trials payments of $0.1 million and $0.2 million for the years ended December 31, 2022 and 2021, respectively.

Pursuant to the Daiichi Sankyo License Agreement, Daiichi Sankyo had the right to continue to conduct three clinical trials and prepare final reports with respect to these clinical trials, and such right expires upon all subjects completing the study treatment. We have agreed to reimburse Daiichi Sankyo certain third-party expenses incurred while conducting such trials.

Additionally, we are required to pay Daiichi Sankyo a high single digit royalty based on the annual net sales of products containing milademetan as an active pharmaceutical ingredient (the "Products"), subject to reduction at an agreed rate upon expiration of the licensed patent in the particular country where the Products are sold. To date, no royalty payments have been made to Daiichi Sankyo under the Daiichi Sankyo License Agreement. The royalty obligation terminates on a country-by-country and Product-by-Product basis on the later of: (i) loss of all market exclusivity for such Product in such country, (ii) the last-to-expire patent that covers the Licensed Compound or the Product in such country and (iii) twelve years from launch of the first Product sold by us in such country.

Unless sooner terminated, the Daiichi Sankyo License Agreement will remain in full force and effect until we, our affiliates and our sublicensees cease all development and commercial activity related to the Licensed Compound and Products. Either party may terminate the Daiichi Sankyo License Agreement for cause in the event of the other party's uncured material breach after a certain cure period. With respect to Daiichi Sankyo's uncured material breach, however, we may only terminate the Daiichi Sankyo License Agreement with respect to the countries affected by such uncured material breach. Daiichi Sankyo may also terminate the Daiichi Sankyo License Agreement in the event of our bankruptcy or insolvency. Additionally, Daiichi Sankyo may terminate the Daiichi Sankyo License Agreement immediately upon written notice if we, our affiliates or our sublicensors initiate or join any challenge to the validity or enforceability of a licensed patent, subject to certain exclusions. Furthermore, we may terminate the Daiichi Sankyo License Agreement in its entirety or on a country-by-country basis for bona fide material concerns regarding the (i) lack of safety for human use arising from toxicity of the Licensed Compound or Product(s), (ii) lack of efficacy of the Licensed Compound or Product(s) or (iii) adverse economic impact to us in connection with our continued development of the Products, in each case, upon six months' prior written notice to Daiichi Sankyo. In addition, if we are acquired by a third party that is developing and commercializing a competing compound and the acquiring party decides not to discontinue the development or commercialization of such competing compound, such third party must terminate the Daiichi Sankyo License Agreement within 30 days of such acquisition if it does not discontinue such development or commercialization. Upon termination of the Daiichi Sankyo License Agreement by Daiichi Sankyo for our uncured material breach or by us for our bona fide material concerns regarding the safety, efficacy or adverse economic impacts relating to the Licensed Compound or Products, or our development thereof, we are required to, among other actions, if requested by Daiichi Sankyo (i) transfer to Daiichi Sankyo ongoing clinical trials, data, reports, records and materials, (ii) grant to Daiichi Sankyo an exclusive, irrevocable, sublicensable, fully paid-up license under any patents and know-how that are controlled and actually used by us at the time of termination in connection with the Products to allow Daiichi Sankyo exploit the Licensed Compound or Products in countries that are affected by

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the termination, (iii) grant to Daiichi Sankyo an exclusive, irrevocable, sublicensable, fully paid up license to use trademarks that are specific to the Products and (iv) assign any applicable sublicenses.

#### Drexel License Agreement and Sponsored Research Agreement
On July 30, 2020, we entered into an intellectual property license agreement (the "Drexel License Agreement") with Drexel University ("Drexel"). Pursuant to the Drexel License Agreement, Drexel granted to us a license under Drexel's patent rights relating to RAD52 inhibitors for the treatment of cancer. We made payments of $53,118 and $34,387 under the Drexel License Agreement for the years ended December 31, 2022 and 2021, respectively.

In February 2023, we decided to discontinue further development of our preclinical program focused on targeting RAD52 in the DNA damage repair pathway, and we notified Drexel of the termination of the Drexel License Agreement pursuant to its terms to focus use of financial and personnel resources on the milademetan clinical program.

#### Roche Clinical Supply Agreement
In December 2021, we entered into a clinical supply agreement with Roche for the supply of the anti-Programmed Death Ligand-1 (PD-L1) monoclonal antibody, atezolizumab. Clinical trials are planned to evaluate milademetan, in combination with atezolizumab for the treatment of patients in genetically selected populations. Under this agreement, we are the sponsor of the anticipated clinical trials, and Roche will supply atezolizumab. We do not have any financial commitments to Roche under this agreement.

#### Manufacturing and Supply
We do not own or operate, and currently have no plans to establish any manufacturing facilities. We currently rely and expect to continue to rely for the foreseeable future, on third parties for the manufacture of our drug candidates for preclinical and clinical testing, as well as for commercial manufacture of any drugs that we may commercialize.

Clinical drug product supplies and active pharmaceutical ingredients (API) for the milademetan program were produced and supplied to us by Daiichi Sankyo. Clinical drug product manufactured in Daiichi Sankyo's GMP production facilities was supplied to us as brite stock and is being used in our ongoing LPS trial and basket trial. For the milademetan program, we have selected and transferred Daiichi Sankyo processes to suitable commercial contract manufacturing organizations to supply API and clinical drug product for our clinical trials and in preparation for submission of marketing applications and potential future commercial supplies.

We obtain our supplies from contract manufacturers on a purchase order basis. We do not currently have arrangements in place for redundant supply for APIs and drug product. We intend to identify and qualify additional manufacturers to provide the APIs and drug product for our future development plan for milademetan. All our drug candidates are compounds of low molecular weight, generally called small molecules. We expect to continue to develop drug candidates that can be produced cost-effectively at contract manufacturing facilities.

Manufacturing clinical products is subject to extensive regulations that impose various procedural and documentation requirements, which govern record keeping, manufacturing processes and controls, personnel, quality control and quality assurance. Our contract manufacturers and their subcontractors are required to register their establishments with the FDA and certain state agencies and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with Current Good Manufacturing Practice (cGMP) requirements which impose certain production, manufacturing, procedural and documentation requirements upon us and our third-party manufacturers. Changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require prior FDA

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approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP requirements and impose reporting requirements upon us and any third-party manufacturers that we may decide to use. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMP requirements and other aspects of regulatory compliance.

#### Intellectual Property
We strive to protect the proprietary technologies, inventions and improvements that we believe are important to our business, including pursuing, obtaining, maintaining, defending and enforcing patent rights, whether developed internally or licensed from third parties, intended to cover the composition of matter of our product candidates, including milademetan, their methods of use, related technologies, such as biomarkers, solid state forms, formulations, etc. and other inventions that are important to our business. In addition to patent protection, we also rely on trade secrets, know-how, continuing technological innovation and in-licensing opportunities to develop, strengthen and maintain our proprietary position in our field.

Our future commercial success depends in part upon our ability to obtain and maintain patent and other proprietary protection for our drug candidates and other commercially important technologies, inventions and know-how related to our business; defend and enforce our intellectual property, in particular, our patent rights; preserve the confidentiality of our trade secrets; and operate without infringing, misappropriating or violating the valid and enforceable intellectual property and proprietary rights of third parties. Our ability to stop third parties from making, using, selling, offering to sell or importing our products may depend on the extent to which we have rights under valid and enforceable patents or trade secrets that cover these activities.

The patent positions for biotechnology companies like us are generally uncertain and can involve complex legal, scientific and factual issues. We cannot predict whether the patent applications we are currently pursuing will issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide sufficient proprietary protection from competitors. We also cannot ensure that patents will be issued with respect to any patent applications that we or our licensors may file in the future, nor can we ensure that any of our owned or licensed patents or future patents will be commercially useful in protecting our product candidates and methods of manufacturing the same. In addition, the coverage claimed in a patent application can be significantly reduced before a patent is issued, and its scope can be reinterpreted and even challenged after issuance. Moreover, many jurisdictions permit third parties to challenge issued patents in administrative proceedings, which may result in further narrowing or even cancellation of patent claims. As a result, we cannot guarantee that any of our drug candidates will be protected or remain protectable by enforceable patents. Moreover, any patents that we hold may be challenged, circumvented or invalidated by third parties. For more information regarding the risks related to our intellectual property, please see "Risk Factors—Risks Related to Our Intellectual Property."

We generally file patent applications directed to our key programs in an effort to secure our intellectual property positions vis-a-vis these programs. As of December 31, 2022, we owned or in-licensed eighteen U.S. patents, five pending U.S. patent applications, one hundred and twenty foreign patents, two allowed foreign patent applications, five U.S. pending non-provisional patent applications, and thirty-four foreign pending patent applications.

The intellectual property portfolio for our most advanced programs as of December 31, 2022, is summarized below. Prosecution is a lengthy process, during which the scope of the claims initially submitted for examination by the U.S. Patent and Trademark Office and foreign patent offices may be significantly narrowed before issuance, if issued at all. We expect this may be the case with respect to some of our pending patent applications referred to below.

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#### Milademetan
With regard to milademetan, as of December 31, 2022, our patent portfolio contained fourteen issued U.S. patents, three pending U.S. non-provisional patent applications, over one hundred issued and allowed foreign patents, and twenty pending foreign patent applications, all exclusively licensed from Daiichi Sankyo. One patent family in the milademetan portfolio is directed to the composition of matter of milademetan where we have issued patents in various jurisdictions including the United States, Japan, thirty-seven countries in Europe, Australia, Canada, China, Colombia, Indonesia, India, Israel, Korea, Malaysia, Mexico, New Zealand, Philippines, Russia, South Africa, Taiwan, Singapore, and Vietnam and pending patent applications in various jurisdictions including the United States, Brazil, Egypt, and Thailand, all of which are expected to expire in March 2032, excluding potential patent term adjustments or patent term extensions, where applicable. Another patent family supporting milademetan pertains to crystal-forms of milademetan. Under this patent family, we have eight issued U.S. patents and fifteen issued foreign patents in various jurisdictions including Japan, certain countries in Europe, Canada, China, Brazil, Hong Kong, Korea, Russia and Taiwan, and pending patent applications in Brazil and India, all of which are expected to expire in 2033, excluding potential patent term adjustments or patent term extensions, where applicable.

Furthermore, we exclusively licensed from Daiichi Sankyo three patent families directed to combination therapies with milademetan, methods of synthesis of milademetan, and dosing regimens of Milademetan within these three patent families, we have four issued U.S. patents, two pending U.S. patent applications, twenty-one issued foreign patents and sixteen pending foreign patent applications, including in Japan, Europe, Canada, China, Hong Kong, Korea, India, Brazil and Taiwan, all of which are expected to expire between September 2034 and October 2037, excluding potential patent term adjustments or patent term extensions, where applicable. These combination therapy, method of synthesis, and method of use (dosing regimen) patents and patent applications will not present barriers to our competitors with respect to any unclaimed therapies or methods of synthesis or use involving milademetan.

We intend to pursue additional patent protection for milademetan and other development candidates relating to milademetan, its methods of use and related technologies that we consider important to our business.

*Patent Terms*

The term of individual patents depends upon the legal term of the patents in the countries in which they are obtained. In most countries in which we file, the patent term is 20 years from the earliest date of filing a non-provisional patent application.

In the United States, the term of a patent covering an FDA-approved drug may, in certain cases, be eligible for a patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984 (Hatch-Waxman Act) as compensation for the loss of patent term during the FDA regulatory review process. The period of extension may be up to five years but cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval. Only one patent applicable to an approved drug is eligible for extension and only those claims covering the approved drug, a method for using it, or a method for manufacturing it may be extended. Similar provisions are available in Europe and in certain other jurisdictions to extend the term of a patent that covers an approved drug. It is possible that issued U.S. patents covering milademetan or our preclinical programs, if issued, and products from our intellectual property may or will be entitled to patent term extensions. If our drug candidates receive FDA approval, we intend to apply for patent term extensions, if available, to extend the term of patents that cover the approved use or the drug candidates. We also intend to seek patent term extensions in any jurisdictions where they are available; however, there is no guarantee that the applicable authorities, including the FDA, will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions.

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*Protection of Proprietary Information*

In addition to patent protection, we also rely on trade secret protection and confidential know-how for our proprietary information that is not amenable to, or that we do not consider appropriate for, patent protection, including certain aspects of our manufacturing processes. However, trade secrets can be difficult to protect. Although we take steps to protect our proprietary information, including restricting access to our confidential information, as well as entering into non-disclosure and confidentiality agreements with our employees, consultants, independent contractors, advisors, contract manufacturers, contract research organizations (CROs), hospitals, independent treatment centers, suppliers, collaborators and other third parties, such parties may breach such agreements and disclose our proprietary information including our trade secrets, and we may not be able to obtain adequate remedies for such breaches. Furthermore, these agreements may not provide meaningful protection. Third parties may also independently develop the same or similar proprietary information or may otherwise gain access to our proprietary information. Despite any measures taken to protect our intellectual property, unauthorized parties may attempt to copy aspects of our products or to obtain or use information that we regard as proprietary. As a result, we may be unable to meaningfully protect our trade secrets and proprietary information. For more information regarding the risks related to our intellectual property please see "Risk Factors—Risks Related to Our Intellectual Property."

#### Government Regulations
Government authorities in the United States, at the federal, state, local levels, and in other countries and jurisdictions, including the European Union, extensively regulate, among other things, the research, development, testing, product approval, manufacture, quality control, manufacturing changes, packaging, storage, recordkeeping, labeling, promotion, advertising, sales, distribution, marketing, and import and export of drugs and biologic products. All of our foreseeable product candidates are expected to be regulated as drugs. The processes for obtaining regulatory approval in the United States and in foreign countries and jurisdictions, along with compliance with applicable statutes and regulations and other regulatory authorities both pre- and post-commercialization, are a significant factor in the production and marketing of our products and our research and development activities and require the expenditure of substantial time and financial resources.

#### Review and Approval of Drugs in the United States
In the United States, the FDA and other government entities regulate drugs under the Federal Food, Drug, and Cosmetic Act (FDCA) and its implementing regulations, as well as other federal and state statutes and regulations. Failure to comply with applicable legal and regulatory requirements in the United States at any time during the product development process, approval process, or after approval, may subject us to a variety of administrative or judicial sanctions, such as a delay in approving or refusal by the FDA to approve pending applications, withdrawal of approvals, delay or suspension of clinical trials, issuance of warning letters and other types of regulatory letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil monetary penalties, refusals of or debarment from government contracts, exclusion from the federal healthcare programs, restitution, disgorgement of profits, civil or criminal investigations by the FDA, U.S. Department of Justice, State Attorneys General, and/or other agencies, False Claims Act suits and/or other litigation, and/or criminal prosecutions.

An applicant seeking approval to market and distribute a new drug in the United States must typically undertake the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(1) completion of pre-clinical laboratory tests, animal studies, and formulation studies in compliance with the FDA's good laboratory practice (GLP) regulations or other applicable regulations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(2) submission to the FDA of an IND Application for human clinical testing, which must become effective without FDA objection before human clinical trials may begin;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(3) approval by an independent institutional review board (IRB) or ethics committee representing each clinical site before each clinical trial may be initiated;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(4) performance of adequate and well-controlled human clinical trials in accordance with good clinical practice (GCP) regulations, to establish the safety and effectiveness of the proposed drug product for each indication for which approval is sought;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(5) preparation and submission to the FDA of a New Drug Application (NDA);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(6) satisfactory review of the NDA by an FDA advisory committee, where appropriate or if applicable,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(7) satisfactory completion of one or more FDA inspections of the manufacturing facility or facilities at which the drug is produced to assess compliance with current good manufacturing practice (cGMP) regulations and to assure that the facilities, methods, and controls are adequate to ensure the product's identity, strength, quality, and purity, and of selected clinical investigation sites to assess compliance with GCP; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(8) payment of user fees, as applicable, and securing FDA review approval of the NDA.

#### Preclinical Studies and an IND
Preclinical studies can include in vitro and animal studies to assess the potential for adverse events and, in some cases, to establish a rationale for therapeutic use. The conduct of preclinical studies is subject to federal regulations and requirements, including GLP regulations. Other studies include laboratory evaluation of the purity, stability and physical form of the manufactured drug substance or active pharmaceutical ingredient and the physical properties, stability and reproducibility of the formulated drug or drug product. An IND sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical trials, among other things, to the FDA as part of an IND. An IND is a request for authorization from the FDA to administer an investigational new drug product to humans. Some preclinical testing, such as longer-term toxicity testing, animal tests of reproductive adverse events and carcinogenicity, may continue after the IND is submitted. An IND automatically becomes effective 30 days after receipt by the FDA, unless before that time the FDA raises concerns or questions related to a proposed clinical trial and places the trial on clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. As a result, submission of an IND may not result in the FDA allowing clinical trials to commence.

Following commencement of a clinical trial under an IND, the FDA may place a clinical hold on that trial. A clinical hold is an order issued by the FDA to the sponsor to delay a proposed clinical investigation or to suspend an ongoing investigation. A partial clinical hold is a delay or suspension of only part of the clinical work requested under the IND, such as restrictions on dosing or patient enrollment. No more than 30 days after imposition of a clinical hold or partial clinical hold, the FDA will provide the sponsor a written explanation of the basis for the hold. Following issuance of a clinical hold or partial clinical hold, an investigation may only resume in full or in part, as applicable, after the FDA has notified the sponsor that the investigation may proceed. The FDA will base that determination on information provided by the sponsor correcting the deficiencies previously cited or otherwise satisfying the FDA that the investigation can proceed.

#### Human Clinical Trials in Support of an NDA
Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with Current Good Clinical Practices (cGCP) requirements, which include, among other things, the requirement that all research subjects provide their informed consent in writing before their participation in any clinical trial. Clinical trials are conducted under written study protocols detailing, among other things, the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. A protocol for each clinical trial and any

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subsequent protocol amendments must be submitted to the FDA as part of the IND. In addition, an IRB or ethics committee representing each institution participating in the clinical trial must review and approve the plan for any clinical trial before it commences at that institution, and the IRB must conduct continuing review and reapprove the study at least annually. The IRB must review and approve, among other things, the study protocol and informed consent information to be provided to study subjects. An IRB must operate in compliance with FDA regulations. Some studies also include oversight by an independent group of qualified experts organized by the clinical trial sponsor, known as a data safety monitoring board, which provides authorization for whether or not a study may move forward at designated check points based on access to certain data from the study and may halt the clinical trial if it determines that there is an unacceptable safety risk for subjects or other grounds, such as no demonstration of efficacy. Information about certain clinical trials must be submitted within specific timeframes to the NIH for public dissemination on its ClinicalTrials.gov website.

Human clinical trials are typically conducted in three sequential phases, which may overlap or be combined:

● Phase 1: The product candidate is initially introduced into healthy human subjects or patients with the target disease or condition and tested for safety, dosage tolerance, absorption, metabolism, distribution, excretion and, if possible, to gain an early indication of its effectiveness.

● Phase 2: The product candidate is administered to a limited patient population to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance and optimal dosage.

● Phase 3: The product candidate is administered to an expanded patient population, generally at geographically dispersed clinical trial sites, in well-controlled clinical trials to generate enough data to statistically evaluate the efficacy and safety of the product for approval, to establish the overall risk-benefit profile of the product, and to provide adequate information for the labeling of the product.

Post-approval trials, sometimes referred to as Phase 4 studies, may be conducted after initial marketing approval. These trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication. In certain instances, the FDA may mandate the performance of Phase 4 clinical trials as a condition of approval of an NDA.

Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA and more frequently if serious adverse events occur. Furthermore, the FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB's requirements or if the drug has been associated with unexpected serious harm to patients.

During the development of a new drug, sponsors are given opportunities to meet with the FDA at certain points. These points may be prior to submission of an IND, at the end of Phase 2, and before an NDA is submitted. Meetings at other times may be requested. These meetings can provide an opportunity for the sponsor to share information about the data gathered to date, for the FDA to provide advice, and for the sponsor and the FDA to reach agreement on the next phase of development. Sponsors typically use the meetings at the end of the Phase 2 trial to discuss Phase 2 clinical results and present plans for the pivotal Phase 3 clinical trials that they believe will support approval of the new drug.

Concurrent with clinical trials, companies usually complete additional animal studies and must also develop additional information about the chemistry and physical characteristics of the drug and finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The

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manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, the manufacturer must develop methods for testing the identity, strength, quality and purity of the final drug. In addition, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life.

While the IND is active and before approval, progress reports summarizing the results of the clinical trials and nonclinical studies performed since the last progress report must be submitted at least annually to the FDA, and written IND safety reports must be submitted to the FDA and investigators for serious and unexpected suspected adverse events, findings from other studies suggesting a significant risk to humans exposed to the same or similar drugs, findings from animal or in vitro testing suggesting a significant risk to humans, and any clinically important increased incidence of a serious suspected adverse reaction compared to that listed in the protocol or investigator brochure.

#### Submission of an NDA to the FDA
Assuming successful completion of required clinical testing and other requirements, the results of the preclinical studies and clinical trials, together with detailed information relating to the product's chemistry, manufacture, controls and proposed labeling, among other things, are submitted to the FDA as part of an NDA requesting approval to market the drug product for one or more indications. Under federal law, the submission of most NDAs is additionally subject to an application user fee, currently $3,117,218 for fiscal year 2022, for applications requiring clinical data, and the sponsor of an approved NDA is also subject to an annual program fee, currently $369,413 for fiscal year 2022. These fees are adjusted annually.

Under certain circumstances, the FDA will waive the application fee for the first human drug application that a small business, defined as a company with less than 500 employees, including employees of affiliates, submits for review. An affiliate is defined as a business entity that has a relationship with a second business entity if one business entity controls, or has the power to control, the other business entity, or a third-party controls, or has the power to control, both entities. In addition, an application to market a prescription drug product that has received orphan designation is not subject to a prescription drug user fee unless the application includes an indication for other than the rare disease or condition for which the drug was designated.

The FDA conducts a preliminary review of an NDA within 60 days of its receipt and informs the sponsor by the 74th day after the FDA's receipt of the submission to determine whether the application is sufficiently complete to permit substantive review. The FDA may request additional information rather than accept an NDA for filing. In this event, the application must be resubmitted with the additional information. The resubmitted application is also subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review. The FDA reviews an NDA to determine, among other things, whether a product is safe and effective for its intended use and whether its manufacturing is cGMP-compliant to assure and preserve the product's identity, strength, quality and purity. Under the Prescription Drug User Fee Act (PDUFA), the FDA has agreed to specified performance goals in the review process of NDAs. Specifically, the FDA has a goal of reviewing most NDAs for new molecular entities within ten months from the date of filing, and of reviewing most "priority review" NDAs within six months of the filing date. The review process may be extended by the FDA for three additional months to consider new information or clarification provided by the applicant.

The FDA is required to refer an application for a novel drug to an advisory committee or explain why such referral was not made. Typically, an advisory committee is a panel of independent experts, including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

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Before approving an NDA, the FDA typically will inspect the facility or facilities where the product is manufactured. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving an NDA, the FDA will typically inspect one or more clinical sites to assure compliance with cGCP. If the FDA determines that the application, manufacturing process or manufacturing facilities are not acceptable, it will outline the deficiencies in the submission and often will request additional testing or information. Notwithstanding the submission of any requested additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

The FDA also may require submission of a risk evaluation and mitigation strategy (REMS) plan to mitigate any identified or suspected serious risks. The REMS plan could include medication guides, physician communication plans, assessment plans, and elements to assure safe use, such as restricted distribution methods, patient registries, or other risk minimization tools.

#### The FDA's Decision on an NDA
On the basis of the FDA's evaluation of the NDA and accompanying information, including the results of the inspection of the manufacturing facilities and clinical sites, the FDA may issue an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A complete response letter indicates that the review cycle is complete, and the application will not be approved in its present form. A complete response letter generally outlines the deficiencies in the submission and may require substantial additional clinical or nonclinical testing or other information in order for the FDA to reconsider the application. If and when those deficiencies have been addressed to the FDA's satisfaction in a resubmission of the NDA, the FDA will issue an approval letter. The FDA has committed to reviewing such resubmissions in two or six months of receipt depending on the type of information included. Even with submission of this additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

If the FDA approves a product, it may limit the approved indications for use for the product, require that contraindications, warnings or precautions be included in the product labeling, require that post-approval studies be conducted to further assess the drug's safety after approval, require testing and surveillance programs to monitor the product after commercialization, or impose other conditions, including distribution restrictions or other risk management mechanisms, including REMS, which can materially affect the potential market and profitability of the product. After approval, the FDA may seek to prevent or limit further marketing of a product based on the results of post-market studies or surveillance programs. Some types of changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further testing requirements and FDA review and approval.

#### Orphan Drug Designation
Under the Orphan Drug Act, the FDA may grant orphan drug designation to a drug intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States and for which there is no reasonable expectation that the cost of developing and making available in the United States a drug for this type of disease or condition will be recovered from sales in the United States for that drug. Orphan drug designation entitles the applicant to incentives such as grant funding towards clinical trial costs, tax advantages, and waivers of FDA user fees. Orphan drug designation must be requested before submitting an NDA, and both the drug and the disease or condition must meet certain criteria specified in the Orphan Drug Act and FDA's implementing regulations at 21 C.F.R. Part 316. The granting of an orphan drug designation does not alter the standard regulatory requirements and process for obtaining marketing approval.

After the FDA grants orphan drug designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. If a product that has orphan drug designation subsequently

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receives the first FDA approval for the disease for which it has such designation, the product is entitled to orphan product exclusivity, which means that the FDA may not approve any other application to market the same drug for the same indication for seven years, except in very limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for which the drug was designated. Orphan drug exclusivity does not prevent the FDA from approving a different drug for the same disease or condition, or the same drug for a different disease or condition.

A designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. In addition, orphan drug exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or, as noted above, if a second applicant demonstrates that its product is clinically superior to the approved product with orphan exclusivity or the manufacturer of the approved product is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.

The scope of the Orphan Drug Act and implementing regulations could be subject to future litigation, which may impact the orphan drug process for future therapeutics. In January 2023, the FDA published notice that it intends to follow its longstanding practice in assessing orphan drug candidates, rather than a federal appellate court's interpretation of the Orphan Drug Act. The appellate court's decision broadened the scope of orphan drug exclusivity to the entire disease or condition for which a therapeutic receives orphan drug designation, even if the drug is only approved for certain uses within that disease or condition. By contrast, the FDA's traditional interpretation is that exclusivity is specific to the orphan indication for which the drug was actually approved. As a result, the scope of exclusivity has been narrow and protected only against competition from the same "use or indication" rather than the broader "disease or condition." Future litigation could challenge FDA's interpretation of the law.

#### Expedited Review and Accelerated Approval Programs
A sponsor may seek approval of its product candidate under programs designed to accelerate the FDA's review and approval of NDAs. For example, Fast Track Designation may be granted to a drug intended for treatment of a serious or life-threatening disease or condition and data demonstrate its potential to address unmet medical needs for the disease or condition. Fast Track Designation applies to the combination of the product candidate and the specific indication for which it is being studied. The sponsor of a Fast Track product candidate has opportunities for more frequent interactions with the applicable FDA review team during product development and, once an NDA is submitted, the product candidate may be eligible for priority review. A Fast Track product may also be eligible for rolling review, where the FDA may consider for review sections of the NDA on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the NDA, the FDA agrees to accept sections of the NDA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the NDA. .

In addition, the Food and Drug Administration Safety and Innovation Act of 2012 established the Breakthrough Therapy Designation. A sponsor may seek FDA designation of its product candidate as a breakthrough therapy if the drug is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The designation includes all of the Fast Track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product candidate, including involvement of senior managers.

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Any marketing application for a drug submitted to the FDA for approval, including a product candidate with a Fast Track Designation and/or Breakthrough Therapy Designation, may be eligible for other types of FDA programs intended to expedite the FDA review and approval process, such as priority review and accelerated approval. NDAs for drugs intended to treat serious or life-threatening conditions may be eligible for priority review where there is evidence that the product candidate, if approved, would provide a significant improvement in the safety or effectiveness of the treatment, diagnosis, or prevention of a serious condition.

The FDA may grant accelerated approval for an NDA if the drug treats a serious or life-threatening condition, provides a meaningful advantage over available therapies, and demonstrates an effect on either (1) a surrogate endpoint that is reasonably likely to predict clinical benefit, or (2) on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. Post-marketing studies or completion of ongoing studies after marketing approval are generally required to verify the drug's clinical benefit in relationship to the surrogate endpoint or ultimate outcome in relationship to the clinical benefit. Products receiving accelerated approval may be subject to expedited withdrawal procedures if the sponsor fails to conduct the required post-marketing studies or if such studies fail to verify the predicted clinical benefit. In addition, the FDA currently requires as a condition for accelerated approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.

#### Post-approval Requirements
Drugs manufactured or distributed pursuant to FDA approvals are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to recordkeeping, periodic reporting, product sampling and distribution, advertising and promotion and reporting of adverse experiences with the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are continuing, annual program fee requirements for any marketed products.

In addition, drug manufacturers and other entities involved in the manufacture and distribution of approved drugs are required to register their establishments with the FDA and state agencies and are subject to periodic unannounced inspections by the FDA and these state agencies for compliance with cGMP requirements. Changes to the manufacturing process are strictly regulated and often require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon the sponsor and any third-party manufacturers that the sponsor may decide to use. Accordingly, manufacturers must continue to expend time, money, and effort in the area of production and quality control to maintain cGMP compliance.

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events or problems with manufacturing processes of unanticipated severity or frequency, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:

● restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from the market or product recalls;

● fines, warning letters or holds on post-approval clinical trials;

● refusal of the FDA to approve pending NDAs or supplements to approved NDAs, or suspension or revocation of product license approvals;

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● clinical holds on ongoing or planned clinical trials;

● product seizure or detention, or refusal to permit the import or export of products; or

● consent decrees, corporate integrity agreements, debarment or exclusion from federal healthcare programs

● mandated modification of promotional materials and labeling and the issuance of corrective information;

● injunctions or the imposition of civil or criminal penalties.

The FDA strictly regulates marketing, labeling, advertising and promotion of products that are placed on the market. Drugs may be promoted only for the approved indications and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant liability.

In addition, the distribution of prescription pharmaceutical products is subject to the Prescription Drug Marketing Act (PDMA), which regulates the distribution of drugs and drug samples at the federal level and sets minimum standards for the registration and regulation of drug distributors by the states. Both the PDMA and state laws limit the distribution of prescription pharmaceutical product samples and impose requirements to ensure accountability in distribution.

#### Marketing Exclusivity
Market exclusivity provisions authorized under the FDCA can delay the submission or the approval of certain marketing applications. The FDCA provides a five-year period of non-patent marketing exclusivity within the United States to the first applicant to obtain approval of an NDA for a new chemical entity. A drug is a new chemical entity if the FDA has not previously approved any other new drug containing the same active moiety, which is the molecule or ion responsible for the action of the drug substance. During the exclusivity period, the FDA may not approve or even accept for review an abbreviated new drug application (ANDA), or an NDA submitted under Section 505(b)(2) (505(b)(2) NDA), submitted by another company for another drug based on the same active moiety, regardless of whether the drug is intended for the same indication as the original innovative drug or for another indication, where the applicant does not own or have a legal right of reference to all the data required for approval. However, an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement to one of the patents listed with the FDA by the innovator NDA holder.

The FDCA alternatively provides three years of marketing exclusivity for an NDA, or supplement to an existing NDA if new clinical investigations, other than bioavailability studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application, for example new indications, dosages or strengths of an existing drug. This three-year exclusivity covers only the modification for which the drug received approval on the basis of the new clinical investigations and does not prohibit the FDA from approving ANDAs or 505(b)(2) NDAs for drugs containing the active agent for the original indication or condition of use. Five-year and three-year exclusivity will not delay the submission or approval of a full NDA. However, an applicant submitting a full NDA would be required to conduct or obtain a right of reference to any preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

Pediatric exclusivity is another type of marketing exclusivity available in the United States. Pediatric exclusivity provides for an additional six months of marketing exclusivity attached to another period of exclusivity if a sponsor conducts clinical trials in children in response to a written request from the FDA. The issuance of a written request does not require the sponsor to undertake the described clinical trials. In

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addition, orphan drug exclusivity, as described above, may offer a seven-year period of marketing exclusivity, except in certain circumstances.

#### FDA Approval and Regulation of Companion Diagnostics
If safe and effective use of a drug candidate depends on an in vitro diagnostic, then the FDA generally will require approval or clearance of that diagnostic, known as a companion diagnostic, at the same time that the FDA approves the therapeutic product. In prior final guidance, FDA clarified the requirements that will apply to approval of therapeutic products and in vitro companion diagnostics. If FDA determines that a companion diagnostic device is essential to the safe and effective use of a novel therapeutic product or indication, FDA generally will not approve the drug or new indication if the companion diagnostic device is not approved or cleared for that indication. Approval or clearance of the companion diagnostic device will ensure that the device has been adequately evaluated and has adequate performance characteristics in the intended population. The review of in vitro companion diagnostics in conjunction with the review of our product candidates will, therefore, likely involve coordination of review by the FDA's Center for Drug Evaluation and Research and the FDA's Center for Devices and Radiological Health Office of In Vitro Diagnostics and Radiological Health.

Under the FDCA, in vitro diagnostics, including companion diagnostics, are regulated as medical devices. In the United States, the FDCA and its implementing regulations, and other federal and state statutes and regulations govern, among other things, medical device design and development, preclinical and clinical testing, premarket clearance or approval, registration and listing, manufacturing, labeling, storage, advertising and promotion, sales and distribution, export and import, and post-market surveillance. Unless an exemption applies, diagnostic tests require marketing clearance or approval from the FDA prior to commercial distribution. The two primary types of FDA marketing authorization applicable to a medical device are premarket notification, also called 510(k) clearance, and premarket approval (PMA).

The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device's safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing, and labeling. PMA applications are subject to an application fee. In addition, PMAs for certain devices must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, a PMA application typically requires data regarding analytical and clinical validation studies. As part of the PMA review, the FDA will typically inspect the manufacturer's facilities for compliance with the Quality System Regulation (QSR), which imposes elaborate testing, control, documentation, and other quality assurance requirements.

PMA approval is not guaranteed, and the FDA may ultimately respond to a PMA submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time -consuming to generate and that can substantially delay approval. If the FDA's evaluation of the PMA application is favorable, the FDA typically issues an approvable letter requiring the applicant's agreement to specific conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA's evaluation of the PMA or manufacturing facilities is not favorable, the FDA will deny approval of the PMA or issue a not approvable letter. A not approvable letter will outline the deficiencies in the application and, where practical, will identify what is necessary to make the PMA approvable. The FDA may also determine that additional clinical trials are necessary, in which case the PMA approval may be delayed for several months or years while the trials are conducted and then the data submitted in an amendment to the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution. Once granted, PMA approval

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may be withdrawn by the FDA if compliance with post approval requirements, conditions of approval or other regulatory standards are not maintained or problems are identified following initial marketing.

After a device is placed on the market, it remains subject to significant regulatory requirements. Medical devices may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must also establish registration and device listings with the FDA. A medical device manufacturer's manufacturing processes and those of its suppliers are required to comply with the applicable portions of the QSR, which cover the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Domestic facility records and manufacturing processes are subject to periodic unscheduled inspections by the FDA. The FDA also may inspect foreign facilities that export products to the United States.

#### Review and Approval of Drug Products in the European Union
In order to market any pharmaceutical product outside of the United States, a company must also comply with numerous and varying regulatory requirements of other countries and jurisdictions governing, among other things, research and development, testing, manufacturing, quality control, safety, efficacy, clinical trials, marketing authorization, packaging, storage, record keeping, reporting, export and import, advertising and other promotional practices involving pharmaceutical products, as well as commercial sales, distribution and post-approval monitoring and reporting of our products. Whether or not it obtains FDA approval for a pharmaceutical product, the company would need to obtain the necessary approvals by the comparable foreign regulatory authorities before it can commence clinical trials or marketing of the pharmaceutical product in those countries or jurisdictions. The approval process ultimately varies between countries and jurisdictions and can involve additional product testing and additional administrative review periods, as evidenced by the preliminary feedback from the EMA on the design of our planned Phase 3 liposarcoma trial. The time required to obtain approval in other countries and jurisdictions might differ from and be longer and far more difficult than that required to obtain FDA approval. Regulatory approval in one country or jurisdiction does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country or jurisdiction may negatively impact the regulatory process in others.

The United Kingdom (UK) formally left the European Union (EU) on January 31, 2020 and the transition period, during which EU laws continued to apply to the UK, expired on December 31, 2020. This means EU laws now only apply to the UK in respect of Northern Ireland as laid out in the Protocol on Ireland and Northern Ireland. Following the end of the transition period, the EU and the UK concluded a trade and cooperation agreement (TCA), which applied provisionally from January 1, 2021 and entered into force on May 1, 2021.

The TCA includes provisions affecting the life sciences sector (including on customs and tariffs) but areas for further discussion between the EU and the UK remain. In addition, there are some specific provisions concerning pharmaceuticals. These include the mutual recognition of Good Manufacturing Practice (GMP) and issued GMP documents. The TCA does not, however, contain wholesale mutual recognition of UK and EU pharmaceutical regulations and product standards.

Since January 1, 2021, the EU laws which have been transposed into UK law through secondary legislation continue to be applicable in the UK as "retained EU law." As there is no general power to amend these regulations, the UK government has enacted the Medicines and Medical Devices Act 2021. The purpose of the act is to enable the existing regulatory frameworks in relation to human medicines, clinical trials of human medicines, veterinary medicines and medical devices to be updated. The powers under the act may only be exercised in relation to specified matters and must safeguard public health.

Specified provisions of the Medicines and Medical Devices Act 2021 entered into force on February 11, 2021. The remaining provisions came into effect within two months of February 11, 2021 or will otherwise come into effect as stipulated in subsequent statutory instruments. The Medicines and Medical Devices Act 2021 supplements the UK Medical Devices Regulations 2002 (UK Regulations), which are based

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on the EU Medical Devices Directive as amended to reflect the UK's post-Brexit regulatory regime. Notably, the UK Regulations do not include any of the revisions that have been made by the EU Medical Devices Regulation (EU) 2017/745, which, since May 26, 2021, now applies in all EU Member States.

The UK's Medicines and Healthcare products Regulatory Agency (MHRA) conducted a comprehensive consultation between September and November 2021 on proposals to develop a new UK regime for medical devices in the UK. The proposals include more closely aligning definitions for medical devices and in vitro medical devices with internationally recognized definitions and changing the classification of medical devices according to levels or risk. The proposals are intended to improve patient and public safety and increase the appeal of the UK market. The new regime is planned to come into force on July 1, 2023, which will align with the date from which the UK is due to stop accepting CE marked medical devices and require UKCA (UK Conformity Assessed) marking. It is envisaged that, in Northern Ireland, the amended regime could run in parallel with any existing or future EU rules in accordance with the Protocol on Ireland and Northern Ireland.

*Drug Development Process*

Clinical trials are studies intended to discover or verify the effects of one or more investigational medicines. The regulation of clinical trials aims to ensure that the rights, safety and well-being of trial participants are protected and the results of clinical trials are credible. Regardless of where they are conducted, all clinical trials included in applications for marketing authorization for human medicines in the EU and Iceland, Norway, and Liechtenstein (together, the European Economic Area or EEA) must have been carried out in accordance with EU regulations. This means that clinical trials conducted in the EU / EEA have to comply with EU clinical trial legislation but also that clinical trials conducted outside the EU / EEA have to comply with ethical principles equivalent to those set out in the EEA, including adhering to international good clinical practice and the Declaration of Helsinki. The conduct of clinical trials in the EU is governed by the EU Clinical Trials Regulation (EU) No. 536/2014 (CTR) which entered into force on January 31, 2022. The CTR replaced the Clinical Trials Directive 2001/20/EC (Clinical Trials Directive) and introduced a complete overhaul of the existing regulation of clinical trials for medicinal products in the EU.

Under the former regime, which will expire after a transition period of one or three years, respectively, as outlined below in more detail, before a clinical trial can be initiated it must be approved in each EU Member State in which the clinical trial is to be conducted. The approval must be obtained from two separate entities: the National Competent Authority (NCA) and one or more Ethics Committees. The NCA of the EU Member States in which the clinical trial will be conducted must authorize the conduct of the trial, and the independent Ethics Committee must grant a positive opinion in relation to the conduct of the clinical trial in the relevant EU Member State before the commencement of the trial. Any substantial changes to the trial protocol or other information submitted with the clinical trial applications must be submitted to or approved by the relevant NCA and Ethics Committees. Under the current regime all suspected unexpected serious adverse reactions to the investigated drug that occur during the clinical trial must be reported to the NCA and to the Ethics Committees of the EU Member State where they occur.

A more unified procedure applies under the new CTR. A sponsor is able to submit a single application for approval of a clinical trial through a centralized EU clinical trials portal. One national regulatory authority (the reporting EU Member State proposed by the applicant) takes the lead in validating and evaluating the application consult and coordinate with the other concerned Member States. If an application is rejected, it may be amended and resubmitted through the EU clinical trials portal. If an approval is issued, the sponsor may start the clinical trial in all concerned Member States. However, a concerned EU Member State may in limited circumstances declare an "opt-out" from an approval and prevent the clinical trial from being conducted in such Member State. The CTR also aims to streamline and simplify the rules on safety reporting, and introduces enhanced transparency requirements such as mandatory submission of a summary of the clinical trial results to the EU Database. The "go live" of these systems and, accordingly, the coming into force of the regulation, took place on January 31, 2022. The CTR foresees a three-year transition period. Member States will work in CTIS immediately after the system has gone live. Since 31 January 2023, submission of

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initial clinical trial applications via CTIS are mandatory, and by 31 January 2025, all ongoing trials approved under the former Clinical Trials Directive will need to comply with the CTR and have to be transitioned to CTIS.

Under both the former regime and the new CTR, national laws, regulations, and the applicable Good Clinical Practice (GCP) and Good Laboratory Practice standards must also be respected during the conduct of the trials, including the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines on Good Clinical Practice and the ethical principles that have their origin in the Declaration of Helsinki.

During the development of a medicinal product, the European Medicines Agency (EMA) and national regulators within the EU provide the opportunity for dialogue and guidance on the development program. At the EMA level, this is usually done in the form of scientific advice, which is given by the Committee for Medicinal Products for Human Use (CHMP) on the recommendation of the Scientific Advice Working Party (SAWP). A fee is incurred with each scientific advice procedure, but is significantly reduced for designated orphan medicines. Advice from the EMA is typically provided based on questions concerning, for example, quality (chemistry, manufacturing and controls testing), nonclinical testing and clinical studies, and pharmacovigilance plans and risk-management programs. Advice is not legally binding with regard to any future Marketing Authorization Application (MAA) of the product concerned.

*Marketing Authorization Procedures*

In the EU and EEA, pharmaceutical products may only be placed on the market after obtaining a Marketing Authorization (MA).

Marketing Authorizations have an initial duration of five years. After these five years, the authorization may be renewed on the basis of a reevaluation of the risk-benefit balance. Once renewed, the MA is valid for an unlimited period unless the EC or the national competent authority decides on justified grounds relating to pharmacovigilance, to proceed with one additional five-year renewal. Applications for renewal must be made to the EMA at least nine months before the five-year period expires.

*Data and Market Exclusivity in the European Union*

As in the United States, it may be possible to obtain a period of market and/or data exclusivity in the European Union that would have the effect of postponing the entry into the marketplace of a competitor's generic, hybrid or biosimilar product (even if the pharmaceutical product has already received an MA) and prohibiting another applicant from relying on the MA holder's pharmacological, toxicological and clinical data in support of another MA for the purposes of submitting an application, obtaining MA or placing the product on the market.

New Chemical Entities (NCE) approved in the EU qualify for eight years of data exclusivity upon marketing authorization and an additional two years of market exclusivity.

An additional non-cumulative one-year period of market exclusivity is possible if during the data exclusivity period (the first eight years of the 10-year market exclusivity period), the MA holder obtains an authorization for one or more new therapeutic indications that are deemed to bring a significant clinical benefit compared to existing therapies.

The data exclusivity period begins on the date of the product's first MA in the EU. After eight years, a generic product application may be submitted and generic companies may rely on the MA holder's data. However, a generic product cannot launch until two years later (or a total of 10 years after the first MA in the EU of the innovator product), or three years later (or a total of 11 years after the first MA in the EU of the innovator product) if the MA holder obtains MA for a new indication with significant clinical benefit within the eight-year data exclusivity period. Additionally, another noncumulative one-year period of data exclusivity can

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be added to the eight years of data exclusivity where an application is made for a new indication for a well-established substance, provided that significant pre-clinical or clinical studies were carried out in relation to the new indication. Another year of data exclusivity may be added to the eight years, where a change of classification of a pharmaceutical product has been authorized on the basis of significant pre-trial tests or clinical trials (when examining an application by another applicant for or holder of market authorization for a change of classification of the same substance the competent authority will not refer to the results of those tests or trials for one year after the initial chance was authorized).

Products may not be granted data exclusivity since there is no guarantee that a product will be considered by the European Union's regulatory authorities to include a NCE. Even if a compound is considered to be a NCE and the MA applicant is able to gain the prescribed period of data exclusivity, another company nevertheless could also market another version of the medicinal product if such company can complete a full MAA with their own complete database of pharmaceutical tests, preclinical studies and clinical trials and obtain MA of its product.

*Orphan Drug Designation and Exclusivity*

The criteria for designating an orphan medicinal product in the European Union are similar in principle to those in the United States. The EMA grants Orphan Drug Designation if the medicinal product is intended for the treatment, prevention or diagnosis of a disease that is life-threatening or chronically debilitating, affecting not more than five in 10,000 people in the European Union and for which no satisfactory method of diagnosis, prevention or treatment of the condition concerned can be authorized, or, if such a method exists, the medicine must be of significant benefit to those affected by the condition (prevalence criterion). In addition, Orphan Drug Designation can be granted if, for economic reasons, the medicinal product would be unlikely to be developed without incentives and if there is no other satisfactory method approved in the European Union of diagnosing, preventing, or treating the condition, or if such a method exists, the proposed medicinal product is a significant benefit to patients affected by the condition. An application for orphan drug designation (which is not a marketing authorization, as not all orphan-designated medicines reach the authorization application stage) must be submitted first before an application for marketing authorization of the medicinal product is submitted. The applicant will receive a fee reduction for the marketing authorization application if the orphan drug designation has been granted, but not if the designation is still pending at the time the marketing authorization is submitted, and sponsors must submit an annual report to EMA summarizing the status of development of the medicine. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process. Designated orphan medicines are eligible for conditional marketing authorization.

The EMA's Committee for Orphan Medicinal Products (COMP) reassesses the Orphan Drug Designation of a product in parallel with the review for a marketing authorization; for a product to benefit from market exclusivity it must maintain its Orphan Drug Designation at the time of marketing authorization review by the EMA and approval by the EC. Additionally, any marketing authorization granted for an orphan medicinal product must only cover the therapeutic indication(s) that are covered by the Orphan Drug Designation. Upon the grant of a marketing authorization, Orphan Drug Designation provides up to ten years of market exclusivity in the orphan indication.

During this ten-year period, with a limited number of exceptions, the regulatory authorities of the EU Member States and the EMA may not accept applications for marketing authorization, accept an application to extend an existing marketing authorization or grant marketing authorization for other similar medicinal products for the same therapeutic indication. A similar medicinal product is defined as a medicinal product containing a similar active substance or substances as contained in a currently authorized orphan medicinal product, and which is intended for the same therapeutic indication. An orphan medicinal product can also obtain an additional two years of market exclusivity for an orphan-designated condition when the results of specific studies are reflected in the Summary of Product Characteristics (SmPC), addressing the pediatric population and completed in accordance with a fully compliant Pediatric Investigation Plan (PIP). No

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extension to any supplementary protection certificate can be granted on the basis of pediatric studies for orphan indications.

The 10-year market exclusivity may be reduced to six years if, at the end of the fifth year, it is established that the product no longer fulfils the criteria for an Orphan Drug Designation, i.e. the condition prevalence or financial returns criteria under Article 3 of Regulation (EC) No. 141/2000 on orphan medicinal products. When the period of orphan market exclusivity for an indication ends, the orphan drug designation for that indication expires as well. Orphan exclusivity runs in parallel with normal rules on data exclusivity and market protection. Additionally, a marketing authorization may be granted to a similar medicinal product (orphan or not) for the same or overlapping indication subject to certain requirements.

*Pediatric Development*

In the EU, companies developing a new medicinal product are obligated to study their product in children and must therefore submit a Pediatric Investigation Plan (PIP) together with a request for agreement to the EMA. The EMA issues a decision on the PIP based on an opinion of the EMA's Pediatric Committee (PDCO). Companies must conduct pediatric clinical trials in accordance with the PIP approved by the EMA, unless a deferral (e.g. until enough information to demonstrate its effectiveness and safety in adults is available) or waiver (e.g. because the relevant disease or condition occurs only in adults) has been granted by the EMA. The MAA for the medicinal product must include the results of all pediatric clinical trials performed and details of all information collected in compliance with the approved PIP, unless a waiver or a deferral has been granted, in which case the pediatric clinical trials may be completed at a later date. Medicinal products that are granted a marketing authorization (MA) on the basis of the pediatric clinical trials conducted in accordance with the approved PIP are eligible for a six month extension of the protection under a supplementary protection certificate (if any is in effect at the time of approval) or, in the case of orphan medicinal products, a two year extension of the orphan market exclusivity is granted. This pediatric reward is subject to specific conditions and is not automatically available when data in compliance with the approved PIP are developed and submitted. An approved PIP is also required when a marketing authorization holder wants to add a new indication, medicinal form or route of administration for a medicine that is already authorized and covered by intellectual property rights.

*Approval and Regulation of Companion Diagnostics*

In Europe, in vitro diagnostic medical devices are currently regulated by Regulation (EU) 2017/746 on In-Vitro Diagnostic Devices (IVDR) which replaced Directive 98/79/EC as of 26 May 2022, following a staggered transition period until May 2028, depending on the respective product. It regulates the placing on the market, putting into service, the CE-marking, the essential requirements, the conformity assessment procedures, the registration obligations for manufactures and devices as well as the vigilance procedure. In vitro diagnostic medical devices must comply with the requirements provided for in the IVDR, and with further requirements implemented at national level (as the case may be). During the transition period, manufacturers can opt to place in-vitro diagnostic devices on the market under Directive 98/79/EC or under the new Regulation if they fully comply with it.

Companion diagnostics can also be considered "combination products" which are governed by a different regulatory pathway depending on the mode of action of the products. A combination medicine/device product could either be regulated as a medicinal product or a medical device based on its primary mode of action. In principle, if a medical device incorporates a substance which, if used separately, is likely to be considered as a medicinal product and act on the human body by an action ancillary to that of the device, the device must be evaluated and authorized in accordance with the medical device regulations. However, if the medicinal substance constitutes the main function of the product, then the product is considered as a medicinal product. Currently, for such combination products, the manufacturer will have to consult, prior to obtaining the CE marking of the device, the EMA or NCA to obtain scientific advice on the quality and safety of the medicinal substance, including the benefit/risk profile of its incorporation into the device.

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The regulation of companion diagnostics is subject to further requirements as of the entry into force of the IVDR which introduced a new classification system for companion diagnostics which are now specifically defined as diagnostic tests that support the safe and effective use of a specific medicinal product, by identifying patients that are suitable or unsuitable for treatment. Companion diagnostics have to undergo a conformity assessment by a notified body. Before it can issue a CE certificate, the notified body must seek a scientific opinion from the EMA on the suitability of the companion diagnostic to the medicinal product concerned if the medicinal product falls exclusively within the scope of the centralized procedure for the authorization of medicines, or the medicinal product is already authorized through the centralized procedure, or a marketing authorization application for the medicinal product has been submitted through the centralized procedure. For other substances, the notified body can seek the opinion from a NCA or the EMA.

*Post-approval Regulation*

Similar to the United States, both marketing authorization holders and manufacturers of medicinal products are subject to comprehensive regulatory oversight by the EMA, the EC and/or the competent regulatory authorities of the EU Member States. This oversight applies both before and after grant of manufacturing licenses and marketing authorizations. It includes control of compliance with EU good manufacturing practices rules, manufacturing authorizations, pharmacovigilance rules and requirements governing advertising, promotion, sale, and distribution, recordkeeping, importing and exporting of medicinal products.

The holder of an EU marketing authorization for a pharmaceutical product must also comply with EU pharmacovigilance legislation and its related regulations and guidelines, which entail many requirements for conducting pharmacovigilance, or the assessment and monitoring of the safety of pharmaceutical products.

Failure by us or by any of our third-party partners, including suppliers, manufacturers and distributors to comply with EU laws and the related national laws of individual EU Member States governing the conduct of clinical trials, manufacturing approval, marketing authorization of medicinal products and marketing of such products, both before and after grant of marketing authorization, manufacturing of pharmaceutical products, statutory health insurance, bribery and anti-corruption or other applicable regulatory requirements may result in administrative, civil or criminal penalties. These penalties could include delays or refusal to authorize the conduct of clinical trials or to grant marketing authorization, product withdrawals and recalls, product seizures, suspension, withdrawal or variation of the marketing authorization, total or partial suspension of production, distribution, manufacturing or clinical trials, operating restrictions, injunctions, suspension of licenses, fines and criminal penalties.

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*Advertising and Promotion*

In the EU, the advertising and promotion of our products is also subject to EU laws concerning promotion of medicinal products, interactions with physicians, misleading and comparative advertising and unfair commercial practices. In addition, other national legislation of individual EU Member States may apply to the advertising and promotion of medicinal products and may differ from one country to another. These laws require that promotional materials and advertising in relation to medicinal products comply with the product's Summary of Product Characteristics (SmPC) as approved by the competent regulatory authorities. The SmPC is the document that provides information to physicians concerning the safe and effective use of the medicinal product. It forms an intrinsic and integral part of the marketing authorization granted for the medicinal product. Promotion of a medicinal product that does not comply with the SmPC is considered to constitute off-label promotion. All advertising and promotional activities for the product must be consistent with the approved SmPC and therefore all off-label promotion is prohibited. Direct-to-consumer advertising of prescription-only medicines is also prohibited in the EU. Violations of the rules governing the promotion of medicinal products in the European Union could be penalized by administrative measures, fines and imprisonment. These laws may further limit or restrict the advertising and promotion of our products to the general public and may also impose limitations on its promotional activities with healthcare professionals. For instance, the provision of benefits or advantages to physicians to induce or encourage the prescription, recommendation, endorsement, purchase, supply, order or use of pharmaceutical products is prohibited in the EU. Relationships with healthcare professionals and associations are subject to stringent anti-gift statutes and anti-bribery laws, the scope of which differs across the EU. In addition, payments made to physicians in certain EU Member States must be publicly disclosed. Moreover, agreements with physicians must often be the subject of prior notification and approval by the physician's employer, his/her regulatory professional organization, and/or the authorities of the individual EU Member States. Failure to comply with these requirements could result in reputational risk, public reprimands, administrative penalties, fines or imprisonment.

*Pricing and Reimbursement Environment*

Even if a pharmaceutical product obtains a marketing authorization in the European Union, there can be no assurance that reimbursement for such product will be secured on a timely basis or at all. The EU Member States are free to restrict the range of pharmaceutical products for which their national health insurance systems provide reimbursement, and to control the prices and reimbursement levels of pharmaceutical products for human use. An EU Member State may approve a specific price or level of reimbursement for the pharmaceutical product, or alternatively adopt a system of direct or indirect controls on the profitability of the company responsible for placing the pharmaceutical product on the market, including volume-based arrangements, caps and reference pricing mechanisms.

Reference pricing used by various EU Member States and parallel distribution, or arbitrage between low-priced and high-priced Member States, can further reduce prices. In some countries, we may be required to conduct a clinical study or other studies that compare the cost-effectiveness of our product candidates, if any, to other available therapies in order to obtain or maintain reimbursement or pricing approval. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any of our products. Historically, pharmaceutical products launched in the European Union do not follow price structures of the United States and generally published and actual prices tend to be significantly lower. Publication of discounts by third party payers or authorities and public tenders may lead to further pressure on the prices or reimbursement levels within the country of publication and other countries.

The so-called health technology assessment (HTA) of pharmaceutical products is becoming an increasingly common part of the pricing and reimbursement procedures in some EU Member States, including France, Germany, Ireland, Italy and Sweden. The HTA process, which is governed by the national laws of these countries, is the procedure according to which the assessment of the public health impact, therapeutic impact, and the economic and societal impact of use of a given pharmaceutical product in the

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national healthcare systems of the individual country is conducted. HTA generally focuses on the clinical efficacy and effectiveness, safety, cost, and cost-effectiveness of individual pharmaceutical products as well as their potential implications for the healthcare system. Those elements of pharmaceutical products are compared with other treatment options available on the market. The outcome of HTA regarding specific pharmaceutical products will often influence the pricing and reimbursement status granted to pharmaceutical products by the regulatory authorities of individual EU Member States. A negative HTA of one of our products by a leading and recognized HTA body could not only undermine our ability to obtain reimbursement for such product in the EU Member State in which such negative assessment was issued, but also in other EU Member States. For example, EU Member States that have not yet developed HTA mechanisms could rely to some extent on the HTA performed in other countries with a developed HTA framework, when adopting decisions concerning the pricing and reimbursement of a specific pharmaceutical product.

On January 31, 2018, the European Commission adopted a proposal for a regulation on health technology assessment. This legislative proposal is intended to boost EU level cooperation among EU Member States in assessing health technologies, including new pharmaceutical products, and providing the basis for cooperation at the EU level for joint clinical assessments in these areas. The proposal provides that EU Member States will be able to use common HTA tools, methodologies and procedures across the European Union, working together in four main areas, including joint clinical assessment of the innovative health technologies with the most potential impact for patients, joint scientific consultations whereby developers can seek advice from HTA authorities, identification of emerging health technologies to identify promising technologies early, and continuing voluntary cooperation in other areas. Individual EU Member States will continue to be responsible for assessing non-clinical (e.g., economic, social, ethical) aspects of health technology, and making decisions on pricing and reimbursement. While EU Member States could choose to delay participation in the joint work until three years after the rules enter into force, it will become mandatory after six years. The European Commission has stated that the role of the HTA regulation is not to influence pricing and reimbursement decisions, but there can be no assurance that the HTA regulation will not affect such decisions. The HTA entered into force on January 11, 2022 and applies as of January 2025 followed by a further three-year transitional period during which EU Member States must fully adapt to the new system.

To obtain reimbursement or pricing approval in some countries, including the EU Member States, we may be required to conduct studies that compare the cost-effectiveness of our product candidates to other therapies that are considered the local standard of care (SOC). There can be no assurance that any country will allow favorable pricing, reimbursement and market access conditions for any of our products, or that we will be feasible to conduct additional cost-effectiveness studies, if required.

In certain of the EU Member States, pharmaceutical products that are designated as orphan pharmaceutical products may be exempted or waived from having to provide certain clinical, cost-effectiveness and other economic data in connection with their filings for pricing/reimbursement approval.

*European Union Data Laws*

The collection and use of personal health data and other personal data in the European Union is governed by the provisions of the European General Data Protection Regulation (EU) 2016/679 (GDPR), which came into force in May 2018, and related data protection laws in individual EU Member States.

The GDPR imposes a number of strict obligations and restrictions on the ability to process (processing includes collecting, analyzing and transferring) personal data of individuals, in particular with respect to health data from clinical trials and adverse event reporting. The GDPR includes requirements relating to the legal basis of the processing (such as consent of the individuals to whom the personal data relates), the information provided to the individuals prior to processing their personal data, the notification obligations to the national data protection authorities, and the security and confidentiality of the personal data. EU Member States may also impose additional requirements in relation to health, genetic and biometric data through their national legislation.

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In addition, the GDPR imposes specific restrictions on the transfer of personal data to countries outside of the European Union /EEA that are not considered by the European Commission to provide an adequate level of data protection (including the United States). Appropriate safeguards are required to enable such transfers. Among the appropriate safeguards that can be used, the data exporter may use the standard contractual clauses (SCCs), issued by the European Commission. In this respect, recent legal developments in Europe have created complexity and compliance uncertainty regarding certain transfers of personal data from the EU/EEA. For example, following the Schrems II decision of the Court of Justice of the European Union on July 16, 2020, in which the Court invalidated the Privacy Shield under which personal data could be transferred from the EU/EEA to United States entities who had self-certified under the Privacy Shield scheme, there is uncertainty as to the general permissibility of international data transfers under the GDPR. The Court did not invalidate the then-current SCCs, but ruled that data exporters relying on these SCCs are required to verify, on a case-by-case basis, if the law of the third country ensures an adequate level of data protection that is essentially equivalent to that guaranteed in the EU/EEA. In light of the implications of this decision, we may face difficulties regarding the transfer of personal data from the European Union/EEA to third countries. In 2021 the EU Commission issued a new set of SCCs. Since December 27, 2022, only the incorporation of the new set of SCCs ensures that the transfer is subject to appropriate safeguards. When relying on SCCs, the data exporters are also required to conduct a transfer risk assessment to verify if anything in the law and/or practices of the third country may impinge on the effectiveness of the SCCs in the context of the transfer at stake and, if so, to identify and adopt supplementary measures that are necessary to bring the level of protection of the data transferred to the EU standard of essential equivalence. Where no supplementary measure is suitable, the data exporter should avoid, suspend or terminate the transfer. On June 18, 2021, the European Data Protection Board adopted recommendations to assist data exporters with such assessment and their duty to identify and implement supplementary measures where they are needed to ensure compliance with the EU level of protection to the personal data they transfer to third countries. On March 25, 2022, the EC and the United States announced that they have agreed in principle on a new Trans-Atlantic Data Privacy Framework. Following this statement, President Biden signed an Executive Order on 'Enhancing Safeguards for United States Signals Intelligence Activities' on October 7, 2022. Along with the regulations issued by the Attorney General, the Executive Order implements into U.S. law the agreement in principle announced in March 2022. On that basis, the EC prepared a draft adequacy decision and launched its adoption procedure. While this new EU-US privacy framework is expected to enter into force in 2023, there is still some uncertainty around the new framework.

In the event of a personal data breach, the GDPR also requires us, as a controller, to notify the competent supervisory authorities and/or the affected data subjects. Such notification must be issued without undue delay, where feasible, not later than 72 hours after having become aware of the data breach. The notification obligation exists regardless of whether the processing is carried out on our or our vendors' systems. The only exception where such notification may be omitted is if the personal data breach is unlikely to result in a risk to the rights and freedoms of natural persons. In addition to the disruptions to our business and impact to our reputation that any such breach of security could cause, we may be subject to regulatory fines, class actions, or other costly measures if there is a personal data breach on our or our vendors' systems. Furthermore, under the GDPR, when we act as a processor, we must notify the relevant controller without undue delay after become aware of a personal data breach.

Failure to comply with the requirements of the GDPR and the related national data protection laws of the EU Member States may result in significant monetary fines for noncompliance of up to €20 million or 4% of the annual global revenues of the noncompliant company, whichever is greater, other administrative penalties and a number of criminal offenses (punishable by uncapped fines) for organizations and, in certain cases, their directors and officers, as well as civil liability claims from individuals whose personal data was processed. Data protection authorities from the different EU Member States may still implement certain variations, enforce the GDPR and national data protection laws differently, and introduce additional national regulations and guidelines, which adds to the complexity of processing personal data in the European Union. Guidance developed at both EU level and at the national level in individual EU Member States concerning implementation and compliance practices are often updated or otherwise revised.

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There is, moreover, a growing trend towards required public disclosure of clinical trial data in the European Union which adds to the complexity of obligations relating to processing health data from clinical trials. Such public disclosure obligations are provided in the new EU Clinical Trials Regulation, EMA disclosure initiatives and voluntary commitments by industry. Failing to comply with these obligations could lead to government enforcement actions and significant penalties against us, harm to our reputation, and adversely impact our business and operating results. The uncertainty regarding the interplay between different regulatory frameworks, such as the Clinical Trials Regulation and the GDPR, further adds to the complexity that we face with regard to data protection regulation.

With regard to the transfer of data from the European Union to the United Kingdom on June 28, 2021, the European Commission adopted two adequacy decisions for the United Kingdom – one under the GDPR and the other for the Law Enforcement Directive. Personal data may now freely flow from the European Union to the United Kingdom since the United Kingdom is deemed to have an adequate data protection level. Additionally, following the UK's withdrawal from the European Union and the EEA, companies also have to comply with the UK's data protection laws (including the UK GDPR, which is based on the EU GDPR), the latter regime having the ability to separately fine up to the greater of £17.5 million or 4% of global turnover. The adequacy decisions include a 'sunset clause' which entails that the decisions will automatically expire four years after their entry into force. Furthermore, transfers from the UK to other countries, including the EEA, are subject to specific transfer rules under the UK regime. These UK transfer rules broadly mirror the EU GDPR rules. On March 25, 2022, the international data transfer agreement, (IDTA), the international data transfer addendum to the EC's standard contractual clauses for international data transfers (Addendum), and a document setting out transitional provisions came into force and replaced the old EU SCCs. However, the transitional provisions, adopted with the IDTA and the Addendum, allow the continued use, until March 21, 2024, of any EU SCCs, valid as at December 31, 2020, so long as the contract was entered into before September 21, 2022.

*New Legislation and Regulations*

From time to time, legislation is drafted, introduced and passed in the European Union, its Member States and other states of Europe that could significantly change the statutory provisions governing the testing, approval, manufacturing, marketing, coverage and reimbursement of pharmaceutical products. In addition to new legislation, pharmaceutical regulations and policies are often revised or interpreted by the EMA and national agencies in ways that may significantly affect our business and our products.

#### U.S. Pharmaceutical Coverage, Pricing and Reimbursement
Significant uncertainty exists as to the coverage and reimbursement status of products approved by the FDA and other government authorities. Sales of products will depend, in part, on the extent to which the costs of the products will be covered by third-party payors, including government health programs such as, in the United States, Medicare and Medicaid, commercial health insurers and managed care organizations. The process for determining whether a payor will provide coverage for a product may be separate from the process for setting the price or reimbursement rate that the payor will pay for the product once coverage is approved. Third-party payors may limit coverage to specific products on an approved list, or formulary, which might not include all of the approved products for a particular indication.

In order to secure coverage and reimbursement for any product that might be approved for sale, a company may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of the product, in addition to the costs required to obtain FDA or other comparable regulatory approvals. A payor's decision to provide coverage for a drug product does not necessarily imply that an adequate reimbursement rate will be approved. Third-party reimbursement may not be sufficient to maintain price levels high enough to realize an appropriate return on our investment in product development.

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The containment of healthcare costs has become a priority of federal, state and foreign governments, and the prices of drugs have been a focus in this effort. Third-party payors are increasingly challenging the prices charged for medical products and services and examining the medical necessity and cost-effectiveness of medical products and services, in addition to their safety and efficacy. If these third-party payors do not consider a product to be cost effective compared to other available therapies, they may not cover the product after approval as a benefit under their plans or, if they do, the level of payment may not be sufficient to allow a company to sell its products at a profit. Even if favorable coverage and reimbursement status is attained for one or more products that receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

The U.S. government and state legislatures have shown significant interest in implementing cost containment programs to limit the growth of government-paid health care costs, including price controls, risk sharing, restrictions on reimbursement and requirements for substitution of generic products for branded prescription drugs. Adoption of such controls and measures and tightening of restrictive policies in jurisdictions with existing controls and measures, could limit payments for pharmaceuticals. As a result, the marketability of any product which receives regulatory approval for commercial sale may suffer if the government and third-party payors fail to provide adequate coverage and reimbursement.

#### U.S. Healthcare Reform
In the United States, there have been, and we expect there will continue to be, a number of legislative and regulatory changes to the healthcare system. In addition, an increasing emphasis on managed care in the United States has increased and will continue to increase the pressure on drug pricing. Coverage policies, third-party reimbursement rates and drug pricing regulation may change at any time.

In particular, the Inflation Reduction Act of 2022 (IRA) contains provisions intended to lower beneficiary drug spending. Beginning in 2023, the IRA enables Medicare to negotiate prescription drug prices with manufacturers of certain high-cost drugs for the first time. A separate provision requires drug manufacturers to pay rebates to Medicare if their drug prices increase faster than the rate of inflation (the so-called inflation rebate provision). Additionally, effective in 2024, IRA will eliminate 5% coinsurance for catastrophic coverage under Medicare Part D; in 2025, the IRA will cap beneficiary annual out-of-pocket expenditure at $2,000. These efforts to reduce aggregate beneficiary spending are expected to shift some costs to drug manufacturers.

States have also become increasingly active in implementing regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures and, in some cases, mechanisms to encourage importation from other countries and bulk purchasing. Furthermore, there has been increased interest by third party payors and governmental authorities in reference pricing systems and publication of discounts and list prices.

#### Healthcare Laws and Regulations
Healthcare providers, physicians and third-party payors will play a primary role in the recommendation and prescription of drug products that are granted marketing approval. Arrangements with healthcare providers, physicians, third-party payors and customers are subject to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we market, sell and distribute products for which we obtain marketing approval. Restrictions under applicable federal and state healthcare laws and regulations, include the following:

● the federal healthcare Anti-Kickback Statute prohibits, among other things, persons from soliciting, offering, receiving or providing any remuneration (in cash or in kind), directly or indirectly, to induce or reward either the referral of an individual for, or the purchase, lease, order

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or recommendation of, any item, facility or service for which payment may be made in whole or in part under a federal healthcare program such as Medicare and Medicaid;

● the federal Foreign Corrupt Practices Act, or FCPA, prohibits, among other things, U.S. corporations and persons acting on their behalf from offering, promising, authorizing or making payments to any foreign government official (including certain healthcare professionals in many countries), political party, or political candidate in an attempt to obtain or retain business or otherwise seek preferential treatment abroad;

● the federal False Claims Act, which may be enforced by the U.S. Department of Justice or private whistleblowers to bring civil actions (qui tam actions) on behalf of the federal government, imposes civil penalties, as well as liability for treble damages and for attorneys' fees and costs, on individuals or entities for knowingly presenting, or causing to be presented, to the federal government, claims for payment that are false or fraudulent, making a false statement material to a false or fraudulent claim, or improperly avoiding, decreasing, or concealing an obligation to pay money to the federal government. In addition, the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the civil False Claims Act;

● the Department of Health and Human Services' Civil Monetary Penalties authorities, which imposes administrative sanctions for, among other things, presenting or causing to be presented false claims for government payment and providing remuneration to government health program beneficiaries to influence them to order or receive healthcare items or services;

● the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, imposes criminal and civil liability for, among other conduct, executing a scheme to defraud any healthcare benefit program and making false statements relating to healthcare matters;

● HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act and its implementing regulations, also imposes criminal and civil liability and penalties on those who violate requirements, including mandatory contractual terms, intended to safeguard the privacy, security, transmission and use of individually identifiable health information;

● the federal false statements statute relating to healthcare matters prohibits falsifying, concealing or covering up a material fact or making any materially false statement in connection with the delivery of or payment for healthcare benefits, items or services;

● the federal Physician Payment Sunshine Act requires manufacturers of drugs (among other products) to report to the Centers for Medicare and Medicaid Services within the U.S. Department of Health and Human Services, or HHS, information related to payments and other transfers of value to various healthcare professionals, including physicians, physician assistants, nurse practitioners, clinical nurse specialists, certified nurse anesthetists, certified nurse-midwives, and teaching hospitals; as well as physician ownership and investment interests in the reporting manufacturers;

● similar state and foreign laws and regulations, such as state anti-kickback and false claims laws, may apply to sales or marketing arrangements and claims involving healthcare items or services reimbursed by nongovernmental third-party payors, including private insurers;

● certain state laws require pharmaceutical companies to comply with voluntary compliance guidelines promulgated by a pharmaceutical industry association and relevant compliance guidance issues by HHS Office of Inspector General; bar drug manufacturers from offering or

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providing certain types of payments or gifts to physicians and other health care providers; and/or require disclosure of gifts or payments to physicians and other healthcare providers; and

● Various state and foreign laws also govern the privacy and security of health information in some circumstances; many of these laws differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

Violation of any of such laws or any other governmental regulations that apply may result in penalties, including, without limitation, civil and criminal penalties, damages, fines, additional reporting obligations, the curtailment or restructuring of operations, exclusion from participation in governmental healthcare programs and imprisonment.

#### Competition
The biotechnology industry is characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. While we believe that our technology and scientific knowledge provide us with competitive advantages, we face potential competition from many different sources, including pharmaceutical and biotechnology companies, ranging in size from early stage to major global companies, academic institutions, government agencies and other public and private research organizations that conduct research, seek patent protection and establish collaborative arrangements for the research, development, manufacturing and commercialization of cancer therapies. Any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

We compete in the segments of the pharmaceutical, biotechnology and other related markets that develop cancer therapies. We focus on the development of precision small molecule therapies for patients with cancers where there is a high unmet medical need. There are numerous other companies that have commercialized or are developing cancer therapies for the same or similar targets.

With respect to our lead product candidate, milademetan, there are no approved drugs targeting MDM2. There are multiple companies testing MDM2 inhibitors and degraders in various stages of development and various indications, including, Kartos Therapeutics (navtemadlin), Ascentage Pharma (alrizomadlin), Boehringer Ingelheim (BI-907828), Kymera (KT-253), and others.

Many of the companies against which we are competing or against which we may compete in the future have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and commercializing and marketing approved drugs than we do. Mergers and acquisitions in the pharmaceutical, biotechnology and diagnostic industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and enrolling subjects for our clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

We could see a reduction or elimination of our commercial opportunities if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient to administer, are less expensive or obtain more favorable reimbursement than any products that we or our collaborators may develop. Our competitors also may obtain FDA or foreign regulatory approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we or our collaborators are able to enter the market. The key competitive factors affecting the success of all our product candidates, if approved, are likely to be their efficacy, safety, convenience, price, the effectiveness of companion diagnostics, if required, the level of

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biosimilar or generic competition, and the availability of reimbursement from government and other third-party payors.

#### Employees and Human Capital Resources
As of December 31, 2022, we had 63 full-time employees, of whom 47 were engaged in research and development activities and 16 were engaged in general and administrative activities. None of our employees are represented by labor unions or covered by collective bargaining agreements. We consider our relationship with our employees to be good. Recruiting and retaining experienced and qualified scientific personnel to perform research and development work now and in the future will be critical to our business success. We may not be able to attract and retain personnel on acceptable terms given the competition among pharmaceutical and biotechnology companies, academic and research institutions and government agencies for experienced scientists.

Our values—relentless, energetic, and committed to excellence—guide how we make decisions, and treat each other. All employees are responsible for upholding these values, the Rain Code of Conduct, and Employee Handbook form the foundation of our policies and practices and ethical business culture.

Our human capital resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing and integrating our existing and additional employees.

#### Inclusion
Diversity and inclusion are instrumental in driving innovation and delivering stronger business growth. Among our 63 full-time employees, 56% are women. Over 20 languages are spoken by our employees and they hail from many countries around the world.

#### Compensation and Benefits
We strive to provide pay, benefits, and services that help meet the varying needs of our employees. Our total rewards package includes market-competitive pay, broad-based stock grants and bonuses, an employee stock purchase plan, healthcare and retirement benefits, paid time off and family leave, and flexible work schedules.

#### Growth and Development
We are dedicated to helping each employee take charge to lead, and to grow professionally and personally. Through our regular self-evaluation, goal setting and performance review, employees can voice learning and development experiences.

#### Health and Safety
We are committed to providing a safe and healthy work environment for our employees, and all other individuals working on our behalf.

#### Environmental Matters
We are committed to operating our business in a manner that protects the environment as much as possible, and are further committed to compliance with all applicable environmental laws, regulations, and industry best practices, such as those that affect hazardous waste disposal, emissions, and water purity.

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#### Name Change
On December 30, 2022, we changed our name from Rain Therapeutics Inc. to Rain Oncology Inc. to better reflect our focus on addressing unmet needs for cancer patients through precision oncology.

#### Corporate Information
We were incorporated in the State of Delaware on April 6, 2017. Our corporate offices are located at 8000 Jarvis Avenue, Suite 204, Newark, California 94560 and our telephone number is (510) 953-5559. Our website address is www.rainoncology.com. Information contained on or accessible through our website is not a part of this Annual Report on Form 10-K, and the inclusion of our website address in this Annual Report on Form 10-K is an inactive textual reference only.

We file electronically with the SEC our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, proxy statements and any amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the Exchange Act). We make available on our website at www.rainoncology.com, under "Investors," free of charge, copies of these reports as soon as reasonably practicable after filing or furnishing these reports with the SEC. The reports that we file or furnished to SEC can be obtained electronically by means of the SEC's website at www.sec.gov.

#### Implications of Being an Emerging Growth Company and a Smaller Reporting Company
We are an emerging growth company, as defined in Section 2(a) of the Securities Act of 1933, as amended (the Securities Act), as modified by the Jumpstart Our Business Startups Act of 2012 (the JOBS Act), and we may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies, including relief from the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, as amended, less extensive disclosure obligations regarding executive compensation in our registration statements, periodic reports and proxy statements, exemptions from the requirements to hold a nonbinding advisory vote on executive compensation, and exemptions from stockholder approval of any golden parachute payments not previously approved. We may also elect to take advantage of other reduced reporting requirements in future filings. As a result, our stockholders may not have access to certain information that they may deem important and the information that we provide to our stockholders may be different than, and not comparable to, information presented by other public reporting companies. We could remain an emerging growth company until the earlier of (1) the last day of the year following the fifth anniversary of the completion of our initial public offering (IPO), (2) the last day of the year in which we have total annual gross revenue of at least $1.235 billion, (3) the last day of the year in which we are deemed to be a "large accelerated filer" as defined in Rule 12b-2 under the Exchange Act, which would occur if the market value of our common stock held by non-affiliates exceeded $700.0 million as of the last business day of the second fiscal quarter of such year or (4) the date on which we have issued more than $1.0 billion in non-convertible debt securities during the prior three-year period.

In addition, the JOBS Act also provides that an emerging growth company may take advantage of the extended transition period provided in the Securities Act for complying with new or revised accounting standards. An emerging growth company may therefore delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. We have elected to avail ourselves of this exemption and, as a result, will not be subject to the same implementation timing for new or revised accounting standards as are required of other public companies that are not emerging growth companies, which may make comparison of our financial information to those of other public companies more difficult.

We are also a smaller reporting company, as defined in the Exchange Act. We may continue to be a smaller reporting company even after we are no longer an emerging growth company. We may take advantage of certain of the scaled disclosures available to smaller reporting companies and will be able to

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take advantage of these scaled disclosures for so long as (i) our voting and non-voting common stock held by non-affiliates is less than $250.0 million measured on the last business day of our second fiscal quarter or (ii) our annual revenue is less than $100.0 million during the most recently completed fiscal year and our voting and non-voting common stock held by non-affiliates is less than $700.0 million measured on the last business day of our second fiscal quarter.

#### Item 1A. RISK FACTORS.
*Investing in our common stock involves significant risks. You should carefully consider the risks and uncertainties described below, together with all of the other information in this Annual Report on Form 10-K, including "Management's Discussion and Analysis of Financial Condition and Results of Operations" and our audited financial statements and related notes, and other filings we have made and make in the future with the Securities and Exchange Commission. If any of the following risks are realized, our business, financial condition, results of operations and prospects could be materially and adversely affected. In such case, the trading price of our common stock would likely decline, and you may lose all or part of your investment. Below is a summary of some of the risks we face. We caution you that the risks, uncertainties and other factors referred to below and elsewhere in this Annual Report on Form 10-K may not contain all of the risks, uncertainties and other factors that may affect our future results and operations. Moreover, new risks will emerge from time to time. It is not possible for our management to predict all risks.*

#### Risk Factor Summary
An investment in our common stock involves significant risks. You should carefully consider the risks and uncertainties described below before making a decision to invest in our common stock. If we are unable to successfully address these risks and uncertainties, our business, financial condition, results of operations, or prospects could be materially adversely affected. In such case, the trading price of our common stock would likely decline, and you may lose all or part of your investment. Below is a summary of some of the risks we face.

● We have a limited operating history, and have no products approved for commercial sale, which may make it difficult for you to evaluate our current business and likelihood of success and viability.

● We have incurred significant losses since inception, and we expect to incur significant losses for the foreseeable future and may not be able to achieve or sustain profitability in the future. We have not generated any revenue from our product candidates and may never generate revenue or become profitable.

● If we are unable to raise such capital when needed, or on acceptable terms, we may be forced to delay, reduce and/or eliminate one or more of development programs or future commercialization efforts.

● Our future growth depends on our ability to identify and acquire or in-license products.

● We are substantially dependent on the success of our lead product candidate, milademetan, and our anticipated clinical trials of milademetan may not be successful.

● We may find it difficult to enroll patients in our clinical trials given the relatively small patient populations with the indications for which our product candidates are being developed.

● The results of our preclinical testing and early clinical trials may not be predictive of the success of our later clinical trials, and the results of our clinical trials may not satisfy the requirements of the FDA or other comparable foreign regulatory authorities.

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● We face substantial competition, which may result in others discovering, developing, licensing or commercializing products before or more successfully than we do.

● The regulatory approval processes of the FDA and other comparable foreign regulatory authorities are lengthy, time-consuming and inherently unpredictable.

● We currently rely, and plan to rely in the future, on third parties to conduct and support our preclinical studies and clinical trials.

● We currently rely and expect to rely in the future on the use of manufacturing suites in third-party facilities or on third parties to manufacture our product candidates, and we may rely on third parties to produce and process our products, if approved.

● We may, in the future, form or seek collaborations or strategic alliances or enter into licensing arrangements, and we may not realize the benefits of such collaborations, alliances or licensing arrangements.

● Our ability to protect our patents and other proprietary rights is uncertain, exposing us to the possible loss of competitive advantage.

● We may be subject to patent infringement claims or may need to file claims to protect our intellectual property, which could result in substantial costs and liability and prevent us from commercializing our potential products.

● We license patent rights from third-party owners and we rely on such owners to obtain, maintain and enforce the patents underlying such licenses.

#### Risks Related to Our Limited Operating History, Business, Financial Condition, Results of Operations and Need for Additional Capital
***We have a limited operating history, and have no products approved for commercial sale, which may make it difficult for you to evaluate our current business and likelihood of success and viability.***

We are a clinical-stage company with limited operating history. Since our inception in 2017, we have incurred significant operating losses and have utilized substantially all of our resources to date in-licensing and developing our product candidates, organizing and staffing our company and providing other general and administrative support for our operations. We have no significant experience as a company in initiating, conducting or completing clinical trials, including global late-stage clinical trials. In particular, Daiichi Sankyo conducted the Phase 1 trial for our lead product candidate, RAIN-32, prior to our in-license of milademetan in September 2020. In part because of this lack of significant experience, we cannot be certain that our planned clinical trials will begin or be completed on time, if at all. In addition, we have not yet demonstrated an ability to obtain marketing approvals, manufacture a commercial-scale product or arrange for a third party to do so on our behalf, or conduct sales, marketing and distribution activities necessary for successful product commercialization. Consequently, any predictions you make about our future success or viability may not be as accurate as they could be if we had a longer operating history. Further, we may encounter unexpected expenses, challenges and complications from known and unknown factors.

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***We have incurred significant losses since inception, and we expect to incur significant losses for the foreseeable future and may not be able to achieve or sustain profitability in the future. We have not generated any revenue from our product candidates and may never generate revenue or become profitable.***

Investment in biopharmaceutical product development is a highly speculative undertaking and entails substantial upfront capital expenditures and significant risks that any product candidate will fail to demonstrate adequate efficacy or an acceptable safety profile, gain regulatory approval and become commercially viable. We have no products approved for commercial sale, we have not generated any revenue from product sales to date, and we continue to incur significant research and development and other expenses related to our ongoing operations. We do not expect to generate product revenue unless or until we successfully complete preclinical and clinical development and obtain regulatory approval of, and then successfully commercialize, at least one product candidate. We may never succeed in these activities and, even if we do, may never generate revenues that are significant or large enough to achieve profitability. If we are unable to generate sufficient revenue through the sale of our current product candidates or any future product candidates, we may be unable to continue operations without additional funding.

We have incurred significant net losses in each period since we commenced operations in April 2017. Our net losses were $75.7 million and $51.4 million for the years ended December 31, 2022 and 2021, respectively. We expect to continue to incur significant losses for the foreseeable future. Our failure to become profitable would decrease the value of our company and could impair our ability to raise capital, maintain our research and development efforts, expand our business and/or continue our operations. A decline in the value of our company could also cause you to lose all or part of your investment.

***We will require substantial additional capital to finance our operations in the future. If we are unable to raise such capital when needed, or on acceptable terms, we may be forced to delay, reduce and/or eliminate one or more of development programs or future commercialization efforts.***

Developing biopharmaceutical products is a very long, time-consuming, expensive and uncertain process that takes years to complete. We expect our expenses to increase in connection with our ongoing activities, particularly as we conduct clinical trials of, and seek marketing approval for milademetan, and advance our other product candidates and future product candidates. Even if one or more of the product candidates that we develop is approved for commercial sale, we anticipate incurring significant costs associated with sales, marketing, manufacturing and distribution activities to launch any such product. Our expenses could increase beyond expectations if we are required by the FDA or other regulatory agencies to perform preclinical studies or clinical trials in addition to those that we currently anticipate or if our clinical trials take longer than expected to complete. Because the design and outcome of our planned and anticipated clinical trials are highly uncertain, we cannot reasonably estimate the actual amount of funding that will be necessary to successfully complete the development and commercialization of any product candidate we develop. Our future capital requirements depend on many factors, including factors that are not within our control. We will also incur additional costs associated with operating as a public company. Accordingly, we will require substantial additional funding to continue our operations. Based on our current operating plan, we believe that our existing cash, cash equivalents and short-term marketable securities, will be sufficient to fund our operations for at least the next twelve months following the date of this Annual Report on Form 10-K. This estimate is based on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we currently expect.

We do not have any committed external sources of funds other than as a result of any sales that we may make pursuant to the Sales Agreement for our ATM Facility and adequate additional financing may not be available to us on acceptable terms, or at all. We may be required to seek additional funds sooner than planned through public or private equity offerings, debt financings, collaborations and licensing arrangements or other sources. Such financing may dilute our stockholders or the failure to obtain such financing may restrict our operating activities. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms may include liquidation or

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other preferences and anti-dilution protections that adversely affect your rights as a stockholder. Debt financing may result in imposition of debt covenants, increased fixed payment obligations or other restrictions that may affect our business. If we raise additional funds through upfront payments or milestone payments pursuant to future collaborations with third parties, we may have to relinquish valuable rights to our product candidates or grant licenses on terms that are not favorable to us. Our ability to raise additional capital may be adversely impacted by potential worsening global macroeconomic conditions and the disruptions to and volatility in the credit and financial markets in the United States and worldwide. Our failure to raise capital as and when needed or on acceptable terms would have a negative impact on our financial condition and our ability to pursue our business strategy, and we may have to delay, reduce the scope of, suspend or eliminate one or more of our research-stage programs, clinical trials or future commercialization efforts.

#### Our future growth depends on our ability to identify and acquire or in-license products.
We have in-licensed the rights to all of our current product candidates from third parties who conducted the initial development of each product candidate. An important part of our business strategy is to continue to develop a pipeline of product candidates by acquiring or in-licensing products, businesses or technologies. Future in-licenses or acquisitions, however, may entail numerous operational and financial risks. In addition, we may compete with competitors in pursuing these in-licensing opportunities and such competitors may have access to greater financial resources than us and may have greater experience in identifying and evaluating new opportunities.

***If we breach any of the agreements under which we license rights to our product candidates from others, we could lose the ability to develop and commercialize our product candidates.***

In September 2020, we entered into a worldwide, exclusive license agreement with Daiichi Sankyo relating to milademetan for all human prophylactic or therapeutic uses. Because we have in-licensed the rights to milademetan from Daiichi Sankyo, if there is any dispute between us and Daiichi Sankyo regarding our rights under the license agreement, our ability to develop and commercialize our product candidate may be adversely affected. Any uncured, material breach under the license agreement could result in our loss of exclusive rights to the product candidate and may lead to a complete termination of our product development efforts for such product candidate.

***Due to the significant resources required for the development of our product candidates, we must prioritize development of certain product candidates and/or the pursuit of treatments for certain indications. We may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize on product candidates or indications that may be more profitable or for which there is a greater likelihood of success.***

We are developing therapies for patients with genetically defined cancers with unmet needs. We apply a tumor-agnostic development approach to the essential biological pathways and molecular machinery of cancer. Our lead product candidate, milademetan, is a small molecule, oral inhibitor of MDM2, may be oncogenic in numerous cancers. Our decisions concerning the allocation of research, development, collaboration, management and financial resources toward particular product candidates or indications may not lead to the development of any viable commercial product and may divert resources away from better opportunities with other product candidates or for other indications that later prove to have greater commercial potential or a greater likelihood of success. For example, we are deprioritizing the Phase 2 MANTRA-3 trial in Merkel cell carcinoma as an area of focus due to our continued effort to rationalize use of capital in the current market environment.

In addition, even if milademetan receives marketing approval, it may not achieve commercial success, including as a result of the gravity of the patients' illnesses in our target market. The primary endpoint for the pivotal Phase 3 trial for milademetan that we commenced in DDLPS (MANTRA) is progression-free survival (PFS) evaluated by Response Evaluation Criteria in Solid Tumors. Even if the primary endpoint of such trial is met and milademetan demonstrates meaningful increases in PFS, there is no

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guarantee that such increases in PFS will lead to the market acceptance or commercial success of milademetan, if approved. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through future collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights. We may make incorrect determinations regarding the viability or market potential of any of our programs or product candidates or misread trends in our industry.

#### Risks Related to Product Development

#### We are substantially dependent on the success of our lead product candidate, milademetan, and our anticipated clinical trials of milademetan may not be successful.
Our future success is substantially dependent on our ability to timely obtain marketing approval for, and then successfully commercialize, milademetan, our lead product candidate. We are investing a majority of our efforts and financial resources into the research and development of milademetan. We announced the completion of enrollment into our MANTRA Phase 3 randomized, global, registrational trial of our lead product candidate, milademetan, an oral, small molecule inhibitor of the MDM2-p53 complex that reactivates p53 in August 2022. We anticipate topline data from our MANTRA Phase 3 trial in the second quarter of 2023. We announced preliminary data in the multicenter, single arm, open-label, Phase 2 basket trial evaluating milademetan, an MDM2 inhibitor, for the treatment of MDM2-amplified advanced solid tumors (our MANTRA-2 trial) in November 2022. We also expect to commence a Phase 1/2 MANTRA-4 clinical trial to evaluate the safety, tolerability and efficacy of milademetan in combination with atezolizumab in patients with loss of CDKN2A and wildtype p53 advanced solid tumors in mid-2023.

Milademetan will require additional clinical development, evaluation of clinical, preclinical and manufacturing activities, marketing approval in multiple jurisdictions, substantial investment and significant marketing efforts before we generate any revenues from product sales. We are not permitted to market or promote milademetan, or any other product candidates, before we receive marketing approval from the FDA and comparable foreign regulatory authorities, and we may never receive such marketing approvals.

The success of milademetan will depend on a variety of factors. We do not have complete control over many of these factors, including certain aspects of clinical development and the regulatory submission process, potential threats to our intellectual property rights and the manufacturing, marketing, distribution and sales efforts of any future collaborator. Accordingly, we cannot assure you that we will ever be able to generate revenue through the sale of milademetan, even if approved. If we are not successful in commercializing milademetan, or are significantly delayed in doing so, our business will be materially harmed.

***We may find it difficult to enroll patients in our clinical trials given the relatively small patient populations with the indications for which our product candidates are being developed. If we experience delays or difficulties in the enrollment of patients in clinical trials, including failure to develop or use existing companion diagnostic tests, our successful completion of clinical trials or receipt of marketing approvals could be delayed or prevented.***

We may not be able to initiate or continue clinical trials for our product candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials. Because our product candidates are focused on indications with relatively small patient populations, our ability to enroll eligible patients in our clinical trials may be limited or may result in slower enrollment than we anticipate. Moreover, because specific genetic mutations will be used to identify the appropriate patients for our programs and our current or future product candidates, successful enrollment of eligible patients to these trials may depend, in part, on our ability to use existing companion diagnostic tests and genetic sequencing, or to develop novel companion diagnostics in collaboration with partners. Patient enrollment may be affected by various factors, including if our competitors have ongoing clinical trials for product candidates that are under development for the same indications as our product candidates, and patients instead enroll in such other clinical trials. In

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addition, we have clinical trial sites in Russia, Georgia and surrounding countries, which may be impacted by the current situation with Ukraine and Russia and could result in difficulties enrolling or completing our clinical trials on schedule. Our inability to enroll a sufficient number of patients or a delay in enrolling such patients, could result in significant delays in completing clinical trials, increased development costs, or a delay or inability to receive marketing approvals and may require us to abandon one or more clinical trials altogether.

***The results of our preclinical testing and early clinical trials may not be predictive of the success of our later clinical trials, and the results of any of our clinical trials may not satisfy the requirements of the FDA or other comparable foreign regulatory authorities.***

We will be required to demonstrate with substantial evidence through well-controlled clinical trials that our product candidates are safe and effective before we can seek marketing approvals for their commercial sale. Demonstrations of efficacy or an acceptable safety profile in our prior preclinical studies does not mean that future clinical trials will yield the same results. For instance, we do not know whether milademetan will perform in future clinical trials as milademetan has performed in preclinical studies and early clinical trials conducted by Daiichi Sankyo, and, despite decades of research on p53 as a target for precision medicines, prior product development efforts have been unsuccessful. Product candidates, including milademetan, may fail to demonstrate in later-stage clinical trials sufficient safety and efficacy to the satisfaction of the FDA and other comparable foreign regulatory authorities despite having progressed through preclinical studies and earlier stage clinical trials. Regulatory authorities may also limit the scope of later-stage trials until we have demonstrated satisfactory safety or efficacy results in preclinical studies or earlier-stage trials, which could prevent us from conducting the clinical trials we currently anticipate. For example, our open-label Phase 2 basket trial evaluating milademetan across solid tumors in patients with pre-specified MDM2 amplification levels may not meet the primary endpoint of an objective response rate as measured by RECIST criteria. We may not meet the secondary endpoints, including duration of response, disease control rate progression-free survival by investigator assessment, overall survival, and growth modulation index. Even if we are able to initiate our planned clinical trials on schedule, there is no guarantee that we will be able to complete such trials on the timelines we anticipate, that such trials will produce positive results, or that positive results will result in FDA approval or the commercial sale of any product candidate. Any limitation on our ability to conduct clinical trials could delay or prevent regulatory approval or limit the size of the patient population to which we may market our product candidates, if approved.

***Preclinical and clinical development involves a lengthy and expensive process with uncertain outcomes, and results of earlier studies and trials may not be predictive of future clinical trial results. If our preclinical studies and clinical trials are not sufficient to support regulatory approval of any of our product candidates, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development of such product candidates.***

Before obtaining marketing approval from regulatory authorities for the sale of any product candidate, we must complete preclinical studies and then conduct extensive clinical trials to demonstrate the safety and efficacy of our product candidates in humans. Our clinical trials may not be conducted as planned or completed on schedule, if at all, and a failure of one or more clinical trials can occur at any stage of testing. The outcome of preclinical studies and early-stage clinical trials may not be predictive of the success of later clinical trials. In particular, we initiated a pivotal Phase 3 trial for milademetan in DDLPS patients (MANTRA) in July 2021. Although data from DDLPS patients in our Phase 1 clinical trial demonstrated median PFS approximately three to four times greater than the current SOC, the efficacy of the SOC in prior preclinical studies does not mean that future clinical trials will yield the same results. Unexpectedly favorable results of the SOC in our MANTRA trial could lead to unfavorable comparisons to milademetan. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval of their product candidates.

We cannot guarantee that any clinical trials will be initiated or conducted as planned or completed on schedule, if at all. We also cannot be sure that submission of an investigational new drug application (IND) or

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similar application will result in the FDA or other regulatory authority, as applicable, allowing clinical trials to begin in a timely manner, if at all. Moreover, even if these trials begin, issues may arise that could cause regulatory authorities to suspend or terminate such clinical trials. Events that may prevent successful or timely initiation or completion of clinical trials include: inability to generate sufficient preclinical, toxicology or other *in vivo* or *in vitro* data to support the initiation or continuation of clinical trials; delays in reaching a consensus with regulatory authorities on study design or implementation of the clinical trials; delays or failure in obtaining regulatory authorization to commence a trial; delays in reaching agreement on acceptable terms with prospective CROs and clinical trial sites, the terms of which can be subject to extensive negotiation and may vary significantly among different CROs and clinical trial sites; delays in identifying, recruiting and training suitable clinical investigators; delays in obtaining required institutional review board (IRB) approval at each clinical trial site; delays in manufacturing, testing, releasing, validating or importing/exporting sufficient stable quantities of our product candidates for use in clinical trials or the inability to do any of the foregoing; failure by our CROs, other third parties or us to adhere to clinical trial protocols; failure to perform in accordance with the FDA's or any other regulatory authority's good clinical practice requirements (GCPs) or applicable regulatory guidelines in other countries; changes to the clinical trial protocols; clinical sites deviating from trial protocol or dropping out of a trial; changes in regulatory requirements and guidance that require amending or submitting new clinical protocols; selection of clinical endpoints that require prolonged periods of observation or analyses of resulting data; transfer of manufacturing processes to larger-scale facilities operated by a contract manufacturing organization (CMO) and delays or failure by our CMOs or us to make any necessary changes to such manufacturing process; and third parties being unwilling or unable to satisfy their contractual obligations to us.

We could also encounter delays if a clinical trial is suspended or terminated by us, by the IRBs of the institutions in which such clinical trials are being conducted, by the Data Safety Monitoring Board, if any, for such clinical trial or by the FDA or other regulatory authorities. Such authorities may suspend or terminate a clinical trial due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical trial protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from the product candidates, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. If we are required to conduct additional clinical trials or other testing of our product candidates beyond those that we currently contemplate, if we are unable to successfully complete clinical trials of our product candidates, if the results of these trials are not positive or are only moderately positive or if there are safety concerns, our business and results of operations may be adversely affected, and we may incur significant additional costs.

***Preliminary, "topline" or interim data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures.***

From time to time, we may publicly disclose preliminary or topline data from our preclinical studies and clinical trials, which are based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data. We also make assumptions, estimations, calculations and conclusions as part of our analyses of these data without the opportunity to fully and carefully evaluate complete data. As a result, the preliminary or top-line results that we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results once additional data have been received and fully evaluated or subsequently made subject to audit and verification procedures. Any preliminary or top-line data should be viewed with caution until the final data are available. From time to time, we may also disclose interim data from our preclinical studies and clinical trials. Interim data are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available or as patients from our clinical trials continue other treatments. Further, others, including regulatory agencies, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular

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program, the approvability or commercialization of the particular product candidate and our company in general. In addition, the information we choose to publicly disclose regarding a particular preclinical study or clinical trial is based on what is typically extensive information, and you or others may not agree with what we determine is material or otherwise appropriate information to include in our disclosure. If the preliminary, top-line or interim data that we report differ from actual results, or if others, including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for, and commercialize, our product candidates may be harmed, which could harm our business, operating results, prospects or financial condition.

***We plan to pursue the development of milademetan in combination with other approved therapeutics. If the FDA revokes approval of any such therapeutic, or if safety, efficacy, manufacturing, or supply issues arise with any therapeutic that we use in combination with milademetan in the future, we may be unable to further develop and/or market our product candidate or we may experience significant regulatory delays or supply shortages, and our business could be materially and adversely affected.***

We plan to pursue the development of our product candidate in combination with other approved therapeutics. Specifically, we anticipate commencing a Phase 1/2 basket trial to evaluate milademetan in combination with atezolizumab (MANTRA-4). We have not developed or obtained regulatory approval for, nor will we manufacture or sell, atezolizumab or any other approved therapeutics. In addition, this combinations has not been previously tested and may, among other things, fail to demonstrate synergistic activity, may fail to achieve superior outcomes relative to the use of single agents or other combination therapies, may exacerbate adverse events associated with milademetan when used as monotherapy, or may fail to demonstrate sufficient safety or efficacy traits in clinical trials to enable us to complete those clinical trials or obtain marketing approval for the combination therapy.

If the FDA revokes its approval of any combination therapeutic, we would not be able to continue clinical development of or market any product candidate in combination with such revoked therapeutic. If safety or efficacy issues were to arise with any therapeutics that we seek to combine with, we could experience significant regulatory delays, and the FDA could require us to redesign or terminate the applicable clinical trials. In addition, we may need, for supply, data referencing, or other purposes, to collaborate or otherwise engage with the companies who market these approved therapeutics. If we are unable to do so on a timely basis, on acceptable terms, or at all, we may have to curtail the development of a product candidate or indication, reduce or delay its development program, delay its potential commercialization or reduce the scope of any sales or marketing activities.

#### A variety of risks associated with marketing our product candidates internationally may materially adversely affect our business.
We plan to eventually seek regulatory approval of our product candidates outside of the United States and, accordingly, we expect that we will be subject to additional risks related to operating in foreign countries and meeting differing regulatory requirements in foreign countries. Risks associated with international operations may materially adversely affect our business, financial condition and results of operations.

#### We face substantial competition, which may result in others discovering, developing, licensing or commercializing products before or more successfully than we do.
We face substantial competition from major pharmaceutical companies and biotechnology companies worldwide. Many of our competitors have significantly greater financial, technical and human resources. Smaller and early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. As a result, our competitors may discover, develop, license or commercialize products before or more successfully than we do.

In particular, we are aware of molecules that are being explored for p53 upregulation and activation of mutant p53 in various stages of clinical development by Actavalon, Aprea Therapeutics, CDG Therapeutics,

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Cotinga Pharmaceuticals, Innovation Pharmaceuticals, PMV Pharmaceuticals and Senhwa Biosciences, among others. We are also aware of selective small molecule inhibitors that are designed to target WT p53 containing tumors through the p53-MDM2 interaction, which are in various stages of clinical development by Ascentage Pharma, Boehringer Ingelheim, Kartos Therapeutics, Novartis, and Roche, including testing MDM2 inhibitors in combination with a variety of other anti-cancer agents.

We face competition with respect to our current product candidates and will face competition with respect to any future product candidates from segments of the pharmaceutical, biotechnology and other related industries that pursue targeted therapies for patients with genetically defined cancers. If milademetan or our future product candidates do not offer sustainable advantages over competing products, we may otherwise not be able to successfully compete against current and future competitors.

Our competitors may obtain regulatory approval of their products more rapidly than we may or may obtain patent protection or other intellectual property rights that limit our ability to develop or commercialize our product candidates. Our competitors may also develop drugs that are more effective, more convenient, more widely used and less costly or have a better safety profile than our products and these competitors may also be more successful than us in manufacturing and marketing their products. In addition, we will likely need to develop our product candidates in collaboration with companion diagnostic companies, and we will face competition from other companies in establishing these future collaborations.

Furthermore, we also face competition more broadly across the market for existing cost-effective and reimbursable cancer treatments. Our product candidates, if any are approved, may compete with these existing drug and other therapies but may not be competitive with them in price. We expect that if our product candidates are approved, they will be priced at a significant premium over competitive generic, including branded generic, products. As a result, obtaining market acceptance of, and gaining significant share of the market for, any of our product candidates that we successfully introduce to the market will pose challenges.

***Our product candidates may cause significant adverse events, toxicities or other undesirable side effects that may result in a safety profile that could prevent regulatory approval, marketing approval or market acceptance, or limit their commercial potential.***

If our product candidates are associated with undesirable side effects or have unexpected characteristics in preclinical studies or clinical trials when used alone or in combination with other approved products or INDs, we may need to interrupt, delay or abandon their development or limit development to more narrow uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective. Treatment-related side effects could also affect patient recruitment or the ability of enrolled patients to complete the trial or result in potential product liability claims. Any of these occurrences may prevent us from achieving or maintaining market acceptance of the affected product candidate and may adversely affect our business, financial condition and prospects significantly.

In general, the anticipated clinical trials of milademetan will include cancer patients who are very sick and whose health is deteriorating, and we expect that additional clinical trials of milademetan and our other product candidates will include similar patients with deteriorating health. A number of patients in milademetan trials have experienced adverse events, including blood and lymphatic disorders and gastrointestinal disorders.

The inclusion of critically ill patients in our clinical trials may result in deaths or other adverse medical events due to other therapies or medications that such patients may be using or due to the gravity of such patients' illnesses. For example, it is expected that many of the patients enrolled in our milademetan clinical trials will die or experience major clinical events either during the course of our clinical trials or after participating in such trials. Such outcomes may make it more difficult for us to identify a clinical benefit in our targeted patient populations, and could ultimately prevent us from obtaining regulatory approval for milademetan in such critically ill populations, including DDLPS. Additionally, such adverse events or deaths in

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clinical trials involving our product candidates, even if not ultimately attributable to our product or product candidates, could result in increased government regulation, unfavorable public perception and publicity, potential regulatory delays in the testing or licensing of our product candidates, stricter labeling requirements for those product candidates that are licensed and a decrease in demand for any such product candidates.

Additionally, if one or more of our product candidates receives marketing approval and we or others later identify undesirable side effects or adverse events caused by such products, a number of potentially significant negative consequences could result. For example, regulatory authorities may suspend, limit or withdraw approvals of such product or seek an injunction against its manufacture or distribution, require additional warnings on the label, including "boxed" warnings, or issue safety alerts, require press releases or other communications containing warnings or other safety information about the product, require us to change the way the product is administered or conduct additional clinical trials or post-approval studies, require us to create a risk evaluation and mitigation strategy (REMS) which could include a medication guide outlining the risks of such side effects for distribution to patients, impose fines, injunctions or criminal penalties. We could also be sued and held liable for harm caused to patients, and our reputation may suffer. Any of these events could prevent us from achieving or maintaining market acceptance of the particular product candidate, if approved, and could seriously harm our business.

#### Risks Related to Regulatory Process and Other Legal Compliance Matters
***The regulatory approval processes of the FDA and other comparable foreign regulatory authorities are lengthy, time-consuming and inherently unpredictable. If we are not able to obtain, or if there are delays in obtaining, required regulatory approvals for our product candidates, we will not be able to commercialize, or will be delayed in commercializing, our product candidates, and our ability to generate revenue will be materially impaired.***

The process of obtaining regulatory approvals, both in the United States and abroad, is unpredictable, expensive and typically takes many years following commencement of clinical trials, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type, complexity and novelty of the product candidates involved. We cannot commercialize product candidates in the United States without first obtaining regulatory approval from the FDA. Similarly, we cannot commercialize product candidates outside of the United States without obtaining regulatory approval from comparable foreign regulatory authorities. Before obtaining regulatory approvals for the commercial sale of our product candidates, including our lead product candidate milademetan, we must demonstrate through lengthy, complex and expensive preclinical studies and clinical trials that our product candidates are both safe and effective for each targeted indication. Securing regulatory approval also requires the submission of information about the drug manufacturing process to, and inspection of manufacturing facilities by, the relevant regulatory authority. Further, our product candidates may not be effective, may be only moderately effective or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude our obtaining marketing approval. The FDA and comparable foreign regulatory authorities have substantial discretion in the approval process and may refuse to accept any application or may decide that our data are insufficient for approval and require additional preclinical, clinical or other data. Our product candidates could be delayed in receiving, or fail to receive, regulatory approval for many reasons, including: the FDA or comparable foreign regulatory authorities may disagree with the design or implementation of our clinical trials; we may be unable to demonstrate to the satisfaction of the FDA or comparable foreign regulatory authorities that a product candidate is safe and effective for its proposed indication; the results of clinical trials may not meet the level of statistical significance required by the FDA or comparable foreign regulatory authorities for approval; serious and unexpected drug-related side effects may be experienced by participants in our clinical trials or by individuals using drugs similar to our product candidates; we may be unable to demonstrate that a product candidate's clinical and other benefits outweigh its safety risks; the FDA or comparable foreign regulatory authorities may disagree with our interpretation of data from preclinical studies or clinical trials; the data collected from clinical trials of our product candidates may not be acceptable or sufficient to support the submission of an NDA or other submission or to obtain regulatory approval in the United States or elsewhere, and we may be required to conduct additional clinical trials; the FDA or the

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applicable foreign regulatory authority may disagree regarding the formulation, labeling and/or the specifications of our product candidates; the FDA or comparable foreign regulatory authorities may fail to approve the manufacturing processes or facilities of third-party manufacturers with which we contract for clinical and commercial supplies; and the approval policies or regulations of the FDA or comparable foreign regulatory authorities may significantly change in a manner rendering our clinical data insufficient for approval. Thus, the approval requirements for our product candidates are likely to vary by jurisdiction such that success in one jurisdiction is not necessarily predicative of success elsewhere.

Of the large number of drugs in development, only a small percentage successfully complete the FDA or foreign regulatory approval processes and are commercialized. The lengthy approval process as well as the unpredictability of future clinical trial results may result in our failing to obtain regulatory approval to market our product candidates, which would significantly harm our business, results of operations and prospects.

If we were to obtain approval, regulatory authorities may approve any of our product candidates for fewer or more limited indications than we request, including failing to approve the most commercially promising indications, may grant approval contingent on the performance of costly post-marketing clinical trials, or may approve a product candidate with a label that does not include the labeling claims necessary or desirable for the successful commercialization of that product candidate. If we are not able to obtain, or if there are delays in obtaining, required regulatory approvals for our product candidates, we will not be able to commercialize, or will be delayed in commercializing, our product candidates and our ability to generate revenue will be materially impaired.

***If we are required by the FDA to obtain approval of a companion diagnostic test in connection with approval of any of our product candidates and we fail to obtain or face delays in obtaining FDA approval of a diagnostic device, we could be delayed or may not be able to commercialize such product candidate and our ability to generate revenue will be materially impaired.***

If safe and effective use of any of our product candidates depends on an *in vitro* diagnostic that is not otherwise commercially available, then the FDA generally will require approval or clearance of that diagnostic, known as a companion diagnostic, at the same time that the FDA approves our product candidates, if at all. Companion diagnostics are developed in conjunction with clinical programs for the associated product and are subject to regulation as medical devices by the FDA and comparable regulatory authorities, and, to date, the FDA has required premarket approval of all companion diagnostics for cancer therapies, such as those we are developing. The approval of a companion diagnostic as part of the therapeutic product's labeling limits the use of the therapeutic product to only those patients who express the specific genetic alteration that the companion diagnostic was developed to detect.

According to FDA guidance, if the FDA determines that a companion diagnostic device is essential to the safe and effective use of a novel therapeutic product or indication, the FDA generally will not approve the therapeutic product or new therapeutic product indication if the companion diagnostic is not also approved or cleared for that indication. If a satisfactory companion diagnostic is not commercially available, we may be required to develop or obtain one that would be subject to regulatory approval requirements. The process of obtaining or creating such diagnostics is time-consuming and costly. If the FDA or a comparable foreign regulatory authority requires approval of a companion diagnostic for any of our product candidates, whether before or after it obtains marketing approval, we, and/or future collaborators, may encounter difficulties in developing and obtaining approval for such product candidate. Any delay or failure by us or third-party collaborators to develop or obtain regulatory approval of a companion diagnostic could delay or prevent approval or continued marketing of such product candidate. We may also experience delays in developing a sustainable, reproducible and scalable manufacturing process for the companion diagnostic or in transferring that process to commercial partners or negotiating insurance reimbursement plans, all of which may prevent us from completing our clinical trials or commercializing our product candidates, if approved, on a timely or profitable basis, if at all.

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***We may seek orphan drug designation for our product candidates, but we may be unable to obtain such designation or to obtain or maintain the benefits associated with orphan drug designation, including market exclusivity, which may cause our product revenue, if any, to be reduced.***

We have obtained orphan drug designation in the United States for milademetan for the treatment of LPS and we may seek additional orphan drug designations for milademetan or our other product candidates; however, we may never receive such designations. See the section titled "Business—Government Regulation—Review and Approval of Drugs in the United States—Orphan Drug Designation" in this Annual Report on Form 10-K.

Exclusive marketing rights in the United States may be unavailable if we or our collaborators seek approval for an indication broader than the orphan designated indication and may be lost if the FDA later determines that the request for designation was materially defective. Even if we obtain orphan drug designation, we may not be the first to obtain marketing approval for any particular orphan indication due to the uncertainties associated with developing pharmaceutical products. Further, even if we obtain orphan drug exclusivity for a product candidate, that exclusivity may not effectively protect the product from competition because different drugs can be approved for the same condition. Even after an orphan drug is approved, the FDA can subsequently approve the same drug for the same condition if the FDA concludes that the later drug is clinically superior in that it is safer, is more effective, or makes a major contribution to patient care. Orphan drug designation neither shortens the development time or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process.

***Even if we receive regulatory approval of our product candidates, we will be subject to extensive ongoing regulatory obligations and continued regulatory review, which may result in significant additional expense and we may be subject to penalties if we fail to comply with regulatory requirements or experience unanticipated problems with our product candidates.***

Any regulatory approvals that we may receive for our product candidates will require the submission of reports to regulatory authorities and surveillance to monitor the safety and efficacy of the product candidate, may contain significant limitations related to use restrictions for specified age groups, warnings, precautions or contraindications, and may include burdensome post-approval study or risk management requirements. For example, the FDA may require a REMS in order to approve our product candidates, which could entail requirements for a medication guide, physician training and communication plans or additional elements to ensure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. In addition, if the FDA or comparable foreign regulatory authorities approve our product candidates, our product candidates and the activities associated with their development and commercialization, including their design, testing, manufacture, safety, efficacy, recordkeeping, labeling, storage, approval, advertising, promotion, sale, distribution, import and export will be subject to comprehensive regulation by the FDA and other regulatory agencies in the United States and by comparable foreign regulatory authorities. These requirements include submissions of safety and other post-marketing information and reports, registration, as well as on-going compliance with current good manufacturing practices (cGMPs) and GCPs for any clinical trials that we conduct following approval. In addition, manufacturers of drug products and their facilities are subject to continual review and periodic, unannounced inspections by the FDA and other regulatory authorities for compliance with cGMPs.

If we or a regulatory authority discover previously unknown problems with a product, such as adverse events of unanticipated severity or frequency, or problems with the facilities where the product is manufactured, a regulatory authority may impose restrictions on that product, the manufacturing facility or us, including requiring recall or withdrawal of the product from the market or suspension of manufacturing. restrictions on our ability to conduct clinical trials, including full or partial clinical holds on ongoing or planned trials, restrictions on the manufacturing process, warning or untitled letters, civil and criminal penalties, injunctions, product seizures, detentions or import bans, voluntary or mandatory publicity requirements and imposition of restrictions on operations, including costly new manufacturing requirements. The occurrence of any event or penalty described above may inhibit our ability to commercialize our product candidates and

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generate revenue and could require us to expend significant time and resources in response and could generate negative publicity.

***Even if we are able to commercialize any product candidates, due to unfavorable pricing regulations and/or third-party coverage and reimbursement policies, we may not be able to offer such products at competitive prices which would seriously harm our business.***

Our ability to successfully commercialize any products that we may develop also will depend in part on the extent to which reimbursement for these products and related treatments will be available from government health administration authorities, private health insurers and other organizations. Government authorities and other third-party payors, such as private health insurers and health maintenance organizations, decide which medications they will pay for and establish reimbursement levels. Government authorities and other third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. See the sections titled "Business—Government Regulation—Review and Approval of Drug Products in the European Union" "Business—Government Regulation—Review and Approval of Drug Products in the United States" and "Business—Government Regulation—U.S. Healthcare Reform" in this Annual Report on Form 10-K.

***The FDA and other regulatory agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses and any infraction could subject us to liability.***

If any of our product candidates are approved and we are found to have improperly promoted off-label uses of those products, we may become subject to significant liability. See the section titled "Business—Government Regulation—Review and Approval of Drugs in the United States—Post-approval Requirements" in this Annual Report on Form 10-K. If we do not appropriately manage the promotion of our product candidates, if approved, we could become subject to significant liability, which would materially adversely affect our business and financial condition.

***Our employees, independent contractors, consultants, commercial collaborators, principal investigators, CROs, suppliers and vendors may engage in misconduct or other improper activities, including noncompliance with regulatory standards and requirements.***

We are exposed to the risk that our employees, independent contractors, consultants, commercial collaborators, principal investigators, CROs, suppliers and vendors acting for or on our behalf may engage in misconduct or other improper activities. We have adopted a code of conduct, but it is not always possible to identify and deter misconduct by these parties and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to comply with these laws or regulations.

***Our business operations and current and future arrangements with investigators, healthcare professionals, consultants, third-party payors, patient organizations and customers will be subject to applicable healthcare regulatory laws, which could expose us to penalties.***

Our business operations and current and future arrangements with investigators, healthcare professionals, consultants, third-party payors, patient organizations and customers may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations. These laws may constrain the business or financial arrangements and relationships through which we conduct our operations, including how we research, market, sell and distribute our product candidates, if approved. See the section titled "Business—Government Regulation—Healthcare Laws and Regulations" in this Annual Report on Form 10-K for a more detailed description of the laws that may affect our ability to operate.

Ensuring that our internal operations and future business arrangements with third parties comply with applicable healthcare laws and regulations will involve substantial costs. If our operations, including certain

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arrangements we have with physicians who are compensated in the form of stock or stock options for services provided to us, are found to be in violation of any of these laws or any other governmental laws and regulations that may apply to us, we may be subject to significant penalties, including civil, criminal and administrative penalties, damages, fines, exclusion from government-funded healthcare programs, integrity oversight and reporting obligations to resolve allegations of non-compliance, disgorgement, individual imprisonment, contractual damages, reputational harm, diminished profits and the curtailment or restructuring of our operations. Further, defending against any such actions can be costly and time-consuming and may require significant personnel resources. Therefore, even if we are successful in defending against any such actions that may be brought against us, our business may be impaired.

***If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could have a material adverse effect on the success of our business.***

We are subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our operations may involve the use of hazardous and flammable materials, including chemicals and biological and radioactive materials. In addition, we may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or commercialization efforts. Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

***Current and future legislation may increase the difficulty and cost for us, and any collaborators, to obtain marketing approval of and commercialize our drug candidates and affect the prices we, or they, may obtain.***

Heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products has resulted in several recent Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for products. We expect that additional state and federal healthcare reform measures will be adopted in the future, particularly in light of the new presidential administration, any of which could limit the amounts that federal and state governments will pay for healthcare therapies, which could result in reduced demand for our product candidates or additional pricing pressures. Most recently, on August 16, 2022, President Biden signed into law the Inflation Reduction Act of 2022 (IRA), which, among other provisions, included several measures intended to lower the cost of prescription drugs and related healthcare reforms. We cannot be sure whether additional legislation or rulemaking related to the IRA will be issued or enacted, or what impact, if any, such changes will have on the profitability of any of our drug candidates, if approved for commercial use, in the future.

#### Risks Related to Employee Matters, Managing Our Growth and Other Risks Related to Our Business
***We are highly dependent on our key personnel and anticipate hiring new key personnel. If we are not successful in attracting and retaining highly qualified personnel, we may not be able to successfully implement our business strategy.***

Our ability to compete in the highly competitive biotechnology and pharmaceutical industries depends upon our ability to attract and retain highly qualified managerial, scientific and medical personnel. We are highly dependent on our managerial, scientific and medical personnel, including our Chief Executive Officer and our Chief Scientific Officer. If we do not succeed in attracting and retaining qualified personnel, it could materially adversely affect our business, financial condition and results of operations. We could in the future have difficulty attracting and retaining experienced personnel and may be required to expend significant financial resources in our employee recruitment and retention efforts.

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***In order to successfully implement our plans and strategies, we will need to grow the size of our organization and we may experience difficulties in managing this growth.***

We expect to experience significant growth in the number of our employees and the scope of our operations, particularly in the areas of drug development, clinical operations, regulatory affairs and, potentially, sales and marketing. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. We are dependent on our limited financial resources and the experience of our management team in managing a company with such anticipated growth, and we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel.

***Our internal computer systems, or those of any of our CROs, manufacturers, other contractors or consultants or potential future collaborators, may fail or suffer security or data privacy breaches or other unauthorized or improper access to, use of, or destruction of our proprietary or confidential data, employee data or personal data, which could result in additional costs, loss of revenue, significant liabilities, harm to our brand and material disruption of our operations.***

Despite the implementation of security measures in an effort to protect systems that store our information, given their size and complexity and the increasing amounts of information maintained on our internal information technology systems and those of our third-party CROs, other contractors (including sites performing our clinical trials) and consultants, these systems are potentially vulnerable to breakdown or other damage or interruption from service interruptions, system malfunction, natural disasters, terrorism, war and telecommunication and electrical failures, as well as security breaches from inadvertent or intentional actions by our employees, contractors, consultants, business partners and/or other third parties, or from cyber-attacks by malicious third parties, which may compromise our system infrastructure or lead to the loss, destruction, alteration or dissemination of, or damage to, our data. To the extent that any disruption or security breach were to result in a loss, destruction, unavailability, alteration or dissemination of, or damage to, our data or applications, or for it to be believed or reported that any of these occurred, we could incur liability and reputational damage and the development and commercialization of our product candidates could be delayed. Further, our insurance policies may not be adequate to compensate us for the potential losses arising from any such disruption in, or failure or security breach of, our systems or third-party systems where information important to our business operations or commercial development is stored.

#### Risks Related to Reliance on Third Parties
***We currently rely, and plan to rely in the future, on third parties to conduct and support our preclinical studies and clinical trials. If these third parties do not properly and successfully carry out their contractual duties or meet expected deadlines, we may not be able to obtain regulatory approval of or commercialize our product candidates.***

We have utilized and plan to continue to utilize and depend upon independent investigators and collaborators, such as medical institutions, CROs, CMOs and strategic partners, to conduct and support our preclinical studies and clinical trials under agreements with us. We will rely heavily on these third parties over the course of our preclinical studies and clinical trials, and we control only certain aspects of their activities. As a result, we will have less direct control over the conduct, timing and completion of these preclinical studies and clinical trials and the management of data developed through preclinical studies and clinical trials than would be the case if we were relying entirely upon our own staff. Nevertheless, we are responsible for ensuring that each of our studies and trials is conducted in accordance with the applicable protocol, legal, regulatory and scientific standards, and our reliance on these third parties does not relieve us of our regulatory responsibilities. We and our third-party contractors and CROs are required to comply with GCP regulations, which are regulations and guidelines enforced by the FDA and comparable foreign regulatory authorities for all of our products candidates in clinical development. If we or any of these third parties fail to comply with applicable GCP regulations, the clinical data generated in our clinical trials may be deemed

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unreliable and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical trials comply with GCP regulations. In addition, our clinical trials must be conducted with product produced under cGMP regulations. Our failure to comply with these regulations may require us to repeat clinical trials, which would delay the regulatory approval process. Moreover, our business may be implicated if any of these third parties violates federal or state fraud and abuse or false claims laws and regulations or healthcare privacy and security laws.

Any third parties conducting our clinical trials will not be our employees and, except for remedies available to us under our agreements with such third parties, we cannot control whether they devote sufficient time and resources to our product candidates. These third parties may also have relationships with other commercial entities, including our competitors, for whom they may also be conducting clinical trials or other product development activities, which could affect their performance on our behalf. If these third parties do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical protocols or regulatory requirements or for other reasons, our clinical trials may be extended, delayed or terminated and we may not be able to complete development of, obtain regulatory approval of or successfully commercialize our product candidates.

***We currently rely and expect to rely in the future on the use of manufacturing suites in third-party facilities or on third parties to manufacture our product candidates, and we may rely on third parties to produce and process our products, if approved. Our business could be adversely affected if we are unable to use third-party manufacturing suites or if the third-party manufacturers fail to provide us with sufficient quantities of our product candidates or fail to do so at acceptable quality levels or prices.***

We do not currently own any facility that may be used as our clinical-scale manufacturing and processing facility and must currently rely on CMOs to manufacture our product candidates. We have not yet caused our product candidates to be manufactured on a commercial scale and may not be able to do so for any of our product candidates, if approved. We received a batch of our product candidate that we believe is representative of our anticipated early commercial batch requirements. However, as a clinical-stage company with no prior history of product sales or commercialization of products, representative batches of our product candidate received to date may not represent what will be required to meet our future commercial requirements or be manufactured at scale. We may not control the manufacturing process of, and may be completely dependent on, our contract manufacturing partners for compliance with cGMP requirements and any other regulatory requirements of the FDA or other regulatory authorities for the manufacture of our product candidates. Beyond periodic audits, we have no control over the ability of our CMOs to maintain adequate quality control, quality assurance and qualified personnel. If the FDA or a comparable foreign regulatory authority does not approve these facilities for the manufacture of our product candidates or if it withdraws any approval in the future, we may need to find alternative manufacturing facilities, which would require the incurrence of significant additional costs and materially adversely affect our ability to develop, obtain regulatory approval for or market our product candidates, if approved. Similarly, our failure, or the failure of our CMOs, to comply with applicable regulations could result in sanctions being imposed on us, including fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of product candidates or drugs, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect supplies of our product candidates or drugs and harm our business and results of operations.

Moreover, if any CMOs on which we will rely fail to manufacture quantities of our product candidates at quality levels necessary to meet regulatory requirements and at a scale sufficient to meet anticipated demand at a cost that allows us to achieve profitability, our business, financial condition and prospects could be materially and adversely affected. Our business could be materially adversely affected by business disruptions to our third-party providers that could materially adversely affect our potential future revenue and

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financial condition and increase our costs and expenses. Each of these risks could delay or prevent the completion of our clinical trials or the approval of any of our product candidates by the FDA, result in higher costs or adversely impact commercialization of our product candidates.

***We may, in the future, form or seek collaborations or strategic alliances or enter into licensing arrangements, and we may not realize the benefits of such collaborations, alliances or licensing arrangements.***

We may, in the future, form or seek strategic alliances, create joint ventures or collaborations, or enter into licensing arrangements with third parties that we believe will complement or augment our development and commercialization efforts with respect to our product candidates and any future product candidates that we may develop. Any of these relationships may require us to increase our near and long-term expenditures, issue securities that dilute our existing stockholders or disrupt our management and business.

#### Risks Related to Our Intellectual Property

#### Our ability to protect our patents and other proprietary rights is uncertain, exposing us to the possible loss of competitive advantage.
We rely upon a combination of patents, trademarks, trade secret protection and confidentiality agreements to protect the intellectual property related to our products and technologies and to prevent third parties from copying and surpassing our achievements, thus eroding our competitive position in our market. Our success depends in large part on our ability to obtain and maintain patent protection for our platform technologies, product candidates and their uses, as well as our ability to operate without infringing on or violating the proprietary rights of others. We own and have licensed rights to pending patent applications and expect to continue to file patent applications in the United States and abroad related to our novel discoveries and technologies that are important to our business. However, we may not be able to protect our intellectual property rights throughout the world and the legal systems in certain countries may not favor enforcement or protection of patents, trade secrets and other intellectual property. Filing, prosecuting and defending patents on product candidates worldwide would be prohibitively expensive and our intellectual property rights in some foreign jurisdictions can be less extensive than those in the United States. As such, we do not have patents in all countries or all major markets and may not be able to obtain patents in all jurisdictions even if we apply for them. Our competitors may operate in countries where we do not have patent protection and can freely use our technologies and discoveries in such countries to the extent such technologies and discoveries are publicly known or disclosed in countries where we do have patent protection or pending patent applications. Our pending and future patent applications may not result in patents being issued. Any issued patents may not afford sufficient protection of our product candidates or their intended uses against competitors, nor can there be any assurance that the patents issued will not be infringed, designed around, invalidated by third parties, or effectively prevent others from commercializing competitive technologies, products or product candidates. Further, even if these patents are granted, they may be difficult to enforce. Obtaining and maintaining our patent protection depends on compliance with various procedural, document submission, fee payment and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated if we fail to comply with these requirements. Further, any issued patents that we may license or own covering our product candidates could be narrowed or found invalid or unenforceable if challenged in court or before administrative bodies in the United States or abroad, including the United States Patent and Trademark Office (USPTO). Also, patent terms, including any extensions or adjustments that may or may not be available to us, may be inadequate to protect our competitive position on our product candidates for an adequate amount of time, and we may be subject to claims challenging the inventorship, validity, enforceability of our patents and/or other intellectual property. Finally, changes in U.S. patent law, or laws in other countries, could diminish the value of patents in general, thereby impairing our ability to protect our product candidates. Further, if we encounter delays in our clinical trials or delays in obtaining regulatory approval, the period of time during which we could market our product candidates under patent protection

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would be reduced. Thus, the patents that we own, and license may not afford us any meaningful competitive advantage.

Moreover, we or our licensors may be subject to a third-party preissuance submission of prior art to the USPTO or become involved in opposition, derivation, revocation, reexamination, *inter partes* review, post-grant review or interference proceedings challenging our patent rights or the patent rights of others. An adverse determination in any such submission, proceeding or litigation could reduce the scope of, or invalidate, our patent rights, allow third parties to commercialize our technology or product candidates and compete directly with us, without payment to us, or result in our inability to manufacture or commercialize drugs without infringing third-party patent rights. If the breadth or strength of protection provided by our patents and patent applications is threatened, regardless of the outcome, it could dissuade companies from collaborating with us to license, develop or commercialize current or future product candidates. In addition to seeking patents for some of our technology and product candidates, we may also rely on trade secrets, including unpatented know-how, technology and other proprietary information, to maintain our competitive position. Any disclosure, either intentional or unintentional, by our employees, the employees of third parties with whom we share our facilities or third-party consultants and vendors that we engage to perform research, clinical trials or manufacturing activities, or misappropriation by third parties (such as through a cybersecurity breach) of our trade secrets or proprietary information could enable competitors to duplicate or surpass our technological achievements, thus eroding our competitive position in our market. In order to protect our proprietary technology and processes, we rely in part on confidentiality agreements with our collaborators, employees, consultants, outside scientific collaborators and sponsored researchers and other advisors. These agreements may not effectively prevent disclosure of confidential information and may not provide an adequate remedy in the event of unauthorized disclosure of confidential information. We may need to share our proprietary information, including trade secrets, with future business partners, collaborators, contractors and others located in countries at heightened risk of theft of trade secrets, including through direct intrusion by private parties or foreign actors and those affiliated with or controlled by state actors. In addition, while we undertake efforts to protect our trade secrets and other confidential information from disclosure, others may independently discover trade secrets and proprietary information, and in such cases, we may not be able to assert any trade secret rights against such party. Costly and time-consuming litigation could be necessary to enforce and determine the scope of our proprietary rights and failure to obtain or maintain trade secret protection could adversely affect our competitive business position.

As is common in the biotechnology and pharmaceutical industries, we employ individuals and engage the services of consultants who previously worked for other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Although no claims against us are currently pending, we may be subject to claims that these employees or we have inadvertently or otherwise used or disclosed trade secrets or other proprietary information of their former employers, or that our consultants have used or disclosed trade secrets or other proprietary information of their former or current clients. Litigation may be necessary to defend against these claims. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Even if we are successful in defending against such claims, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses, and could distract our technical and management personnel from their normal responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments, and, if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. This type of litigation or proceeding could substantially increase our operating losses and reduce our resources available for development activities. We may not have sufficient financial or other resources to adequately conduct such litigation or proceedings. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their substantially greater financial resources. Uncertainties resulting from the initiation and continuation of patent litigation or other intellectual property related proceedings could adversely affect our ability to compete in the marketplace.

Lastly, if our trademarks and trade names are not registered or adequately protected, then we may not be able to build name recognition in our markets of interest and our business may be adversely affected.

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#### Patent terms may be inadequate to protect our competitive position on our product candidates for an adequate amount of time.
Patents have a limited lifespan. In the United States, if all maintenance fees are timely paid, the natural expiration of a patent is generally 20 years from its earliest U.S. non-provisional filing date. Various extensions may be available, but the life of a patent, and the protection it affords, is limited. Even if patents covering our product candidates are obtained, once the patent life has expired, we may be open to competition from competitive products, including generics or biosimilars. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to ours.

***If we do not obtain patent term extension in the United States under the Hatch-Waxman Act and in foreign countries under similar legislation, thereby potentially extending the term of our marketing exclusivity for any product candidates we may develop, our business may be materially harmed.***

In the United States, the patent term of a patent that covers an FDA-approved drug may be eligible for limited patent term extension, which permits patent term restoration as compensation for the patent term lost during the FDA regulatory review process. The Drug Price Competition and Patent Term Restoration Act of 1984, also known as the Hatch-Waxman Act, permits a patent term extension of up to five years beyond the expiration of the patent. The length of the patent term extension is related to the length of time the drug is under regulatory review. Patent extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval, and only one patent applicable to an approved drug may be extended and only those claims covering the approved drug, a method for using it, or a method for manufacturing it may be extended. Similar provisions are available in Europe and certain other non-United States jurisdictions to extend the term of a patent that covers an approved drug. While, in the future, if and when our product candidates receive FDA approval, we expect to apply for patent term extensions on patents covering those product candidates, there is no guarantee that the applicable authorities will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions. We may not be granted patent term extension either in the United States or in any foreign country because of, for example, failing to exercise due diligence during the testing phase or regulatory review process, failing to apply within applicable deadlines, failing to apply prior to expiration of relevant patents or otherwise failing to satisfy applicable requirements. Moreover, the term of extension, as well as the scope of patent protection during any such extension, afforded by the governmental authority could be less than we request. If we are unable to obtain any patent term extension or the term of any such extension is less than we request, our competitors may obtain approval of competing products following the expiration of our patent rights, and our business, financial condition, results of operations and prospects could be materially harmed.

It is possible that we will not obtain patent term extension under the Hatch-Waxman Act for a U.S. patent covering any of our product candidates that we may identify even where that patent is eligible for patent term extension, or if we obtain such an extension, it may be for a shorter period than we had sought. Further, for our licensed patents, we may not have the right to control prosecution, including filing with the USPTO, a petition for patent term extension under the Hatch-Waxman Act. Thus, if one of our licensed patents is eligible for patent term extension under the Hatch-Waxman Act, we may not be able to control whether a petition to obtain a patent term extension is filed, or obtained, from the USPTO.

Also, there are detailed rules and requirements regarding the patents that may be submitted to the FDA for listing in the Approved Drug Products with Therapeutic Equivalence Evaluations (the Orange Book). We may be unable to obtain patents covering our product candidates that contain one or more claims that satisfy the requirements for listing in the Orange Book. Even if we submit a patent for listing in the Orange Book, the FDA may decline to list the patent, or a manufacturer of generic drugs may challenge the listing. If one of our product candidates is approved and a patent covering that product candidate is not listed in the Orange Book, a manufacturer of generic drugs would not have to provide advance notice to us of any

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abbreviated new drug application filed with the FDA to obtain permission to sell a generic version of such product candidate.

***Changes to patent laws in the United States and other jurisdictions could diminish the value of patents in general, thereby impairing our ability to protect our products.***

Changes in either the patent laws or interpretation of patent laws in the United States, including patent reform legislation such as the Leahy-Smith America Invents Act (the Leahy-Smith Act) could increase the uncertainties and costs surrounding the prosecution of our owned and in-licensed patent applications and the maintenance, enforcement or defense of our owned and in-licensed issued patents. The Leahy-Smith Act includes a number of significant changes to United States patent law. These changes include provisions that affect the way patent applications are prosecuted, redefine prior art, provide more efficient and cost-effective avenues for competitors to challenge the validity of patents, and enable third-party submission of prior art to the USPTO during patent prosecution and additional procedures to attack the validity of a patent at USPTO-administered post-grant proceedings, including post-grant review, *inter partes* review, and derivation proceedings. Assuming that other requirements for patentability are met, prior to March 2013, in the United States, the first to invent the claimed invention was entitled to the patent, while outside the United States, the first to file a patent application was entitled to the patent. After March 2013, under the Leahy-Smith Act, the United States transitioned to a first-to-file system in which, assuming that the other statutory requirements for patentability are met, the first inventor to file a patent application will be entitled to the patent on an invention regardless of whether a third party was the first to invent the claimed invention. As such, the Leahy-Smith Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents, all of which could have a material adverse effect on our business, financial condition, results of operations and prospects.

In addition, the patent positions of companies in the development and commercialization of biologics and pharmaceuticals are particularly uncertain. Recent U.S. Supreme Court rulings have narrowed the scope of patent protection available in certain circumstances and weakened the rights of patent owners in certain situations. This combination of events has created uncertainty with respect to the validity and enforceability of patents once obtained. Depending on future actions by the U.S. Congress, the federal courts and the USPTO, the laws and regulations governing patents could change in unpredictable ways that could have a material adverse effect on our patent rights and our ability to protect, defend and enforce our patent rights in the future.

***We may not identify relevant third-party patents or may incorrectly interpret the relevance, scope or expiration of a third-party patent, which might adversely affect our ability to develop and market our products.***

We cannot guarantee that any of our patent searches or analyses, including the identification of relevant patents, the scope of patent claims or the expiration of relevant patents, are complete or thorough, nor can we be certain that we have identified each and every third-party patent and pending application in the United States and abroad that is relevant to or necessary for the commercialization of our product candidates in any jurisdiction. The scope of a patent claim is determined by an interpretation of the law, the written disclosure in a patent and the patent's prosecution history. Our interpretation of the relevance or the scope of a patent or a pending application may be incorrect. For example, we may incorrectly determine that our products are not covered by a third-party patent or may incorrectly predict whether a third-party's pending application will issue with claims of relevant scope. Our determination of the expiration date of any patent in the United States or abroad that we consider relevant may be incorrect. Our failure to identify and correctly interpret relevant patents may negatively impact our ability to develop and market our products.

In addition, because some patent applications in the United States may be maintained in secrecy until the patents are issued, patent applications in the United States and many foreign jurisdictions are typically not published until 18 months after filing, and publications in the scientific literature often lag behind actual discoveries, we cannot be certain that others have not filed patent applications for technology covered by our

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issued patents or our pending applications, or that we were the first to invent the technology. Our competitors may have filed, and may in the future file, patent applications covering our products or technology similar to ours. Any such patent application may have priority over our patent applications or patents, which could require us to obtain rights to issued patents covering such technologies.

#### We may be subject to claims challenging the inventorship of our patents and other intellectual property.
We may be subject to claims that former employees, collaborators or other third parties have an interest in our patents or other intellectual property as an inventor or co-inventor. The failure to name the proper inventors on a patent application can result in the patents issuing thereon being unenforceable. Inventorship disputes may arise from conflicting views regarding the contributions of different individuals named as inventors, the effects of foreign laws where foreign nationals are involved in the development of the subject matter of the patent, conflicting obligations of third parties involved in developing our product candidates or as a result of questions regarding co-ownership of potential joint inventions. Litigation may be necessary to resolve these and other claims challenging inventorship and/or ownership. Alternatively, or additionally, we may enter into agreements to clarify the scope of our rights in such intellectual property. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights, such as exclusive ownership of, or right to use, valuable intellectual property. Such an outcome could have a material adverse effect on our business. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management and other employees.

***We may be subject to patent infringement claims or may need to file claims to protect our intellectual property, which could result in substantial costs and liability and prevent us from commercializing our potential products.***

Because the intellectual property landscape in the biotechnology industry is rapidly evolving and interdisciplinary, it is difficult to conclusively assess our freedom to operate without infringing on or violating third party rights. However, if certain of our product candidates are ultimately granted regulatory approval, we are currently aware of certain patent rights held by third parties that, if found to be valid and enforceable, could be alleged to render one or more of our product candidates infringing. If a third party successfully brings a claim against us, we may be required to pay substantial damages, be forced to abandon any affected product and/or seek a license from the patent holder. In addition, any intellectual property claims (e.g., patent infringement or trade secret theft) brought against us, whether or not successful, may cause us to incur significant legal expenses and divert the attention of our management and key personnel from other business concerns. We cannot be certain that patents owned or licensed by us will not be challenged by others in the course of litigation. Some of our competitors may be able to sustain the costs of complex intellectual property litigation more effectively than we can because they have substantially greater resources. In addition, any uncertainties resulting from the initiation and continuation of any litigation could have a material adverse effect on our ability to raise funds and on the market price of our common stock.

Competitors may infringe or otherwise violate our patents, trademarks, copyrights or other intellectual property. To counter infringement or other violations, we may be required to file claims, which can be expensive and time-consuming. Any such claims could provoke these parties to assert counterclaims against us, including claims alleging that we infringe their patents or other intellectual property rights. In addition, in a patent infringement proceeding, a court or administrative body may decide that one or more of the patents we assert is invalid or unenforceable, in whole or in part, construe the patent's claims narrowly or refuse to prevent the other party from using the technology at issue on the grounds that our patents do not cover the technology. Similarly, if we assert trademark infringement claims, a court or administrative body may determine that the marks we have asserted are invalid or unenforceable or that the party against whom we have asserted trademark infringement has superior rights to the marks in question. In such a case, we could ultimately be forced to cease use of such marks. In any intellectual property litigation, even if we are successful, any award of monetary damages or other remedy we receive may not be commercially valuable.

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Further, we may be required to protect our patents through procedures created to attack the validity of a patent at the USPTO. An adverse determination in any such submission or proceeding could reduce the scope or enforceability of, or invalidate, our patent rights, which could adversely affect our competitive position. Because of a lower evidentiary standard in USPTO proceedings compared to the evidentiary standard in United States federal courts necessary to invalidate a patent claim, a third party could potentially provide evidence in a USPTO proceeding sufficient for the USPTO to hold a claim invalid even though the same evidence would be insufficient to invalidate the claim if first presented in a district court action.

In addition, if our product candidates are found to infringe the intellectual property rights of third parties, these third parties may assert infringement claims against our future licensees and other parties with whom we have business relationships and we may be required to indemnify those parties for any damages they suffer as a result of these claims, which may require us to initiate or defend protracted and costly litigation on behalf of licensees and other parties regardless of the merits of such claims. If any of these claims succeed, we may be forced to pay damages on behalf of those parties or may be required to obtain licenses for the products they use.

Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation or other legal proceedings relating to our intellectual property rights, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation or other proceedings.

#### We license patent rights from third-party owners, and we rely on such owners to obtain, maintain and enforce the patents underlying such licenses.
We are a party to certain licenses, including with our licensor Daiichi Sankyo, that provide us rights to intellectual property that are necessary or useful for our product candidate, milademetan, and its components, formulations, methods of manufacturing and methods of treatment. The license agreement requires us to satisfy certain obligations and, if these agreements are terminated (e.g., as a result of our failure to satisfy such obligations), our technology and our business could be adversely affected. We also expect to enter into additional licenses to third-party intellectual property in the future; however, we may not be able to obtain such licenses on economically feasible terms or other reasonable terms and conditions, or at all.

Our licensors may not successfully prosecute the patent applications that we are licensed. Even if patents are issued in respect of these patent applications, our licensors may fail to maintain these patents, may determine not to pursue litigation against other companies that are infringing these patents, or may pursue such litigation less aggressively than we would. Without protection for the intellectual property we license, other companies might be able to offer substantially identical products for sale, which could adversely affect our competitive business position and harm our business prospects.

Additionally, we may sometimes collaborate with academic institutions to accelerate our preclinical research or development under written agreements with these institutions. These institutions may provide us with an option to negotiate a license to any of the institution's rights in technology resulting from the collaboration. Regardless of such option, we may be unable to negotiate a license within the specified timeframe or under terms that are acceptable to us. If we are unable to do so, the institution may offer the intellectual property rights to others, potentially blocking our ability to pursue our program.

We have limited, if any, control over the amount or timing of resources that our licensors devote on our behalf or the priority they place on maintaining these patent rights and prosecuting these patent applications to our advantage. For example, should Daiichi Sankyo decide it no longer wants to maintain any of the patents licensed to us, Daiichi Sankyo is required to afford us the opportunity to do so at our expense. However, we cannot be sure that Daiichi Sankyo will perform as required. If Daiichi Sankyo does not perform, and if we do not assume the maintenance of the licensed patents in sufficient time to make required payments or filings with the appropriate governmental agencies, we risk losing the benefit of all or some of those patent rights. In the event our licensors fail to adequately pursue and maintain patent protection for

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patents and applications they control, and to timely cede control of such prosecution to us, our competitors might be able to enter the market, which would have a material adverse effect on our business.

#### Our technology licensed from various third parties may be subject to retained rights.
Our licensors often retain certain rights under their agreements with us, including the right to use the underlying technology for noncommercial academic and research use, to publish general scientific findings from research related to the technology, and to make customary scientific and scholarly disclosures of information relating to the technology. It is difficult to monitor whether our licensors limit their use of the technology to these uses, and we could incur substantial expenses to enforce our rights to our licensed technology in the event of misuse. Further, the U.S. government may retain certain rights under the Bayh-Dole Act for research funded by the Federal Government.

We may not be able to effectively secure first-tier technologies when competing against other companies or investors.

Our future success may require that we acquire patent rights and know-how to new or complimentary technologies. However, we compete with a substantial number of other companies that may also compete for technologies we desire. In addition, many venture capital firms and other institutional investors, as well as other biotechnology companies, invest in companies seeking to commercialize various types of emerging technologies. Many of these companies have greater financial, scientific and commercial resources than us. Therefore, we may not be able to secure the technologies we desire. Furthermore, should any commercial undertaking by us prove to be successful, there can be no assurance competitors with greater financial resources will not offer competitive products and/or technologies.

#### Risks Related to Our Common Stock

#### The price of our stock may be volatile, and you could lose all or part of your investment.
The trading price of our common stock is likely to be highly volatile and could be subject to wide fluctuations in response to various factors, some of which are beyond our control, including the factors discussed in this "Risk Factors" section and elsewhere in this Annual Report on Form 10-K. The realization of any of these factors could have a dramatic and adverse impact on the market price of our common stock.

In addition, the stock market in general, and the market for biotechnology companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. In particular, the trading prices for biotechnology companies have been highly volatile. In addition, broad market and industry factors may negatively affect the market price of our common stock, regardless of our actual operating performance. In the past, securities class action litigation has often been instituted against companies following periods of volatility in the market price of a company's securities. This type of litigation, if instituted, could result in substantial costs and a diversion of management's attention and resources, which would materially adversely affect our business, financial condition and results of operation.

***Our principal stockholders and management own a significant percentage of our stock and will be able to exert significant influence over matters subject to stockholder approval.***

As of December 31, 2022, our executive officers, directors, holders of 5% or more of our capital stock and their respective affiliates beneficially owned a significant portion of our outstanding voting common stock. These stockholders, acting together, may be able to impact matters requiring stockholder approval. For example, they may be able to impact elections of directors, amendments of our organizational documents or approval of any merger, sale of assets or other major corporate transaction. This may prevent or discourage unsolicited acquisition proposals or offers for our common stock that you may feel are in your best interest as one of our stockholders. The interests of this group of stockholders may not always coincide with your

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interests or the interests of other stockholders and they may act in a manner that advances their best interests and not necessarily those of other stockholders, including seeking a premium value for their common stock, and might affect the prevailing market price for our common stock.

#### A sale of a substantial number of shares of our common stock may cause the price of our common stock to decline.
We cannot predict what effect, if any, sales of our shares in the public market or the availability of shares for sale will have on the market price of our common stock. However, future sales of substantial amounts of our common stock in the public market, including shares sold through our ATM Facility or shares issued upon exercise of outstanding options, or the perception that such sales may occur, could adversely affect the market price of our common stock. We also expect that significant additional capital may be needed in the future to continue our planned operations. To raise capital, we may sell common stock, convertible securities, or other equity securities in one or more transactions at prices and in a manner we determine from time to time. These sales, or the perception in the market that the holders of a large number of shares intend to sell shares, could reduce the market price of our common stock.

#### General Risk Factors
***Our business could be adversely affected by economic downturns, inflation, increases in interest rates, natural disasters, public health crises such as the COVID-19 pandemic, political crises, geopolitical events, such as the crisis in Ukraine, or other macroeconomic conditions, which could have a material and adverse effect on our results of operations and financial condition.***

The global economy, including credit and financial markets, has experienced extreme volatility and disruptions, including, among other things, diminished liquidity and credit availability, declines in consumer confidence, declines in economic growth, supply chain shortages, increases in inflation rates, higher interest rates, and uncertainty about economic stability. For example, the COVID-19 pandemic resulted in widespread unemployment, economic slowdown and extreme volatility in the capital markets. The Federal Reserve has raised interest rates multiple times in response to concerns about inflation and it may raise them again. Higher interest rates, coupled with reduced government spending and volatility in financial markets, may increase economic uncertainty and affect consumer spending. Similarly, the ongoing military conflict between Russia and Ukraine has created extreme volatility in the global capital markets and may have further global economic consequences, including disruptions of the global supply chain. Any such volatility and disruptions may adversely affect our business or the third parties on whom we rely. If the equity and credit markets deteriorate, including as a result of political unrest or war, it may make any necessary debt or equity financing more costly, more dilutive, or more difficult to obtain in a timely manner or on favorable terms, if at all. Increased inflation rates can adversely affect us by increasing our costs, including labor and employee benefit costs.

We have experienced and may in the future experience disruptions as a result of such macroeconomic conditions, including delays or difficulties in initiating or expanding clinical trials and manufacturing sufficient quantities of materials. Any one or a combination of these events could have a material and adverse effect on our results of operations and financial condition.

***Provisions in our amended and restated certificate of incorporation and amended and restated bylaws and Delaware law might discourage, delay or prevent a change in control of our company or changes in our management and, therefore, depress the market price of our common stock.***

Our amended and restated certificate of incorporation and amended and restated bylaws contain provisions that could delay or prevent a change of control of our company or changes in our board of directors that our stockholders might consider favorable. In addition, Section 203 of the General Corporation Law of the State of Delaware (DGCL) prohibits a publicly held Delaware corporation from engaging in a business combination with an interested stockholder for a period of three years after the date of the

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transaction in which the person became an interested stockholder, unless the business combination is approved in a prescribed manner. Any provision of our amended and restated certificate of incorporation, amended and restated bylaws or Delaware law that has the effect of delaying or preventing a change in control could limit the opportunity for our stockholders to receive a premium for their shares of our capital stock and could also affect the price that some investors are willing to pay for our common stock.

***Our amended and restated certificate of incorporation provides that the Court of Chancery of the State of Delaware and the federal district courts of the United States will be the exclusive forums for substantially all disputes between us and our stockholders, which could limit our stockholders' ability to obtain a favorable judicial forum for disputes.***

***The dual class structure of our common stock may limit your ability to influence corporate matters and may limit your visibility with respect to certain transactions.***

The dual class structure of our common stock may limit your ability to influence corporate matters. Holders of our common stock are entitled to one vote per share, while holders of our non-voting common stock are not entitled to any votes. Nonetheless, each share of our non-voting common stock may be converted at any time into one share of our common stock at the option of its holder by providing written notice to us, subject to the limitations provided for in our amended and restated certificate of incorporation. Consequently, if holders of our non-voting common stock exercise their option to make this conversion, this will have the effect of increasing the relative voting power of those prior holders of our non-voting common stock, and correspondingly decreasing the voting power of the holders of our common stock, which may limit your ability to influence corporate matters. Additionally, stockholders who hold, in the aggregate, more than 10% of our common stock and non-voting common stock, but 10% or less of our common stock, and are not otherwise an insider, may not be required to report changes in their ownership due to transactions in our non-voting common stock pursuant to Section 16(a) of the Exchange Act, and may not be subject to the short-swing profit provisions of Section 16(b) of the Exchange Act.

#### Item 1B. UNRESOLVED STAFF COMMENTS.
None.

#### Item 2. PROPERTIES.
Our corporate headquarters are located in Newark, California where we occupy approximately 3,900 square feet of office space under a lease that expires on September 30, 2024. In October 2022, we amended the lease agreement to expand the leased premises by approximately 3,880 square feet. We use this facility for administrative purposes. We believe that our facility is sufficient to meet our current needs. We also believe we will be able to obtain additional space, as needed, on commercially reasonable terms.

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#### Item 3. LEGAL PROCEEDINGS.
We are currently not a party to any material legal proceedings. From time to time, we may become involved in legal proceedings arising in the ordinary course of our business. Regardless of outcome, litigation can have an adverse impact on us due to defense and settlement costs, diversion of management resources, negative publicity, reputational harm and other factors, and there can be no assurances that favorable outcomes will be obtained.

#### Item 4. MINE SAFETY DISCLOSURES.
Not applicable.

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#### PART II

#### Item 5. MARKET FOR REGISTRANT'S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES.

#### Market Information
Our common stock is traded on The Nasdaq Global Select Market under the symbol "RAIN."

#### Holders
As of February 28, 2023, we had 27 holders of record of our common stock. Since many of our shares of common stock are held by brokers and other institutions on behalf of stockholders, we are unable to estimate the total number of stockholders represented by these record holders.

#### Dividend Policy
We have never declared or paid dividends on our capital stock. We currently intend to retain any future earnings and do not anticipate paying dividends in the foreseeable future. Any future determination to pay dividends will be at the discretion of our Board of Directors and will be dependent on a number of factors, including our financial condition, results of operations, capital requirements, contractual restrictions, general business conditions, and any other factors that our board may deem relevant.

#### Use of Proceeds from our Initial Public Offering
On April 27, 2021, we completed our IPO, in which we issued and sold 7,352,941 shares of our common stock, $0.001 par value per share, at the public offering price of $17.00 per share. On May 7, 2021, the underwriters exercised their option to purchase 492,070 additional shares of our common stock at the public offering price (the Overallotment) and the Overallotment closed on May 11, 2021.

The offer and sale of all of the shares of our common stock in the IPO were registered under the Securities Act pursuant to our Registration Statement on Form S-1, as amended (File No. 333-254998), which was declared effective on April 22, 2021. Goldman Sachs & Co. LLC, Citigroup, Global Markets, Inc., Piper, Sandler & Co., and Guggenheim Securities LLC acted as joint book-running managers for the IPO.

We received net proceeds from our IPO of approximately $121.5 million, after deducting underwriting discounts and commissions, and other offering fees, inclusive of the Overallotment. None of the underwriting discounts and commissions or other offering expenses were incurred or paid, directly or indirectly, to any of our directors or officers or their associates or to persons owning 10% or more of our common stock or to any of our affiliates.

The net proceeds from the IPO (including the Overallotment) have been used and will be used, to fund a pivotal Phase 3 trial in LPS, a Phase 2 tumor-agnostic basket trial in certain solid tumors and Phase 1/2 basket trial in patients with loss of CDKN2A and wildtype p53 advanced solid tumors, in each case, for our lead product candidate, milademetan, to fund the purchase of raw materials and drug substance and drug product manufacturing for our milademetan program and to fund various clinical pharmacology, biomarker and translational studies for our milademetan program, and for working capital, including continuing to advance our pipeline through preclinical studies and clinical trials, and general corporate purposes. This use of proceeds represents a change from our intended use of proceeds from our IPO as described in the prospectus filed with the SEC pursuant to Rule 424(b)(4) on April 23, 2021, as we are now focusing on our development efforts on our Phase 3 registrational trial for the treatment of DD LPS, our Phase 2 trial for the treatment of MDM2-amplified advanced solid tumors and our Phase 1/2 basket trial in patients with loss of CDKN2A and wildtype p53 advanced solid tumors.

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#### Item 6. Reserved.

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#### Item 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS.
You should read the following discussion and analysis of our financial condition and results of operations together with our audited consolidated financial statements and the related notes and other financial information included elsewhere in this Annual Report on Form 10-K. This discussion and analysis contain forward-looking statements based upon our current plans and expectations that involve risks, uncertainties and assumptions, such as statements regarding our plans, objectives, expectations, intentions and beliefs. Our actual results and the timing of events could differ materially from those anticipated in these forward-looking statements as a result of various factors, including those set forth under the section titled "Risk Factors" and included elsewhere in this Annual Report on Form 10-K. You should carefully read the sections titled "Note Regarding Forward-Looking Statements" and "Risk Factors" to gain an understanding of the important factors that could cause actual results to differ materially from the results described below.

#### Overview
We are a late-stage precision oncology company developing therapies that target oncogenic drivers to genetically select patients we believe will most likely benefit. This approach includes using a tumor-agnostic strategy to select patients based on their tumors' underlying genetics rather than histology. We have in-licensed product candidates, each with a differentiated profile relative to available therapies, and we intend to continue strengthening our pipeline through focused business development and internal research efforts.

Our lead product candidate, milademetan (also known as RAIN-32) is an oral, small molecule inhibitor of the mouse double minute 2 (MDM2-p53) complex that reactivates p53. We in-licensed milademetan from Daiichi Sankyo Company, Limited (Daiichi Sankyo) in September 2020 based on the results of a Phase 1 clinical trial, which demonstrated meaningful antitumor activity in an MDM2-amplified subtype of liposarcoma (LPS) and other solid tumors. Data from de-differentiated liposarcoma (DDLPS) patients in the Phase 1 clinical trial of milademetan demonstrated median progression-free survival (mPFS) of approximately seven to eight months. Importantly, this result was accomplished with a rationally designed dosing schedule designed to mitigate safety concerns and widen the therapeutic window of MDM2 inhibition unlocking the potential for milademetan in a broad range of MDM2-dependent cancers. Based on these data, we commenced a pivotal Phase 3 trial in LPS (MANTRA) in July 2021. We expect to report topline data from our MANTRA trial in the second quarter of 2023. We also commenced a Phase 2 tumor-agnostic basket trial in certain solid tumors (MANTRA-2) in November 2021. We anticipate commencing a Phase 1/2 basket trial to evaluate the safety, tolerability and efficacy of milademetan in combination with atezolizumab in patients with loss of cyclin-dependent kinase inhibitor 2A (CDKN2A) and wildtype p53 advanced solid tumors (MANTRA-4) in mid-2023.

Since our inception in 2017, we have incurred significant operating losses and have utilized substantially all of our resources to date in-licensing and developing our product candidates, organizing and staffing our company and providing other general and administrative support for our operations. As of December 31, 2022, we had an accumulated deficit of $165.7 million and we incurred net losses of approximately $75.7 million and $51.4 million for the years ended December 31, 2022 and 2021, respectively. Our operations to date have been funded primarily through the issuance of convertible promissory notes, the issuance of convertible preferred stock, as well as issuance and sale of common stock through our initial public offering (IPO) and our November 2022 Offering. From our inception through December 31, 2022, we have raised aggregate gross proceeds of $9.9 million from the issuance of convertible promissory notes and $81.9 million from the issuance of convertible preferred stock. On April 27, 2021, we completed our IPO in which we issued and sold 7,352,941 shares of common stock at a public offering price of $17.00 per share. On May 11, 2021, we issued an additional 492,070 shares of common stock in connection with the exercise of the underwriters' option to purchase additional shares at the public offering price. Our net proceeds from the sale of shares in the IPO, including the sale of shares pursuant to the exercise of the underwriters' option to purchase additional shares, was $121.5 million, net of underwriting discounts and commissions, and other

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offering fees. In November 2022, we completed a registered direct offering of an aggregate of 8,576,330 shares of common stock and non-voting common stock at $5.83 per share. In addition, we issued an additional 1,140,068 shares of common stock in connection with the exercise of the underwriters' option to purchase additional shares at the offering price. We received net proceeds from our November 2022 Offering of approximately $52.9 million, after deducting underwriting discounts and commissions, and other offering fees. As of December 31, 2022, we had cash, cash equivalents and short-term investments of $130.5 million. Although we believe, based on our current business plans, that our existing cash, cash equivalents and short-term investments, together with proceeds available under our ATM Facility, will be sufficient to meet our obligations for at least the next twelve months, we anticipate that we will require additional capital in the future in order to continue the research and development of our drug candidates. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our product candidates. We expect to continue to incur significant expenses and increasing operating losses for at least the next several years as we continue our development of, and seek regulatory approvals for, our product candidates and begin to commercialize any approved products, seek to expand our product pipeline, invest in our organization, as well as incur expenses associated with operating as a public company.

We do not expect to generate any revenue from product sales unless and until we successfully complete development and obtain regulatory approval for one or more product candidates, which will not be for many years, if ever. Accordingly, until such time as we can generate significant revenue from sales of our product candidates, if ever, we expect to finance our cash needs through public or private equity offerings, debt financings or other capital sources which may include strategic collaborations, licensing arrangements or other arrangements with third parties. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on favorable terms or at all. If we raise funds through strategic collaborations or other similar arrangements with third parties, we may have to relinquish valuable rights to our platform technology, future revenue streams, research programs or product candidates or we may have to grant licenses on terms that may not be favorable to us and/or may reduce the value of our common stock. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts. Our ability to raise additional funds may be adversely impacted by potential worsening global macroeconomic conditions and the disruptions to and volatility in the credit and financial markets in the United States and worldwide. Because of the numerous risks and uncertainties associated with our product development, we cannot predict the timing or amount of increased expenses and cannot assure you that we will ever be profitable or generate positive cash flow from operating activities. Based upon our current operating plan, we estimate that our cash, cash equivalents and short-term investments as of December 31, 2022 will be sufficient to fund our current and planned clinical trials for our milademetan program.

We do not own or operate, and currently have no plans to establish, any manufacturing facilities. We currently rely and expect to continue to rely for the foreseeable future, on third parties for the manufacture of our drug candidates for preclinical and clinical testing, as well as for commercial manufacture of any drugs that we may commercialize. We expect to continue to develop drug candidates that can be produced cost-effectively at contract manufacturing facilities. For the milademetan program, we have transferred Daiichi Sankyo Company, Limited (Daiichi Sankyo) processes to suitable third-party contract manufacturing organizations to supply active pharmaceutical ingredients and clinical drug product for our clinical trials and in preparation for submission of marketing applications and potential future commercial supplies.

#### Collaboration and License Agreements
We are party to a number of license agreements for the in-license of our product candidates and development programs. See Note 7 to our audited consolidated financial statements included elsewhere in this Annual Report on Form 10-K.

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#### Components of Our Results of Operations

#### Revenue
To date, we have not generated any revenue from product sales, licenses or collaborations and do not expect to generate any revenue from the sale of products in the foreseeable future. If our development efforts for our product candidates are successful and result in regulatory approval, we may generate revenue from future product sales. If we enter into license or collaboration agreements for any of our product candidates or intellectual property, we may generate revenue in the future from payments as a result of such license or collaboration agreements. We cannot predict if, when, or to what extent we will generate revenue from the commercialization and sale of our product candidates or from license or collaboration agreements. We may never succeed in obtaining regulatory approval for any of our product candidates.

#### Operating Expenses
Our operating expenses since inception have consisted solely of research and development costs, including acquisition of in-process research and development, and general and administrative costs.

#### Research and Development Expenses
To date, our research and development expenses have related to the discovery and clinical development of our product candidates, including acquisition of in-process research and development. Research and development expenses are recognized as incurred and payments made prior to the receipt of goods or services to be used in research and development are capitalized until the goods or services are received.

Research and development expenses include:

● salaries, payroll taxes, employee benefits and stock-based compensation charges for those individuals involved in research and development efforts;

● expenses incurred in connection with research, laboratory consumables and preclinical studies;

● external research and development expenses incurred under agreements with CROs and consultants to conduct and support our planned clinical trials of our product candidates;

● the cost of consultants engaged in research and development-related services and the cost to manufacture drug product for use in our preclinical studies and clinical trials;

● costs related to regulatory compliance;

● the cost of annual license fees and the cost of acquiring in-process research and development, including upfront license payments; and

● any development milestone payments that we may make under our license agreements.

We track external development costs by product candidate or development program, but we do not allocate personnel costs or other internal costs to specific development programs or product candidates as our personnel works across multiple development programs and product candidates. These costs are included in unallocated research and development expenses in the table below.

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The following table summarizes our research and development expenses by product candidate or development program:

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| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
|  | **(in thousands)** | **(in thousands)** |
| Milademetan | $35174 | $23261 |
| Other research and clinical candidates | 680 | 1761 |
| Unallocated internal research and development costs | 25546 | 15751 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total research and development expenses | $61400 | $40773 |

---

We plan to substantially increase our research and development expenses for the foreseeable future as we continue to expand the development of our product candidates. We cannot predict with certainty the timing for initiation or completion of, the duration of, or the costs of current or future clinical trials and nonclinical studies of any of our product candidates due to the inherently unpredictable nature of clinical and preclinical development. The clinical development timeline, probability of success of clinical trials and development costs can differ materially from expectations. In addition, we cannot forecast which product candidates may be subject to future collaborations, when such arrangements will be secured, if at all, and to what degree such arrangements would affect our development plans and capital requirements.

Our future clinical development costs may vary significantly. See the section titled "Risk Factors—Risks Related to Product Development— Preclinical and clinical development involves a lengthy and expensive process with uncertain outcomes, and results of earlier studies and trials may not be predictive of future clinical trial results. If our preclinical studies and clinical trials are not sufficient to support regulatory approval of any of our product candidates, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development of such product candidates."

#### General and Administrative Expenses
General and administrative expenses consist of salaries and employee-related costs, including stock-based compensation, for personnel in executive, finance and other administrative functions, legal fees relating to intellectual property and corporate matters, professional fees for accounting and consulting services and facility-related costs. We anticipate that our general and administrative expenses will continue to increase in the future to support our continued research and development activities, pre-commercial preparation activities for our product candidates and, if any product candidate receives marketing approval, commercialization activities. We also anticipate increased expenses related to audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and SEC requirements, director and officer insurance premiums and investor relations costs associated with operating as a public company.

#### Interest Income
Interest income consists of interest on our available-for-sale (AFS) securities.

#### Income Taxes
We are subject to corporate U.S. federal and state income taxation. As of December 31, 2022, we had federal and state net operating loss carryforwards of approximately $85.1 million and $127.8 million respectively. $0.2 million of the $85.1 million of federal net operating loss carryforwards will begin expiring in 2037 and the remaining $84.9 million can be carried forward indefinitely. The yearly utilization of such federal net operating loss carryforwards is limited to 80 percent of taxable income. The state tax loss carryforwards will begin expiring in 2031, if not utilized. As of December 31, 2022, we had federal and state research and development tax credits of approximately $10.7 million and $1.7 million, respectively. If not utilized, the

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federal research tax credit will begin to expire in 2039. The California research tax credit can be carried forward indefinitely.

Utilization of the net operating loss carryforwards and other tax attributes may be subject to a substantial annual limitation due to the ownership change limitations provided by Sections 382 and 383 of the Internal Revenue Code of 1986, as amended (the Code), and similar state provisions. Specifically, under Sections 382 and 383 of the Code, if a corporation undergoes an "ownership change" (generally defined as a greater than 50% change (by value) in its equity ownership by 5% stockholders over a three-year period), our ability to use such pre-change net operating loss carryforwards and other pre-change tax attributes to offset its post-change taxable income may be limited. As a result of our most recent private placements and other transactions that have occurred over the past three years, we may have experienced, and, upon the closing of this offering, may experience, an "ownership change." We may also experience ownership changes in the future as a result of subsequent shifts in our stock ownership.

We estimate our income tax provision, including deferred tax assets and liabilities, based on management's judgment. We record a valuation allowance to reduce our deferred tax assets to the amounts that are more likely than not to be realized. We consider future taxable income, ongoing tax planning strategies and our historical financial performance in assessing the need for a valuation allowance. If we expect to realize deferred tax assets for which we have previously recorded a valuation allowance, we will reduce the valuation allowance in the period in which such determination is first made.

We record liabilities related to uncertain tax positions in accordance with the guidance that clarifies the accounting for uncertainty in income taxes recognized in an enterprise's financial statements by prescribing a minimum recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return.

#### Results of Operations

#### Comparison of Years Ended December 31, 2022 and 2021
The following table summarizes our results of operations for the years ended December 31, 2022 and 2021, together with the changes in those items in dollars:

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| | | | |
|:---|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** | |
|  | **2022** | **2021** | <br>**Change** |
|  | **(in thousands)** | **(in thousands)** |  |
| Operating expenses: |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Research and development | $61400 | $40773 | $20627 |
| &nbsp;&nbsp;&nbsp;&nbsp;General and administrative | 15736 | 10739 | 4997 |
| Total operating expenses | 77136 | 51512 | 25624 |
| Loss from operations | (77136) | (51512) | (25624) |
| Other income: |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Interest and other income | 1415 | 120 | 1295 |
| Total other income | 1415 | 120 | 1295 |
| Net loss before income tax expense | $(75721) | $(51392) | $24329 |

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#### Research and Development Expenses
Research and development (R&D) expenses were $61.4 million and $40.8 million for the years ended December 31, 2022 and 2021, respectively. The increase in R&D expenses was primarily related to clinical trial costs for milademetan, higher payroll-related costs for our R&D personnel, and various other R&D costs for milademetan. Non-cash stock-based compensation expenses, included as part of personnel costs, were $3.8 million and $2.5 million for the years ended December 31, 2022 and 2021, respectively. We expect our

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R&D costs to continue to increase in 2023 as we continue our Phase 3 trial in LPS and our Phase 2 tumor-agnostic basket trial for milademetan.

#### General and Administrative Expenses
General and administrative (G&A) expenses were $15.7 million and $10.7 million for the years ended December 31, 2022 and 2021, respectively. The increase in G&A expenses was primarily due to payroll-related costs of $2.0 million, professional services costs of $1.3 million, legal costs of $0.3 million, and various third-party G&A costs of $1.0 million. Non-cash stock-based compensation expense included in G&A expenses was approximately $1.1 million and $0.6 million for the years ended December 31, 2022 and 2021, respectively. We expect our general and administrative expenses to continue to increase in 2023 as we continue to build out systems and infrastructure to support our operations.

#### Other Income
Other income for the years ended December 31, 2022 and 2021 represents interest income from money market or short-term investments.

#### Liquidity and Capital Resources
Since our inception, we have incurred significant operating losses. We expect to continue to incur significant expenses and operating losses for the foreseeable future as we advance the preclinical and clinical development of our research programs and product candidates. We expect that our research and development and general and administrative costs will increase in connection with conducting additional preclinical studies and clinical trials, expanding our intellectual property portfolio and providing general and administrative support for our operations. As a result, we will need additional capital to fund our operations, which we may obtain from additional equity or debt financings, collaborations, licensing arrangements or other sources.

We do not currently have any approved products and have not generated any revenue from product sales since inception. To date, we have financed our operations through the issuance of convertible promissory notes and the issuance of convertible preferred stock and common stock. From our inception through December 31, 2022, we have raised aggregate gross proceeds of $9.9 million from the issuance of convertible promissory notes and $81.9 million from the issuance of convertible preferred stock.

On April 27, 2021, we completed our IPO in which we issued and sold 7,352,941 shares of common stock at a public offering price of $17.00 per share. On May 11, 2021, we issued an additional 492,070 shares of common stock in connection with the exercise of the underwriters' option to purchase additional shares at the public offering price. Our net proceeds from the sale of shares in the IPO, including the sale of shares pursuant to the exercise of the underwriters' option to purchase additional shares, was $121.5 million, net of underwriting discounts and commissions, and other offering fees.

In May 2022, we entered into a sales agreement (the "Sales Agreement") with Oppenheimer & Co. Inc. (the "Sales Agent") pursuant to which we may offer and sell up to $50.0 million of shares of our common stock, from time to time, in "at-the-market" offerings (the "ATM Facility"). The Sales Agent is entitled to compensation at a commission equal to 3.0% of the aggregate gross sales price per share sold under the Sales Agreement. As of December 31, 2022, we have not sold shares pursuant to the ATM Facility.

In November 2022, we completed a registered direct offering of an aggregate of 8,576,330 shares of common stock and non-voting common stock at $5.83 per share. In addition, we issued an additional 1,140,068 shares of common stock in connection with the exercise of the underwriters' option to purchase additional shares at the public offering price. We received net proceeds from our November 2022 Offering of approximately $52.9 million, after deducting underwriting discounts and commissions, and other offering fees.

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As of December 31, 2022, we had cash, cash equivalents and short-term investments of $130.5 million. Although we believe, based on our current business plans, that our existing cash, cash equivalents and short-term investments, including proceeds available from our ATM Facility, will be sufficient to meet our obligations for at least the next twelve months, we anticipate that we will require additional capital in the future in order to continue the research and development of our drug candidates. We have based this estimate on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect.

#### Future Funding Requirements
We expect our expenses to increase substantially in connection with our ongoing development activities related to milademetan and other product candidates and programs, which are still in the early stages of development. In addition, we expect to continue to incur additional costs associated with operating as a public company. We expect that our expenses will increase substantially if and as we:

● continue our on-going clinical trials and initiate new clinical trials for our milademetan program;

● initiate and continue research and preclinical and clinical development of our product candidates;

● seek to identify and develop additional product candidates;

● seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

● establish a sales, marketing, manufacturing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

● require the manufacture of larger quantities of our product candidates for clinical development and potentially commercialization;

● maintain, expand, protect and enforce our intellectual property portfolio;

● acquire or in-license other drugs and technologies;

● defend against any claims of infringement, misappropriation or other violation of third-party intellectual property;

● hire and retain additional clinical, quality control and scientific personnel;

● build out new facilities or expand existing facilities to support our ongoing development activity;

● add operational, financial and management information systems and personnel, including personnel to support our drug development, any future commercialization efforts and our transition to a public company;

● potentially experience the effects of the recent disruptions to and volatility in the credit and financial markets in the United States and worldwide from ongoing macroeconomic conditions and the geopolitical environment; and

● operate as a public company.

Because of the numerous risks and uncertainties associated with the development of milademetan and other product candidates and programs and because the extent to which we may enter into

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collaborations with third parties for development of our product candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our product candidates and programs. Our future capital requirements will depend on many factors, including:

● the scope, progress, results and costs of our current and future clinical trials of milademetan for our current targeted indications;

● the scope, progress, results and costs of drug discovery, preclinical research and clinical trials for other product candidates;

● the number of future product candidates that we pursue and their development requirements;

● the costs, timing and outcome of regulatory review of our product candidates;

● the extent to which we acquire or invest in businesses, products and technologies, including entering into or maintaining licensing or collaboration arrangements for product candidates on favorable terms, although we currently have no commitments or agreements to complete any such transactions;

● the costs of preparing, filing and prosecuting patent applications, maintaining, protecting and enforcing our intellectual property rights and defending intellectual property-related claims;

● our headcount growth and associated costs as we expand our business operations and our research and development activities;

● our ability to successfully acquire or in-license other drugs and technologies;

● the costs and timing of future commercialization activities, including drug sales, marketing, manufacturing and distribution, for any of our product candidates for which we receive marketing approval, to the extent that such sales, marketing, manufacturing and distribution are not the responsibility of any collaborator that we may have at such time;

● the amount of revenue, if any, received from commercial sales of our product candidates, should any of our product candidates receive marketing approval; and

● the costs of operating as a public company.

Developing drug products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval for any product candidates or generate revenue from the sale of any products for which we may obtain marketing approval. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of drugs that we do not expect to be commercially available for many years, if at all. Accordingly, we will need to obtain substantial additional funds to achieve our business objectives.

Until such time, if ever, as we can generate product revenues to support our cost structure, we expect to finance our cash needs through public or private equity offerings, including our ATM Facility, debt financings or other capital sources which may include strategic collaborations, licensing arrangements or other arrangements with third parties. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our stockholders could be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our stockholders. Debt financing and equity financing, if available, may involve agreements that include

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covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise funds through strategic collaborations or other similar arrangements with third parties, we may have to relinquish valuable rights to our technology, future revenue streams, research programs or product candidates or may have to grant licenses on terms that may not be favorable to us and/or may reduce the value of our common stock. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts. Our ability to raise additional funds may be adversely impacted by potential worsening global macroeconomic conditions and the disruptions to and volatility in the credit and financial markets in the United States and worldwide. Because of the numerous risks and uncertainties associated with product development, we cannot predict the timing or amount of increased expenses and cannot assure you that we will ever be profitable or generate positive cash flow from operating activities.

#### Cash Flows
The following table summarizes our sources and uses of cash and cash equivalents for the years ended December 31, 2022 and 2021:

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| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
|  | **(in thousands)** | **(in thousands)** |
| Net cash provided by (used in): |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Operating activities | $(63199) | $(37463) |
| &nbsp;&nbsp;&nbsp;&nbsp;Investing activities | 47194 | (118235) |
| &nbsp;&nbsp;&nbsp;&nbsp;Financing activities | 53180 | 121615 |
| Net increase (decrease) in cash and cash equivalents | $37175 | $(34083) |

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#### Operating Activities
We have incurred losses since inception. Net cash used in operating activities for the year ended December 31, 2022 was $63.2 million, consisting primarily of net loss of $75.7 million, resulting from expenses associated with research and development activities for our lead product candidate and general and administrative expenses, partially offset by changes in operating assets and liabilities of $8.9 million and non-cash adjustments of $3.6 million.

Net cash used in operating activities for the year ended December 31, 2021 was $37.5 million, consisting primarily of net loss of $51.4 million, resulting from expenses associated with research and development activities for our lead product candidate and general and administrative expenses, partially offset by changes in operating assets and liabilities of $5.2 million and non-cash adjustments of $8.7 million.

#### Investing Activities
Net cash provided by investing activities for the year ended December 31, 2022 was $47.2 million, which related to $123.4 million of proceeds received from available for sale securities maturities, offset by purchases of available for sale securities of $76.2 million.

Net cash used in investing activities for the year ended December 31, 2021 was $118.2 million, which was primarily related to purchases of available for sale securities of $163.6 million, and payment of $2.5 million to Daiichi Sankyo for in-process research and development expense, partially offset by maturities of available for sale securities of $48.0 million.

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#### Financing Activities
Net cash provided by financing activities for the year ended December 31, 2022 was $53.2 million, which primarily related to the net proceeds from the November 2022 Offering, after deducting underwriting discounts and commissions, and other offering fees.

Net cash provided by financing activities for the year ended December 31, 2021 was $121.6 million, which primarily relates to the net proceeds from IPO, after deducting underwriting discounts and commissions, and other offering fees.

#### Obligations and other Commitments
As discussed in Note 7 to the audited consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we are party to agreements to license intellectual property. The license agreements may require us to pay future milestones if certain developmental, regulatory and commercial milestones are achieved, as well as to pay royalties on net sales of products applicable to the license agreements. We cannot estimate if milestone and/or royalty payments will occur in future periods and the agreements are cancelable by us at any time upon prior written notice to the licensor.

In the normal course of business, we enter into contracts with CROs and other vendors for preclinical studies and clinical trials, research and development supplies and other testing and manufacturing services. These contracts generally do not contain minimum purchase commitments and are cancelable by either party at any time upon prior written notice.

Our incurred and accrued research and development obligations as of December 31, 2022 and 2021 were $8.2 million and $4.3 million, respectively.

We pay the office operating lease obligation at the beginning of each month. Under our office operating leases as noted in Note 8 to the audited consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, our obligation as of December 31, 2022 and 2021 were $0.3 million and $0.4 million, respectively.

#### Critical Accounting Estimates
The discussion and analysis of our financial condition and results of operations is based upon our financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States (GAAP). The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, expenses, and related disclosure of contingent assets and liabilities. On an ongoing basis, we evaluate our estimates and base our estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances. Actual results may differ from these estimates under different assumptions or conditions and could have a material impact on our reported results. While our significant accounting policies are more fully described in the notes to our financial statements included elsewhere in this Report, we believe the following accounting policies to be the most critical in understanding the judgments and estimates we use in preparing our financial statements.

#### Accrued Research and Development
We are required to estimate our expenses resulting from our obligations under contracts with vendors, consultants, CROs and clinical site agreements in connection with conducting preclinical activities and clinical trials. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the expense. However, some payments

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are made in arrears and expenditures are accrued for the time periods which services are performed on a pre-determined schedule or when contractual milestones are met. Payments under some of these contracts depend on factors such as the successful enrollment of patients and the completion of clinical trial milestones.

This process involves reviewing open contracts and purchase orders, communicating with our applicable personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred when we have not yet been invoiced or otherwise notified of actual costs. During the course of a preclinical study or clinical trial, we adjust our prepaid and expense recognition if actual results differ from our estimates. To date, we have not experienced any material differences between accrued costs and actual costs incurred. The accrued research and development balances were $8.2 million and $4.3 million as of December 31, 2022 and 2021, respectively.

#### Stock-Based Compensation
We follow the provision of the Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 718, "Compensation – Stock Compensation" (ASC 718), which requires the measurement and recognition of compensation expense for all stock-based payment awards.

We estimate the fair value of our stock options using the Black-Scholes option pricing model, which requires us to develop subjective estimates to be used in calculating the fair value of stock options. The use of the model requires us to make estimates of subjective assumptions, such as expected stock price volatility and the estimated expected term of each award. The fair value of restricted stock units (RSUs) granted is based on our closing stock price on the date of grant.

Stock-based compensation expense based on the fair value estimated is recognized over the requisite service period of the awards (generally the vesting period) on a straight-line basis. Prior to the IPO, the estimated fair value of the underlying common stock was determined on the date of grant by our board of directors. For the years ended December 31, 2022 and 2021, stock-based compensation expense was $4.9 million and $3.1 million, respectively. The following table summarizes unvested equity compensation costs not yet recognized as of the years ended December 31, 2022 and 2021.

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| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Unvested equity compensation costs not yet recognized (in millions) | $10.8 | $9.8 |
| Weighted average period over which the unvested awards are expected to be recognized (in years) | 2.5 | 3.1 |

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#### Recent Accounting Pronouncements
A description of recent accounting pronouncements that may potentially impact our financial position, results of operations or cash flows is disclosed in Note 2 to our audited consolidated financial statements for the year ended December 31, 2022, included elsewhere in this Annual Report on Form 10-K.

#### Item 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.
We are a smaller reporting company, as defined by Rule 12b-2 under the Securities and Exchange Act of 1934 and in Item 10(f)(1) of Regulation S-K, and are not required to provide the information under this item.

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#### Item 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA.
**Index to Consolidated Financial Statements**

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| | |
|:---|:---|
| [Report of Independent Registered Public Accounting Firm](#Report) | 76 |
| &nbsp;&nbsp;&nbsp;&nbsp;Auditor Name: Ernst & Young LLP<br>Auditor Location: San Diego, California<br>Auditor Firm ID: 42 |  |
| [Consolidated Balance Sheets](#BalanceSheets_517121) | 77 |
| [Consolidated Statements of Operations and Comprehensive Loss](#StatementsofOperationsandComprehensiveLo) | 78 |
| [Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit)](#StatementsofConvertiblePreferredStockand) | 79 |
| [Consolidated Statements of Cash Flows](#StatementsofCashFlows_919660) | 80 |
| [Notes to Consolidated Financial Statements](#NotestoFinancialStatements_327730) | 81 |

---

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**Report of Independent Registered Public Accounting Firm**

To the Stockholders and the Board of Directors of Rain Oncology Inc.

#### Opinion on the Financial Statements
We have audited the accompanying consolidated balance sheets of Rain Oncology Inc. (the Company) as of December 31, 2022 and 2021, the related consolidated statements of operations and comprehensive loss, convertible preferred stock and stockholders' equity (deficit) and cash flows for the years then ended, and the related notes (collectively referred to as the "consolidated financial statements"). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2022 and 2021, and the results of its operations and its cash flows for the years then ended, in conformity with U.S. generally accepted accounting principles.

#### Basis for Opinion
These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

/s/ Ernst & Young LLP

We have served as the Company's auditor since 2019.

San Diego, California

March 9, 2023

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**Rain Oncology Inc.**

**Consolidated Balance Sheets**

**(In thousands, except share and per share data)**

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| **Assets** |  |  |
| Current assets: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Cash and cash equivalents | $61955 | $24780 |
| &nbsp;&nbsp;&nbsp;&nbsp;Short-term investments | 68499 | 115438 |
| &nbsp;&nbsp;&nbsp;&nbsp;Prepaid and other current assets | 3174 | 5928 |
| Total current assets | 133628 | 146146 |
| Property and equipment, net | 93 | 165 |
| Operating lease right-of-use asset | 258 | 386 |
| Other assets | 1201 | 443 |
| Total assets | $135180 | $147140 |
| **Liabilities and stockholders' equity** |  |  |
| Current liabilities: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Accounts payable | $7146 | $6112 |
| &nbsp;&nbsp;&nbsp;&nbsp;Accrued research and development | 8232 | 4349 |
| &nbsp;&nbsp;&nbsp;&nbsp;Other accrued liabilities | 6424 | 5694 |
| &nbsp;&nbsp;&nbsp;&nbsp;Operating lease liability, current portion | 164 | 160 |
| Total current liabilities | 21966 | 16315 |
| &nbsp;&nbsp;&nbsp;&nbsp;Operating lease liability, net of current portion | 113 | 252 |
| &nbsp;&nbsp;&nbsp;&nbsp;Other long-term liabilities | 65 | 69 |
| Total liabilities | 22144 | 16636 |
| Commitments and contingencies |  |  |
| Stockholders' equity: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Preferred stock, $0.001 par value; 10,000,000 shares authorized; no shares issued and outstanding |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Common stock, $0.001 par value; 250,000,000 shares authorized as of December 31, 2022 and December 31, 2021, respectively; 36,290,292 shares (comprised of 25,947,572 shares of common stock and 10,342,720 shares of non-voting common stock) and 26,475,812 shares (comprised of 18,748,342 shares of common stock and 7,727,470 shares of non-voting common stock) issued and outstanding as of December 31, 2022 and December 31, 2021, respectively | 37 | 27 |
| &nbsp;&nbsp;&nbsp;&nbsp;Additional paid-in capital | 278853 | 220530 |
| &nbsp;&nbsp;&nbsp;&nbsp;Accumulated other comprehensive loss | (166) | (89) |
| &nbsp;&nbsp;&nbsp;&nbsp;Accumulated deficit | (165688) | (89964) |
| Total stockholders' equity | 113036 | 130504 |
| Total liabilities and stockholders' equity | $135180 | $147140 |

---

See accompanying Notes to Consolidated Financial Statements.

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**Rain Oncology Inc.**

**Consolidated Statements of Operations and Comprehensive Loss**

**(In thousands, except share and per share data)**

---

| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| Operating expenses: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Research and development | $61400 | $40773 |
| &nbsp;&nbsp;&nbsp;&nbsp;General and administrative | 15736 | 10739 |
| Total operating expenses | 77136 | 51512 |
| Loss from operations | (77136) | (51512) |
| Other income: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Interest and other income | 1415 | 120 |
| Total other income | 1415 | 120 |
| Net loss before income tax expense | (75721) | (51392) |
| Income tax expense | (3) | (2) |
| Net loss | $(75724) | $(51394) |
| Net loss per share, basic and diluted | $(2.71) | $(2.65) |
| Weighted-average shares used to compute net loss per share, basic and diluted | 27985446 | 19405833 |
| Net loss | $(75724) | $(51394) |
| Other comprehensive loss: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Unrealized loss on short-term investments | (77) | (89) |
| Comprehensive loss | $(75801) | $(51483) |

---

See accompanying Notes to Consolidated Financial Statements.

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**Rain Oncology Inc.**

**Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit)**

**(In thousands, except share amounts)**

---

| | | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
|  | **Series A** | **Series A** | **Series B** | **Series B** |  |  | | | | |
|  | **Convertible Preferred** | **Convertible Preferred** | **Convertible Preferred** | **Convertible Preferred** |  |  | | | | |
|  | **Stock** | **Stock** | **Stock** | **Stock** | **Common Stock** | **Common Stock** | | | | |
|  | **Shares** | **Amount** | **Shares** | **Amount** | **Shares** | **Amount** | <br>**Additional**<br>**Paid-in**<br>**Capital** | <br>**Accumulated**<br>**Deficit** | **Accumulated**<br>**Other**<br>**Comprehensive**<br>**Loss** | <br>**Total**<br>**Stockholders'**<br>**Equity (Deficit)** |
| **Balance as of December 31, 2020** | 3731208 | $20147 | 12542198 | $74550 | 3530975 | $4 | $1149 | $(38570) | $— | $(37417) |
| Conversion of convertible preferred stock to common stock | (3731208) | (20147) | (12542198) | (74550) | 15069330 | 15 | 94682 |  |  | 94697 |
| Issuance of common stock upon IPO, net of issuance cost |  |  |  |  | 7845011 | 8 | 121486 |  |  | 121494 |
| Exercise of stock options |  |  |  |  | 30496 |  | 121 |  |  | 121 |
| Stock-based compensation expense |  |  |  |  |  |  | 3092 |  |  | 3092 |
| Unrealized loss on investments |  |  |  |  |  |  |  |  | (89) | (89) |
| Net loss |  |  |  |  |  |  |  | (51394) |  | (51394) |
| **Balance as of December 31, 2021** |  | $— |  | $— | 26475812 | $27 | $220530 | $(89964) | $(89) | $130504 |
| Exercise of stock options | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;40220 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;169 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;169 |
| Issuance of common stock from employee stock purchase plan | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;57862 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;440 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;440 |
| Issuance of common stock in connection with the November 2022 Offering, net of issuance cost | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;9716398 | &nbsp;&nbsp;&nbsp;&nbsp;10 | &nbsp;&nbsp;&nbsp;&nbsp;52859 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;52869 |
| Stock-based compensation expense | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;4855 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;4855 |
| Unrealized loss on investments | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;(77) | &nbsp;&nbsp;&nbsp;&nbsp;(77) |
| Net loss | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;(75724) | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;(75724) |
| **Balance as of December 31, 2022** |  | $— |  | $— | 36290292 | $37 | $278853 | $(165688) | $(166) | $113036 |

---

See accompanying Notes to Consolidated Financial Statements.

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**Rain Oncology Inc.**

**Consolidated Statements of Cash Flows**

**(In thousands)**

---

| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| **Operating activities** |  |  |
| Net loss | $(75724) | $(51394) |
| Adjustments to reconcile net loss to cash used in operating activities: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;In-process research and development expense (reduction) | (1000) | 5500 |
| &nbsp;&nbsp;&nbsp;&nbsp;Depreciation and amortization expense | 80 | 71 |
| &nbsp;&nbsp;&nbsp;&nbsp;Stock-based compensation expense | 4855 | 3092 |
| &nbsp;&nbsp;&nbsp;&nbsp;Amortization of premium and accretion of discounts on short-term investments, net | (331) | 81 |
| &nbsp;&nbsp;&nbsp;&nbsp;Fair value loss on investments | (9) | (1) |
| &nbsp;&nbsp;&nbsp;&nbsp;**Changes in operating assets and liabilities:** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Prepaid and other current assets | 2754 | (5266) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Operating lease right-of-use asset and liability, net | (7) | 19 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other assets | (460) | 181 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accounts payable | 1034 | 5288 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued research and development | 3883 | 2822 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other accrued liabilities | 1726 | 2144 |
| Net cash used in operating activities | (63199) | (37463) |
| **Investing activities** |  |  |
| Purchases of short-term investments | (76198) | (163557) |
| Purchases of property and equipment | (8) | (128) |
| Payment of in-process research and development expense |  | (2500) |
| Maturities of short-term investments | 123400 | 47950 |
| Net cash provided by (used in) investing activities | 47194 | (118235) |
| **Financing Activities** |  |  |
| Proceeds from initial public offering |  | 133366 |
| Proceeds from the issuance of common stock under the Company's equity incentive plans and employee stock purchase plan | 609 | 121 |
| Proceeds from issuance of common stock in connection with the November 2022 Offering | 56647 |  |
| Payments of issuance costs related to the IPO |  | (11872) |
| Payments of issuance costs related to the November 2022 Offering | (3778) |  |
| Payments of issuance costs related to the ATM Facility | (298) |  |
| Net cash provided by financing activities | 53180 | 121615 |
| **Net increase (decrease) in cash and cash equivalents** | 37175 | (34083) |
| **Cash and cash equivalents at beginning of period** | 24780 | 58863 |
| **Cash and cash equivalents at end of period** | $61955 | $24780 |
| **Supplemental schedule of non-cash investing and financing activities:** |  |  |
| Conversion of convertible preferred stock to common stock | $— | $94697 |
| Non-cash in-process research and development accrual (reduction) | $(1000) | $3000 |
| Non-cash additions to property and equipment | $— | $9 |

---

See accompanying Notes to Consolidated Financial Statements.

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**Rain Oncology Inc.**

**Notes to Consolidated Financial Statements**

#### Note 1 – Organization and Nature of Operations

#### Description of Business
Rain Oncology Inc. ("Rain" or the "Company"), formerly known as Rain Therapeutics Inc., was incorporated in the state of Delaware in April 2017. Rain is a late-stage precision oncology company developing therapies that target oncogenic drivers for which the Company is able to genetically select patients the Company believes will most likely benefit. This approach includes using a tumor-agnostic strategy to select patients based on their tumors' underlying genetics rather than histology. Rain's lead product candidate, milademetan, is a small molecule, oral inhibitor of the MDM2-p53 complex that reactivates p53. The Company operates in one business segment and its principal operations are in the United States, with its headquarters in Newark, California.

On June 22, 2022, the Company formed Rain Oncology Australia Pty Ltd ("Rain Oncology Australia"), a wholly owned subsidiary incorporated under the laws of Australia. As of December 31, 2022, Rain Oncology Australia was not yet operational.

On December 22, 2022, the Company filed a Certificate of Amendment to its Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to effect a change of the Company's name from "Rain Therapeutics Inc." to "Rain Oncology Inc." effective as of December 30, 2022.

#### Initial Public Offering
On April 27, 2021, the Company completed its initial public offering ("IPO") in which the Company issued and sold 7,352,941 shares of common stock at a public offering price of $17.00 per share. On May 11, 2021, the Company issued an additional 492,070 shares of common stock in connection with the exercise of the underwriters' option to purchase additional shares at the public offering price. The Company's net proceeds from the sale of shares in the IPO, including the sale of shares pursuant to the exercise of the underwriters' option to purchase additional shares, was $121.5 million, net of underwriting discounts and commissions, and other offering fees.

Immediately prior to the closing of the IPO, 8,344,905 shares of the Company's convertible preferred stock were exchanged for 7,727,470 shares of non-voting common stock. Upon the closing of the IPO, 7,928,501 shares of the Company's convertible preferred stock were automatically converted into 7,341,860 shares of common stock. As of December 31, 2022 and 2021, there were no shares of convertible preferred stock outstanding.

#### November 2022 Offering
In November 2022, the Company entered into an underwriting agreement with Guggenheim Securities, LLC, as the representative of the underwriters named therein (the "Underwriters") relating to the offering, issuance and sale (the "November 2022 Offering") of an aggregate of 8,576,330 shares of common stock and non-voting common stock at an offering price per share of $5.83. On November 15, 2022, the Company issued an additional 1,140,068 shares of common stock in connection with the exercise of the Underwriters' option to purchase additional shares at the offering price. The Company's net proceeds from the sale of shares in the November 2022 Offering, including the sale of shares pursuant to the exercise of the Underwriters' option to purchase additional shares, was approximately $52.9 million, net of underwriting discounts and commissions, and other offering fees.

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#### Basis of Presentation
The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP"). These consolidated financial statements include the accounts of the Company and Rain Oncology Australia. All significant inter-company transactions, balances and expenses have been eliminated upon consolidation. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification and Accounting Standards Updates ("ASU") promulgated by the Financial Accounting Standards Board ("FASB").

#### Liquidity and Capital Resources
The Company has devoted substantially all of its efforts to drug discovery and development, raising capital and building operations. The Company has a limited operating history and has not generated any revenue since its inception, and the sales and income potential of the Company's business is unproven. The Company has incurred net losses and negative cash flows from operating activities since its inception and expects to continue to incur net losses into the foreseeable future as it continues the development of its product candidates. From inception through December 31, 2022, the Company has funded its operations through net proceeds from its IPO in April 2021 and the November 2022 Offering, and the issuance of convertible promissory notes and convertible preferred stock.

The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern. Management believes that the Company's current cash, cash equivalents and short-term investments will provide sufficient funds to enable the Company to meet its obligations for at least twelve months from the filing date of this report.

#### Note 2 – Summary of Significant Accounting Policies

#### Use of Estimates
The preparation of the Company's consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent liabilities in the Company's consolidated financial statements and accompanying notes. The most significant estimate in the Company's consolidated financial statements relates to the clinical trial expense accruals. Management evaluates its estimates on an ongoing basis. Although these estimates are based on the Company's historical experience, knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.

#### Cash and Cash Equivalents
The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash equivalents include commercial paper and money market funds.

#### Available-for-Sale Investments
The Company holds investment grade securities consisting of commercial paper, corporate debt securities, U.S. government securities and U.S. agency bonds, classified as available-for-sale (AFS) securities at the time of purchase, since it is the Company's intent that these investments be available for current operations. The Company has classified all of its AFS securities as current assets on the consolidated balance sheets even though the stated maturity date may be one year or more beyond the current consolidated balance sheet date, which reflects management's intention to use the proceeds from sales of these securities to fund its operations, as necessary.

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The Company carries these securities at fair value and reports unrealized gains and losses, if any, as a separate component of accumulated other comprehensive loss. The cost of debt securities is adjusted for amortization of purchase premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income (expense) in the consolidated statements of operations and comprehensive loss. Realized gains and losses on sales of securities are determined using the specific identification method and recorded in other income (expense), net in the consolidated statement of operations and comprehensive loss.

Investments are considered to be impaired when a decline in fair value is judged to be other-than-temporary. The Company consults with its investment managers and considers available quantitative and qualitative evidence in evaluating potential impairment of its investments on a quarterly basis. If the cost of an individual investment exceeds its fair value, the Company evaluates among other factors, general market conditions, the duration and extent to which the fair value is less than cost, and the Company's intent and ability to hold the investment. Once an impairment is determined to be other-than-temporary, an impairment charge is recorded and a new cost basis in the investment is established. Declines in the value of AFS securities determined to be other than temporary are included in other income (expense), net.

#### Fair Value of Financial Instruments
The carrying amounts of all cash equivalents, prepaid expenses and other assets, accounts payable and accrued and other current liabilities are reasonable estimates of their fair value because of the short-term nature of these items.

#### Concentration of Credit Risk
Financial instruments, which potentially subject the Company to significant concentration of credit risk, consist primarily of cash, cash equivalents and short-term investments. The Company maintains cash and money market deposits in a federally insured major financial institution in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institution in which those deposits are held.

#### Research and Development Costs
Research and development costs primarily consist of costs associated with the Company's research and development activities, including its drug discovery efforts, and the preclinical and clinical development of its product candidates. Research and development costs are expensed as incurred.

#### Property and Equipment
Property and equipment, net consists of computer equipment, furniture and equipment and leasehold improvements. Leasehold improvements are amortized over the shorter of the estimated useful life or the remainder of the lease term. Computer equipment and furniture and equipment are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally two to three years). Repairs and maintenance costs are charged to expense as incurred.

#### Long-Lived Assets
The Company regularly reviews the carrying value and estimated lives of all of its long-lived assets, including property and equipment, to determine whether indicators of impairment may exist which warrant adjustments to carrying values or estimated useful lives. Should an impairment exist, the impairment loss would be measured based on the excess over the carrying amount of the asset's fair value. The Company has not recognized any impairment losses from inception through December 31, 2022.

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#### Commitments
The Company recognizes a liability with regard to loss contingencies when it believes it is probable that a liability has occurred, and the amount can be reasonably estimated. If some amount within a range of loss appears at the time to be a better estimate than any other amount within the range, the Company accrues that amount. When no amount within the range is a better estimate than any other amount, the Company accrues the minimum amount in the range. The Company has not recorded any such liabilities as of December 31, 2022.

#### Leases
At the inception of a contractual arrangement, the Company determines whether the contract contains a lease by assessing whether there is an identified asset and whether the contract conveys the right to control the use of the identified asset in exchange for consideration over a period of time. If both criteria are met, the Company records the associated lease liability and corresponding right-of-use asset upon commencement of the lease using the implicit rate or a discount rate based on a credit- adjusted secured borrowing rate commensurate with the term of the lease. The Company additionally evaluates leases at their inception to determine if they are to be accounted for as an operating lease or a finance lease. Operating lease assets represent a right to use an underlying asset for the lease term and operating lease liabilities represent an obligation to make lease payments arising from the lease. Operating lease liabilities with a term greater than one year and their corresponding right-of-use assets are recognized on the consolidated balance sheet at the commencement date of the lease based on the present value of lease payments over the expected lease term. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received. As the Company's leases do not typically provide an implicit rate, the Company utilizes the appropriate incremental borrowing rate, determined as the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term and in a similar economic environment. Lease cost is recognized on a straight-line basis over the lease term and variable lease payments are recognized as operating expenses in the period in which the obligation for those payments is incurred. Variable lease payments primarily include common area maintenance, utilities, real estate taxes, insurance and other operating costs that are passed on from the lessor in proportion to the space leased by the Company. The Company has elected the practical expedient to not separate lease and non-lease components.

#### Preclinical Studies and Clinical Trial Accruals
The Company is required to estimate its expenses resulting from its obligations under contracts with vendors, consultants, clinical research organizations and clinical site agreements in connection with conducting preclinical activities and clinical trials. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects preclinical study and clinical trial expenses in its consolidated financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical study or clinical trial as measured by the timing of various aspects of the preclinical study, clinical trial or related activities. The Company determines accrual and prepaid estimates through review of the underlying contracts along with preparation of financial models taking into account correspondence with clinical and other key personnel and third- party service providers as to the progress of preclinical studies, clinical trials or other services being conducted. During the course of a preclinical study or clinical trial, the Company adjusts its expense recognition if actual results differ from its estimates. To date, the Company has not experienced any material differences between accrued costs and actual costs incurred.

#### In-Process Research and Development
The Company evaluates whether acquired intangible assets are a business under applicable accounting standards. Additionally, the Company evaluates whether the acquired assets have a future

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alternative use. Intangible assets that do not have future alternative use, such as the license the Company acquired from Daiichi Sankyo Company, Limited, (Daiichi Sankyo), are considered acquired in-process research and development. When the acquired in-process research and development assets are not part of a business combination, the value of the consideration paid is expensed on the acquisition date. Future costs to develop these assets are recorded to research and development expenses as they are incurred.

#### Patent Costs
Costs related to filing and pursuing patent applications are recorded as general and administrative expense and expensed as incurred since recoverability of such expenditures is uncertain.

#### General and Administrative Expenses
General and administrative expenses consist of salaries, stock-based compensation, facilities and third-party expenses. General and administrative expenses are associated with the activities of the executive, finance, accounting, information technology, legal and human resource functions.

#### Stock-Based Compensation
Stock-based compensation expense represents the grant date fair value of equity awards recognized over the requisite service period of the awards (generally the vesting period) on a straight-line basis. The Company recognizes forfeitures as they occur. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model. The fair value of restricted stock units ("RSUs") granted is based on the Company's closing stock price on the date of grant. Prior to the IPO, the exercise price for all stock options granted was at the estimated fair value of the underlying common stock as determined on the date of grant by the Board of Directors.

#### Income Taxes
The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date.

The Company recognizes deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.

The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more likely than not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability.

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Effective January 1, 2022, we adopted ASU 2019-12 - Simplifying the Accounting for Income Taxes. The adoption of this standard did not impact the Company's consolidated financial statements or related disclosures.

#### Comprehensive Loss
Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. The Company's comprehensive loss includes unrealized gains and losses from short-term investments.

#### Net Loss Per Share
Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the sum of the weighted-average number of shares of common stock plus the potential dilutive effects of potential dilutive securities outstanding during the period. Potential dilutive securities are excluded from diluted earnings or loss per share if the effect of such inclusion is antidilutive. The Company's potentially dilutive securities, which include shares from the 2021 Employee Stock Purchase Plan (the "ESPP") and outstanding stock options and RSUs under the Company's equity incentive plan, have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For the periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company's net loss position.

#### Recent Accounting Pronouncements
There were no significant updates to the recently issued accounting standards for the year ended December 31, 2022. Although there are several other new accounting pronouncements issued or proposed by the FASB, based on the Company's preliminary assessment, the Company does not believe any of those accounting pronouncements have had or will have a material impact on its financial position or operating results.

#### Note 3 – Fair Value Measurements
The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or non-recurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

*Level 1*: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

*Level 2*: Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability.

*Level 3*: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

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Financial assets measured at fair value on a recurring basis consist of the Company's cash equivalents and AFS securities. The Company obtains pricing information from its investment manager and generally determines the fair value of investment securities using standard observable inputs, including reported trades, broker/dealer quotes, and bids and/or offers.

Investments are classified as Level 1 within the fair value hierarchy if their quoted prices are available in active markets for identical securities. Investments in money market funds and U.S. government securities were classified as Level 1 instruments.

Investments in commercial paper, corporate debt securities and U.S. agency bonds are valued using Level 2 inputs. The Company classifies investments within Level 2 if the investments are valued using model driven valuations using observable inputs such as quoted market prices, benchmark yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency. Investments are held by custodians who obtain investment prices from a third-party pricing provider that incorporates standard inputs in various asset pricing models.

The carrying amounts of cash, prepaid expenses and other current assets, other assets, accounts payable, accrued research and development, other current liabilities and other long-term liabilities are reasonable estimates of their fair value due to the short-term nature of these accounts.

The Company's money market funds under cash and cash equivalents are classified using Level 1 inputs within the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. There were no transfers between levels of the fair value hierarchy during the years ended December 31, 2022 and 2021.

The following table summarizes financial assets that the Company measured at fair value on a recurring basis, classified in accordance with the fair value hierarchy (in thousands):

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Fair Value Measurements at Reporting Date Using:** | **Fair Value Measurements at Reporting Date Using:** | **Fair Value Measurements at Reporting Date Using:** | **Fair Value Measurements at Reporting Date Using:** |
|  | **Level 1** | **Level 2** | **Level 3** | **Total** |
| **As of December 31, 2022** |  |  |  |  |
| Money market funds | $8528 | $— | $— | $8528 |
| Commercial paper | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;83423 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;83423 |
| U.S. government securities | &nbsp;&nbsp;&nbsp;&nbsp;10837 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;10837 |
| U.S. agency bonds | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;22143 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;22143 |
| Corporate debt securities | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;997 | &nbsp;&nbsp;&nbsp;&nbsp;— | &nbsp;&nbsp;&nbsp;&nbsp;997 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total cash equivalents and short-term investments | $19365 | $106563 | $— | $125928 |
| Reported as: |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Cash and cash equivalents (includes cash of $4,526) |  |  |  | $61955 |
| &nbsp;&nbsp;&nbsp;&nbsp;Short-term investments |  |  |  | 68499 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total cash, cash equivalents and short-term investments |  |  |  | $130454 |

---

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---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Fair Value Measurements at Reporting Date Using:** | **Fair Value Measurements at Reporting Date Using:** | **Fair Value Measurements at Reporting Date Using:** | **Fair Value Measurements at Reporting Date Using:** |
|  | **Level 1** | **Level 2** | **Level 3** | **Total** |
| **As of December 31, 2021** |  |  |  |  |
| Money market funds | $10585 | $— | $— | $10585 |
| Commercial paper |  | 84616 |  | 84616 |
| U.S. government securities | 27824 |  |  | 27824 |
| U.S. agency bonds |  | 8531 |  | 8531 |
| Corporate debt securities |  | 8265 |  | 8265 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total cash equivalents and short-term investments | $38409 | $101412 | $— | $139821 |
| Reported as: |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Cash and cash equivalents (includes cash of $397) |  |  |  | $&nbsp;&nbsp;&nbsp;&nbsp;24780 |
| &nbsp;&nbsp;&nbsp;&nbsp;Short-term investments |  |  |  | &nbsp;&nbsp;&nbsp;&nbsp;115438 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total cash, cash equivalents and short-term investments |  |  |  | $&nbsp;&nbsp;&nbsp;&nbsp;140218 |

---

There were no liabilities measured at fair value on a recurring basis as of December 31, 2022 and 2021.

#### Note 4 – Investments
We invest in available-for-sale securities consisting of money market funds, commercial paper, U.S. government securities, U.S. agency bonds and corporate debt securities. Available-for-sale securities are classified as either cash and cash equivalents or short-term investments on the consolidated balance sheets.

The following table summarizes, by major types of cash equivalents, and investments that are measured at fair value on a recurring basis (in thousands):

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **As of December 31, 2022** | **As of December 31, 2022** | **As of December 31, 2022** | **As of December 31, 2022** |
|  | **Amortized**<br>**Cost** | **Unrealized**<br>**Gains** | **Unrealized**<br>**Losses** | **Estimated**<br>**Fair Value** |
| Money market funds | $8528 | $— | $— | $8528 |
| Commercial paper | 83479 | 11 | (67) | 83423 |
| U.S. government securities | 10910 |  | (73) | 10837 |
| U.S. agency bonds | 22175 | 4 | (36) | 22143 |
| Corporate debt securities | 1002 |  | (5) | 997 |
| &nbsp;&nbsp;&nbsp;&nbsp;Cash equivalents and short-term investments | $&nbsp;&nbsp;&nbsp;&nbsp;126094 | $&nbsp;&nbsp;&nbsp;&nbsp;15 | $&nbsp;&nbsp;&nbsp;&nbsp;(181) | $&nbsp;&nbsp;&nbsp;&nbsp;125928 |

---

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **As of December 31, 2021** | **As of December 31, 2021** | **As of December 31, 2021** | **As of December 31, 2021** |
|  | **Amortized**<br>**Cost** | **Unrealized**<br>**Gains** | **Unrealized**<br>**Losses** | **Estimated**<br>**Fair Value** |
| Money market funds | $&nbsp;&nbsp;&nbsp;&nbsp;10585 | $— | $— | $10585 |
| Commercial paper | &nbsp;&nbsp;&nbsp;&nbsp;84642 | 2 | (28) | 84616 |
| U.S. government securities | &nbsp;&nbsp;&nbsp;&nbsp;27870 |  | (46) | 27824 |
| U.S. agency bonds | &nbsp;&nbsp;&nbsp;&nbsp;8546 |  | (15) | 8531 |
| Corporate debt securities | &nbsp;&nbsp;&nbsp;&nbsp;8267 |  | (2) | 8265 |
| &nbsp;&nbsp;&nbsp;&nbsp;Cash equivalents and short-term investments | $&nbsp;&nbsp;&nbsp;&nbsp;139910 | $2 | $(91) | $139821 |

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The contractual maturities of the Company's AFS securities were as follows (in thousands):

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Due within one year | $63595 | $105173 |
| Due within one to two years | 4904 | 10265 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total | $68499 | $115438 |

---

The available-for-sale investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current consolidated balance sheet date, which reflects management's intention to use the proceeds from sales of these securities to fund the Company's operations, as necessary. There were no realized gains or losses due to investment sales for the years ended December 31, 2022 and 2021. As of December 31, 2022, $85.9 million of the Company's marketable securities were in gross unrealized loss positions, of which none had been in such position for greater than 12 months and $53.6 million will mature within three months of December 31, 2022.

At each reporting date, the Company performs an evaluation of its marketable securities to determine if any unrealized losses are other-than-temporary. Factors considered in determining whether a loss is other-than-temporary include (i) the financial strength of the issuing institution, (ii) the length of time and extent for which fair value has been less than the cost basis and (iii) the Company's intent and ability to hold its investments in unrealized loss positions until their amortized cost basis has been recovered. Based on the Company's evaluation, it determined that its unrealized losses were not other-than-temporary at December 31, 2022 and 2021. The Company does not intend to sell the investments before maturity, and it is unlikely that the Company will be required to sell the investments before recovery of their amortized cost bases.

#### Note 5 – Consolidated Balance Sheet Details

#### Prepaid and Other Current Assets
Prepaid and other current assets consist of the following (in thousands):

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Prepaid research | $1103 | $4329 |
| Prepaid insurance | 913 | 827 |
| FICA tax credit receivable | 571 | 452 |
| Other current assets | 152 | 205 |
| Prepaid other | 416 | 96 |
| Deposits | 19 | 19 |
| &nbsp;&nbsp;&nbsp;&nbsp;Prepaid and other current assets | $3174 | $5928 |

---

Property and equipment, net, consist of the following (in thousands):

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Furniture and equipment | $204 | $204 |
| Leasehold improvements | 67 | 67 |
| Computer equipment | 50 | 50 |
| Construction in progress | 8 |  |
|  | $329 | $321 |
| Less: accumulated depreciation and amortization expense | (236) | (156) |
| &nbsp;&nbsp;&nbsp;&nbsp;Property and equipment, net | $93 | $165 |

---

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Depreciation and amortization expense for each of the years ended December 31, 2022 and 2021 was $0.1 million.

#### Other Non-Current Assets
Other non-current assets consist of the following (in thousands):

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Deposits | $781 | $75 |
| FICA tax credit receivable | 52 | 298 |
| Other | 368 | 70 |
| &nbsp;&nbsp;&nbsp;&nbsp;Other non-current assets | $1201 | $443 |

---

#### Other Accrued Liabilities
Other accrued liabilities consist of the following (in thousands):

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Accrued bonus | $3379 | $1933 |
| Accrued payroll and related | 229 | 39 |
| ESPP liability | 155 | 369 |
| Other | 2661 | 3353 |
| &nbsp;&nbsp;&nbsp;&nbsp;Other accrued liabilities | $6424 | $5694 |

---

#### Note 6 – Convertible Preferred Stock and Stockholders' Equity (Deficit)
In 2020, the Company amended its Certificate of Incorporation to authorize the issuance of 24,000,000 shares of common stock, par value $0.001 per share, and 16,273,406 shares of preferred stock, par value $0.001 per share, of which 3,731,208 shares were designated Series A convertible preferred stock and 12,542,198 shares were designated Series B convertible preferred stock.

In April 2021, the Company filed a certificate of amendment to its certificate of incorporation, which authorized 260,000,000 shares of capital stock, consisting of 250,000,000 shares of common stock, par value $0.001 per share, and 10,000,000 shares of undesignated preferred stock, par value $0.001 per share that may be issued from time to time by the Board of Directors in one or more series. Of the 250,000,000 shares of common stock, 200,000,000 shares were designated as "Common Stock" and 50,000,000 shares were designated as "Non-Voting Common Stock."

Rights, preferences, powers, privileges and restrictions, qualifications and limitations for holders of the Company's Common Stock and Non-Voting Common Stock are:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a) Voting Common Stock Voting Rights . Each holder of Voting Common Stock, as such, shall be entitled to one vote for each share of Voting Common Stock held of record by such holder on all matters on which stockholders generally are entitled to vote; provided, however, that, except as otherwise required by law, holders of Voting Common Stock, as such, shall not be entitled to vote on any amendment to the Certificate of Incorporation, including any certificate of designations relating to any series of Preferred Stock (each hereinafter referred to as a "Preferred Stock Designation"), that relates solely to the terms of one or more outstanding series of Preferred Stock if the holders of such affected series are entitled, either separately or together with the

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holders of one or more other such series, to vote thereon pursuant to the Certificate of Incorporation (including any Preferred Stock Designation).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b) Non-Voting Common Stock Voting Rights . Non-Voting Common Stock (i) shall be non-voting except as may be required by law and (ii) shall not entitle the holder thereof to vote on the election of directors at any time.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c) Non-Voting Common Stock Conversion . Each holder of shares of Non-Voting Common Stock shall have the right to convert each share of Non-Voting Common Stock held by such holder into one share (subject to appropriate adjustment in the event of any stock dividend, stock split, reverse stock split, combination or other similar recapitalization with respect to the Voting Common Stock) of Voting Common Stock at such holder's election by providing written notice to the Company ; provided, however, that such shares of Non-Voting Common Stock may only be converted into shares of Voting Common Stock during such time or times as immediately prior to or as a result of such conversion would not result in the holder(s) thereof beneficially owning (for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended and the rules and regulations promulgated thereunder (collectively, the "Exchange Act")), when aggregated with affiliates with whom such holder is required to aggregate beneficial ownership for purposes of Section 13(d) of the Exchange Act, in excess of the Beneficial Ownership Limitation. The "Beneficial Ownership Limitation" means initially 9.99% of the Voting Common Stock. Any holder of Non-Voting Common Stock may increase the Beneficial Ownership Limitation with respect to such holder, not to exceed 19.99% of the Voting Common Stock, upon 61 days ' prior written notice to the Company and may decrease the Beneficial Ownership Limitation at any time upon providing written notice of such election to the Company; provided, however, that no holder may make such an election to change the percentage with respect to such holder unless all holders managed by the same investment advisor as such electing holder make the same election. Before any holder of Non-Voting Common Stock shall be entitled to convert any shares of Non-Voting Common Stock into shares of Voting Common Stock, such holder shall (A) surrender the certificate or certificates therefor (if any), duly endorsed, at the principal corporate office of the Company or of any transfer agent for the Non-Voting Common Stock, and (B) provide written notice to the Company, during regular business hours at its principal corporate office, of such conversion election (in form satisfactory to the Company) and shall state therein the name or names (i) in which the certificate or certificates representing the shares of Voting Common Stock into which the shares of Non-Voting Common Stock are so converted are to be issued (if such shares of Voting Common Stock are certificated) or (ii) in which such shares of Voting Common Stock are to be registered in book-entry form (if such shares of Voting Common Stock are uncertificated). If the shares of Voting Common Stock into which the shares of Non-Voting Common Stock are to be converted are to be issued in a name or names other than the name of the holder of the shares of Non-Voting Common Stock being converted, such notice shall be accompanied by a written instrument or instruments of transfer, in form satisfactory to the Company, duly executed by the holder. The Company shall, as soon as practicable thereafter, issue and deliver at such office to such holder, or to the nominee or nominees of such holder, a certificate or certificates representing the number of shares of Voting Common Stock to which such holder shall be entitled upon such conversion (if such shares of Voting Common Stock are certificated) or shall register such shares of Voting Common Stock in book-entry form (if such shares of Voting Common Stock are uncertificated). Such conversion shall be deemed to be effective immediately prior to the close of business on the date of such surrender of the shares of Non-Voting Common Stock to be converted following or contemporaneously with the provision of written notice of such conversion election as required by this section, the shares of Voting Common Stock issuable upon such conversion shall be deemed to be outstanding as of such time, and the person or persons entitled to receive the shares of Voting Common Stock issuable upon such conversion shall be deemed to be the record holder or holders of such shares of Voting Common Stock as of such time. Notwithstanding anything herein to the contrary, shares of Non-Voting Common Stock represented by a lost, stolen or destroyed stock certificate may be

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converted if the holder thereof notifies the Company or its transfer agent that such certificate has been lost, stolen or destroyed and makes an affidavit of that fact acceptable to the Company and executes an agreement acceptable to the Company to indemnify the Company from any loss incurred by it in connection with such certificate. The effectiveness of any conversion of any shares of Non-Voting Common Stock into shares of Voting Common Stock is subject to the expiration or early termination of any applicable premerger notification and waiting period requirements of the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the rules and regulations promulgated thereunder.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;d) Dividends . Subject to the rights of the holders of any outstanding series of Preferred Stock, the holders of shares of Common Stock shall be entitled to receive any dividends to the extent permitted by law when, as and if declared by the Board of Directors .

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;e) Liquidation . Upon the dissolution, liquidation or winding up of the Company, subject to the rights of the holders of any outstanding series of Preferred Stock, the holders of shares of Common Stock shall be entitled to receive the assets of the Company available for distribution to its stockholders ratably in proportion to the number of shares held by them. The Non-Voting Common Stock shall rank on parity with the Voting Common Stock as to distributions of assets upon dissolution, liquidation or winding up of the Company, whether voluntary or involuntary.

#### Convertible Preferred Stock
*Series A Convertible Preferred Stock.* In April 2018, the Company entered into a Series A convertible preferred stock purchase agreement, pursuant to which the Company issued 2,098,269 shares of Series A convertible preferred stock for an aggregate purchase price of $11.0 million, net of issuance costs. In December 2018, the Company issued an additional 1,390,788 shares of Series A convertible preferred stock for an aggregate purchase price of $7.3 million, net of issuance costs.

*Series B Convertible Preferred Stock.* In September 2020, the Company entered into a Series B convertible preferred stock purchase agreement, pursuant to which the Company issued 10,636,510 shares of Series B convertible preferred stock for an aggregate purchase price of $63.2 million, net of issuance costs.

Rights, preferences, powers, privileges and restrictions, qualifications and limitations for holders of the Company's Series A convertible preferred stock and Series B convertible preferred stock were:

● Dividends: Each holder of the Company's Series A and Series B convertible preferred stock was entitled to receive non-cumulative dividends, when and if declared by the Board of Directors. No dividends have been declared to date.

● Liquidation Preferences: In the event of any liquidation, dissolution or winding up of the Company, the holders of the Series A and Series B convertible preferred stock were entitled to receive, prior and in preference to any distribution of any of the assets of the Company to the holders of common stock, an amount per share equal to the original issue price plus declared but unpaid dividends.

● Conversion: Each share of Series A and Series B convertible preferred stock was convertible at the option of the holder, at any time, into the number of shares of common stock determined by dividing the applicable purchase price by the applicable conversion price at the time of conversion. Each share of Series A and Series B convertible preferred stock will be automatically converted into common stock immediately upon (i) the closing of a firm commitment underwritten IPO resulting in at least $50.0 million of gross proceeds to the Company or (ii) the receipt by the Company of a written request for automatic conversion from the holders of a majority of the outstanding shares of Series A and Series B convertible preferred stock.

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● Voting: The holders of the Series A and Series B convertible preferred stock were entitled to one vote for each share of common stock into which such shares of Series A and Series B convertible preferred stock could then be converted; and with respect to such vote, such holders shall have full voting rights and powers equal to the voting rights and powers of the holders of the common stock.

● Redemption: The Series A and Series B convertible preferred stock were not explicitly redeemable at the option of the holder at a specified date in the future or at the option of the Company.

Prior to the IPO, the Company's Series A and Series B convertible preferred stock were classified as temporary equity on the consolidated balance sheet instead of in stockholders' equity (deficit), as events triggering redemption that were not solely within the Company's control because the preferred stockholders had the ability to effect a liquidation event. The Company determined not to adjust the carrying values of the Series A and Series B convertible preferred stock to the liquidation preferences of such shares because of the uncertainty of whether or when such liquidation events would occur.

On April 27, 2021, immediately prior to the closing of the IPO, 8,344,905 shares of the Company's convertible preferred stock were exchanged for 7,727,470 shares of Non-Voting Common Stock and 7,928,501 shares of the Company's convertible preferred stock converted into 7,341,860 shares of Common Stock. There were no outstanding shares of the Company's convertible preferred stock as of December 31, 2022 and 2021.

#### Equity Incentive Plan
In August 2020, the Board of Directors amended the Amended and Restated 2018 Stock Option—Stock Issuance Plan (the "2018 Plan") to increase the maximum number of shares of common stock that may be issued over the term of the plan. The 2018 Plan provided for the grant of stock options, non-statutory stock options, incentive stock options and stock issuances to employees, nonemployees and consultants of the Company.

In April 2021, the Company's 2021 Equity Incentive Plan (the "2021 Plan") was approved by the Board of Directors and became effective on April 15, 2021. Upon the effectiveness of the 2021 Plan, no further grants may be made under the 2018 Plan.

The 2021 Plan allows the Company to grant equity-based awards to its officers, employees, directors and other key persons (including consultants). The Company initially reserved up to 3,246,120 shares of common stock for issuance under the 2021 Plan, plus (i) 1,722 shares that remained available for the issuance of awards under the 2018 Plan at the time the 2021 Plan became effective, and (ii) any shares subject to outstanding options or other share awards that were granted under the 2018 Plan that terminate or expire prior to exercise or settlement; are forfeited because of the failure to vest; or are reacquired or withheld (or not issued) to satisfy a tax withholding obligation or the purchase or exercise price. The 2021 Plan provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, beginning on January 1, 2022 and each January 1 thereafter through January 31, 2032, by 4.0% of the outstanding number of shares of common stock on the immediately preceding December 31, or such lesser number of shares as determined by the Board of Directors. As a result, the number of shares of common stock reserved for issuance under the 2021 Plan increased by 1,451,611 shares on January 1, 2023.

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***Stock Options***

A summary of the Company's stock option activities during the year ended December 31, 2022 is as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | <br>**Total Options** | **Weighted-**<br>**Average**<br>**Exercise**<br>**Price Per**<br>**Share** | **Weighted-**<br>**Average**<br>**Remaining**<br>**Contract Term**<br>**(in years)** | <br>**Aggregate**<br>**Intrinsic**<br>**Value**<br>**(in millions)** |
| Outstanding as of December 31, 2021 | &nbsp;&nbsp;&nbsp;&nbsp;1734696 | $8.50 | 8.8 | $7.6 |
| &nbsp;&nbsp;&nbsp;&nbsp;Granted | &nbsp;&nbsp;&nbsp;&nbsp;1197328 | $7.99 |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Exercised | &nbsp;&nbsp;&nbsp;&nbsp;(40220) | $4.20 |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Forfeited or cancelled | &nbsp;&nbsp;&nbsp;&nbsp;(298043) | $10.72 |  |  |
| Outstanding as of December 31, 2022 | &nbsp;&nbsp;&nbsp;&nbsp;2593761 | $8.08 | 8.2 | $5.3 |
| Vested and expected to vest as of December 31, 2022 | &nbsp;&nbsp;&nbsp;&nbsp;2593761 | $8.08 | 8.2 | $5.3 |
| Vested and exercisable as of December 31, 2022 | &nbsp;&nbsp;&nbsp;&nbsp;988166 | $6.86 | 7.1 | $3.0 |

---

The weighted-average grant date fair values of option grants during the years ended December 31, 2022 and 2021 were $6.61 and $12.14 per share, respectively. The weighted-average grant date fair values of options forfeited during the years ended December 31, 2022 and 2021 were $9.35 and $6.08 per share, respectively.

***Restricted Stock Units***

A summary of the Company's RSU activities during the year ended December 31, 2022 is as follows:

---

| | | | |
|:---|:---|:---|:---|
|  | <br>**Total**<br>**Restricted**<br>**Stock Units** | **Weighted-**<br>**Average**<br>**Grant Date**<br>**Fair Values** | **Aggregate**<br>**Intrinsic**<br>**Value**<br>**(in millions)** |
| Outstanding as of December 31, 2021 |  | $— | $— |
| &nbsp;&nbsp;&nbsp;&nbsp;Granted | 9289 | $6.25 |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Vested |  | $— |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Forfeited or cancelled | (344) | $6.25 |  |
| Outstanding as of December 31, 2022 | 8945 | $6.25 | $0.1 |

---

There were no RSUs vested during the year ended December 31, 2022.

#### Employee Stock Purchase Plan
The ESPP was approved by the Board of Directors and became effective on April 15, 2021. The ESPP initially reserved and authorized the issuance of up to 259,689 shares of common stock to participating employees. Under the ESPP, eligible employees can contribute up to 15% of their eligible compensation, as defined in the ESPP, towards the purchase of the Company's common stock at a price of 85% of the lower of the fair market value of the Company's common stock on the first trading day of the offering period or on the last trading day of the offering period. The ESPP provides for twenty-four-month offering periods with four six-month purchase periods in each offering period. The ESPP provides that the number of shares reserved and available for issuance will automatically increase each January 1, beginning on January 1, 2022 and each January 1 thereafter through January 31, 2032, by 1.0% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year. As a result, the number of shares of common stock reserved for issuance under the ESPP increased by 362,902 shares on January 1, 2023. Under the ESPP, the Company issued 57,862 shares of common stock for aggregate cash proceeds of $0.4 million during the year ended December 31, 2022.

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#### Stock-Based Compensation Expense
The Company recognized stock-based compensation expense as follows (in thousands):

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| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| Research and development | $3782 | $2486 |
| General and administrative | 1073 | 606 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total stock-based compensation expense | $4855 | $3092 |

---

The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants were as follows:

---

| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| Risk-free interest rate | 1.6% - 4.3% | 0.8% - 1.3% |
| Expected volatility | 88.1% - 112.1% | 113.2% - 118.7% |
| Expected term (in years) | 5.3 - 6.1 | 5.0 – 6.1 |
| Expected dividend yield | 0% | 0% |

---

As of December 31, 2022, the total unrecognized compensation cost related to outstanding stock options and restricted stock units was $10.7 million and is expected to be recognized as expense over approximately 2.6 years.

The weighted average assumptions used in the Black-Scholes option pricing model to estimate the fair value of purchase rights granted under the ESPP were as follows:

---

| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| Risk-free interest rate | 0.2% | 0.1% |
| Expected volatility | 139.6% | 127.8% |
| Expected term (in years) | 2.2 | 1.4 |
| Expected dividend yield | 0% | 0% |

---

As of December 31, 2022, there was $0.1 million of unrecognized compensation cost related to the ESPP and is expected to be recognized over approximately 0.5 years.

The determination of the fair value of share-based payment awards utilizing the Black-Scholes option-pricing model is affected by the Company's stock price and the following assumptions:

*Risk-free interest rate.* The risk-free interest rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company's stock-based awards.

*Expected volatility.* Due to the Company's limited operating history and lack of company-specific historical or implied volatility, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available.

*Expected term.* The expected term represents the weighted-average period the stock-based awards are expected to be outstanding. The Company uses the simplified method for estimating the expected term. The simplified method calculates the expected term as the average of the time-to-vesting and the contractual life of the stock-based awards.

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*Expected dividend yield.* The expected dividend assumption is based on the Company's history and expectation of dividend payouts. The Company has not paid and does not intend to pay dividends.

*Forfeitures*. The Company reduces stock-based compensation expense for actual forfeitures during the period.

#### Common Stock Reserved for Future Issuance
Common stock reserved for future issuance consist of the following:

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Stock options | &nbsp;&nbsp;&nbsp;&nbsp;2593761 | 1734696 |
| Restricted stock units | &nbsp;&nbsp;&nbsp;&nbsp;8945 |  |
| Reserved for future equity award grants | &nbsp;&nbsp;&nbsp;&nbsp;3084732 | 2933930 |
| Reserved for future ESPP issuances | &nbsp;&nbsp;&nbsp;&nbsp;466585 | 259689 |
| &nbsp;&nbsp;&nbsp;&nbsp;Common stock reserved for future issuance | &nbsp;&nbsp;&nbsp;&nbsp;6154023 | &nbsp;&nbsp;&nbsp;&nbsp;4928315 |

---

#### Note 7 – License Agreements
The Company has entered into license agreements, accounted for as asset acquisitions, under which the Company is required to use commercially reasonable efforts to meet certain specified development and regulatory milestones related to the licensed technologies within specified time periods. In consideration of the rights granted to the Company under the agreements, the Company is required to make cash milestone payments to the licensors upon the completion of certain development, regulatory and commercial milestones. For the arrangements that the Company accounted for as asset acquisitions, contingent consideration liabilities are recorded as an additional cost of the acquired assets when the contingency is resolved, and the consideration is paid or becomes payable. Additionally, the Company has agreed to pay royalties on net sales of products applicable to the license agreements. The Company may terminate the agreements upon written notice to the licensors.

#### Daiichi Sankyo License Agreement
On September 2, 2020, the Company licensed the rights to milademetan (DS-3032b) for all human prophylactic or therapeutic uses in all countries and territories of the world from Daiichi Sankyo (the "Daiichi Sankyo License Agreement"). Daiichi Sankyo conducted clinical studies of milademetan prior to the Company's licensing the rights to this product. The Company refers to this product candidate as milademetan.

In accordance with the terms of the Daiichi Sankyo License Agreement, the Company paid Daiichi Sankyo an initial upfront payment of $5.0 million in September 2020.

Under the Daiichi Sankyo License Agreement, the Company obtained worldwide, sublicensable exclusive rights to seven families of patents with respect to milademetan (the "Licensed Compound"). The Company is solely responsible under the Daiichi Sankyo License Agreement for the research, development and registration of milademetan. Pursuant to the Daiichi Sankyo License Agreement, Daiichi Sankyo had the right to continue to conduct three clinical trials and prepare final reports with respect to these clinical trials, and such right expires upon all subjects completing the study treatment. The Company has agreed to reimburse Daiichi Sankyo certain third-party expenses incurred while conducting such trials. On March 3, 2022, the Company and Daiichi Sankyo entered into a Memorandum of Understanding, which provides that Daiichi Sankyo will terminate its U105 study, and the Company will reimburse a total of $2.0 million to Daiichi Sankyo for expenses related to such study in four installments of $0.5 million each until December 31, 2022. As of December 31, 2022, the Company paid total installments of $1.5 million and the remaining $0.5 million

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installment as of December 31, 2022 has been paid in full in the first quarter of 2023. Under the Daiichi Sankyo License Agreement, the Company made other clinical trials payments of $0.1 million and $0.2 million for the years ended December 31, 2022 and 2021, respectively.

The Company is required to make aggregate future milestone payments of up to $223.5 million, contingent on the attainment of certain development, regulatory and sales milestones. The $223.5 million aggregate future milestone payments include a $2.0 million increase that was agreed upon in the Memorandum of Understanding with Daiichi Sankyo. On July 20, 2021, the Company announced that the first patient has been randomized in the multicenter, open-label, Phase 3 registrational trial (MANTRA) evaluating milademetan for the treatment of de-differentiated liposarcoma. Accordingly, pursuant to the Daiichi Sankyo License Agreement, the Company recorded $5.5 million in milestone fees as research and development expense in the consolidated statement of operations and comprehensive loss during the year ended December 31, 2021. Of the $5.5 million milestone fees, $2.5 million was paid in the third quarter of 2021 and $3.0 million was accrued as part of accrued research and development in the consolidated balance sheet as of December 31, 2021. On June 29, 2022, the Company and Daiichi Sankyo entered into an amendment to the Daiichi Sankyo License Agreement. The amendment reduced the $3.0 million milestone fee liability associated with the previously achieved milestone to $2.0 million and accordingly reduced research and development expense on the consolidated statements of operations and comprehensive loss by $1.0 million for the year ended December 31, 2022. The amendment also extended the due date of the milestone fee payment to June 30, 2023. During the year ended December 31, 2022, the Company incurred no milestone research and development expense under the Daiichi Sankyo License Agreement.

Additionally, the Company is required to pay Daiichi Sankyo a high single digit royalty based on the annual net sales of products containing milademetan as an active pharmaceutical ingredient (the Products), subject to reduction at an agreed rate upon expiration of the licensed patent in the particular country where the Products are sold. To date, no royalty payments have been made to Daiichi Sankyo under the Daiichi Sankyo License Agreement. The royalty obligation terminates on a country-by-country and on a product-by-product basis on the later of: (i) loss of all market exclusivity for such Product in such country, (ii) the last-to-expire patent that covers the Licensed Compound or the Product in such country and (iii) twelve years from launch of the first Product sold by the Company in such country.

Unless sooner terminated or extended, the Daiichi Sankyo License Agreement will remain in full force and effect until the Company, its affiliates and its sublicensees cease all development and commercial activity related to milademetan. Either party may terminate the Daiichi Sankyo License Agreement for cause in the event of an uncured material breach (subject to a 90-day cure period). However, the Company may only terminate the Daiichi Sankyo License Agreement with respect to the countries affected by such uncured material breach. Daiichi Sankyo may also terminate the Daiichi Sankyo License Agreement in the event of Rain's bankruptcy or insolvency. Additionally, Daiichi Sankyo may terminate the Daiichi Sankyo License Agreement immediately upon written notice if the Company, its affiliates or its sublicensors initiate or join any challenge to the validity or enforceability of a licensed patent, subject to certain exclusions. Furthermore, the Company may terminate the Daiichi Sankyo License Agreement in its entirety or on a country-by-country basis for bona fide material concerns regarding the (i) lack of safety for human use arising from toxicity of the Licensed Compound or Product(s), (ii) lack of efficacy of the Licensed Compound or Product(s) or (iii) adverse economic impact to the Company in connection with its continued development of the Products, in each case, upon six months' prior written notice to Daiichi Sankyo. In addition, if the Company is acquired by a third party that is developing and commercializing a competing compound and the acquiring party decides not to discontinue the development or commercialization of such competing compound, such third party must terminate the Daiichi Sankyo License Agreement within 30 days of such acquisition if it does not discontinue such development or commercialization. Upon termination of the Daiichi Sankyo License Agreement by Daiichi Sankyo for the Company's uncured material breach or by the Company for its bona fide material concerns regarding the safety, efficacy or adverse economic impacts relating to the Licensed Compound or Products, or its development thereof, the Company is required to, among other actions, if requested by Daiichi Sankyo (i) transfer to Daiichi Sankyo ongoing clinical trials, data, reports, records and materials, (ii) grant to Daiichi Sankyo an exclusive, irrevocable, sublicensable, fully paid-up license under any

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patents and know-how that are controlled and actually used by the Company at the time of termination in connection with the Products to allow Daiichi Sankyo exploit the Licensed Compound or Products in countries that are affected by the termination, (iii) grant to Daiichi Sankyo an exclusive, irrevocable, sublicensable, fully paid up license to use trademarks that are specific to the Products and (iv) assign any applicable sublicenses.

#### Drexel License Agreement and Sponsored Research Agreement
On July 30, 2020, the Company entered into an intellectual property license agreement (the "Drexel License Agreement") with Drexel University ("Drexel"). Pursuant to the Drexel License Agreement, Drexel granted to the Company a license to make and commercialize products related to RAD52 inhibitors for the treatment of cancer. The Company made payments of $53,118 and $34,387 under the Drexel License Agreement for the years ended December 31, 2022 and 2021, respectively.

In February 2023, the Company decided to discontinue further development of its preclinical program focused on targeting RAD52 in the DNA damage repair pathway, and the Company notified Drexel of the termination of the Drexel License Agreement pursuant to its terms to focus use of financial and personnel resources on the milademetan clinical program.

#### Roche Clinical Supply Agreement
In December 2021, the Company entered into a clinical supply agreement with Roche for the supply of the anti-Programmed Death Ligand-1 (PD-L1) monoclonal antibody, atezolizumab. Clinical trials are planned to evaluate milademetan, in combination with atezolizumab for the treatment of patients in genetically selected populations. Under this agreement, Rain is the sponsor of the anticipated clinical trials, and Roche will supply atezolizumab. The Company does not have any financial commitments to Roche under this agreement.

#### Note 8 – Commitments and Contingencies

#### Leases
In September 2018, the Company entered into a noncancelable operating lease agreement for office space for its corporate headquarters in Newark, California with an initial term of 5.25 years. The lease commenced in January 2019 and ends March 2024. Under the terms of the lease, the Company pays annual base rent, subject to an annual fixed percentage increase of 2% on March 1st of each year. The Company is obligated to pay for its share of direct expenses including operating expense and taxes, which are considered variable lease costs and are expensed as incurred.

In March 2020, Governor Newsom issued State of California Executive Order No. N-33-20 instructing all individuals in California to stay at home due to the COVID-19 pandemic. In connection with such order, the Company entered into an amendment to the noncancelable operating lease agreement in June 2020. The amendment provided the Company rent relief for three months in 2020. In consideration of the rent relief, the Company agreed to adjust the base rent annual fixed percentage increase of 3% on February 1st of each year and extend the lease until September 2024. The amendment was determined to be a lease modification that qualified as a change of accounting on the existing lease and not a separate contract. Remeasurement of the right-of-use asset and operating lease liabilities at the date of modification did not result in a material increase of the right-of-use asset and operating lease liabilities.

In October 2022, the Company entered into an amendment to its corporate headquarters lease agreement to expand the leased premises by approximately 3,880 square feet. The lease commencement date for the expansion premises is expected to be March 2023 and will expire in November 2024 concurrently with the existing lease. Total future lease payments over the life of the lease are estimated to increase by approximately $0.3 million as a result of the amendment.

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The future minimum lease payments required under the operating lease are summarized as follows (in thousands):

---

| | |
|:---|:---|
|  | **As of December 31, 2022** |
| 2023 | $171 |
| 2024 | 129 |
| 2025 |  |
| Total minimum lease payments | $300 |
| Less: amount representing interest | (23) |
| Present value of operating lease liabilities | $277 |
| Operating lease liabilities, current | 164 |
| Operating lease liabilities, non-current | 113 |
| Total operating lease liabilities | $277 |
| Weighted-average remaining lease term (in years) | 1.7 |
| Weighted-average incremental borrowing rate | 10.0% |

---

In addition to what is included in the table above, the future minimum lease payments for the operating lease not yet commenced are summarized as follows (in thousands):

---

| | |
|:---|:---|
|  | **As of December 31, 2022** |
| 2023 | $144 |
| 2024 | 158 |
| 2025 |  |
| Total minimum lease payments | $302 |

---

The table below summarizes the Company's lease costs and cash payments in connection with operating lease obligations (in thousands):

---

| | | | |
|:---|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** | **2020** |
| Total operating lease expense | $160 | $160 | $130 |
| Operating cash flows used for operating lease | $167 | $162 | $130 |

---

#### Contingencies
In the event the Company becomes subject to claims or suits arising in the ordinary course of business, the Company would accrue a liability for such matters when it is probable that future expenditures will be made, and such expenditures can be reasonably estimated.

#### Note 9 – Employee Benefits
The Company has a defined contribution 401(k) plan available to eligible employees. Under the terms of the plan, employees may make voluntary contributions as a percent of compensation, limited to the maximum amount allowable under federal tax regulations. The Company, at its discretion, may make certain contributions to the 401(k) plan. The Company made matching contributions of $541,471 and $233,831 for the years ended December 31, 2022 and 2021, respectively.

#### Note 10 – Income Taxes
The Company recorded de minimis state income tax expense for the years ended December 31, 2022 and 2021 primarily as a result of the Company maintaining a full valuation allowance against its loss

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from operations for tax purposes. The net losses for the years ended December 31, 2022 and 2021 were generated solely in the United States.

The provision for income taxes is comprised of the following (in thousands):

---

| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| Current: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;State | $3 | $2 |
| Provision for income taxes | $3 | $2 |

---

The provision for income taxes differs from the amount computed by applying the federal statutory income tax rate to income before taxes as follows (in thousands):

---

| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| Federal tax benefit at statutory rate | $(15901) | $(10792) |
| State taxes | (6867) | 604 |
| Non-deductible expenses | 539 | 490 |
| R&D credits | (4807) | (2177) |
| Change in valuation allowance | 31449 | 11870 |
| Return-to-provision adjustment | (4341) |  |
| Other | (69) | 7 |
| &nbsp;&nbsp;&nbsp;&nbsp;Provision for income taxes | $3 | $2 |

---

The Company petitioned for a ruling with the California Franchise Tax Board to apply an alternate apportionment method in California and the ruling was approved in November 2022. As a result of the ruling, the Company recorded a $3.4 million return-to-provision adjustment to true up the California net operating losses (NOL) deferred tax asset in the 2022 provision. The return to provision adjustment of the California NOL deferred tax asset is fully offset by a valuation allowance.

Deferred income taxes reflect the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The components of deferred income tax assets and liabilities are as follows (in thousands):

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Deferred tax assets: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Accrued expenses and other | $1045 | $407 |
| &nbsp;&nbsp;&nbsp;&nbsp;Fixed assets | 19 | 10 |
| &nbsp;&nbsp;&nbsp;&nbsp;Intangibles | 2915 | 2378 |
| &nbsp;&nbsp;&nbsp;&nbsp;Net operating losses | 29151 | 16993 |
| &nbsp;&nbsp;&nbsp;&nbsp;R&D and Orphan Drug credits | 8384 | 2615 |
| &nbsp;&nbsp;&nbsp;&nbsp;Section 174 capitalization | 11509 |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Stock-based compensation | 1100 | 287 |
| &nbsp;&nbsp;&nbsp;&nbsp;Lease liability | 80 | 87 |
| &nbsp;&nbsp;&nbsp;&nbsp;Other | 18 | 2 |
| Total deferred tax assets | $54221 | $22779 |
| Valuation allowance | (54146) | (22698) |
| Total net deferred tax assets | $75 | $81 |
| Deferred tax liabilities: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Right-of-use asset | $(75) | (81) |
| Total deferred tax liabilities | $(75) | $(81) |
| Net deferred tax assets | $— | $— |

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Realization of deferred tax assets is dependent upon the Company's ability to generate sufficient taxable income within the carryforward period. In assessing the realizability of some portion or all of the deferred tax assets, the Company evaluated both positive and negative evidence to determine if some or all of its deferred tax assets should be recognized. Based on the available objective evidence, the Company has concluded it is not more likely than not that its deferred tax assets will be realized.

Therefore, a valuation allowance in the amount of $54.1 million has been recorded for 2022 against the Company's deferred tax assets.

The net valuation allowance increased by $31.4 million and $11.9 million during the years ended December 31, 2022 and 2021, respectively.

The following table sets forth the Company's federal and state net operating loss and R&D credits carryforwards as of December 31, 2022 (in thousands):

---

| | | |
|:---|:---|:---|
|  | **Amount** | **Expiration Years** |
| Net operating losses, Federal—pre TCJA | $159 | 2037 |
| Net operating losses, Federal—post TCJA | $84927 | N/A |
| Net operating losses, state | $127790 | 2031-2042 |
| R&D and Orphan Drug credits, Federal | $10666 | 2039-2042 |
| R&D credits, California | $1739 | N/A |

---

Utilization of the Company's net operating loss and R&D credits may be subject to substantial limitations due to the ownership changes limitations provided by the Internal Revenue Code and similar state provisions. Such annual limitation could result in the expiration of the net operating loss before their utilization. Sections 382 and 383 of the Internal Revenue Code ("IRC Sections 382 and 383") impose limitations on a corporation's ability to utilize its net operating losses and credit carryforwards if it experiences an "ownership change" as defined by IRC Sections 382 and 383. The Company has performed an analysis under Section 382 of the Internal Revenue Code which subjects the amount of pre-change net operating losses and certain other tax attributes that can be utilized to an annual limitation. Based on the analysis, ownership changes have occurred in 2018 and 2021. There had been no additional ownership changes in 2022.

The Company is required to recognize in the financial statements the impact of a tax position, if that position is more likely than not of being sustained on audit, based on the technical merits of the position.

The following table reflects changes in the gross unrecognized tax benefits (in thousands):

---

| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| Balance at beginning of year | $&nbsp;&nbsp;&nbsp;&nbsp;1442 | $&nbsp;&nbsp;&nbsp;&nbsp;402 |
| &nbsp;&nbsp;&nbsp;&nbsp;Additions based on tax positions related to current year | &nbsp;&nbsp;&nbsp;&nbsp;2167 | &nbsp;&nbsp;&nbsp;&nbsp;1040 |
| &nbsp;&nbsp;&nbsp;&nbsp;Additions to tax position of prior years | &nbsp;&nbsp;&nbsp;&nbsp;432 | &nbsp;&nbsp;&nbsp;&nbsp;— |
| &nbsp;&nbsp;&nbsp;&nbsp;Reductions to tax position of prior years | &nbsp;&nbsp;&nbsp;&nbsp;(19) | &nbsp;&nbsp;&nbsp;&nbsp;— |
| Balance at end of year | $&nbsp;&nbsp;&nbsp;&nbsp;4022 | $&nbsp;&nbsp;&nbsp;&nbsp;1442 |

---

The Company recognizes interest and penalties as a component of income tax expense. There were no interest or penalties recognized in the statements of operations and comprehensive loss. The total unrecognized tax benefits of $4.0 million and $1.4 million were recorded as of December 31, 2022 and 2021, respectively, which, if recognized currently, should not impact the effective tax rate due to the Company maintaining a full valuation allowance. The Company expects the unrecognized tax benefits will not change significantly within the next 12 months.

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The Company is subject to examination by the United States federal and state tax authorities for the tax years 2017 and later.

The Inflation Reduction Act of 2022 ("IRA") was signed into law on August 16, 2022. The bill was meant to address the high inflation rate in the United States through various climate, energy, healthcare and other incentives. These incentives are meant to be paid for by the tax provisions included in the IRA, such as a new 15 percent corporate minimum tax, a 1 percent new excise tax on stock buybacks, additional IRS funding to improve taxpayer compliance and other provisions. At this time, none of the IRA tax provisions are expected to have a material impact to the Company's tax provision. The Company will continue to monitor updates to the Company's business along with guidance issued with respect to the IRA to determine whether any adjustments are needed to the Company's tax provision in future periods.

Effective for tax years beginning on or after January 1, 2022, pursuant to the Tax Cuts and Jobs Act of 2017, companies are required to capitalize and amortize Internal Revenue Code Section 174 research and experimental expenses paid or incurred over 5 years for research and development performed in the United States and 15 years for research and development performed outside of the United States. As a result of the Internal Revenue Code Section 174 research and experimental expense capitalization, the Company recognized a deferred tax asset for the future tax benefit of the amortization deductions with an offsetting increase in the valuation allowance on deferred tax assets.

#### Note 11 – Net Loss Per Share
The following tables summarize the computation of the basic and diluted net loss per share (in thousands, except share and per share data):

---

| | | |
|:---|:---|:---|
|  | **Year Ended December 31,** | **Year Ended December 31,** |
|  | **2022** | **2021** |
| **Numerator:** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Net loss | $&nbsp;&nbsp;&nbsp;&nbsp;(75724) | $(51394) |
| **Denominator:** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Weighted-average shares of common stock outstanding, basic and diluted | &nbsp;&nbsp;&nbsp;&nbsp;27985446 | 19405833 |
| Weighted-average shares used to compute net loss per share, basic and diluted | &nbsp;&nbsp;&nbsp;&nbsp;27985446 | 19405833 |
| Net loss per share, basic and diluted | $&nbsp;&nbsp;&nbsp;&nbsp;(2.71) | $(2.65) |

---

The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive:

---

| | | |
|:---|:---|:---|
|  | **As of December 31,** | **As of December 31,** |
|  | **2022** | **2021** |
| Stock options  | &nbsp;&nbsp;&nbsp;&nbsp;2593761 | &nbsp;&nbsp;&nbsp;&nbsp;1734696 |
| Restricted stock units | &nbsp;&nbsp;&nbsp;&nbsp;8945 | &nbsp;&nbsp;&nbsp;&nbsp;— |
| ESPP shares | &nbsp;&nbsp;&nbsp;&nbsp;43757 | &nbsp;&nbsp;&nbsp;&nbsp;85031 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total | &nbsp;&nbsp;&nbsp;&nbsp;2646463 | &nbsp;&nbsp;&nbsp;&nbsp;1819727 |

---

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#### Note 12 – Subsequent Events
In February 2023, a holder of non-voting common stock converted 500,000 shares of non-voting common stock into an equal number of shares of common stock. As of February 28, 2023, there were 9,842,720 shares of non-voting common stock outstanding.

In January and February 2023, the Company sold an aggregate of 32,000 shares of common stock in "at-the-market" offerings pursuant to its sales agreement with Oppenheimer & Co. Inc. as sales agent, for net proceeds of $0.3 million, net of commissions and offering expenses.

In February 2023, the Company decided to discontinue further development of its preclinical program focused on targeting RAD52 in the DNA damage repair pathway, and the Company notified Drexel of the termination of the Drexel License Agreement pursuant to its terms to focus use of financial and personnel resources on the milademetan clinical program.

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#### Item 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE.
None.

#### Item 9A. CONTROLS AND PROCEDURES.

#### Management's Evaluation of Disclosure Controls and Procedures
As of December 31, 2022, our management, with the participation and supervision of our principal executive officer and our principal financial officer, evaluated our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act). The term "disclosure controls and procedures," as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, means controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC's rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to the Company's management, including its principal executive and principal financial officers, as appropriate to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies its judgment in evaluating the cost benefit relationship of possible controls and procedures. Based on this evaluation, our principal executive officer and our principal financial officer concluded that our disclosure controls and procedures were effective as of December 31, 2022 to provide reasonable assurance that information we are required to disclose in reports that we file or submit under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in SEC rules and forms, and that such information is accumulated and communicated to our management, including our principal executive officer and our principal financial officer, as appropriate, to allow timely decisions regarding required disclosure.

#### Management's Annual Report on Internal Controls over Financial Reporting
***Our management is responsible for establishing and maintaining adequate internal control over financial reporting (as defined in Rules 13a-15(f) under the Exchange Act). Internal control over financial reporting is a process designed under the supervision and with the participation of our management, including our principal executive officer and our principal financial officer, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles in the United States.***

***As of December 31, 2022, our management assessed the effectiveness of our internal control over financial reporting using the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission in Internal Control-Integrated Framework. Based on this assessment, our management concluded that our internal control over financial reporting was effective as of December 31, 2022.***

#### Attestation Report of the Registered Public Accounting Firm
As an emerging growth company, we are not required to provide an attestation report on our internal control over financial reporting issued by the Company's independent registered public accounting firm.

#### Changes in Internal Control over Financial Reporting
There were no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) identified in management's evaluation pursuant to Rules 13a-15(d) or 15d-15(d) of the Exchange Act that occurred during the quarter ended December 31, 2022, that materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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#### Item 9B. OTHER INFORMATION.
None.

#### Item 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS.
Not applicable.

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#### PART III

#### Item 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE.
The information required by this Item will be set forth in the Company's definitive proxy statement to be filed with the SEC in connection with the Company's 2023 Annual Meeting of Stockholders (the "2023 Proxy Statement") within 120 days of the end of the Company's fiscal year ended December 31, 2022, including under the heading "Corporate Governance", and is incorporated herein by reference.

We have adopted a Code of Business Conduct and Ethics that applies to all of our directors, officers and employees, including our principal executive, principal financial and principal accounting officers, or persons performing similar functions. Our Code of Business Conduct and Ethics is posted on our website located at www.rainoncology.com, under "Governance Documents." We intend to disclose on our website any amendments to, or waivers from, the code of business conduct and ethics that are required to be disclosed pursuant to the disclosure requirements of Item 5.05 of Form 8-K within four business days following the date of the amendment or waiver.

#### Item 11. EXECUTIVE COMPENSATION.
The information required by this Item will be set forth in the Company's 2023 Proxy Statement, including under the headings "Executive Compensation" and "Corporate Governance", and is incorporated herein by reference.

#### Item 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS.
The information required by this Item will be set forth in the Company's 2023 Proxy Statement, including under the headings "Security Ownership of Certain Beneficial Owners and Management" and "Securities Authorized for Issuance Under Equity Compensation Plans", and is incorporated herein by reference.

#### Item 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE.
The information required by this Item will be set forth in the Company's 2023 Proxy Statement, including under the heading "Corporate Governance" and "Certain Relationships and Related Party Transactions", and is incorporated herein by reference.

#### Item 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES.
The information required by this Item will be set forth in the Company's 2023 Proxy Statement, including under the heading "Ratification of Independent Auditor Selection", and is incorporated herein by reference.

[**Table of Contents**](#TOC)

#### PART IV

#### Item 15. EXHIBITS, FINANCIAL STATEMENT SCHEDULES.
The following documents are filed as part of this report on Form 10-K:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) Financial Statements:

Reference is made to the Index to the registrant's Financial Statements under Item 8 in Part II of this Form 10-K.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) Financial Statement Schedules:

Financial statement schedules have been omitted because the required information is not present or not present in the amounts sufficient to require submission of the schedule or because the information is already included in the financial statements or notes thereto.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) Exhibits:

The documents listed in the following Exhibit Index are incorporated by reference or are filed with this Annual Report on Form 10-K.

[**Table of Contents**](#TOC)

**Exhibit Index**

---

| | |
|:---|:---|
| **ExhibitNumber** | **Description of Exhibit** |
| 3.1 | [Amended and Restated Certificate of Incorporation of the Registrant (incorporated by reference from Exhibit 3.1 to the Registrant's Current Report on Form 8-K filed on April 27, 2021).](https://www.sec.gov/Archives/edgar/data/1724979/000119312521134262/d175057dex31.htm) |
| 3.2 | [Certificate of Amendment of the Amended and Restated Certificate of Incorporation of the Registrant (incorporated by reference from Exhibit 3.1 to the Registrant's Current Report on Form 8-K filed on December 29, 2022).](https://www.sec.gov/Archives/edgar/data/1724979/000110465922130944/tm2233569d1_ex3-1.htm) |
| 3.3 | [Second Amended and Restated Bylaws of the Registrant (incorporated by reference from Exhibit 3.1 to the Registrant's Current Report on Form 8-K filed on February 22, 2023).](https://www.sec.gov/Archives/edgar/data/1724979/000119312523044873/d431240dex31.htm) |
| 4.1 | [Form of Common Stock Certificate of the Registrant (incorporated by reference from Exhibit 4.1 of the Registrant's Amendment No. 1 to Registration Statement on Form S-1 filed on April 9, 2021).](https://www.sec.gov/Archives/edgar/data/1724979/000119312521111673/d26404dex41.htm) |
| 4.2 | [Amended and Restated Investors' Rights Agreement, dated September 2, 2020, by and among the Registrant and certain of its stockholders (incorporated by reference from Exhibit 4.2 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex42.htm) |
| 4.3 | [Description of Securities (incorporated by reference from Exhibit 4.3 of the Registrant's Annual Report on Form 10-K for the Year Ended December 31, 2021).](https://www.sec.gov/Archives/edgar/data/1724979/000156459022008531/rain-ex43_74.htm) |
| 10.1+ | [Form of Indemnification Agreement for directors and executive officers (incorporated by reference from Exhibit 10.1 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex101.htm) |
| 10.2+ | [Amended and Restated 2018 Stock Option/Stock Issuance Plan and form of award agreement thereunder (incorporated by reference from Exhibit 10.2 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex102.htm) |
| 10.3+ | [2021 Equity Incentive Plan (incorporated by reference from Exhibit 10.3 of the Registrant's Amendment No. 2 to Registration Statement on Form S-1 filed on April 19, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521120267/d26404dex103.htm) |
| 10.4+ | [2021 Employee Stock Purchase Plan (incorporated by reference from Exhibit 10.4 of the Registrant's Amendment No. 2 to Registration Statement on Form S-1 filed on April 19, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521120267/d26404dex104.htm) |
| 10.5+ | [Director Offer Letter, dated March 19, 2018, by and between the Registrant and Tran Nguyen (incorporated by reference from Exhibit 10.5 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex105.htm) |
| 10.6+ | [Director Offer Letter, dated March 19, 2018, by and between the Registrant and Peter Radovich (incorporated by reference from Exhibit 10.6 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex106.htm) |
| 10.7+ | [Employment Agreement, dated September 10, 2020, by and between the Registrant and Avanish Vellanki (incorporated by reference from Exhibit 10.7 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex107.htm) |
| 10.8+ | [Employment Agreement, dated September 10, 2020, by and between the Registrant and Robert Doebele (incorporated by reference from Exhibit 10.8 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex108.htm) |
| 10.9+ | [Offer Letter, dated October 1, 2020, by and between the Registrant and Nelson Cabatuan (incorporated by reference from Exhibit 10.9 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex109.htm) |

---

[**Table of Contents**](#TOC)

---

| | |
|:---|:---|
| 10.10+ | [Rain Therapeutics Inc. Executive Severance Plan and Form of Participation Agreement (incorporated by reference from Exhibit 10.1 of the Registrant's Current Report on Form 8-K filed on August 17, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521248309/d214439dex101.htm) |
| 10.11+ | [Form of Employee 2021 Equity Incentive Plan Grant Notice for Nonqualified Stock Options (incorporated by reference from Exhibit 10.3 of the Registrant's Quarterly Report on Form 10-Q for the Quarterly Period ended June 30, 2022)](https://www.sec.gov/Archives/edgar/data/1724979/000155837022012194/rain-20220630xex10d3.htm). |
| 10.12+ | [Form of Director 2021 Equity Incentive Plan Grant Notice for Nonqualified Stock Options (incorporated by reference from Exhibit 10.4 of the Registrant's Quarterly Report on Form 10-Q for the Quarterly Period ended June 30, 2022).](https://www.sec.gov/Archives/edgar/data/1724979/000155837022012194/rain-20220630xex10d4.htm) |
| 10.13\*+ | [First Amendment to Rain Oncology Inc. 2021 Equity Incentive Plan.](rain-20221231xex10d13.htm) |
| 10.14\*+ | [First Amendment to Rain Oncology Inc. Amended and Restated 2018 Stock Option/Stock Issuance Plan.](rain-20221231xex10d14.htm) |
| 10.15\*+ | [First Amendment to Rain Oncology Inc. 2021 Employee Stock Purchase Plan.](rain-20221231xex10d15.htm) |
| 10.16# | [License Agreement, dated September 2, 2020, between the Registrant and Daiichi Sankyo Company, Limited (incorporated by reference from Exhibit 10.10 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex1010.htm) |
| 10.17 | [Amendment to License Agreement dated June 29, 2022, between the Registrant and Daiichi Sankyo Company Limited (incorporated by reference from Exhibit 10.2 of the Registrant's Quarterly Report on Form 10-Q for the Quarterly Period ended June 30, 2022).](https://www.sec.gov/Archives/edgar/data/1724979/000155837022012194/rain-20220630xex10d2.htm) |
| 10.18 | [Office Lease Agreement, dated September 25, 2018, between the Registrant and BSP Senita 8000 Jarvis, LLC, as amended (incorporated by reference from Exhibit 10.12 of the Registrant's Registration Statement on Form S-1 filed on April 2, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521105078/d26404dex1012.htm) |
| 10.19\* | [Second Amendment to Office Lease Agreement, dated October 4, 2022, between the Registrant and BSP Senita 8000 Jarvis, LLC.](rain-20221231xex10d19.htm) |
| 10.20 | [Exchange Agreement, dated April 17, 2021, by and among the Registrant and the stockholders listed therein (incorporated by reference from Exhibit 10.13 of the Registrant's Amendment No. 2 to Registration Statement on Form S-1 filed on April 19, 2021).](https://www.sec.gov/Archives/edgar/data/0001724979/000119312521120267/d26404dex1013.htm) |
| 10.21 | [Sales Agreement, by and between the Registrant and Oppenheimer & Co. Inc., dated May 27, 2022 (incorporated by reference from Exhibit 1.2 of the Registrant's Registration Statement on Form S-3 filed on May 27, 2022).](https://www.sec.gov/Archives/edgar/data/1724979/000119312522162471/d262771dex12.htm) |
| 21.1\* | [List of subsidiaries.](rain-20221231xex21d1.htm) |
| 23.1\* | [Consent of Independent Registered Public Accounting Firm.](rain-20221231xex23d1.htm) |
| 31.1\* | [Certification of the principal executive officer pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934.](rain-20221231xex31d1.htm) |
| 31.2\* | [Certification of the principal financial officer pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934.](rain-20221231xex31d2.htm) |
| 32.1 (1) | [Certification of the principal executive officer and principal financial officer pursuant to 18 U.S.C. Section 1350 and Rule 13a-14(b) under the Securities Exchange Act of 1934.](rain-20221231xex32d1.htm) |
| 101.INS\* | Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because XBRL tags are embedded within the Inline XBRL document. |
| 101.SCH\* | Inline XBRL Taxonomy Extension Schema Document. |
| 101.CAL\* | Inline XBRL Taxonomy Extension Calculation Linkbase Document. |

---

[**Table of Contents**](#TOC)

---

| | |
|:---|:---|
| 101.DEF\* | Inline XBRL Taxonomy Extension Definition Linkbase Document. |
| 101.LAB\* | Inline XBRL Taxonomy Extension Label Linkbase Document. |
| 101.PRE\* | Inline XBRL Taxonomy Extension Presentation Linkbase Document. |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). |

---

\*Filed herewith.

+Indicates management contract or compensatory plan.

#Portions of the exhibit have been omitted for confidentiality purposes.

(1)The certifications on Exhibit 32 hereto are deemed not "filed" for purposes of Section 18 of the Exchange Act or otherwise subject to the liability of that Section. Such certifications will not be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act.

#### Item 16. FORM 10-K SUMMARY.
None.

[**Table of Contents**](#TOC)

#### SIGNATURES
Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this Report to be signed on its behalf by the undersigned, thereunto duly authorized**.**

---

| | | |
|:---|:---|:---|
|  | Company Name | Company Name |
| Date: March 9, 2023 | By: | /s/ Avanish Vellanki |
|  |  | Avanish Vellanki |
|  |  | *Chairman and Chief Executive Officer*<br>*(principal executive officer)* |
| Date: March 9, 2023 | By: | /s/ Nelson Cabatuan |
|  |  | Nelson Cabatuan |
|  |  | *Senior Vice President of Finance and Operations*<br>*(principal financial and accounting officer)* |

---

[**Table of Contents**](#TOC)

#### POWER OF ATTORNEY
KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Avanish Vellanki and Nelson Cabatuan, and each of them, the true and lawful attorneys-in-fact and agents of the undersigned, with full power of substitution and resubstitution, for and in the name, place and stead of the undersigned, to sign in any and all capacities (including, without limitation, the capacities listed below), this Annual Report on Form 10-K, any and all amendments thereto, and to file the same, with all exhibits thereto, and all other documents in connection therewith, with the Securities and Exchange Commission, and hereby grants to such attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and anything necessary to be done to enable the registrant to comply with the provisions of the Securities Exchange Act and all the requirements of the Securities and Exchange Commission, as fully to all intents and purposes as the undersigned might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or their or his or her substitute, or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, this Report has been signed below by the following persons on behalf of the Registrant in the capacities and on the dates indicated.

---

| | | |
|:---|:---|:---|
| **Name** | **Title** | **Date** |
| /s/ Avanish Vellanki | Chief Executive Officer and Chairman | March 9, 2023 |
| **Avanish Vellanki** | (*principal executive officer*) |  |
| /s/ Nelson Cabatuan | Senior Vice President of Finance and Operations | March 9, 2023 |
| **Nelson Cabatuan** | (*principal financial and accounting officer*) |  |
| /s/ Franklin M. Berger | Director | March 9, 2023 |
| **Franklin M. Berger** |  |  |
| /s/ Aaron Davis | Director | March 9, 2023 |
| **Aaron Davis** |  |  |
| /s/ Gorjan Hrustanovic | Director | March 9, 2023 |
| **Gorjan Hrustanovic, Ph.D.** |  |  |
| /s/ Tran Nguyen | Director | March 9, 2023 |
| **Tran Nguyen** |  |  |
| /s/ Peter Radovich | Director | March 9, 2023 |
| **Peter Radovich** |  |  |
| /s/ Stefani Wolff | Director | March 9, 2023 |
| **Stefani Wolff** |  |  |

---

## Exhibit 10.13

**Exhibit 10.13**

**FIRST AMENDMENT TO**

**RAIN THERAPEUTICS INC. 2021**

 **EQUITY INCENTIVE PLAN**

**WHEREAS**, Rain Oncology Inc. (f/k/a Rain Therapeutics Inc.), a Delaware corporation (the "<u>Company</u>") maintains the Rain Therapeutics Inc. 2021 Incentive Plan (the "<u>Plan</u>");

**WHEREAS**, pursuant to Section 20 of the Plan, the Board of Directors of the Company (the "<u>Board</u>") may amend the Plan;

**WHEREAS,** pursuant to a Certificate of Amendment to its Amended and Restated Certificate of Incorporation, the Company changed its name from "Rain Therapeutics Inc." to "Rain Oncology Inc." effective December 30, 2022; and

**WHEREAS**, the Board desires to amend the Plan to incorporate the Company's name change.

**NOW, THEREFORE**, pursuant to its authority under Section 20 of the Plan, the Board hereby amends the Plan as follows, effective as of December 30, 2022 (the "<u>Amendment Effective Date</u>"):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. The Plan shall hereby be referred to as the "Rain Oncology Inc. 2021 Equity Incentive Plan."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. Section 2(l) of the Plan is hereby amended and restated in its entirety to read as follows:

"(l) "***Company***" means Rain Oncology Inc., a Delaware corporation, and except as utilized in the definition of Change in Control, any successor corporation."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. All references in the Plan and in any Award Agreements (as defined in the Plan) to "Rain Therapeutics Inc." shall instead refer to "Rain Oncology Inc."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4. This First Amendment shall be interpreted and construed in accordance with the laws of the State of Delaware and applicable federal law.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5. All capitalized terms used but not otherwise defined herein shall have the meaning assigned to them in the Plan. Except as expressly amended hereby, the Plan shall remain in full force and effect in accordance with its terms.

[Signature Page Follows]

------

**IN WITNESS WHEREOF**, the undersigned has executed this First Amendment to the Plan as of the Amendment Effective Date.

**RAIN ONCOLOGY INC.** 

By: <u>/s/ Avanish Vellanki</u> 

Name: Avanish Vellanki

Title: Chief Executive Officer

------

## Exhibit 10.14

**Exhibit 10.14**

**FIRST AMENDMENT TO**

**RAIN THERAPEUTICS INC. AMENDED AND RESTATED** **2018**

 **STOCK OPTION/STOCK ISSUANCE PLAN**

**WHEREAS**, Rain Oncology Inc. (f/k/a Rain Therapeutics Inc.), a Delaware corporation (the "<u>Company</u>") maintains the Rain Therapeutics Inc. Amended and Restated 2018 Stock Option/Stock Issuance Plan (the "<u>Plan</u>");

**WHEREAS**, pursuant to Section III of Article Four of the Plan, the Board of Directors of the Company (the "<u>Board</u>") may amend the Plan;

**WHEREAS,** pursuant to a Certificate of Amendment to its Amended and Restated Certificate of Incorporation, the Company changed its name from "Rain Therapeutics Inc." to "Rain Oncology Inc." effective December 30, 2022; and

**WHEREAS**, the Board desires to amend the Plan to incorporate the Company's name change.

**NOW, THEREFORE**, pursuant to its authority under Section III of Article Four of the Plan, the Board hereby amends the Plan as follows, effective as of December 30, 2022 (the "<u>Amendment Effective Date</u>"):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. The Plan shall hereby be referred to as the " Rain Oncology Inc. Amended and Restated 2018 Stock Option/ Stock Issuance Plan."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. Section F of the Appendix attached to the Plan is hereby amended and restated in its entirety to read as follows:

"F.**Corporation** shall mean Rain Oncology Inc., a Delaware corporation, and any successor corporation to all or substantially all of the assets or voting stock of Rain Oncology Inc. which shall by appropriate action adopt the Plan."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. All references in the Plan and in any award agreements issued thereunder to "Rain Therapeutics Inc." shall instead refer to "Rain Oncology Inc."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4. This First Amendment shall be interpreted and construed in accordance with the laws of the State of Delaware and applicable federal law.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5. All capitalized terms used but not otherwise defined herein shall have the meaning assigned to them in the Plan. Except as expressly amended hereby, the Plan shall remain in full force and effect in accordance with its terms.

[Signature Page Follows]

------

**IN WITNESS WHEREOF**, the undersigned has executed this First Amendment to the Plan as of the Amendment Effective Date.

**RAIN ONCOLOGY INC.** 

By: <u>/s/ Avanish Vellanki</u> 

Name: Avanish Vellanki

Title: Chief Executive Officer

------

## Exhibit 10.15

**Exhibit 10.15**

**FIRST AMENDMENT TO**

**RAIN THERAPEUTICS INC. 2021**

 **EMPLOYEE STOCK PURCHASE PLAN**

**WHEREAS**, Rain Oncology Inc. (f/k/a Rain Therapeutics Inc.), a Delaware corporation (the "<u>Company</u>") maintains the Rain Therapeutics Inc. 2021 Employee Stock Purchase Plan (the "<u>Plan</u>");

**WHEREAS**, pursuant to Section 19 of the Plan, the Board of Directors of the Company (the "<u>Board</u>") may amend the Plan;

**WHEREAS,** pursuant to a Certificate of Amendment to its Amended and Restated Certificate of Incorporation, the Company changed its name from "Rain Therapeutics Inc." to "Rain Oncology Inc." effective December 30, 2022; and

**WHEREAS**, the Board desires to amend the Plan to incorporate the Company's name change.

**NOW, THEREFORE**, pursuant to its authority under Section 19 of the Plan, the Board hereby amends the Plan as follows, effective as of December 30, 2022 (the "<u>Amendment Effective Date</u>"):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. The Plan shall hereby be referred to as the "Rain Oncology Inc. 2021 Employee Stock Purchase Plan."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. Section 2(f) of the Plan is hereby amended and restated in its entirety to read as follows:

"(f) "***Company***" means Rain Oncology Inc., a Delaware corporation, and any successor corporation."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. All references in the Plan to "Rain Therapeutics Inc." shall instead refer to "Rain Oncology Inc."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4. This First Amendment shall be interpreted and construed in accordance with the laws of the State of Delaware and applicable federal law.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5. All capitalized terms used but not otherwise defined herein shall have the meaning assigned to them in the Plan. Except as expressly amended hereby, the Plan shall remain in full force and effect in accordance with its terms.

[Signature Page Follows]

------

**IN WITNESS WHEREOF**, the undersigned has executed this First Amendment to the Plan as of the Amendment Effective Date.

**RAIN ONCOLOGY INC.** 

By: <u>/s/ Avanish Vellanki</u> 

Name: Avanish Vellanki

Title: Chief Executive Officer

------

## Exhibit 10.19

**Exhibit 10.19**

**SECOND AMENDMENT TO OFFICE LEASE AGREEMENT**

**THIS SECOND AMENDMENT TO OFFICE LEASE AGREEMENT** (this "**Amendment**") is made effective as of October 4, 2022 (the "**Effective Date**"), by and between **BSP SENITA 8000 JARVIS, LLC**, a Delaware limited liability company ("**Landlord**"), and **RAIN THERAPEUTICS INC.**, a Delaware corporation ("**Tenant**").

**RECITALS**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**A.**Landlord (as successor-in-interest to 8000 Jarvis Avenue Equities LLC, a California limited liability company) and Tenant are parties to that certain lease entitled "Office Lease Agreement" dated September 25, 2018 ("**Original Lease**"), as amended by that certain First Amendment to Office Lease Agreement dated as of June 3, 2020 ("**First Amendment**", and, together with the Original Lease, collectively and as amended, the "**Lease**"), pursuant to which Tenant leases from Landlord the premises in the building located at 8000 Jarvis Avenue, Newark, California ("**Building**") consisting of approximately 3,857 rentable square feet located in the Building and commonly referred to as Suite 204, as more particularly described in the Lease (the "**Original Premises**").

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**B.**Landlord and Tenant desire to expand the Original Premises covered by the Lease to include approximately 3,880 rentable square feet commonly known as Suite 200 in the Building (the "**Expansion Premises**"), as more particularly described on <u>Exhibit A</u> attached hereto.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**C.**Landlord and Tenant desire to amend the Lease to increase the area of the Original Premises to include the Expansion Premises and to modify other provisions of the Lease, all as more particularly set forth herein and subject to the terms hereof.

**AGREEMENT**

**NOW, THEREFORE**, in consideration of the mutual covenants contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, Landlord and Tenant agree that the Lease is amended as follows:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1.**Defined Terms**. Capitalized terms used and not otherwise defined herein shall have the same meanings ascribed to them in the Lease. From and after the date hereof, unless the context otherwise clearly requires, the use of the term "Lease" herein shall mean the Lease, as amended by this Amendment.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2.**Expansion of the Original Premises**. On the earlier of (i) January 1, 2023 and (ii) the date the Expansion Premises are delivered to Tenant with the Tenant Improvements Substantially Complete (as each such term is defined in the Work Letter attached hereto) (such earlier date, the "**Expansion Premises Commencement Date**"), and continuing through September 30, 2024 (the "**Expiration Date**"), Landlord shall lease to Tenant and Tenant shall lease from Landlord the Expansion Premises on all of the terms and conditions of the Lease, as amended hereby. As of the Expansion Premises Commencement Date all references in the Lease

------

or this Amendment to the "Premises" shall be deemed to include the Expansion Premises, and, together with the Original Premises (collectively referred to herein as the "**Premises**") shall consist of a total of approximately 7,737 rentable square feet. The Expansion Premises Commencement Date shall be confirmed in a notice (the "**Notice of Terms**") which Notice of Terms shall be prepared by Landlord and confirmed by Tenant within a reasonable time after the Expansion Premises Commencement Date occurs. Notwithstanding anything set forth herein to the contrary, this Amendment is entirely subject to and entirely contingent upon Nexient, LLC, a Delaware limited liability company ("**Nexient**") vacating, surrendering and releasing the Expansion Premises to Landlord on September 30, 2022 (the expiration day as set forth in Nexient's lease). Any delay due to Nexient's failure to deliver the Expansion Premises on or before September 30, 2022 shall not subject Landlord to any liability nor shall the validity of this Amendment nor the obligations of Tenant hereunder be affected, provided, however, the Expansion Premises Commencement Date shall be delayed until such time as Nexient delivers the Expansion Premises as required hereunder.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.**Term**. The Term of the Lease for the Expansion Premises and the Expiration Date shall be coterminous with that of the Original Premises.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4.**Condition of the Expansion Premises**. Landlord shall have no obligation to construct leasehold improvements for Tenant or to repair or refurbish any portion of the Original Premises or the Expansion Premises, except (i) that the Expansion Premises shall be delivered to Tenant with the roof, parking lots, HVAC, plumbing, electrical and related mechanical systems serving the Expansion Premises in good working order and condition and (ii) as set forth in <u>Section 7</u> below. Neither Landlord nor its agents or representatives have made any representations or promises with respect to the Property, the Building or the Premises, except as specifically set forth in the Lease or this Amendment, and Tenant confirms that the Premises is suited for Tenant's use and is in good and satisfactory condition. Tenant confirms to Landlord that prior to executing this Amendment it has made such investigations as it deems appropriate with respect to the suitability of the Premises for its continued use and occupancy.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.**Monthly Payments**.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a.*Monthly Base Rent*. Prior to the Expansion Premises Commencement Date, Tenant shall continue to pay Monthly Base Rent in accordance with Section 3 of the Original Lease, as amended by Section 2 of the First Amendment. Effective as of the Expansion Premises Commencement Date, in addition to all other charges payable pursuant to the Lease, Tenant shall pay the following installments of Monthly Base Rent for the Premises, in accordance with the terms of the Lease as follows:

---

| | | |
|:---|:---|:---|
| &nbsp;&nbsp;**Scheduled Dates** | &nbsp;&nbsp;**Monthly Base Rent for the Premises** | &nbsp;&nbsp;**Monthly Rental Rate Per Square Foot**<br> (rounded to 2 decimal pts) |
| &nbsp;&nbsp;Expansion Premises Commencement Date – January 31, 2023 | &nbsp;&nbsp;$27930.57 | &nbsp;&nbsp;$3.61 |

---

------

---

| | | |
|:---|:---|:---|
| &nbsp;&nbsp;February 1, 2023 – September 30, 2024 | &nbsp;&nbsp;$28704.27 | &nbsp;&nbsp;$3.71 |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b.*Amortized Tenant Improvement Costs*. Effective as of the Expansion Premises Commencement Date, in addition to monthly Base Rent and all other charges payable pursuant to the Lease, Tenant shall pay the following installments of the Amortized Tenant Improvement Costs (as currently estimated to be) at the same time as monthly Base Rent, in accordance with Section 3.3 of the Original Lease:

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| | |
|:---|:---|
| &nbsp;&nbsp;**Scheduled Dates** | &nbsp;&nbsp;**Monthly Amortized Tenant Improvement Costs** |
| &nbsp;&nbsp;Expansion Premises Commencement Date – January 31, 2023 | &nbsp;&nbsp;$7126.31 |
| &nbsp;&nbsp;February 1, 2023 – September 30, 2024 | &nbsp;&nbsp;$7126.31 |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6.**Additional Provisions**.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a.*Building*: Due to a recent re-measurement in accordance with BOMA Office Buildings Standard Methods of Measurement and Calculating Rentable Area (2010) – Method A, the definition of Rentable Area of Building as set forth in the Basic Lease Information is hereby deleted in its entirety and shall be replaced with the following:

"**Rentable Area of the Building**: Approximately 50,136 rentable square feet."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b.*Tenant's Share*: As of the Expansion Premises Commencement Date, the definition of Tenant's Share as set forth in the Basic Lease Information is hereby deleted in its entirety and shall be replaced with the following:

"**Tenant's Share**: 15.43% (7,737/50,136)"

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c.*Parking*: Tenant shall continue to have the Parking Allocation of four (4) unreserved parking spaces per 1,000 rentable square feet of Premises upon the Expansion Premises Commencement Date at no cost during the Term of the Lease.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7.**Landlord Work; Tenant Improvements; Amortized Tenant Improvement Costs**.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a.*Landlord Work*. Landlord, at Landlord's sole cost, shall perform the following in the Premises: (i) demolition of the two offices and conference room currently existing in the Original Premises (noted in red on <u>Exhibit A</u> attached hereto, but only with respect to the Original Premises), (ii) associated repair of the grid, patching carpet, and other associated cleanup and (iii) the balancing of the HVAC system serving the Original Premises and the Expansion Premises (collectively, the "**Landlord Work**").

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b.*Tenant Improvements*. Additionally, Landlord shall cause for the completion of the Tenant Improvements to the Premises in accordance with the work letter attached hereto as <u>Exhibit B</u> (the "**Work Letter**"). Tenant understands that the Landlord Work and the completion of the Tenant Improvements will be performed during Tenant's occupancy and use of the Original Premises, and may result in inconvenience to Tenant (including noise, vibration and displacement from portions of the Original Premises from time to time). Tenant will fully cooperate with Landlord's efforts to efficiently and expeditiously complete the Landlord Work and the Tenant Improvements by, among other things, vacating portions of the Original Premises from time to time to permit work to proceed and/or removing any personal property (such as computers, artwork and other valuable or fragile personal property) from within the Original Premises that may be affected by the completion of the Landlord Work and the Tenant Improvements. Landlord will make reasonable efforts to minimize the inconvenience and disturbance caused by the Landlord Work and the Tenant Improvements, but Landlord is not responsible for business interruption or damage to Tenant's personal property which results from the completion of the Landlord Work and/or the Tenant Improvements.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c.*Amortized Tenant Improvement Costs*. Landlord shall advance the amount of the Amortized Tenant Improvement Costs (as defined in the Work Letter) for permitted expenditures incurred in connection with Tenant Improvements. Tenant shall repay the Amortized Tenant Improvement Costs until paid in full, in twenty-one (21) equal monthly installments over the remaining Term of the Lease as set forth in <u>Section 5(b)</u> herein; provided, however, in the event (i) the remaining Term following the Expansion Premises Commencement Date does not allow for the repayment of the Amortized Tenant Improvement Costs in equal monthly payments as set forth in Section 5(b), or (ii) the amount currently estimated to be the Amortized Tenant Improvement Costs exceeds the amount of $149,652.44, the Notice of Terms shall set forth a modified monthly Amortized Tenant Improvement Costs amount. Each payment shall be payable at the same time and in the same manner that Base Rent is payable pursuant to the Lease. All payments received shall be applied to principal reduction. The Amortized Tenant Improvement Costs may be prepaid in full or in part at any time without premium or penalty. The repayment of the Amortized Tenant Improvement Costs by Tenant to Landlord shall not constitute the payment of Rent but rather the repayment of a loan; provided, however, that any default in the payment of any sums to be paid by Tenant pursuant to this <u>Section 7(c)</u> shall, at the election of Landlord, constitute an Event of Default under the Lease, and, in addition to giving rise to the right of acceleration set forth in the next succeeding sentence, shall entitle Landlord to exercise any and all remedies available to Landlord under the Lease, at law or in equity, for a monetary default under the Lease. The unpaid principal balance of the Amortized Tenant Improvement Costs shall be immediately due and payable at the option of Landlord upon any Event of Default under the Lease, or upon any default in the payment of any installment of the Amortized Tenant Improvement Costs as and when due hereunder. Any failure of Landlord to exercise such option to accelerate shall not constitute a waiver of the right to exercise such option to accelerate at any future time.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8.**Temporary Space**. On and after the Effective Date Tenant shall be permitted to occupy Suite 120 in the Building consisting of approximately 4,292 rentable square feet (the "**Temporary Space**"), provided Tenant has provided certificates of insurance to Landlord

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including the Temporary Space as required under Section 11.1 of the Original Lease. The Temporary Space shall be made available to Tenant in its "AS IS" condition and Landlord shall <u>Section 7(c)</u> have no obligation to construct leasehold improvements for Tenant or to repair or refurbish the Temporary Space or perform any other work in the Temporary Space. Landlord agrees that Tenant shall not be required to pay Base Rent for the Temporary Space, however Tenant shall be obligated to pay Tenant's Share of Operating Costs and Taxes (estimated at $1.00 per month times the rentable square footage of the Temporary Space) for the Temporary Space and any separately metered utilities. Provided, further, for any time periods following the expiration of the Move-Out Period (as defined below), Tenant shall be additionally responsible to pay monthly Base Rent for the Temporary Space, which rent shall be equal to $715.00 per day (the "**Temporary Space Rent**"), for the period commencing upon the expiration of the Move-Out Period and extending to the date Tenant vacates the Temporary Space in accordance with the terms hereof. Excepting the payment of Base Rent for the Temporary Space (other than Temporary Space Rent following the Move-Out Period, if applicable) all other terms and conditions of this Lease shall apply to Tenant's use of the Temporary Space. Tenant shall surrender the Temporary Space to Landlord in broom clean condition, free of all of Tenant's personal property and otherwise in substantially the same condition the Temporary Space was delivered to Tenant no later than five (5) days after the date the Expansion Premises are Ready for Occupancy (such 5-day period, the "**Move-Out Period**"). Tenant's failure to surrender the Temporary Space following the expiration of the Move-Out Period shall be an Event of Default under this Lease and Landlord shall be entitled to all rights and remedies available at law or in equity with respect thereto.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9.**Furniture**. It is acknowledged that Nexient has agreed to leave the office furniture and fixtures at the Premises listed on <u>Exhibit C</u> attached hereto (collectively, the "**Furniture**"). Tenant acknowledges that Landlord makes no representations or warranty regarding the ownership, existence or condition of any item of the Furniture and Tenant agrees to accept the Furniture in its "**AS IS**" condition and, subject to the rights of any such unknown claimants, Tenant shall be deemed to own the furniture as Tenant's personal property from and after the Effective Date hereof. Upon the expiration or termination of the Lease, such Furniture (other than the refrigerator and the dishwasher, which are fixtures) would be considered personal property and subject to removal by Tenant in accordance with Section 19.1 of the Original Lease. During the time the Tenant Improvements are being completed, the Furniture shall be stored in the Conference Room of the Expansion Premises, where no Tenant Improvements are planned.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10.**Security Deposit**. Landlord currently holds a Security Deposit in the amount of $75,000.00 (the "**Original Security Deposit**") pursuant to the terms of Section 4 of the Original Lease. In connection with this Amendment Landlord requires that the Original Security Deposit be increased to the amount of $109,939.79 (the "**Security Deposit**"). Upon the execution of this Amendment Tenant shall pay to Landlord the amount of $34,939.79. Thereafter, the definition of Security Deposit as set forth in the Basic Lease Information is hereby deleted in its entirety and shall be replaced with the following:

"**Security Deposit**:$109,939.79"

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11.**Brokers**. Tenant represents and warrants to Landlord that it has not engaged any broker, finder or other person who would be entitled to any commission or fees in respect of the negotiation, execution or delivery of this Amendment, other than CBRE, and shall indemnify, defend and hold harmless Landlord against any loss, cost, liability or expense incurred by Landlord as a result of any claim asserted by any such broker, finder or other person on the basis of any arrangements or agreements made or alleged to have been made by or on behalf of Tenant. The provisions of this section shall not apply to brokers with whom Landlord has an express written broker agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12.**Specific Representations By Tenant**. Tenant represents and warrants to Landlord that, as of the date hereof: (i) Tenant is not in breach or default of any of its obligations under the Lease, and no events have occurred which with the passage of time and/or the giving of notice would constitute a breach or default by Tenant under the Lease; (ii) to Tenant's knowledge, Landlord is not in breach or default of any of its obligations under the Lease, and no events have occurred which with the passage of time and/or the giving of notice would constitute a breach or default by Landlord under the Lease; (iii) the Lease is in full force and effect and constitutes the only agreement between Landlord and Tenant regarding the leasing of the Premises; (iv) other than as specifically set forth in this Amendment, Tenant is not entitled to any credits, offsets, concessions or abatements under the Lease, or otherwise against the payment of rent or other charges under the Lease; (v) Tenant is not a party to any bankruptcy or similar proceeding; and (vi) Tenant holds the entire interest of the "Tenant" under the Lease, and has not assigned or sublet any interest therein.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13.**Accessibility**. To Landlord's actual knowledge, the property being leased or rented pursuant to this Amendment has not undergone inspection by a Certified Access Specialist (CASp). A CASp can inspect the Premises and determine whether the Premises comply with all of the applicable construction-related accessibility standards under State law. Although State law does not require a CASp inspection of the Premises, the Landlord may not prohibit Tenant from obtaining a CASp inspection of the Premises for the occupancy or potential occupancy of Tenant, if requested by Tenant. The parties shall mutually agree on the arrangements for the time and manner of a CASp inspection requested by Tenant, the payment of the fee for such a Tenant requested CASp inspection, and the cost of making any repairs necessary to correct violations of construction-related accessibility standards within the Premises. This <u>Section 13</u> is included in this Lease solely for the purpose of complying with California Civil Code Section 1938 and shall not in any manner affect Landlord's and Tenant's respective responsibilities for compliance with construction-related accessibility standards as provided under the Lease.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14.**Continuing Effectiveness**. The Lease, except as amended hereby, remains un- amended, and, as amended hereby, remains in full force and effect.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;15.**Entire Agreement**. This Amendment embodies the entire understanding between Landlord and Tenant with respect to its subject matter and can be changed only by an instrument in writing signed by Landlord and Tenant.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;16.**Corporate And Partnership Authority**. If Tenant is a corporation or partnership, or is comprised of either or both of them, each individual executing this Amendment

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for the corporation or partnership represents that he or she is duly authorized to execute and deliver this Amendment for the corporation or partnership and that this Amendment is binding upon the corporation or partnership in accordance with its terms.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;17.**Attorneys' Fees**. The provisions of the Lease respecting attorneys' fees shall apply to this Amendment or, if the Lease does not contain an attorney's fees clause, then if legal action shall be commenced to enforce or declare the effect of any provision of this Amendment or of the Lease, the court as a part of its judgment shall award reasonable attorneys' fees and costs to the prevailing party.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;18.**Execution By Both Parties**. Submission of this instrument for examination or signature by Tenant does not constitute a reservation of or option to lease, and it is not effective as an amendment to lease or otherwise until execution by and delivery to both Landlord and Tenant, and execution and delivery hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;19.**Electronic Signatures**. This Amendment may be executed in counterparts, each of which shall constitute an original, and all of which, together, shall constitute one document. Each party hereto, and their respective successors and assigns shall be authorized to rely upon the signatures of all of the parties hereto on this Amendment which are delivered by facsimile, telecopier or electronic mail transmission (including pdf or any electronic signature complying with the U.S. federal ESIGN Act of 2000, e.g., www.docusign.com) as constituting a duly authorized, irrevocable, actual, current delivery of this Amendment with original ink signatures of each person and entity.

**(SIGNATURES ON NEXT PAGE)**

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**IN WITNESS WHEREOF,** the parties hereto have executed this Amendment as of the date first above written.

**LANDLORD:**

**BSP SENITA 8000 JARVIS, LLC**,

a Delaware limited liability company

By:BSP Senita Realty Investors, LLC,

a Delaware limited liability company the Sole Member

By:BSP Senita Manager, LLC,

a Delaware limited liability company its Manager

By: <u>/s/ Mark S. Oddo</u>

Name: Mark S. Oddo

Title:Vice President

**TENANT:**

**RAIN THERAPEUTICS INC.**,

a Delaware corporation

By:<u>/s/ Avanish Vellanki</u> 

Name:Avanish Vellanki

Title:CEO

Approved: <u>/s/ Nelson Cabatuan</u> 

Nelson Cabatuan, SVP

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## Exhibit 21.1

**Exhibit 21.1**

**Subsidiaries of Rain Oncology Inc.**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. Rain Oncology Australia Pty Ltd, an Australian Private Company

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## Exhibit 23.1

**Exhi** **bit** **23.1**

**Consent of Independent Registered Public Accounting Firm**

We consent to the incorporation by reference in the following Registration Statements:

1) Registration Statement (Form S-3 No. 333-265297) of Rain Oncology Inc.,

2) Registration Statement (Form S-8 No. 333-255548) pertaining to the Rain Oncology Inc. 2021 Equity Incentive Plan, the Rain Oncology Inc. 2021 Employee Stock Purchase Plan, and the Rain Oncology Inc. Amended and Restated 2018 Stock Option/Stock Issuance Plan of Rain Oncology Inc., and

3) Registration Statement (Form S-8 No. 333-264753) pertaining to the Rain Oncology Inc. 2021 Equity Incentive Plan and the Rain Oncology Inc. 2021 Employee Stock Purchase Plan of Rain Oncology Inc.;

of our report dated March 9, 2023, with respect to the consolidated financial statements of Rain Oncology Inc. included in this Annual Report (Form 10-K) of Rain Oncology Inc. for the year ended December 31, 2022.

/s/ Ernst & Young LLP

San Diego, California

March 9, 2023

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## Exhibit 31.1

**Exhibit 31.1**

**CERTIFICATION PURSUANT TO**

**RULES 13a-14(a) AND 15d-14(a) UNDER TH** **E SECURITIES EXCHANGE ACT OF 1934, AS ADOPTED PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002**

I, Avanish Vellanki, certify that:

&nbsp;&nbsp;&nbsp;&nbsp;1. I have reviewed this Annual Report on Form 10-K of Rain Oncology Inc.;

&nbsp;&nbsp;&nbsp;&nbsp;2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

&nbsp;&nbsp;&nbsp;&nbsp;3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

&nbsp;&nbsp;&nbsp;&nbsp;4. The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15 15d-15(f)) for the registrant and have:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

&nbsp;&nbsp;&nbsp;&nbsp;5. The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

---

| | | |
|:---|:---|:---|
| Date: March 9, 2023 | By: | /s/ Avanish Vellanki |
|  |  | Avanish Vellanki |
|  |  | Chairman and Chief Executive Officer<br>*(principal executive officer)* |

---

------

## Exhibit 31.2

**Exhibit 31.2**

**CERTIFICATION PURSUANT TO**

**RULES 13a-14(a) AND 15d-14(a) UNDE** **R THE SECURITIES EXCHANGE ACT OF 1934, AS ADOPTED PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002**

I, Nelson Cabatuan, certify that:

&nbsp;&nbsp;&nbsp;&nbsp;1. I have reviewed this Annual Report on Form 10-K of Rain Oncology Inc.;

&nbsp;&nbsp;&nbsp;&nbsp;2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

&nbsp;&nbsp;&nbsp;&nbsp;3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

&nbsp;&nbsp;&nbsp;&nbsp;4. The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15 15d-15(f)) f or the registrant and have:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

&nbsp;&nbsp;&nbsp;&nbsp;5. The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

---

| | | |
|:---|:---|:---|
| Date: March 9, 2023 | By: | /s/ Nelson Cabatuan |
|  |  | Nelson Cabatuan |
|  |  | Senior Vice President of Finance and Operations<br>*(principal financial and accounting officer)* |

---

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## Exhibit 32.1

**Exhibit 32.1**

**CERTIFICATION PURSUANT TO**

**18 U.S.C. SECTION 1** **350, AS ADOPTED PURSUANT TO**

**SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002**

In connection with the Annual Report on Form 10-K of Rain Oncology Inc. (the "Company") for the year ended December 31, 2022 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), each of the undersigned officers of the Company hereby certifies, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to the best of his knowledge:

1. The Report fully complies with the requirements of Section 13(a) or Section 15(d) of the Exchange Act, and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

---

| | | |
|:---|:---|:---|
| Date: March 9, 2023 | By: | /s/ Avanish Vellanki |
|  |  | Avanish Vellanki |
|  |  | Chairman and Chief Executive Officer<br>*(principal executive officer)*<br>|
| Date: March 9, 2023 | By: | /s/ Nelson Cabatuan |
|  |  | Nelson Cabatuan |
|  |  | Senior Vice President of Finance and Operations<br>*(principal financial and accounting officer)* |

---

The foregoing certification is being furnished solely to accompany the Report pursuant to 18 U.S.C. § 1350, and is not being filed for purposes of Section 18 of the Securities Exchange Act of 1934, and is not to be incorporated by reference into any filing of the Company, whether made before or after the date hereof, regardless of any general incorporation language in such filing.

Note: A signed original of this written statement required by § 906 has been provided to Rain Oncology Inc. and will be retained by Rain Oncology Inc. and furnished to the Securities and Exchange Commission or its staff upon request.

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