# EDGAR Filing Document

**Accession Number:** 0001728117
**File Stem:** 0001728117-26-000032
**Filing Date:** 2026-5
**Character Count:** 160835
**Document Hash:** 4a70f615c8e707f8a9aebd4fc45bc948
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001728117-26-000032.hdr.sgml**: 20260515

**ACCESSION NUMBER**: 0001728117-26-000032

**CONFORMED SUBMISSION TYPE**: 10-Q

**PUBLIC DOCUMENT COUNT**: 73

**CONFORMED PERIOD OF REPORT**: 20260331

**FILED AS OF DATE**: 20260515

**DATE AS OF CHANGE**: 20260515

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Gossamer Bio, Inc.
- **CENTRAL INDEX KEY:** 0001728117
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 475461709
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 10-Q
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38796
- **FILM NUMBER:** 26986705

**BUSINESS ADDRESS:**
- **STREET 1:** 3115 MERRYFIELD ROW
- **STREET 2:** SUITE 120
- **CITY:** SAN DIEGO
- **STATE:** CA
- **ZIP:** 92121
- **BUSINESS PHONE:** (858) 684-1300

**MAIL ADDRESS:**
- **STREET 1:** 3115 MERRYFIELD ROW
- **STREET 2:** SUITE 120
- **CITY:** SAN DIEGO
- **STATE:** CA
- **ZIP:** 92121

?xml version='1.0' encoding='ASCII'? goss-20260331

<u>[**Table of Contents**](#i9a97deb1f63b46c3867089c2b6fc256c_7)</u>

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**WASHINGTON, D.C. 20549**

**_________________________**

**FORM 10-Q**

**_________________________**

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

**For the quarterly period ended March 31, 2026**

**OR**

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

**For the transition period from ________to_________.**

**Commission File Number: 001-38796**

**_________________________**

**GOSSAMER BIO, INC.**

**(Exact name of Registrant as specified in its charter).**

**_________________________**

---

| | | | |
|:---|:---|:---|:---|
| **Delaware** | **Delaware** | **Delaware** | **47-5461709** |
| **(State or other jurisdiction of<br>incorporation or organization)** | **(State or other jurisdiction of<br>incorporation or organization)** | **(State or other jurisdiction of<br>incorporation or organization)** | **(I.R.S. Employer<br>Identification No.)** |
| **3115 Merryfield Row, Suite 120** | **San Diego** | **California** | **92121** |
| **(Address of principal executive offices)** | **(Address of principal executive offices)** | **(Address of principal executive offices)** | **(Zip Code)** |

---

**Registrant's telephone number, including area code: (858) 684-1300**

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

---

| | | |
|:---|:---|:---|
| **Title of each class** | **Trading<br>Symbol(s)** | **Name of each exchange on which registered** |
| Common Stock, $0.0001 par value per share | GOSS | Nasdaq Global Select Market |

---

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:&nbsp;&nbsp;&nbsp;&nbsp;Yes&nbsp;&nbsp;&nbsp;&nbsp;☒ &nbsp;&nbsp;&nbsp;&nbsp;No&nbsp;&nbsp;&nbsp;&nbsp; ☐

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).&nbsp;&nbsp;&nbsp;&nbsp;Yes&nbsp;&nbsp;&nbsp;&nbsp; ☒ &nbsp;&nbsp;&nbsp;&nbsp;No&nbsp;&nbsp;&nbsp;&nbsp; ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a 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.

---

| | | | |
|:---|:---|:---|:---|
| 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.&nbsp;&nbsp;&nbsp;&nbsp;☐

------

<u>[**Table of Contents**](#i9a97deb1f63b46c3867089c2b6fc256c_7)</u>

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

As of May 12, 2026, the registrant had 234,696,281 shares of common stock ($0.0001 par value) outstanding.

------

<u>[**Table of Contents**](#i9a97deb1f63b46c3867089c2b6fc256c_7)</u>

**TABLE OF CONTENTS**

---

| | | |
|:---|:---|:---|
| **<u>[PART I. FINANCIAL INFORMATION](#i9a97deb1f63b46c3867089c2b6fc256c_10)</u>** | **<u>[PART I. FINANCIAL INFORMATION](#i9a97deb1f63b46c3867089c2b6fc256c_10)</u>** | |
| [Item 1](#i9a97deb1f63b46c3867089c2b6fc256c_13) | <u>[Condensed Consolidated Financial Statements (unaudited)](#i9a97deb1f63b46c3867089c2b6fc256c_13)</u> | <u>[4](#i9a97deb1f63b46c3867089c2b6fc256c_16)</u> |
|  | <u>[Condensed Consolidated Balance Sheets](#i9a97deb1f63b46c3867089c2b6fc256c_16)</u> <u>as of March 31, 2026 (unaudited) and December 31, 2025</u> | <u>[4](#i9a97deb1f63b46c3867089c2b6fc256c_16)</u> |
|  | <u>[Condensed Consolidated Statements of Operations and Comprehensive Loss](#i9a97deb1f63b46c3867089c2b6fc256c_19)</u> <u>for the Three Months ended March 31, 2026 and 2025 (unaudited)</u> | <u>[5](#i9a97deb1f63b46c3867089c2b6fc256c_19)</u> |
|  | <u>[Condensed Consolidated Statements of Stockholders' Equity (Deficit)](#i9a97deb1f63b46c3867089c2b6fc256c_22)</u> <u>for the Three Months ended March 31, 2026 and 2025 (unaudited)</u> | <u>[6](#i9a97deb1f63b46c3867089c2b6fc256c_22)</u> |
|  | <u>[Condensed Consolidated Statements of Cash Flows](#i9a97deb1f63b46c3867089c2b6fc256c_25)</u> <u>for the Three Months ended March 31, 2026 and 2025 (unaudited)</u> | <u>[7](#i9a97deb1f63b46c3867089c2b6fc256c_25)</u> |
|  | <u>[Notes to Unaudited Condensed Consolidated Financial Statements](#i9a97deb1f63b46c3867089c2b6fc256c_28)</u> | <u>[8](#i9a97deb1f63b46c3867089c2b6fc256c_28)</u> |
| [Item 2](#i9a97deb1f63b46c3867089c2b6fc256c_76) | <u>[Management's Discussion and Analysis of Financial Condition and Results of Operations](#i9a97deb1f63b46c3867089c2b6fc256c_76)</u> | <u>[27](#i9a97deb1f63b46c3867089c2b6fc256c_76)</u> |
| [Item 3](#i9a97deb1f63b46c3867089c2b6fc256c_97) | <u>[Quantitative and Qualitative Disclosures About Market Risk](#i9a97deb1f63b46c3867089c2b6fc256c_97)</u> | <u>[35](#i9a97deb1f63b46c3867089c2b6fc256c_97)</u> |
| [Item 4](#i9a97deb1f63b46c3867089c2b6fc256c_100) | <u>[Controls and Procedures](#i9a97deb1f63b46c3867089c2b6fc256c_100)</u> | <u>[35](#i9a97deb1f63b46c3867089c2b6fc256c_100)</u> |
| **<u>[PART II. OTHER INFORMATION](#i9a97deb1f63b46c3867089c2b6fc256c_103)</u>** | **<u>[PART II. OTHER INFORMATION](#i9a97deb1f63b46c3867089c2b6fc256c_103)</u>** |  |
| [Item 1](#i9a97deb1f63b46c3867089c2b6fc256c_106) | <u>[Legal Proceedings](#i9a97deb1f63b46c3867089c2b6fc256c_106)</u> | <u>[36](#i9a97deb1f63b46c3867089c2b6fc256c_106)</u> |
| [Item 1A](#i9a97deb1f63b46c3867089c2b6fc256c_109) | <u>[Risk Factors](#i9a97deb1f63b46c3867089c2b6fc256c_109)</u> | <u>[36](#i9a97deb1f63b46c3867089c2b6fc256c_109)</u> |
| [Item 2](#i9a97deb1f63b46c3867089c2b6fc256c_112) | <u>[Unregistered Sales of Equity Securities and Use of Proceeds](#i9a97deb1f63b46c3867089c2b6fc256c_112)</u> | <u>[36](#i9a97deb1f63b46c3867089c2b6fc256c_112)</u> |
| [Item 3](#i9a97deb1f63b46c3867089c2b6fc256c_115) | <u>[Defaults Upon Senior Securities](#i9a97deb1f63b46c3867089c2b6fc256c_115)</u> | <u>[36](#i9a97deb1f63b46c3867089c2b6fc256c_115)</u> |
| [Item 4](#i9a97deb1f63b46c3867089c2b6fc256c_118) | <u>[Mine Safety Disclosures](#i9a97deb1f63b46c3867089c2b6fc256c_118)</u> | <u>[36](#i9a97deb1f63b46c3867089c2b6fc256c_118)</u> |
| [Item 5](#i9a97deb1f63b46c3867089c2b6fc256c_121) | <u>[Other Information](#i9a97deb1f63b46c3867089c2b6fc256c_121)</u> | <u>[36](#i9a97deb1f63b46c3867089c2b6fc256c_121)</u> |
| [Item 6](#i9a97deb1f63b46c3867089c2b6fc256c_124) | <u>[Exhibits](#i9a97deb1f63b46c3867089c2b6fc256c_124)</u> | <u>[36](#i9a97deb1f63b46c3867089c2b6fc256c_124)</u> |
|  | <u>[Exhibit Index](#i9a97deb1f63b46c3867089c2b6fc256c_127)</u> | <u>[37](#i9a97deb1f63b46c3867089c2b6fc256c_127)</u> |
|  | <u>[Signatures](#i9a97deb1f63b46c3867089c2b6fc256c_130)</u> | <u>[38](#i9a97deb1f63b46c3867089c2b6fc256c_130)</u> |

---

------

<u>[**Table of Contents**](#i9a97deb1f63b46c3867089c2b6fc256c_7)</u>

**PART I. FINANCIAL INFORMATION**

**ITEM 1. CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (unaudited)**

**GOSSAMER BIO, INC.**

**Condensed Consolidated Balance Sheets**

**(in thousands, except share and par value amounts)**

---

| | | |
|:---|:---|:---|
| | **March 31, 2026** | **December 31, 2025** |
| **ASSETS** | (unaudited) |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Current assets |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Cash and cash equivalents | $41028 | $37732 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Marketable securities | 58187 | 99200 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Receivable from contracts with collaborators | 9252 | 12227 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Prepaid expenses and other current assets | 16069 | 18485 |
| Total current assets | 124536 | 167644 |
| Property and equipment, net | 59 | 64 |
| Operating lease right-of-use assets | 3906 | 4133 |
| Other assets | 398 | 408 |
| **Total assets** | $**128899** | $**172249** |
| &nbsp;&nbsp;&nbsp;**LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)** |  |  |
| Current liabilities |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accounts payable | $10822 | $5959 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued research and development expenses | 17395 | 21662 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Current contract liabilities | 8741 | 19987 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued expenses and other current liabilities | 19548 | 15827 |
| Total current liabilities | 56506 | 63435 |
| Long-term convertible senior notes | 198763 | 198508 |
| Operating lease liabilities - long-term | 3213 | 3460 |
| Long-term contract liabilities | 31900 | 29606 |
| **Total liabilities** | **290382** | **295009** |
| **Commitments and contingencies *(Note 9)*** |  |  |
| **Stockholders' equity (deficit)** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Common stock, $0.0001 par value; 700,000,000 shares authorized as of March 31, 2026 and December 31, 2025; 234,696,282 shares issued and outstanding as of March 31, 2026, and 233,677,057 shares issued and outstanding as of December 31, 2025 | 24 | 24 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Additional paid-in capital | 1328119 | 1321303 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accumulated deficit | (1485602) | (1438938) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accumulated other comprehensive loss | (4024) | (5149) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total stockholders' deficit | (161483) | (122760) |
| **Total liabilities and stockholders' equity (deficit)** | $**128899** | $**172249** |

---

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

------

<u>[**Table of Contents**](#i9a97deb1f63b46c3867089c2b6fc256c_7)</u>

**GOSSAMER BIO, INC.**

**Condensed Consolidated Statements of Operations and Comprehensive Loss**

**(Unaudited)**

**(in thousands, except share and per share amounts)**

---

| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| &nbsp;&nbsp;&nbsp;&nbsp;**Revenue:** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Revenue from contracts with collaborators | $16955 | $9889 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total revenue | 16955 | 9889 |
| &nbsp;&nbsp;&nbsp;&nbsp;**Operating expenses:** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Research and development | 43075 | 38041 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;General and administrative | 18746 | 8658 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total operating expenses | 61821 | 46699 |
| &nbsp;&nbsp;&nbsp;&nbsp;**Loss from operations** | **(44866)** | **(36810)** |
| &nbsp;&nbsp;&nbsp;&nbsp;Other income (expense) |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Interest income | 354 | 294 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Interest expense | (2755) | (2746) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other income, net | 603 | 2624 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total other income (loss), net | (1798) | 172 |
| &nbsp;&nbsp;&nbsp;&nbsp;**Net loss** | $**(46664)** | $**(36638)** |
| &nbsp;&nbsp;&nbsp;&nbsp;Other comprehensive income (loss): |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Foreign currency translation | 1192 | (1903) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Unrealized loss on marketable securities | (67) | (110) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other comprehensive income (loss) | 1125 | (2013) |
| &nbsp;&nbsp;&nbsp;&nbsp;**Comprehensive loss** | $**(45539)** | $**(38651)** |
| Net loss per share, basic and diluted | $(0.20) | $(0.16) |
| Weighted average common shares outstanding, basic and diluted | 234137364 | 226818051 |

---

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

------

<u>[**Table of Contents**](#i9a97deb1f63b46c3867089c2b6fc256c_7)</u>

**GOSSAMER BIO, INC.**

**Condensed Consolidated Statements of Stockholders' Equity (Deficit)**

**(Unaudited)**

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

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| | **Common stock** | **Common stock** | **Additional paid-in capital** | **Accumulated deficit** | **Accumulated other comprehensive income (loss)** | **Total stockholders' equity (deficit)** |
| | **Shares** | **Amount** | **Additional paid-in capital** | **Accumulated deficit** | **Accumulated other comprehensive income (loss)** | **Total stockholders' equity (deficit)** |
| **Balance as of December 31, 2025** | 233677057 | $24 | $1321303 | $(1438938) | $(5149) | $(122760) |
| Exercise of stock options | 211460 |  | 220 |  |  | 220 |
| Stock-based compensation |  |  | 6304 |  |  | 6304 |
| Issuance of common stock pursuant to Employee Stock Purchase Plan | 807765 |  | 292 |  |  | 292 |
| Net loss |  |  |  | (46664) |  | (46664) |
| Other comprehensive income |  |  |  |  | 1125 | 1125 |
| **Balance as of March 31, 2026** | 234696282 | $24 | $1328119 | $(1485602) | $(4024) | $(161483) |

---

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| | **Common stock** | **Common stock** | **Additional paid-in capital** | **Accumulated deficit** | **Accumulated other comprehensive income (loss)** | **Total stockholders' equity (deficit)** |
| | **Shares** | **Amount** | **Additional paid-in capital** | **Accumulated deficit** | **Accumulated other comprehensive income (loss)** | **Total stockholders' equity (deficit)** |
| **Balance as of December 31, 2024** | 226604138 | $23 | $1296848 | $(1268568) | $1189 | $29492 |
| Exercise of stock options | 112617 |  | 132 |  |  | 132 |
| Stock-based compensation |  |  | 2405 |  |  | 2405 |
| Issuance of common stock pursuant to Employee Stock Purchase Plan | 504507 |  | 372 |  |  | 372 |
| Net loss |  |  |  | (36638) |  | (36638) |
| Other comprehensive loss |  |  |  |  | (2013) | (2013) |
| **Balance as of March 31, 2025** | 227221262 | $23 | $1299757 | $(1305206) | $(824) | $(6250) |

---

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

------

<u>[**Table of Contents**](#i9a97deb1f63b46c3867089c2b6fc256c_7)</u>

**GOSSAMER BIO, INC.**

**Condensed Consolidated Statements of Cash Flows**

**(Unaudited)**

**(in thousands)**

---

| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| &nbsp;&nbsp;&nbsp;&nbsp;**Cash flows from operating activities** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Net loss | $(46664) | $(36638) |
| &nbsp;&nbsp;&nbsp;&nbsp;Adjustments to reconcile net loss to net cash used in operating activities: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Depreciation and amortization expense | 5 | 6 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Stock-based compensation expense | 6304 | 2405 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Amortization of operating lease right-of-use assets | 227 | 336 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Amortization of long-term debt discount and issuance costs | 255 | 241 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Amortization of premium on marketable securities, net of accretion of discounts | (660) | (2667) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Changes in operating assets and liabilities: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Receivable from contracts with collaborators | 2975 | (1245) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Prepaid expenses and other current assets | 2416 | (926) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other assets | 10 | (27) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Operating lease liabilities | (227) | (336) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accounts payable | 6156 | (937) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued expenses and other current liabilities | (234) | 490 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued research and development expenses | (4267) | 4301 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued compensation and benefits | 1435 | (5844) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Contract liabilities | (8952) | (1383) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued interest expense | 2500 | 2500 |
| &nbsp;&nbsp;&nbsp;&nbsp;Net cash used in operating activities | (38721) | (39724) |
| &nbsp;&nbsp;&nbsp;&nbsp;**Cash flows from investing activities** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Purchase of marketable securities | (24994) | (101012) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Maturities of marketable securities | 66600 | 123100 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Purchase of property and equipment |  | (26) |
| &nbsp;&nbsp;&nbsp;&nbsp;Net cash provided by investing activities | 41606 | 22062 |
| &nbsp;&nbsp;&nbsp;&nbsp;**Cash flows from financing activities** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Proceeds from issuance of common stock pursuant to Employee Stock Purchase Plan | 292 | 372 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Proceeds from the exercise of stock options | 220 | 132 |
| &nbsp;&nbsp;&nbsp;&nbsp;Net cash provided by financing activities | 512 | 504 |
| &nbsp;&nbsp;&nbsp;&nbsp;Effect of exchange rate changes on cash and cash equivalents | (101) | 105 |
| &nbsp;&nbsp;&nbsp;&nbsp;Net increase (decrease) in cash and cash equivalents | 3296 | (17053) |
| &nbsp;&nbsp;&nbsp;&nbsp;Cash and cash equivalents, at the beginning of the period | 37732 | 46074 |
| &nbsp;&nbsp;&nbsp;&nbsp;**Cash and cash equivalents, at the end of the period** | $**41028** | $**29021** |
| &nbsp;&nbsp;&nbsp;&nbsp;**Supplemental disclosure of cash flow information:** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Cash paid for interest | $— | $— |
| &nbsp;&nbsp;&nbsp;&nbsp;**Supplemental disclosure of noncash investing and financing activities:** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Change in unrealized gain (loss) on marketable securities, net | $(67) | $(110) |

---

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

------

<u>[**Table of Contents**](#i9a97deb1f63b46c3867089c2b6fc256c_7)</u>

**GOSSAMER BIO, INC.**

**Notes to Unaudited Condensed Consolidated Financial Statements**

**Note 1 - Description of Business**

Gossamer Bio, Inc. (including its subsidiaries, referred to as "we," "us," "our,", or the "Company") is a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary hypertension ("PH") including pulmonary arterial hypertension ("PAH") and PH associated with interstitial lung disease ("PH-ILD"). The Company was incorporated in the state of Delaware on October 25, 2015 (originally as FSG Bio, Inc.) and is based in San Diego, California.

The unaudited condensed consolidated financial statements include the accounts of Gossamer Bio, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions among the consolidated entity have been eliminated in consolidation.

***Liquidity and Going Concern***

The Company has incurred significant operating losses since its inception. As of March 31, 2026, the Company had an accumulated deficit of $1,485.6 million. From the Company's inception through March 31, 2026, the Company has funded its operations primarily through equity financings, convertible senior notes and the Chiesi Collaboration Agreement (as defined in Note 10 below).

The Company's existing cash and cash equivalents are not sufficient to fund operating plans for at least one year from the issuance date of these financial statements. Accordingly, these conditions raise substantial doubt about the Company's ability to continue as a going concern. The consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and settlement of liabilities, in the normal course of business, and does not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty.

If the Company is not able to obtain the required funding, through equity or debt financings, license agreements for seralutinib in domestic or foreign markets, or other means, or is unable to obtain funding on terms favorable to the Company, or there is an event of default affecting the Company's 2027 Notes, there will be a material adverse effect on commercialization and development operations, and the Company's ability to execute its strategic development plan for future growth. If the Company cannot successfully raise additional funding and implement its strategic development plan, the Company may be forced to make further reductions in spending, including spending in connection with our clinical development, pre-commercialization activities, extend payment terms with suppliers, suspend or curtail planned operations or cease operations entirely. The Company has concluded that these circumstances and the uncertainties associated with the Company's ability to obtain additional equity or debt financing on terms that are favorable to the Company, or at all, and otherwise succeed in its future operations raise substantial doubt about the Company's ability to continue as a going concern. Management believes that it has sufficient working capital on hand to fund operations into the first quarter of 2027.

On March 16, 2026, we commenced a workforce reduction of 73 individuals, constituting approximately 46% of our workforce, to reduce our operating expenses. Our remaining management and employees will continue the development of seralutinib and explore potential regulatory paths forward. This workforce reduction is expected to be substantially completed by the end of May 2026. The estimated charges associated with the workforce reduction are approximately $6.1 million primarily related to employee severance payments, benefits and related termination costs. These charges were recognized in the first quarter of 2026.

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**Note 2 - Summary of Significant Accounting Policies**

***Basis of Presentation***

The Company's accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States ("GAAP") for interim financial information and with the instructions of the Securities and Exchange Commission ("SEC") on Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by GAAP for complete financial statements. In the opinion of management, the unaudited condensed consolidated financial statements include all adjustments necessary, which are of a normal and recurring nature, for the fair presentation of the Company's financial position and of the results of operations and cash flows for the periods presented. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2025 included in the Company's Annual Report on Form 10-K filed with the SEC on March 17, 2026. The results of operations for the interim period shown in this report are not necessarily indicative of the results that may be expected for any other interim period or for the full year. The balance sheet at December 31, 2025, has been derived from the audited consolidated financial statements at that date.

***Use of Estimates***

The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The most significant estimates in the Company's condensed consolidated financial statements relate to accrued research and development expenses, stand-alone selling price of performance obligations and estimated collaboration expenses associated with the Company's Chiesi Collaboration Agreement. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results could differ from those estimates.

***Segments***

Operating segments are identified as components of an enterprise about which discrete financial information is available for evaluation by the chief operating decision-maker ("CODM") in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating segment. The identification of a single operating and reportable segment is consistent with the management approach as the CODM regularly reviews consolidated financial information for the purpose of assessing performance and allocating resources. See Note 11, "Segment Reporting" for more information.

***Collaborative Arrangements***

The Company assesses whether its licensing and other agreements are collaborative arrangements based on whether they involve joint operating activities and whether both parties have active participation in the arrangement and are exposed to significant risks and rewards. For arrangements that the Company determines are collaborations, it identifies each unit of account, and then determines whether a customer relationship exists for that unit of account. If the Company determines a performance obligation within the collaborative arrangement to be with a customer, it applies its revenue recognition accounting policy. If a portion of a distinct bundle of goods or services within the collaborative arrangement is not with a customer, the Company applies recognition and measurement based on an analogy to authoritative accounting literature or, if there is no appropriate analogy, a reasonable, rational and consistently applied accounting policy election. To the extent the arrangement is within the scope of ASC 808, the Company assesses whether aspects of the arrangement between the Company and the collaboration partner are within the scope of other accounting literature. If the Company concludes that some or all aspects of the arrangement represent a transaction with a customer, the Company accounts for those aspects of the arrangement within the scope of ASC Topic 606, Revenue from Contracts with Customers (ASC 606). See Note 10, "Significant Agreements and Contracts," for more information.

***Revenue Recognition***

The Company recognizes revenue when a customer obtains control of promised goods or services in a contract for an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. For contracts with customers, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the

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performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. As part of the accounting for contracts with customers, the Company develops assumptions that require judgment to determine the standalone selling price of each distinct performance obligation identified in the contract. In addition, variable consideration such as milestone payments are evaluated to determine if they are constrained and, therefore, excluded from the transaction price. The Company then allocates the total transaction price proportionally to each distinct performance obligation based on their estimated standalone selling prices, unless an allocation exception applies. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective distinct performance obligation when (or as) the performance obligation is satisfied.

In a contract with multiple performance obligations, the Company must develop estimates and assumptions that require judgment to determine the underlying standalone selling price for each distinct performance obligation, which determines how the transaction price is allocated among the distinct performance obligations. The estimation of the stand-alone selling price(s) may include estimates regarding forecasted revenues or costs, development timelines, discount rates, and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time. Any change made to estimated progress towards completion of a distinct performance obligation and, therefore, revenue recognized will be recorded as a change in estimate. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price.

If a license to the Company's intellectual property is determined to be distinct from the other performance obligations identified in a contract, the Company recognizes revenues from the transaction price allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from the allocated transaction price. The Company evaluates the measure of progress at each reporting period and, if necessary, adjusts the measure of performance and related revenue or expense recognition as a change in estimate.

At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being reached. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company's or a collaboration partner's control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of milestones that are within its or a collaboration partner's control, such as operational developmental milestones and any related constraint, and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which will affect revenue from sale of licenses and revenue from contracts with collaborators in the period of adjustment. Revisions to the Company's estimate of the transaction price may also result in negative revenue from sale of licenses and revenue from contracts with collaborators in the period of adjustment.

For arrangements that include sales-based royalties, including commercial milestone payments based on the level of sales, and a license is deemed to be the predominant item to which the royalties relate, the Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied, or partially satisfied. To date, the Company has not recognized any royalty revenue from collaborative arrangements.

For arrangements that include cost-share reimbursements, we will recognize such payments when control of the related goods or services are transferred to the customer. Cost-sharing reimbursements are presented as revenue from contracts with collaborators.

***Major Customer and Concentration of Credit Risk***

During the three months ended March 31, 2026, Chiesi was the Company's principal customer, accounting for 100% of its revenue. Consequently, Chiesi represented 100% of the Company's accounts receivable balance as of March 31, 2026, and December 31, 2025.

The Company is exposed to concentration of credit risk through its financial instruments, primarily cash and cash equivalents. The Company's cash and cash equivalents are maintained in financial institutions that management considers to be of high credit quality. Amounts on deposit with these financial institutions have and will continue to exceed federally-insured limits. The Company has not experienced any losses on its deposits of cash and cash equivalents and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

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***Recent Accounting Pronouncements - Adopted***

In July, 2025, the FASB issued ASU No. 2025-05, Credit Losses (Topic 326) - Measurement of Credit Losses for Accounts Receivable and Contract Assets. The amendments provide all entities with a practical expedient to assume that the current conditions as of balance sheet date will remain unchanged for the remaining life of the asset when developing a reasonable and supportable forecast as part of estimating expected credit losses on current accounts receivable and current contract assets arising from transactions accounted for under ASC 606, Revenue from Contracts with Customers. The guidance is effective for all entities for annual reporting periods beginning after December 15, 2025 and interim reporting periods within those annual reporting periods. Entities that use the practical expedient are required to apply the amendments prospectively. The ASU No. 2025-05 does not have the impact on the Company.

***Recent Accounting Pronouncements - Not Yet Adopted***

In November 2024, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, as further clarified by ASU 2025-01, Income Statement - Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date, issued in January, 2025, which requires disaggregated disclosure of certain costs and expenses on an interim and annual basis. ASU No. 2024-03 is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. The disclosure updates are required to be applied prospectively with the option for retrospective application. The Company is currently evaluating the impact of adopting ASU No. 2024-03.

In December 2025, the FASB issued ASU No. 2025-12, Codification Improvements, to address suggestions received from stakeholders on the ASC and to make other incremental improvements to U.S. GAAP. The update represents changes to the ASC that clarify, correct errors in or make other improvements to a variety of topics that are intended to make it easier to understand and apply. ASU No. 2025-12 is effective for fiscal years beginning after December 15, 2026 and interim periods. The Company is currently evaluating the impact of adopting ASU No. 2024-12 on its consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU No. 2025-11, Interim Reporting (Topic 270), which provides clarifications intended to improve the consistency and usability of interim disclosure requirements, including a comprehensive listing of required interim disclosures and a new disclosure principle for reporting material events occurring after the most recent annual period. The amendments do not change the underlying objectives of interim reporting but are designed to enhance clarity in application. ASU No. 2025-11 is effective for fiscal years beginning after December 15, 2027, including interim periods within those fiscal years. The Company is currently evaluating the impact of adopting ASU No. 2024-11 on its consolidated financial statements and related disclosures.

Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force), the American Institute of Certified Public Accountants, and the SEC did not, or are not believed by management to, have a material impact on the Company's present or future financial position, results of operations, cash flows or disclosures.

***Net Loss Per Share***

The Company follows the guidance in FASB ASC 260, Earnings per Share, which establishes standards regarding the computation of earnings per share ("EPS") by companies that have issued securities other than common stock that contractually entitle the holder to participate in dividends and earnings of a company. The guidance requires earnings to be hypothetically allocated between the common, preferred, and other participating stockholders based on their respective rights to receive non-forfeitable dividends, whether or not declared.

Basic and diluted net loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period. In loss periods, basic net loss per share and diluted net loss per share are identical because the otherwise dilutive potential common shares become anti-dilutive and are therefore excluded.

The table below provides potentially dilutive securities not included in the calculation of the diluted net loss per share because to do so would be anti-dilutive (in common stock equivalent shares):

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| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| 2027 Notes | 12321900 | 12321900 |
| Shares issuable upon exercise of stock options | 58816985 | 47739962 |
| Shares issuable upon exercise of Chiesi Equity Option |  | 22494904 |
| Shares issuable upon exercise of warrants | 30675537 | 32467360 |
| Nonvested shares under restricted stock grants | 8150987 |  |
| Total potentially dilutive securities | 109965409 | 115024126 |

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**Note 3 - Balance Sheet Accounts and Supplemental Disclosures**

***Accrued Expenses and Other Current Liabilities***

Accrued expenses and other current liabilities consisted of the following (in thousands):

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| | | |
|:---|:---|:---|
| | **As of** | **As of** |
| | **March 31,<br>2026** | **December 31,<br>2025** |
| Accrued compensation and benefits | $12646 | $11211 |
| Operating lease liabilities | 957 | 938 |
| Accrued consulting fees | 1602 | 1807 |
| Accrued interest | 3333 | 833 |
| Accrued legal fees | 181 | 84 |
| Accrued accounting fees | 393 | 449 |
| Accrued income tax | 6 | 6 |
| Accrued other | 430 | 499 |
| Total accrued expenses and other current liabilities | $19548 | $15827 |

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**Note 4 - Fair Value Measurements and Available for Sale Investments**

***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 nonrecurring 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: Observable inputs such as quoted prices in active markets;

Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The Company classifies its cash equivalents and available-for-sale investments within Level 1 or Level 2. The fair value of the Company's investment grade corporate debt securities and commercial paper classified as Level 2 is determined using proprietary valuation models and analytical tools, which utilize market pricing or prices for similar instruments that are both objective and publicly available, such as matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, and offers.

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***Assets and Liabilities Measured at Fair Value on a Recurring Basis***

The following table presents the hierarchy for assets measured at fair value on a recurring basis as of March 31, 2026 and December 31, 2025 (in thousands):

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| | | | | |
|:---|:---|:---|:---|:---|
| | **Fair Value Measurements at End of Period Using:** | **Fair Value Measurements at End of Period Using:** | **Fair Value Measurements at End of Period Using:** | **Fair Value Measurements at End of Period Using:** |
| | **Total<br>Fair Value** | **Quoted Market<br>Prices for<br>Identical Assets<br>(Level 1)** | **Significant<br>Other Observable<br>Inputs<br>(Level 2)** | **Significant<br>Unobservable<br>Inputs<br>(Level 3)** |
| **As of March 31, 2026** | | | | |
| Money market funds | $24350 | $24350 | $— | $— |
| U.S. Treasury and agency securities | 17150 | 17150 |  |  |
| Commercial paper | 37420 |  | 37420 |  |
| Corporate debt securities | 8000 |  | 8000 |  |
| **As of December 31, 2025** |  |  |  |  |
| Money market funds | $22228 | $22228 | $— | $— |
| U.S. Treasury and agency securities | 8090 | 8090 |  |  |
| Commercial paper | 73592 |  | 73592 |  |
| Corporate debt securities | 27377 |  | 27377 |  |

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The Company did not reclassify any investments between levels in the fair value hierarchy during the periods presented.

***Fair Value of Other Financial Instruments***

As of March 31, 2026 and December 31, 2025, the carrying amounts of the Company's financial instruments, which include cash, prepaid and other current assets, interest receivable, accrued research and development expenses, accounts payable and accrued expenses and other current liabilities, approximate fair values because of their short-term maturities.

There was $0.1 million and $0.3 million interest receivable as of March 31, 2026 and December 31, 2025, respectively. Interest receivable is recorded as a component of prepaid expenses and other current assets on the condensed balance sheets.

As of March 31, 2026 and December 31, 2025, the fair value of the Company's 2027 Notes was $78.5 million and $138.3 million, respectively. The fair value was determined on the basis of market prices observable for similar instruments and is considered Level 2 in the fair value hierarchy. See Note 5, "Indebtedness," for more information.

***Available for Sale Investments***

The Company invests its excess cash in U.S. Treasury and agency securities, corporate debt securities, and commercial paper, which are classified as available-for-sale investments. These investments are carried at fair value and are included in the tables below. The Company evaluates securities with unrealized losses to determine whether such losses, if any, are due to credit-related factors. Realized gains and losses are calculated using the specific identification method and recorded in other income, net in the Company's condensed consolidated statement of operations and comprehensive loss. The Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recover of their amortized cost basis.

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The aggregate market value, cost basis, and gross unrealized gains and losses of available-for-sale investments by security type, classified in marketable securities as of March 31, 2026 and December 31, 2025 are as follows (in thousands except securities amounts):

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| | | | | |
|:---|:---|:---|:---|:---|
| | **Amortized<br>Cost** | **Gross<br>Unrealized<br>Gains** | **Gross<br>Unrealized<br>Losses** | **Total<br>Fair Value** |
| **As of March 31, 2026** | | | | |
| &nbsp;&nbsp;&nbsp;&nbsp;U.S. Treasury and agency securities | $17150 | $— | $— | $17150 |
| &nbsp;&nbsp;&nbsp;&nbsp; Corporate debt securities | 8000 |  |  | 8000 |
| &nbsp;&nbsp;&nbsp;&nbsp; Commercial paper | 33036 | 6 | (5) | 33037 |
| Total marketable securities | $58186 | $6 | $(5) | $58187 |
| Number of securities with unrealized losses |  |  | 6 |  |
| **As of December 31, 2025** |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;U.S. Treasury and agency securities | $8088 | $2 | $— | $8090 |
| &nbsp;&nbsp;&nbsp;&nbsp; Corporate debt securities | 27359 | 18 |  | 27377 |
| &nbsp;&nbsp;&nbsp;&nbsp; Commercial paper | 73544 | 49 | (1) | 73592 |
| Total marketable securities | $108991 | $69 | $(1) | $109059 |
| Number of securities with unrealized losses |  |  | 1 |  |

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At each reporting date, the Company performs an evaluation of impairment to determine if any unrealized losses are due to credit-related factors. The Company records an allowance for credit losses when unrealized losses are due to credit-related factors. Factors considered when evaluating available-for-sale investments for impairment include the severity of the impairment, changes in underlying credit ratings, the financial condition of the issuer, the probability that the scheduled cash payments will continue to be made and the Company's intent and ability to hold the investment until recovery of the amortized cost basis. The Company intends and has the ability to hold its investments in unrealized loss positions until their amortized cost basis has been recovered. As of March 31, 2026 and December 31, 2025, there were no material declines in the market value of the Company's available-for-sale investments due to credit-related factors.

Contractual maturities of available-for-sale debt securities, as of March 31, 2026, were as follows (in thousands):

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| | |
|:---|:---|
| | **Estimated<br> Fair Value** |
| Less than one year | $58187 |
| Greater than one year |  |
| Total | $58187 |

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The Company has the ability, if necessary, to liquidate any of its cash equivalents and marketable securities to meet its liquidity needs in the next 12 months.

**Note 5 - Indebtedness**

***5.00% Convertible Senior Notes due 2027***

On May 21, 2020, the Company issued $200.0 million aggregate principal amount of 5.00% convertible senior notes due 2027 in a public offering (the "2027 Notes"). The 2027 Notes were registered pursuant to the Company's shelf registration statement on Form S-3 filed with the SEC on April 10, 2020. The interest rate on the 2027 Notes is fixed at 5.00% per annum. Interest is payable semi-annually in arrears on June 1 and December 1 of each year, commencing on December 1, 2020. The 2027 Notes will mature on June 1, 2027. The net proceeds from the offering, after deducting the underwriting discounts and commissions and other offering costs, were approximately $193.6 million. The 2027 Notes may be settled in cash, shares of the Company's common stock, or a combination thereof, solely at the Company's election. The initial conversion rate of the 2027 Notes is 61.6095 shares per $1,000 principal amount, which is equivalent to a conversion price of approximately $16.23 per share, subject to adjustments. In addition, following certain corporate events that occur prior to the maturity date or if the Company issues a notice of redemption, the Company will increase the conversion rate for a holder who elects to convert its 2027 Notes in connection with such a corporate event during the related redemption period in certain circumstances.

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The 2027 Notes are senior unsecured obligations of the Company, ranking senior in right of payment to any of the Company's indebtedness that is expressly subordinated in right of payment to the 2027 Notes, and are effectively subordinated to the Company's existing and future secured indebtedness, to the extent of the value of the collateral securing that indebtedness.

Holders may convert their notes at their option only in the following circumstances: (1) during any calendar quarter (and only during such calendar quarter) commencing after the calendar quarter ending on September 30, 2020, if the last reported sale price per share of the Company's common stock exceeds 130% of the conversion price for each of at least 20 trading days (whether or not consecutive) during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (2) during the five consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the "measurement period") in which the trading price per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company's common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on the Company's common stock; (4) if the Company calls such notes for redemption; and (5) at any time from, and including, March 1, 2027 until the close of business on the scheduled trading day immediately before the maturity date.

The Company did not have the right to redeem the 2027 Notes prior to June 6, 2024. As of March 31, 2026, the Company has not redeemed the 2027 Notes. On or after June 6, 2024 and on or before the 50th scheduled trading day immediately before the maturity date, the Company may redeem the 2027 Notes, in whole or in part, if the last reported sale price of the Company's common stock has been at least 130% of the conversion price then in effect on (1) each of at least 20 trading days (whether or not consecutive) during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice; and (2) the trading day immediately before the date the Company sends such notice. In the case of any optional redemption, the Company will redeem the 2027 Notes at a redemption price equal to 100% of the principal amount of such Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date.

If the Company undergoes a fundamental change prior to the maturity date of the 2027 Notes, holders of the 2027 Notes may require the Company to repurchase for cash all or part of their 2027 Notes at a repurchase price equal to 100% of the principal amount of the 2027 Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

The indenture governing the 2027 Notes provides for customary terms and covenants, including that upon certain events of default, either the trustee or the holders of not less than 25% in aggregate principal amount of the 2027 Notes then outstanding may declare the unpaid principal amount of the 2027 Notes and accrued and unpaid interest, if any, thereon immediately due and payable. As of March 31, 2026, the Company was in compliance with these covenants. In the case of certain events of bankruptcy, insolvency or reorganization, the principal amount of the 2027 Notes together with accrued and unpaid interest, if any, thereon will automatically become and be immediately due and payable.

As of March 31, 2026, there were no events or market conditions that would allow holders to convert the 2027 Notes. When the 2027 Notes become convertible within 12 months of the balance sheet date, the carrying value of the 2027 Notes will be reclassified to short-term.

The Company recorded $0.4 million of the debt issuance costs related to the 2027 Notes as a reduction to the liability and amortizes these costs to interest expense over the term of the 2027 Notes.

The net carrying amount of the 2027 Notes was as follows (in thousands):

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| | | |
|:---|:---|:---|
| | **March 31, 2026** | **December 31, 2025** |
| Principal amount | $200000 | $200000 |
| Unamortized debt discount | (1159) | (1398) |
| Unamortized debt issuance cost | (78) | (94) |
| &nbsp;&nbsp;&nbsp;Net carrying amount | $198763 | $198508 |

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The following table sets forth the interest expense recognized related to the 2027 Notes (in thousands):

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|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| Contractual interest expense | $2500 | $2500 |
| Amortization of debt discount | 239 | 226 |
| Amortization of debt issuance cost | 16 | 15 |
| &nbsp;&nbsp;&nbsp;Total interest expense related to the 2027 Notes | $2755 | $2741 |

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**Note 6 - Licenses, Asset Acquisitions and Contingent Consideration**

The following purchased assets were accounted for as asset acquisitions as substantially all of the fair value of the assets acquired were concentrated in a group of similar assets and/or the acquired assets were not capable of producing outputs due to the lack of employees and early stage of development. Because the assets had not yet received regulatory approval, the fair value attributable to these assets was recorded as in process research and development, or IPR&D, expenses in the Company's condensed consolidated statements of operations and comprehensive loss.

The Company accounts for contingent consideration payable upon achievement of certain regulatory, development or sales milestones in such asset acquisitions when the underlying contingency is met.

***License from Pulmokine, Inc. (Seralutinib)***

On October 2, 2017, the Company entered into a license agreement with Pulmokine, Inc. under which it was granted an exclusive worldwide license and sublicense to certain intellectual property rights owned or controlled by Pulmokine to develop and commercialize seralutinib and certain backup compounds for the treatment, prevention and diagnosis of any and all disease or conditions. On November 26, 2024, Pulmokine became a wholly-owned subsidiary of XOMA Royalty Corporation. The Company also has the right to sublicense its rights under the license agreement, subject to certain conditions. The assets acquired are in the early stages of the Food and Drug Administration ("FDA") approval process, and the Company intends to further develop the assets acquired through potential FDA approval as evidenced by the milestone arrangement in the contract. The development activities cannot be performed without significant cost and effort by the Company. The agreement will remain in effect from the effective date, unless terminated earlier, until, on a licensed product-by-licensed product and country-by-country basis, the later of ten years from the date of first commercial sale or when there is no longer a valid patent claim covering such licensed product or specified regulatory exclusivity for the licensed product in such country. The Company is obligated to make future development and regulatory milestone payments of up to $48.0 million, which includes a payment of $5.0 million due upon initiation of a Phase 3 clinical trial in a second indication, commercial milestone payments of up to $45.0 million, and sales milestone payments of up to $190.0 million. The Company is also obligated to pay tiered royalties on sales for each licensed product, at percentages ranging from the mid-single digits to the high single-digits. In addition, if the Company chooses to sublicense or assign to any third parties its rights under the agreement with respect to a licensed product, or the Company's seralutinib operating subsidiary undergoes a change of control, the Company must pay to Pulmokine a specified percentage of all revenue to be received in connection with such transaction. The Company made an upfront payment of $5.5 million in October 2017. The Company made a milestone payment of $5.0 million in connection with the initiation of the first Phase 2 clinical trial of seralutinib in January 2021 and made a milestone payment of $10.0 million, which was accrued in 2023, in connection with the initiation of the Phase 3 clinical trial of seralutinib in January 2024. The Company recognized these milestone payments as research and development expense on its condensed consolidated statements of operations and comprehensive loss. As of March 31, 2026, no other milestones had been accrued as the underlying contingencies had not yet been met.

**Note 7 - Stockholders' Equity**

***Common Stock***

Each share of common stock is entitled to one vote. Common stock owners are entitled to dividends when funds are legally available and declared by the Company's board of directors.

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***Chiesi Equity Option***

On May 3, 2024, pursuant to the Chiesi Collaboration Agreement the Company granted to Chiesi (as defined in Note 10 below) an option to purchase directly from the Company, on one or more occasions, up to an aggregate number of shares of the Company's common stock (the "Equity Option") such that immediately following such issuance, Chiesi's beneficial ownership of the Company's common stock shall not exceed 9.9% of the total number of issued and outstanding shares of the Company's common stock. The Equity Option shall be exercisable by Chiesi, in whole or in part, at any time prior to the earliest to occur of the date on which (a) the last patient is last dosed in either (i) the PROSERA Phase 3 study for PAH or (ii) a Phase 3 clinical trial for the PH-ILD Indication, (b) any third party commences a tender offer or exchange offer for more than 50% of the outstanding shares of the Company's common stock, and (c) the Company publicly announces its intent to consummate a GB002, Inc. change of control. The purchase price of each share the Company's common stock subject to the Equity Option shall be equal to 107.5% of the daily volume-weighted average per share price of the Company's common stock on The Nasdaq Stock Market over the 30-trading day period ending on and including the last trading day prior to the date on which Chiesi delivers an exercise notice to the Company; provided that such purchase price shall be no less than $1.63 per share. The shares of the Company's common stock to be issued will be issued in a private placement in reliance on Section 4(a)(2) of the Securities Act of 1933, as amended, for transactions by an issuer not involving any public offering, pursuant to the terms of a stock issuance agreement to be entered into between the Company and Chiesi in connection with each such exercise of the Equity Option. The Company evaluated the Equity Option granted to Chiesi as consideration payable to a customer and determined it qualified under ASC 718. Due to the market condition included in the Equity Option, the Company used the Geometric Brownian Motion/Monte Carlo model to determine fair market value. The value of the Equity Option is $0.5 million, which is included in additional paid-in capital on the Company's condensed consolidated balance sheets. In November 2025, the Equity Option expired and is no longer exercisable.

**Note 8 - Equity Incentive Plans**

**2023 Employment Inducement Incentive Plan**

In November 2023, the Company approved the 2023 Employment Inducement Incentive Plan (the "2023 Inducement Plan"). The terms of the 2023 Inducement Plan are substantially similar to the terms of the Company's 2019 Incentive Award Plan (as described below) with the exception that incentive stock options may not be issued under the 2023 Inducement Plan and awards under the 2023 Inducement Plan may only be issued to eligible recipients under the applicable Nasdaq rules. The 2023 Inducement Plan was adopted without stockholder approval pursuant to Rule 5635(c)(4) of the Nasdaq Listing Rules. In accordance with Rule 5635(c)(4) of the Nasdaq Listing Rules, awards under the 2023 Inducement Plan may only be made to an employee who has not previously been an employee or member of the board of directors of the Company or any parent or subsidiary, or following a bona fide period of non-employment by the Company or a parent or subsidiary, if he or she is granted such award in connection with his or her commencement of employment with the Company or a subsidiary and such grant is an inducement material to his or her entering into employment with the Company or such subsidiary. The Company has initially reserved 6,762,279 shares of the Company's common stock for issuance pursuant to awards granted under the 2023 Inducement Plan. As of March 31, 2026, an aggregate of 1,751,033 shares of common stock were available for issuance under the 2023 Inducement Plan. As of March 31, 2026 and December 31, 2025, 4,917,080 and 4,811,455 shares of common stock, respectively, were subject to outstanding awards under the 2023 Inducement Plan.

**2019 Equity Incentive Plan** 

In January 2019, the Company's board of directors and stockholders approved and adopted the 2019 Incentive Award Plan (the "2019 Plan"). The 2019 Plan became effective on February 6, 2019, the day prior to the effectiveness of the registration statement filed in connection with the IPO. Under the 2019 Plan, the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units, and other stock or cash-based awards to individuals who are then employees, officers, directors or consultants of the Company, and employees and consultants of the Company's subsidiaries. A total of 5,750,000 shares of common stock were approved to be initially reserved for issuance under the 2019 Plan. The number of shares that remained available for issuance under the 2017 Plan (as defined below) as of the effective date of the 2019 Plan were, and shares subject to outstanding awards under the 2017 Plan as of the effective date of the 2019 Plan that are subsequently canceled, forfeited or repurchased by the Company will be, added to the shares reserved under the 2019 Plan. The Company's board of directors and stockholders approved an amendment and restatement to the 2019 Plan in 2025 to, among other things, increase the aggregate number of shares of common stock authorized for issuance under the 2019 Plan by 11,350,000 shares of common stock. In addition, the number of shares of common stock available for issuance under the 2019 Plan will be automatically increased on the first day of each calendar year during the ten-year term of the 2019 Plan, beginning with January 1, 2026 and ending with January 1, 2035, by an amount equal to 5% of the outstanding number of shares of the Company's common stock on December 31 of the preceding calendar year or such lesser amount as determined by the

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Company's board of directors. As of March 31, 2026, an aggregate of 4,619,694 shares of common stock were available for issuance under the 2019 Plan. As of March 31, 2026 and December 31, 2025, 60,173,197 and 44,796,989 shares of common stock, respectively, were subject to outstanding awards under the 2019 Plan.

**2019 Employee Stock Purchase Plan**

In January 2019, the Company's board of directors and stockholders approved and adopted the 2019 Employee Stock Purchase Plan (the "ESPP"). The ESPP became effective as of February 6, 2019, the day prior to the effectiveness of the registration statement filed in connection with the IPO. The ESPP permits participants to purchase common stock through payroll deductions of up to 20% of their eligible compensation. A total of 700,000 shares of common stock were approved to be initially reserved for issuance under the ESPP. In addition, the number of shares of common stock available for issuance under the ESPP will be automatically increased on the first day of each calendar year during the first ten years of the term of the ESPP, beginning with January 1, 2020 and ending with January 1, 2029, by an amount equal to 1% of the outstanding number of shares of the Company's common stock on December 31 of the preceding calendar year or such lesser amount as determined by the Company's board of directors. During the three months ended March 31, 2026, 807,765 shares were issued pursuant to the ESPP. As of March 31, 2026, an aggregate of 7,250,975 shares of common stock were available for issuance under the ESPP.

**2017 Equity Incentive Plan**

The Company's 2017 Equity Incentive Plan (the "2017 Plan") permitted the granting of incentive stock options, non-statutory stock options, restricted stock, restricted stock units and other stock-based awards. Subsequent to the adoption of the 2019 Plan, no additional equity awards can be made under the 2017 Plan. As of March 31, 2026 and December 31, 2025, 1,877,695 and 1,955,471 shares of common stock, respectively, were subject to outstanding options under the 2017 Plan. As of March 31, 2026, no shares of restricted stock awards granted under the 2017 Plan were unvested.

***Stock Options***

The fair value of each employee and non-employee time-vested stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The Company uses its own volatility to the extent it has sufficient trading history, and for awards in which sufficient trading history is not available, a peer group is used to calculate the expected volatility. Due to the lack of historical exercise history, the expected term of the Company's stock options for employees has been determined utilizing the "simplified" method for awards. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is zero based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.

Effective March 19, 2026, and in accordance with the terms of the 2019 Plan, the Company's board of directors approved a stock option repricing (the "Option Repricing") whereby the exercise price of each Eligible Option (as defined below) was immediately reduced to $0.45 per share, the closing stock price on March 19, 2026. For purposes of the Option Repricing, "Eligible Options" were 48,725,528 outstanding stock options as of March 19, 2026 (vested or unvested) granted under the 2019 Plan and held by those eligible employees of the Company identified by the Company's board of directors, including the Company's executive officers. The reduced exercise price became effective immediately after the repricing. Except for the reduction in the exercise prices of the Eligible Options as described above, the Eligible Options will retain their existing terms and conditions as set forth in the 2019 Plan and the applicable award agreements.

The repricing resulted in $2.9 million of incremental cost, which was calculated using the Black-Scholes option-pricing model, of which $1.4 million of the incremental cost was recognized immediately, and $1.5 million of the incremental cost will be recognized on the straight-line basis over the remaining vesting period of the repriced options. The incremental cost is included in general and administrative expense and research and development expense on the condensed consolidated statements of operations and comprehensive loss.

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The following table summarizes stock option activity during the three months ended March 31, 2026:

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| | | | | |
|:---|:---|:---|:---|:---|
| | **Shares Subject to<br>Options Outstanding** | **Shares Subject to<br>Options Outstanding** | | |
| | **Shares** | **Weighted-<br>Average<br>Exercise<br>Price** | **Weighted-<br>Average**<br>**Remaining<br>Contractual<br>Life<br>(Years)** | **Aggregate<br>Intrinsic Value** |
| | | | | **(in thousands)** |
| Outstanding as of December 31, 2025 | 47436953 | $1.74 | 7.4 | $84257 |
| &nbsp;&nbsp;&nbsp;&nbsp;Options granted | 60881410 | $0.94 |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Options exercised | (211460) | $1.04 |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Options forfeited/cancelled | (49289918) | $1.84 |  |  |
| Outstanding as of March 31, 2026 | 58816985 | $0.82 | 7.4 | $— |
| Options vested and expected to vest as of March 31, 2026 | 58816985 | $0.82 | 7.4 | $— |
| Options exercisable as of March 31, 2026 | 25364126 | $1.11 | 6.3 | $— |

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The aggregate intrinsic value in the above table is calculated as the difference between fair value of the Company's common stock price on March 31, 2026 and the exercise price of the stock options. The aggregate intrinsic value of stock options exercised was $0.3 million during the three months ended March 31, 2026. There was no significant aggregate intrinsic value related to stock options exercised during the three months ended March 31, 2025.

The weighted-average grant date fair value per share for the stock option grants during the three months ended March 31, 2026 and 2025 was $2.30 and $0.90, respectively.

The aggregate fair value of stock options that vested during the three months ended March 31, 2026 and 2025 was $4.1 million and $4.4 million, respectively.

***Warrants***

On July 24, 2023, the Company completed a private placement of 129,869,440 shares of the Company's common stock and accompanying warrants to purchase up to 32,467,360 shares of the Company's common stock at a combined purchase price of $1.63125 per share and accompanying warrant, or with respect to any purchaser that was an officer, director, employee or consultant of the Company, $1.85125 per share and accompanying warrant. Each warrant has an exercise price per share of $2.04, was immediately exercisable on the date of issuance and will expire five years from the closing of the private placement.

Given that the warrants are indexed to the Company's shares of common stock (and otherwise meet the requirements to be classified in equity), the Company recorded the consideration received from the issuance of the warrants as additional paid-in capital on the Company's unaudited condensed consolidated balance sheets.

During the three months ended March 31, 2026, no warrants were exercised. As of March 31, 2026, there were 30,675,537 warrants outstanding.

***Restricted Stock***

Restricted stock grants include performance stock units ("PSUs") and restricted stock units ("RSUs").

The fair value of the PSUs is determined based on the closing market price of the Company's common stock on the grant date. Compensation expense for PSUs is recognized if and when the Company concludes that it is probable that the performance conditions will be achieved. The Company reassesses the probability of vesting at each reporting period for awards with performance conditions and adjusts compensation expense based on its probability assessment.

All PSUs vest in full upon the earlier of (i) the approval of an NDA for seralutinib or (ii) a Change in Control (as defined in the 2019 Plan), in either case on or prior to the fourth anniversary of the grant date, and subject to the participant not experiencing a termination of service prior to the applicable vesting date. In the event the PSUs have not vested on or prior to the fourth anniversary of the grant date due to the failure of either of the above events to occur, the PSUs will be forfeited on such date. As of March 31, 2026, the Company determined that the achievement of the performance condition of the PSUs is not probable, and therefore no compensation expense was recorded during the three months ended March 31, 2026.

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The summary of the Company's restricted stock grants activity during the three months ended March 31, 2026 is as follows:

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| | | |
|:---|:---|:---|
| | **Number of<br>Restricted<br>Stock Grants<br>Outstanding** | **Weighted-<br>Average<br>Grant Date<br>Fair Value** |
| Nonvested at December 31, 2025 | 4126962 | $1.71 |
| &nbsp;&nbsp;&nbsp;&nbsp;Granted | 4039821 | 2.88 |
| &nbsp;&nbsp;&nbsp;&nbsp;Forfeited | (15796) | 1.79 |
| Nonvested at March 31, 2026 | 8150987 | $2.29 |

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***Stock-Based Compensation Expense***

Stock-based compensation expense has been reported in the Company's condensed consolidated statements of operations and comprehensive loss as follows (in thousands):

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| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| Research and development | $2771 | $1138 |
| General and administrative | 3533 | 1267 |
| Total stock-based compensation expense | $6304 | $2405 |

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As of March 31, 2026, the total unrecognized compensation expense related to the unvested stock option awards granted was $44.8 million, which the Company expects to recognize over a weighted-average period of approximately 2.8 years.

As of March 31, 2026, the total unrecognized stock-based compensation expense related to the unvested restricted stock granted was $18.0 million, which the Company expects to recognize over a weighted-average period of approximately 2.3 years.

As of March 31, 2026, the total unrecognized compensation expense related to the ESPP was $1.0 million, which the Company expects to recognize over a weighted-average period of approximately 0.8 years.

**Note 9 - Commitments and Contingencies**

***Leases***

The Company previously leased certain office and laboratory space under a non-cancelable operating lease, which expired in January 2025.

On July 9, 2024, the Company entered into a lease agreement for office space located at 3115 Merryfield Row, Suite 120, San Diego, CA 92121, consisting of approximately 18,421 square feet. The term of the lease is 63 months commencing on August 1, 2024. The base rent is $109,605 per month effective October 1, 2024, and it is subject to a 3% annual increase every October. The lease expires on October 31, 2029 with an option for a one-year extension and an option to terminate on December 1, 2027 with the payment of a termination fee equal to four months of the then-current base rent upon the termination date. As of March 31, 2026, the Company was not reasonably certain that it would exercise the extension options, and therefore did not include these options in the determination of the total operating lease term for accounting purposes.

Monthly rent expense is recognized on a straight-line basis over the term of the leases. The operating leases are included in the condensed consolidated balance sheets at the present value of the lease payments at an incremental borrowing rate of 7% for each of the initial leased space and expansion space and 12.4% for the office lease commenced on August 1, 2024 using the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment as the leases do not provide an implicit rate.

As of March 31, 2026, the weighted average remaining lease term was 3.6 years and weighted average discount rate was 12.4%.

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Lease costs were comprised of the following (in thousands):

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| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| Operating lease cost | $358 | $492 |
| Short-term lease cost | 6 | 6 |
| Total lease cost | $364 | $498 |

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Cash paid for amounts included in the measurement of operating lease liabilities for the three months ended March 31, 2026 and 2025 was $0.4 million and $0.8 million, respectively.

Gross future minimum annual rental commitments as of March 31, 2026, were as follows (in thousands):

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| | |
|:---|:---|
| | **Undiscounted Rent<br>Payments** |
| Year ending December 31 |  |
| 2026 (remaining 9 months) | 1058 |
| 2027 | 1406 |
| 2028 | 1448 |
| 2029 | 1237 |
| Total undiscounted rent payments | $5149 |
| Present value discount | (979) |
| Present value of lease payments | $4170 |
| Current portion of operating lease liabilities (included as a component of accrued expenses and other current liabilities) | 957 |
| Operating lease liabilities - long-term | 3213 |
| Total operating lease liability | $4170 |

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**Note 10 - Significant Agreements and Contracts**

On May 3, 2024, the Company, GB002, Inc., a Delaware corporation and wholly-owned subsidiary of the Company, and Gossamer Bio 002 Ltd., a corporation organized and existing under the laws of Ireland and indirect wholly-owned subsidiary of the Company, entered into a global collaboration and license agreement (the "Chiesi Collaboration Agreement") with Chiesi Farmaceutici S.p.A and Chiesi USA, Inc. (collectively, "Chiesi"). The Company concluded that there were four distinct performance obligations under the Chiesi Collaboration Agreement: the U.S. Territory license (as defined below), the ROW Territory license (as defined below), the research and development services of PAH clinical development and the research and development services of PH-ILD clinical development. Revenue associated with the licenses was recognized upon delivery in May 2024. In addition, the Company granted to Chiesi an option to purchase the Equity Option, as described in Note 7. "Stockholders Equity."

The collaboration is focused on the development and commercialization of seralutinib and licensed products including seralutinib and related licensed compounds ("Licensed Products") in the U.S. ("U.S. Territory") and the rest of the world ("ROW Territory"), for therapeutic, prophylactic and diagnostic uses in humans and animals, for the treatment of PAH and PH-ILD and other indications, as may be permitted under the Chiesi Collaboration Agreement.

Pursuant to the Chiesi Collaboration Agreement, the Company granted two exclusive, sublicensable (with the Company's consent required in the U.S. Territory for third party sublicenses) licenses to Chiesi under intellectual property rights controlled by the Company relating to seralutinib and Licensed Products, for the worldwide development, manufacture and commercialization of seralutinib and Licensed Products. The licenses granted to Chiesi are subject to retained rights of the Company for the worldwide development and manufacture of seralutinib and Licensed Products, commercialization of Licensed Products in the U.S. Territory, and performance of its obligations and exercise of its rights that may be set forth in the

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global development plan and U.S. commercialization plan, in each case in accordance with the Chiesi Collaboration Agreement.

The parties agreed to use commercially reasonable efforts to conduct development and commercialization activities in relation to seralutinib and Licensed Products, under the global development plan and U.S. commercialization plan in accordance with the timelines therein. The Company will continue to lead global development of seralutinib in PAH and PH-ILD, and the parties will equally share the costs for the activities included in the global development plan for all Licensed Products, with the exception of the PROSERA Phase 3 study, which the Company will be solely responsible for conducting at the Company's own cost and expense. With respect to each country in the ROW Territory, such obligation to equally share such development costs shall end when regulatory approval is received for a Licensed Product in such country. With respect to U.S. Territory, the development costs incurred following regulatory approval shall continue to be shared equally. The Company will lead potential commercialization for PAH and PH-ILD in the U.S. Territory, with both parties contributing 50 percent of commercial efforts, including performing 50 percent of the commercialization activities. Chiesi will lead potential commercialization in the U.S. Territory in any additional indications, and Chiesi will have the exclusive right to commercialize Licensed Products in the ROW Territory. Chiesi further agreed to use commercially reasonable efforts to commercialize Licensed Products in certain specified countries in the ROW Territory following receipt of regulatory approvals. Generally, the Company will have the right to lead in manufacturing commercial supply of seralutinib and Licensed Products for the U.S. Territory for PAH and PH-ILD, and, subject to any existing obligations of the Company to third party manufacturers, Chiesi will have the right to lead in manufacturing commercial supply of seralutinib and Licensed Products in the ROW Territory, in each case in accordance with the Chiesi Collaboration Agreement.

Pursuant to the Chiesi Collaboration Agreement, neither party nor its affiliates is permitted to develop or commercialize any compound or product throughout the term whose primary mechanism of action is inhibition of a tyrosine kinase for the treatment of PAH or PH-ILD in the U.S. Territory or ROW Territory, subject to certain restrictions for the European Union and United Kingdom.

In consideration and as reimbursement for the Company's development costs, Chiesi agreed to pay the Company an up-front, nonrefundable payment of $160 million. Additionally, the Company will be eligible to receive up to $146 million in regulatory milestones and $180 million in sales milestones. In the U.S. Territory, the parties agreed to share commercial profits and losses equally. In the ROW Territory, Chiesi will pay the Company an escalating mid-to-high teens percentage royalty on net sales of Licensed Product for PAH and additional indications on a Licensed Product-by-Licensed Product and country-by-country basis with such payment obligations beginning on the first commercial sale of Licensed Product in such country and expiring on a country-by-country basis on the latest of (a) the expiration of a valid claim to the Company's patent right in such country, (b) the expiration of regulatory exclusivity, and (c) the date that is 10 years after the first commercial sale of such Licensed Product in such country.

Potential future payments for variable consideration, such as regulatory and commercial milestones, development costs, and profit sharing U.S. Territory will be recognized when it is probable that, if recorded, a significant reversal will not take place. Potential future royalty payments will be recorded as revenue when the associated sales occur.

Unless earlier terminated, the Chiesi Collaboration Agreement will remain in force until no Licensed Products are being developed or commercialized in the U.S. Territory and in the ROW Territory, on a country-by-country basis, until no royalty terms are in effect for all countries. Either party may terminate the Chiesi Collaboration Agreement for the other party's material breach, subject to a specified notice and cure periods, or due to an insolvency event of the other party. In lieu of termination upon a party's material breach due to non-payment of development costs within a specified time the non-breaching party may elect an alternative remedy which may involve modifications to their performance and payment obligations. The Company has the right to terminate by providing written notice in the event Chiesi or its affiliates or sublicensee brings a patent challenge and Chiesi does not take certain steps to withdraw from or cease supporting such challenge. Chiesi may terminate the Chiesi Collaboration Agreement without cause upon prior written notice to the Company, subject to a notice period in which all rights to Licensed Products will revert back to the Company.

The Company concluded that progress towards completion of the research and development services performance obligation related to the Chiesi Collaboration Agreement is best measured in an amount proportional to the collaboration expenses incurred and the total estimated collaboration expenses. The Company periodically reviews and updates the estimated collaboration expenses, when appropriate, which may adjust revenue recognized for the period. While such changes to the Company's estimates have no impact on the Company's reported cash flows, the amount of revenue recorded in the period could be materially impacted. The transaction price to be recognized as revenue from sale of licenses and revenue from contracts with collaborators under the Chiesi Collaboration Agreement consists of the one-time non-refundable and non-

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creditable development cost reimbursement payment and research and development costs. The transaction price was reduced by the fair value of the Equity Option.

*Revenue Recognition*

The Company determined the transaction price pursuant to the Chiesi Collaboration Agreement is equal to the one-time development cost reimbursement payment of $160.0 million less the fair market value of the Equity Option of $0.5 million. The price allocated for the Equity Option was determined to be at fair market value utilizing the Geometric Brownian Motion/Monte Carlo model and was considered a reduction in the transaction price. The transaction price was allocated to the performance obligations on the basis of the relative stand-alone selling price estimated for each distinct performance obligation. In estimating the stand-alone selling price for each distinct performance obligation, the Company developed assumptions that require judgment and included forecasted revenues or costs, expected development timelines, discount rates and probabilities of technical and regulatory success. A description of the distinct performance obligations identified under the Chiesi Collaboration Agreement, as well as the amount of revenue allocated to each distinct significant performance obligation, is as follows:

*Licenses of Intellectual Property*. The licenses to the Company's intellectual property, bundled with the associated know-how, represents two distinct performance obligations. The licenses and associated know-how were transferred to Chiesi in June 2024, therefore the Company recognized the full revenue related to these distinct performance obligations in the amount of $90.7 million during the year ended December 31, 2024 as revenue from sale of licenses on its consolidated statements of operations and comprehensive loss.

*Research and Development Services*. The progress towards completion of two distinct performance obligations related to PAH and PH-ILD research and development services for the Licensed Products is measured in an amount proportional to the research and development expenses incurred and the total estimated PAH and PH-ILD research and development expenses. In addition, the Company and Chiesi share equally in the costs of ongoing global seralutinib clinical development, with the exception of the PROSERA Phase 3 study, and the costs of commercialization in the U.S. The Company records the revenue from performing research and development services and the cost-sharing payments due from Chiesi as revenue from contracts with collaborators on its condensed consolidated statements of operations and comprehensive loss. For the three months ended March 31, 2026 and 2025, the Company recognized $14.9 million and $9.2 million, respectively, for the PAH and PH-ILD research and development performance obligations. For the three months ended March 31, 2026 and 2025, the Company recognized $2.0 million and $0.7 million, respectively, for the PAH and PH-ILD commercialization activities.

*Milestone Payments.* The Company determined that as of March 31, 2026, it is not probable that a significant revenue reversal will not occur related to the potential milestone payments as their achievement is highly dependent on factors outside the Company's control or are otherwise constrained under the sales and usage based royalty exception. Therefore, these payments have been fully constrained and are therefore not included in the transaction price. At the end of each subsequent reporting period, the Company will re-evaluate the probability of achievement of each milestone and any related constraint. No milestone payments were recognized during the three months ended March 31, 2026 and 2025.

*Royalties.* As the licenses are deemed to be the predominant item to which sales-based royalties relate, the Company will recognize revenue when the related sales occur. No royalty revenue was recognized during the three months ended March 31, 2026 and 2025.

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The following table presents a summary of the activity in the Company's contract liabilities related to the Chiesi Collaboration Agreement (recorded as contract liabilities on the balance sheet) during the three months ended March 31, 2026 and 2025 (in thousands):

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| | | |
|:---|:---|:---|
| | **2026** | **2025** |
| Balance, January 1 | $49593 | $55919 |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from PAH research and development service performance obligations satisfied during reporting period | (7057) | (2789) |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from PH-ILD research and development service performance obligations satisfied during reporting period | (603) | (547) |
| &nbsp;&nbsp;&nbsp;&nbsp; Effect of exchange rate changes on contract liabilities | (1292) | 1953 |
| Balance, March 31 | $40641 | $54536 |

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As of March 31, 2026, the contract liability amount of $40.6 million represents the aggregate transaction price allocated to performance obligations that are unsatisfied under the Chiesi Collaboration Agreement. This amount is expected to be recognized over 4.8 years, which represents the remaining research period under the Chiesi Collaboration Agreement. As of March 31, 2026, the current contract liability balance of $8.7 million is classified as a current liability since the rights to the research and development service are expected to be satisfied within one year, and the remaining contract liability balance of $31.9 million is classified as a long-term liability.

As of March 31, 2026, the Company recorded $9.3 million in accounts receivable associated with the Chiesi Collaboration Agreement. The payments are typically due 30 days after quarterly invoices are issued.

The following table presents the Company's contract revenues from the Chiesi Collaboration Agreement disaggregated by timing of revenue recognition and excluding royalty revenue (in thousands):

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| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| Revenue from Chiesi Collaboration Agreement: |  |  |
| *Over Time:* |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from PAH research and development service performance obligation satisfied during reporting period | 7057 | $2789 |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from PH-ILD research and development service performance obligation satisfied during reporting period | 603 | 547 |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from PAH research and development costs subject to reimbursement | 2458 | 4412 |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from PH-ILD research and development costs subject to reimbursement | 4821 | 1431 |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from PAH commercial costs subject to reimbursement | 1973 | 677 |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from PH-ILD commercial costs subject to reimbursement |  | 64 |
| &nbsp;&nbsp;&nbsp;&nbsp;Effect of exchange rate changes on revenue | 43 | (31) |
| Total revenue from Chiesi Collaboration Agreement | $16955 | $9889 |

---

**Note 11 - Segment Information**

Operating segments are identified as components of an enterprise for which separate discrete financial information is available for evaluation by the CODM in making decisions regarding the allocation of resources and assessing performance. The Company's CODM is its chief executive officer. The Company views its operations and manages its business as one operating segment. The Company's operating segment derives its revenues from the Chiesi Collaboration Agreement. The CODM assesses performance for the Company's single operating segment and decides how to allocate resources based on research and development expenses incurred, which is a component of the Company's consolidated net loss as reported on the consolidated statement of operations and comprehensive loss. The measure of segment assets is reported on the balance sheet as

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total consolidated assets. Further, segment depreciation expense and segment asset additions are consistent with consolidated amounts reported within the consolidated statement of cash flows given the Company's operations are aggregated within a single reportable segment. The CODM uses research and development expenses and results of clinical trial activities completed to date to evaluate how to allocate the Company's resources to advance seralutinib.

Significant segment expenses which are regularly reported to the CODM for purposes of making decisions regarding the allocation of resources are included within the table below and are reconciled to consolidated net loss (in thousands):

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| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| Total revenue | $16955 | $9889 |
| Less: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Seralutinib | 42350 | 36282 |
| &nbsp;&nbsp;&nbsp;&nbsp;Other segment items <sup>(1)</sup> | 19471 | 10417 |
| &nbsp;&nbsp;&nbsp;&nbsp; Interest income | (354) | (294) |
| &nbsp;&nbsp;&nbsp;&nbsp; Interest expense | 2755 | 2746 |
| &nbsp;&nbsp;&nbsp;&nbsp; Other income, net | (603) | (2624) |
| Segment net loss | $(46664) | $(36638) |

---

<sup>(1)</sup> Other segment items include general and administrative expenses, which are provided to the CODM regularly, but are included within other segment items as they are not utilized as part of the decision making process as it relates to the allocation of resources. Further, R&D expenses for other terminated programs are also provided to the CODM. These costs include employee expenses, as well as allocations of consolidated overhead and stock compensation. Other segment items also include costs related to Respira (as defined in Note 13 below).

**Note 12 - Income Taxes**

We calculate the interim income tax provision in accordance with Accounting Standards Codification Topic 270, Interim Reporting, ("ASC 270"), and Topic 740, Accounting for Income Taxes, ("ASC 740"). At the end of each interim period, we estimate our annual effective tax rate and apply that rate to our ordinary quarterly earnings to calculate the tax related to ordinary income. The tax effects for other items that are excluded from ordinary income are discretely calculated and recognized in the period in which they occur. Our annual effective tax rate from continuing operations was 0% for the three months ended March 31, 2026 and 2025.

**Note 13 - Investments in Variable Interest Entities**

The Company reviews its investments in other entities to determine whether the Company is the primary beneficiary of a variable interest entity ("VIE"). The Company would be the primary beneficiary of the VIE and would be required to consolidate the VIE, if it has the power to direct the significant activities of the entity and the obligation to absorb losses or receive benefits from the entity that may be significant to the VIE.

On September 24, 2025, the Company entered into an option agreement with Prana Bio, Inc. ("Prana") to acquire Prana and its wholly-owned subsidiary, Respira Therapeutics, Inc. ("Respira") via merger (the "Respira Merger Option"). The Company identified Prana as a VIE but does not consolidate Prana as the Company lacks the power to direct the activities that significantly impact the economic success of Prana. Pursuant to the agreement, the Company issued 2,500,000 shares of its common stock as consideration for the option grant and agreed to issue up to an additional 1,500,000 shares of common stock following the exercise of the option. Concurrent with the option agreement, the Company entered into a research funding agreement with Prana whereas the Company agreed to provide up to a total of $7.8 million to Respira to carry out chemistry, manufacturing, and controls ("CMC") activities related to Respira's RT234 drug program.

The Respira Merger Option was valued at $7.5 million based on the value of the 2,500,000 shares of common stock issued using the Company's share price as of September 24, 2025, which was $2.99 per share of common stock. The option value was recognized as IPR&D expense in the Company's condensed consolidated statements of operations and comprehensive loss.

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The Company does not consolidate Respira as the Company lacks the power to direct the activities that significantly impact the economic success of Respira. The Company's maximum loss exposure to Prana, prior to the exercise of the option to acquire, is limited to the Respira Merger Option and cost reimbursements for certain research and development activities, which will be recognized as research and development expenses in the Company's condensed consolidated statements of operations and comprehensive loss as incurred.

**Note 14 - Subsequent Events**

The Company has evaluated all subsequent events and transactions through the filing date. There were no material events that impacted the condensed consolidated financial statements or disclosures.

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**ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS**

*The following discussion and analysis and the unaudited interim condensed consolidated financial statements included in this quarterly report on Form 10-Q should be read in conjunction with the consolidated financial statements and notes thereto for the year ended December 31, 2025 and the related Management's Discussion and Analysis of Financial Condition and Results of Operations, both of which are contained in our Annual Report on Form 10-K filed with the Securities and Exchange Commission, or SEC, on March 17, 2026.*

**Forward-Looking Statements**

This quarterly report on Form 10-Q contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and Section 27A of the Securities Act of 1933, as amended, or the Securities Act. All statements other than statements of historical facts contained in this quarterly report, including statements regarding our future results of operations and financial position, including performance under the Chiesi Collaboration Agreement business strategies and plans, research and development plans, the anticipated timing, costs, design and conduct of our ongoing and planned preclinical studies and planned clinical trials for seralutinib, the timing and likelihood of regulatory filings and approvals for seralutinib, timing and likelihood of success, plans and objectives of management for future operations, the potential impact of U.S. trade policy, including tariffs, and future results of seralutinib, are forward-looking statements. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

In some cases, you can identify forward-looking statements by terms such as "may," "will," "should," "expect," "plan," "anticipate," "could," "intend," "target," "project," "contemplates," "believes," "estimates," "predicts," "potential" or "continue" or the negative of these terms or other similar expressions. The forward-looking statements in this quarterly report are only predictions. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition and results of operations. These forward-looking statements speak only as of the date of this quarterly report and are subject to a number of risks, uncertainties and assumptions, including those described in Part II, Item 1A, "Risk Factors" of this report, Part I, Item 1A, "Risk Factors" in our most recent Annual Report on Form 10-K filed with the SEC on March 17, 2026, and Part II, Item 1A, "Risk Factors" of our subsequently filed quarterly reports. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

**Overview**

We are a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of PH, including PAH and PH-ILD. Our goal is to be an industry leader in, and to enhance the lives of patients living with PH. In May 2024, we entered into the Chiesi Collaboration Agreement focused on the development and commercialization of seralutinib. In December 2022, we announced positive topline results from the Phase 2 TORREY Study in PAH patients. In February 2026, we announced topline results from the Phase 3 PROSERA Study in PAH patients. Seralutinib demonstrated a placebo-adjusted improvement in the primary endpoint, 6MWD at Week 24, of 13.3 meters (p = 0.0320), missing the prespecified alpha threshold of 0.025. We believe seralutinib demonstrates a risk benefit profile that supports continued regulatory dialogue. Subject to the outcomes of interactions with the FDA, the Company expects to submit a New Drug Application to the FDA for seralutinib for the treatment of PAH in September 2026. In addition to PAH, we believe that seralutinib holds potential as a therapeutic for the treatment of PH-ILD, and this indication remains an area of focus for us. In October 2025, we activated the first clinical site for the global registrational Phase 3 SERANATA Study for the treatment of PH-ILD. Enrollment in the SERANATA Study was paused in February 2026 to support disciplined resource allocation and to evaluate the implications of PROSERA as we engage with regulators. However, we plan to re-continue PH-ILD development work when feasible based on such resource allocation decisions. We have assembled a deeply experienced and highly skilled group of industry veterans, scientists, clinicians and key opinion leaders from leading biotechnology and pharmaceutical companies, as well as leading academic centers from around the world. Our employees are a team of highly dedicated, passionate individuals who pride themselves on a culture of respect, humility, transparency, inclusion, dedication, collaboration and fun. Our ultimate goal is to enhance and extend the lives of patients.

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We were incorporated in October 2015 and commenced operations in 2017. To date, we have focused primarily on organizing and staffing our company, business planning, raising capital, identifying, acquiring and in-licensing our product candidates and conducting preclinical studies and clinical trials. We have funded our operations primarily through equity and debt financings and the Chiesi Collaboration Agreement. As of March 31, 2026, we had $99.2 million in cash, cash equivalents and marketable securities.

We have incurred significant operating losses since our inception and expect to continue to incur significant operating losses for the foreseeable future. For the three months ended March 31, 2026 and 2025, our net loss was $46.7 million and $36.6 million, respectively. As of March 31, 2026, we had an accumulated deficit of $1,485.6 million. We expect to incur expenses and operating losses for the foreseeable future as we continue our development of and seek regulatory approvals for seralutinib, including the conduct of ongoing and planned clinical trials and other research and development activities; and as we hire additional personnel, protect our intellectual property and incur costs associated with being a public company. In addition, as seralutinib progresses through development and toward commercialization, we will need to make milestone payments to Pulmokine from whom we have in-licensed seralutinib. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending in particular on the timing of our clinical trials and preclinical studies and our expenditures on other research and development activities.

On May 3, 2024, we announced a strategic global partnership with Chiesi. Under the terms of the Chiesi Collaboration Agreement, we granted Chiesi exclusive licenses for the worldwide development, manufacture and commercialization of seralutinib and licensed products and an Equity Option to purchase our common stock, which expired in November 2025 and is no longer exercisable. The total potential transaction value includes the one-time $160.0 million development cost reimbursement payment for licenses, research and development funding, and certain regulatory and commercial milestones. We and Chiesi share equally in the costs of ongoing global seralutinib clinical development and the costs of commercialization in the U.S. Territory, with the exception of the PROSERA Phase 3 study, for which we bear all costs. We are also eligible for double-digit royalties in the mid-to-high teens percentage on tiers of annual net sales outside of the U.S. and to an equal share of profits and losses from the commercialization of seralutinib and licensed products in the U.S.

We do not expect to generate any revenue from product sales unless and until we successfully complete development and obtain regulatory approval for seralutinib, which we expect will take a number of years, if at all. If we obtain regulatory approval for seralutinib, we expect to incur significant commercialization expenses related to product sales, marketing, manufacturing and distribution. Accordingly, until such time as we can generate substantial product revenues to support our cost structure, if ever, we expect to finance our cash needs through equity offerings, debt financings or other capital sources, including potentially collaborations, licenses and other similar arrangements. However, we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all. Our failure to raise capital or enter into such other arrangements when needed could have a negative impact on our financial condition and on our ability to pursue our business plans and strategies. If we are unable to raise additional capital when needed, we could be forced to delay, limit, reduce or terminate seralutinib development or future commercialization efforts or grant additional rights to develop and market seralutinib even if we would otherwise prefer to retain such right.

**Components of Results of Operations**

***Revenue***

To date, we have generated all of our revenue from the Chiesi Collaboration Agreement. Our revenue consists of a one-time development cost reimbursement payment for licenses and ongoing cost-sharing payments for performance of research and development services classified as revenue from contracts with collaborators.

In the future, we may generate revenue from a combination of license fees and other upfront payments, other funded research and development agreements, milestone payments, product sales, other third-party funding, U.S. profit/loss share and royalties in connection with strategic alliances. We expect that any revenue we generate will fluctuate from quarter-to-quarter as a result of the timing of performance of research and development services, the timing of our achievement of regulatory and commercialization milestones, the timing and amount of payments relating to such milestones and the extent to which any of our products are approved and successfully commercialized. If we are unable to fund our development costs or we are unable to develop product candidates in a timely manner or obtain regulatory approval for them, our ability to generate future revenues and our results of operations and financial position would be adversely affected.

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***Operating expenses***

*Research and development*

Research and development expenses relate primarily to preclinical and clinical development of seralutinib, as well as our discontinued clinical product candidates. 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 or could include:

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

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• external research and development expenses incurred under agreements with contract research organizations, or CROs, investigative sites and consultants to conduct our clinical trials and preclinical and non-clinical studies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• laboratory supplies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• costs related to manufacturing our product candidates for clinical trials and preclinical studies, including fees paid to third-party manufacturers;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• costs related to compliance with regulatory requirements; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• facilities, depreciation and other allocated expenses, which include direct and allocated expenses for rent, maintenance of facilities, insurance, equipment and other supplies.

Our direct research and development expenses consist principally of external costs, such as fees paid to CROs, investigative sites and consultants in connection with our clinical trials, preclinical and non-clinical studies, and costs related to manufacturing clinical trial materials. We deploy our personnel and facility related resources across all of our research and development activities. We track external costs and personnel expense on a program-by-program basis and allocate common expenses, such as facility related resources, to each program based on the personnel resources allocated to such program. Stock-based compensation and personnel and common expenses not attributable to a specific program are considered unallocated research and development expenses. We categorize Terminated Programs as any research and development expenses attributable to our clinical stage product candidates that were terminated prior to December 31, 2023 or any research and development expenses that are not directly allocated to seralutinib.

We expect to incur research and development expenses for the foreseeable future as we continue the development of seralutinib. We cannot determine with certainty the timing of initiation, the duration or the completion costs of current or future preclinical studies and clinical trials of seralutinib due to the inherently unpredictable nature of preclinical and clinical development. Clinical and preclinical development timelines, the probability of success and development costs can differ materially from expectations. We anticipate that we will make determinations as to how much funding to direct to seralutinib on an ongoing basis in response to the results of ongoing and future preclinical studies and clinical trials, regulatory developments and our ongoing assessments as to seralutinib's commercial potential. We will need to raise substantial additional capital in the future.

Our clinical development costs may vary significantly based on factors such as:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• per patient trial costs;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the number of trials required for approval;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the number of sites included in the trials;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the countries in which the trials are conducted;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the length of time required to enroll eligible patients;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the number of patients that participate in the trials;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the number of doses that patients receive;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the drop-out or discontinuation rates of patients;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• potential additional safety monitoring requested by regulatory agencies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the duration of patient participation in the trials and follow-up;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the cost and timing of manufacturing seralutinib;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the costs incurred as a result of health epidemics and pandemics and clinical site staff shortages, including clinical trial delays;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the phase 3 stage of development for seralutinib; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the efficacy and safety profile of seralutinib.

*In process research and development*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;In process research and development, or IPR&D, expenses include IPR&D acquired as part of an asset acquisition or in-license, for which there is no alternative future use, and the value of the right to acquire Respira Therapeutics via a merger, or the Respira Merger Option, with Prana Bio, the 100% owner of Respira Therapeutics, and are expensed as incurred.

*General and administrative*

General and administrative expenses consist primarily of salaries and employee-related costs, including stock-based compensation, for personnel in executive, finance and other administrative functions. Other significant costs include facility-related costs, legal fees relating to intellectual property and corporate matters, professional fees for accounting and consulting services, insurance costs and commercial planning expenses. Subject to obtaining clarity on potential regulatory paths forward, we anticipate that our general and administrative expenses may increase in the future to support our continued research and development and commercial planning activities and, if seralutinib receives marketing approval, commercialization activities.

We expect to incur general and administrative expenses for the foreseeable future to support our current infrastructure and continued costs of operating as a public company. These expenses will likely include audit, legal, regulatory, and tax-related services associated with maintaining compliance with exchange listing and SEC requirements, director and officer insurance premiums, as well as commercial preparedness, corporate strategy, business development, corporate communications and investor relations costs associated with operating as a public company.

*Other income (expense), net*

Other income (expense), net consists of (1) interest income on our cash, cash equivalents and marketable securities, (2) investment accretion, (3) research and development tax credit, (4) other miscellaneous income (expense) and (5) interest expense.

*Provision for income taxes*

Our tax provision from income taxes is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that are taken into account in the relevant period.

 **Critical Accounting Policies and Estimates**

Our management's discussion and analysis of our financial condition and results of operations are based on our condensed consolidated financial statements, which have been prepared in accordance with GAAP. The preparation of these financial statements requires us to make judgments and estimates that affect the reported amounts of assets, liabilities, revenue, expenses and the disclosure of contingent assets and liabilities in our condensed consolidated financial statements. We base our estimates on historical experience, known trends and events, and various other factors that are believed to be reasonable under the circumstances. Actual results may differ from these estimates under different assumptions or conditions. On an ongoing basis, we evaluate our judgments and estimates in light of changes in circumstances, facts and experience. During the three months ended March 31, 2026, there have been no significant changes in our critical accounting policies and estimates as discussed in Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations – Critical Accounting Policies and Estimates" in our Annual Report on Form 10-K filed with the SEC on March 17, 2026.

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**Results of Operations – Comparison of the Three Months Ended March 31, 2026 and 2025**

The following table sets forth our selected statements of operations data for the three months ended March 31, 2026 and 2025:

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| | | | |
|:---|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** | |
| | **2026** | **2025** | **2026 vs 2025**<br>**Change** |
| | **(in thousands)** | **(in thousands)** | **(in thousands)** |
| **Revenue:** |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue from contracts with collaborators | 16955 | 9889 | 7066 |
| Total revenue | 16955 | 9889 | 7066 |
| **Operating expenses:** |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Research and development | 43075 | 38041 | 5034 |
| &nbsp;&nbsp;&nbsp;&nbsp;General and administrative | 18746 | 8658 | 10088 |
| Total operating expenses | 61821 | 46699 | 15122 |
| **Loss from operations** | **(44866)** | **(36810)** | **(8056)** |
| Other income (expense) |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Interest income | 354 | 294 | 60 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Interest expense | (2755) | (2746) | (9) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other income, net | 603 | 2624 | (2021) |
| Total other income (loss), net | (1798) | 172 | (1970) |
| **Net loss** | $**(46664)** | $**(36638)** | $**(10026)** |

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*Revenue*

Our revenue is generated from our ongoing collaboration with Chiesi and consists of ongoing research and development service performance and cost-sharing payments for performance of research and development and pre-commercial services. For the three months ended March 31, 2026 and 2025, our revenue was $17.0 million and $9.9 million, respectively, for an increase of $7.1 million, which was attributable to an increase in research and development and pre-commercial services.

*Research and development expenses*

Research and development expenses were $43.1 million for the three months ended March 31, 2026, compared to $38.0 million for the three months ended March 31, 2025, for an increase of $5.0 million, which was primarily attributable to an increase of $6.1 million of costs associated with clinical trials for seralutinib and an increase of $0.7 million of costs associated with Respira, offset by a decrease of $1.8 million of costs associated with preclinical studies and clinical trials for terminated programs.

The following table shows our research and development expenses by program for the three months ended March 31, 2026 and 2025:

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| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| | **(in thousands)** | **(in thousands)** |
| Seralutinib | $42350 | $36282 |
| Other programs | 725 |  |
| Terminated programs |  | 1759 |
| Total research and development | $43075 | $38041 |

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*General and administrative expenses*

General and administrative expenses were $18.7 million for the three months ended March 31, 2026, compared to $8.7 million for the three months ended March 31, 2025, for an increase of $10.1 million, which was primarily attributable to a $1.7 million increase in commercial expenses, a $4.6 million increase in personnel expense due to severance, a $2.2 million increase in stock-based compensation expense and a $1.2 million increase in professional services expense.

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*Other income (loss), net*

Other loss, net was $1.8 million for the three months ended March 31, 2026, compared to the other income, net of $0.2 million for the three months ended March 31, 2025, for a decrease of $2.0 million, which was primarily attributable to a $2.1 million decrease in investment accretion.

**Liquidity and Capital Resources**

We have incurred substantial operating losses since our inception and expect to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of March 31, 2026, we had an accumulated deficit of $1,485.6 million.

Our primary use of cash is to fund operating expenses, which consist primarily of research and development expenditures, and to a lesser extent, general and administrative expenditures, including commercial planning expenditures. Cash used to fund operating expenses is impacted by the timing of when we pay these expenses, as reflected in the change in our outstanding accounts payable and accrued expenses. We may also use cash on hand to repurchase 2027 Notes through open-market transactions, including through a Rule 10b5-1 trading plan to facilitate open-market repurchases, or otherwise, from time to time.

Under our license agreement with Pulmokine, we have payment obligations that are contingent upon future events such as our achievement of specified development, regulatory and commercial milestones and are required to make royalty payments in connection with the sale of products developed under the agreement. As of March 31, 2026, we were unable to estimate the timing or likelihood of achieving the milestones or making future product sales. Other contractual obligations include future payments under the 2027 Notes and existing operating leases.

From our inception through March 31, 2026, our operations have been financed primarily by proceeds of $1,396.9 million from the sale of Series A and Series B convertible preferred stock, proceeds from our IPO, proceeds from the 2027 Notes, proceeds from issuance of common stock in May 2020 and July 2022, proceeds from issuance of common stock and accompanying warrants in July 2023 and the Chiesi Collaboration Agreement. In addition, we have received $48.6 million as of March 31, 2026 through reimbursement related to the Chiesi Collaboration Agreement. As of March 31, 2026 we had cash, cash equivalents and marketable securities of $99.2 million. Cash in excess of immediate requirements is invested in accordance with our investment policy, primarily with a view to capital preservation and liquidity.

On April 10, 2020, we filed a registration statement on Form S-3, or the 2020 Shelf Registration Statement, covering the offering from time to time of common stock, preferred stock, debt securities, warrants and units, which registration statement became automatically effective on April 10, 2020.

On May 21, 2020, we issued $200.0 million aggregate principal amount 5.00% convertible senior notes due 2027 in a registered public offering, or the 2027 Notes. The interest rate on the 2027 Notes is fixed at 5.00% per annum. Interest is payable semi-annually in arrears on June 1 and December 1 of each year commencing on December 1, 2020. The total net proceeds from the 2027 Notes, after deducting the underwriting discounts and commissions and other offering costs, were approximately $193.6 million. Concurrent with the registered underwritten public offering of the 2027 Notes, we completed an underwritten public offering of 9,433,963 shares of our common stock. We received net proceeds of $117.1 million, after deducting underwriting discounts and commissions and other offering costs. Our concurrent offerings of 2027 Notes and common stock were registered pursuant to the 2020 Shelf Registration Statement.

On July 15, 2022, we completed a private placement of 16,649,365 shares of our common stock. The aggregate gross proceeds for the private placement were approximately $120.1 million, before deducting offering expenses. On August 9, 2022, we filed a registration statement on Form S-3 registering the resale of the shares of common stock issued in the private placement, which became automatically effective on August 9, 2022.

On July 24, 2023, we completed a private placement of 129,869,440 shares of our common stock and 32,467,360 accompanying warrants. The aggregate gross proceeds for the private placement were $212.1 million, before deducting offering expenses. On August 18, 2023, we filed a registration statement on Form S-3 registering the resale of the shares of common stock and shares of common stock issuable upon the exercise of warrants issued in the private placement, which was declared effective on August 28, 2023.

On May 3, 2024, we entered into the Chiesi Collaboration Agreement. In consideration and as reimbursement for our development costs, Chiesi paid us an up-front, nonrefundable payment of $160.0 million. In addition, we and Chiesi share equally in the costs of ongoing global seralutinib clinical development, with the exception of the PROSERA Phase 3 study, and

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the costs of commercialization in the U.S. Territory. For the three months ended March 31, 2026, we received cost-sharing payments from Chiesi in the amount of $12.2 million.

On January 28, 2026, we filed a registration statement on Form S-3 ASR, or the 2026 Shelf Registration Statement, covering the offering from time to time of common stock, preferred stock, debt securities, warrants and units, which registration statement became automatically effective upon filing. On March 17, 2026, we filed Post-Effective Amendment No. 1 and Post-Effective Amendment No. 2 to the 2026 Shelf Registration Statement, which became effective on March 18, 2026, to convert the registration statement to a non-automatic shelf registration statement as we were no longer a "well-known seasoned issuer."

Additional information about our long-term borrowings is presented in Note 5 "Indebtedness" and operating leases is presented in Note 9 "Commitments and Contingencies" to the Notes to Unaudited Condensed Consolidated Financial Statements included in Part I, Item 1, of this Form 10-Q.

For additional information regarding our collaboration with Chiesi, see Note 10 "Significant Agreements and Contracts" to the Notes to Unaudited Condensed Consolidated Financial Statements included in Part I, Item 1, of this Form 10-Q.

The opinion of our independent registered public accounting firm on our audited financial statements as of and for the years ended December 31, 2025 contains an explanatory paragraph regarding substantial doubt about our ability to continue as a going concern. Future reports on our financial statements may include an explanatory paragraph with respect to our ability to continue as a going concern. Our consolidated condensed financial statements as of and for the three months ended March 31, 2026 and 2025 included in this Form 10-Q do not include any adjustments relating to the recoverability and classification of recorded asset amounts or amounts of liabilities that might be necessary should we be unable to continue our operations.

The following table shows a summary of our cash flows for each of the three months ended March 31, 2026 and 2025, respectively:

---

| | | |
|:---|:---|:---|
| | **Three months ended March 31,** | **Three months ended March 31,** |
| | **2026** | **2025** |
| | **(in thousands)** | **(in thousands)** |
| Net cash used in operating activities | $(38721) | $(39724) |
| Net cash provided by investing activities | 41606 | 22062 |
| Net cash provided by financing activities | 512 | 504 |
| Effect of exchange rate changes on cash and cash equivalents | (101) | 105 |
| Net increase (decrease) in cash and cash equivalents | $3296 | $(17053) |

---

*Operating activities*

During the three months ended March 31, 2026, operating activities used approximately $38.7 million of cash, primarily resulting from a net loss of $46.7 million and changes in contract liabilities of $9.0 million, reduced by changes in accounts payable of $6.2 million, changes in stock-based compensation expense of $6.3 million, changes in receivable from contracts with collaborators of $3.0 million and changes in prepaid expenses and other current assets of $2.4 million.

During the three months ended March 31, 2025, operating activities used approximately $39.7 million of cash, primarily resulting from the net loss of $36.6 million and changes in accrued compensation and benefits of $5.8 million, reduced by changes in stock-based compensation expense of $2.4 million.

*Investing activities*

During the three months ended March 31, 2026, investing activities provided approximately $41.6 million of cash, primarily resulting from the maturities of marketable securities of $66.6 million, offset by the purchases of marketable securities of $25.0 million.

During the three months ended March 31, 2025, investing activities provided approximately $22.1 million of cash, primarily resulting from the maturities of marketable securities of $123.1 million, offset by the purchases of marketable securities of $101.0 million.

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*Financing activities*

During the three months ended March 31, 2026, financing activities provided $0.5 million of cash, primarily resulting from the proceeds from issuance of common stock pursuant to the ESPP of $0.3 million and the proceeds from the exercise of stock options of $0.2 million.

During the three months ended March 31, 2025, financing activities provided $0.5 million of cash, primarily resulting from the proceeds from issuance of common stock pursuant to the ESPP of $0.4 million and the proceeds from the exercise of stock options of $0.1 million.

*Funding requirements*

Based on our current operating plan, we believe that our existing cash, cash equivalents and marketable securities, will be sufficient to fund our operations into the first quarter of 2027. However, our forecast of the period of time through which our financial resources will be adequate to support our operations is a forward-looking statement that involves risks and uncertainties, and actual results could vary materially. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we expect. Additionally, the process of testing seralutinib in clinical trials and seeking regulatory approval is costly, and the timing of progress and expenses in these trials is uncertain. Pending feedback from the FDA on a potential path forward for seralutinib, we also expect that the level of spending for our ongoing and planned commercial planning activities for seralutinib may increase.

Our future capital requirements will depend on many factors, including:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the costs, timing and outcome of regulatory review of seralutinib;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the type, number, scope, progress, enrollment pace, expansions, results, costs and timing of, our preclinical studies and clinical trials of seralutinib which we are pursuing or may choose to pursue in the future;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the costs and timing of manufacturing for seralutinib;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the costs of obtaining, maintaining and enforcing our patents and other intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our efforts to enhance operational systems and hire additional personnel to satisfy our obligations as a public company, including enhanced internal controls over financial reporting;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the costs associated with hiring additional personnel and consultants to continue the development and potential commercialization of seralutinib;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the timing and amount of the milestone or other payments we must make to Pulmokine from whom we have in-licensed seralutinib;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the costs and timing of establishing or securing sales and marketing capabilities if seralutinib is approved;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our ability to achieve sufficient market acceptance, coverage and adequate reimbursement from third-party payors and adequate market share and revenue for any approved products;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the terms and timing of establishing and maintaining collaborations, licenses and other similar arrangements;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• costs associated with any products or technologies that we may in-license or acquire; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any delays and cost increases that result from epidemic diseases.

Until such time as we can generate substantial product revenues to support our cost structure, if ever, we expect to finance our cash needs through equity offerings, debt financings or other capital sources, including potentially collaborations, licenses and other similar arrangements.

However, we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our stockholders will be or could be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as

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incurring additional debt, making capital expenditures or declaring dividends. If we raise funds through collaborations, licenses and other similar arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to us and/or may reduce the value of our common stock. Our failure to raise capital or enter into such other arrangements when needed could have a negative impact on our financial condition and on our ability to pursue our business plans and strategies. If we are unable to raise additional capital when needed, we could be forced to delay, limit, reduce or terminate seralutinib development or future commercialization efforts or grant rights to develop and market seralutinib even if we would otherwise prefer to develop and market seralutinib ourselves.

**ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK**

As of March 31, 2026, there have been no material changes surrounding our market risk, including interest rate risk, foreign currency exchange risk, and inflation risk, from the discussion provided in Item 7A, "Quantitative and Qualitative Disclosures About Market Risk" in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 filed with the SEC on March 17, 2026.

**ITEM 4. CONTROLS AND PROCEDURES**

**Conclusion Regarding the Effectiveness of Disclosure Controls and Procedures**

We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in our periodic and current reports that we file with the SEC is recorded, processed, summarized and reported within the time periods specified in the SEC's rules and forms, and that such information is accumulated and communicated to our management, including our principal executive officer and principal financial officer, as appropriate, to allow timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognized that any controls and procedures, no matter how well designed and operated, can provide only reasonable and not absolute assurance of achieving the desired control objectives. In reaching a reasonable level of assurance, management necessarily was required to apply its judgment in evaluating the cost-benefit relationship of possible controls and procedures. In addition, the design of any system of controls also is based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions; over time, control may become inadequate because of changes in conditions, or the degree of compliance with policies or procedures may deteriorate. Because of the inherent limitations in a cost-effective control system, misstatements due to error or fraud may occur and not be detected.

Our management, with the participation of our principal executive officer and principal financial officer, has evaluated the effectiveness of our disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act as of the end of the period covered by this quarterly report. Based on such evaluation, our principal executive officer and principal financial officer have concluded that as of such date, our disclosure controls and procedures were effective at the reasonable assurance level.

**Changes in Internal Control Over Financial Reporting**

There have been no changes in our internal control over financial reporting during the three months ended March 31, 2026 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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**PART II. OTHER INFORMATION**

**ITEM 1. LEGAL PROCEEDINGS**

From time to time, we may be involved in legal proceedings or subject to claims incident to the ordinary course of business. Regardless of the outcome, such proceedings or claims can have an adverse impact on us because of defense and settlement costs, diversion of resources and other factors, and there can be no assurances that favorable outcomes will be obtained. We are currently subject to the following legal proceeding:

***Kinnamon vs. Gossamer Bio, Inc., et. al.***

On March 31, 2026, Daniel Kinnamon, individually and on behalf of all others similarly situated, filed a putative class action lawsuit against the Company, certain of its executive officers and directors in the United States District Court for the Southern District of California (Case No. 3:26-cv-2016-CAB-AHG). The complaint was filed on behalf of all persons who purchased or otherwise acquired the Company's securities between June 16, 2025 and February 20, 2026. The complaint alleges that the Company, certain of its executive officers and directors made false and/or misleading statements and failed to disclose material adverse facts about its business, operations and prospects in violation of Sections 10(b) (and Rule 10b-5 promulgated thereunder) and 20(a) of the Securities Exchange Act of 1934, as amended. The plaintiff seeks damages, interest, costs, attorneys' fees, and other unspecified equitable relief. On May 4, 2026, the Court entered an order staying any answer or response to the complaint pending the appointment of a lead plaintiff and lead counsel. The Company intends to vigorously defend this matter. Given the uncertainty of litigation, the preliminary stage of the case, and the legal standards that must be met for, among other things, class certification and success on the merits, the Company cannot estimate the reasonably possible loss or range of loss that may result from this action.

**ITEM 1A. RISK FACTORS**

There have been no material changes to the risk factors previously disclosed by us in Part I, Item 1A "Risk Factors" of our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 filed with the SEC on March 17, 2026.

**ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS**

None.

**Issuer Repurchases of Equity Securities**

None.

**ITEM 3. DEFAULTS UPON SENIOR SECURITIES**

Not Applicable.

**ITEM 4. MINE SAFETY DISCLOSURES**

Not Applicable.

**ITEM 5. OTHER INFORMATION**

During the three months ended March 31, 2026, none of our officers or directors adopted or terminated any contract, instruction or written plan for the purchase or sale of our securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) or any "non Rule 10b5-1 trading arrangement."

**ITEM 6. EXHIBITS**

The exhibits filed or furnished as part of this Quarterly Report on Form 10-Q are set forth on the Exhibit Index, which Exhibit Index is incorporated herein by reference.

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**EXHIBIT INDEX**

---

| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **Exhibit<br>Number** | **Exhibit Description** | **Incorporated by Reference** | **Incorporated by Reference** | **Incorporated by Reference** | **Filed Herewith** |
| | | **Form** | **Date** | **Number** | |
| 3.1 | <u>[Amended and Restated Certificate of Incorporation, as amended.](https://www.sec.gov/Archives/edgar/data/1728117/000172811723000108/goss-20230630xex31.htm)</u> | 10-Q | 8/8/2023 | 3.1 |  |
| 3.2 | <u>[Amended and Restated Bylaws.](https://www.sec.gov/Archives/edgar/data/1728117/000156459020024690/goss-ex32_408.htm)</u> | 10-Q | 5/12/2020 | 3.2 |  |
| 4.1 | <u>[Form of Common Stock Certificate.](https://www.sec.gov/Archives/edgar/data/1728117/000119312519014857/d690055dex41.htm)</u> | S-1/A | 1/23/2019 | 4.1 |  |
| 4.2 | <u>[Indenture, dated as of May 21, 2020, by and between the Company and Wilmington Trust, National Association.](https://www.sec.gov/Archives/edgar/data/1728117/000156459020026546/goss-ex41_10.htm)</u> | 8-K | 5/21/2020 | 4.1 |  |
| 4.3 | <u>[First Supplemental Indenture, dated May 21, 2020, by and between the Company and Wilmington Trust, National Association.](https://www.sec.gov/Archives/edgar/data/1728117/000156459020026546/goss-ex42_11.htm)</u> | 8-K | 5/21/2020 | 4.2 |  |
| 4.4 | <u>[Form of Global Note representing 5.00% Convertible Senior Notes due 2027 (included as part of Exhibit 4.4).](https://www.sec.gov/Archives/edgar/data/1728117/000156459020026546/goss-ex42_11.htm)</u> | 8-K | 5/21/2020 | 4.3 |  |
| 4.5 | <u>[Form of Warrant](https://www.sec.gov/Archives/edgar/data/1728117/000172811723000094/goss-2023x07x19exx41.htm)</u> | 8-K | 7/20/2023 | 4.1 |  |
| 31.1 | <u>[Certification of Chief Executive Officer of Gossamer Bio, Inc., as required by Rule 13a-14(a) or Rule 15d-14(a), as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.](goss-20260331x10qxexx311.htm)</u> |  |  |  | X |
| 31.2 | <u>[Certification of Chief Financial Officer of Gossamer Bio, Inc., as required by Rule 13a-14(a) or Rule 15d-14(a), as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.](goss-20260331x10qxexx312.htm)</u> |  |  |  | X |
| 32.1\* | <u>[Certification of Chief Executive Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.](goss-20260331x10qxexx321.htm)</u> |  |  |  | X |
| 32.2\* | <u>[Certification of Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.](goss-20260331x10qxexx322.htm)</u> |  |  |  | X |
| 101.INS | XBRL Report Instance Document |  |  |  | X |
| 101.SCH | XBRL Taxonomy Extension Schema Document |  |  |  | X |
| 101.CAL | XBRL Taxonomy Calculation Linkbase Document |  |  |  | X |
| 101.LAB | XBRL Taxonomy Label Linkbase Document |  |  |  | X |
| 101.PRE | XBRL Presentation Linkbase Document |  |  |  | X |
| 101.DEF | XBRL Taxonomy Extension Definition Linkbase Document |  |  |  | X |
| 104 | Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101) |  |  |  | X |

---

\* This certification is deemed not filed for purpose of section 18 of the Exchange Act or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act.

# Indicates management contract or compensatory plan.

------

**SIGNATURES**

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

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| | | | |
|:---|:---|:---|:---|
| | | GOSSAMER BIO, INC. | GOSSAMER BIO, INC. |
| Date: | May 15, 2026 | By: | /s/ Faheem Hasnain |
|  |  |  | Faheem Hasnain |
|  |  |  | President and Chief Executive Officer |
|  |  |  | (Principal Executive Officer) |
| Date: | May 15, 2026 | By: | /s/ Bryan Giraudo |
|  |  |  | Bryan Giraudo |
|  |  |  | Chief Financial Officer and Chief Operating Officer |
|  |  |  | (Principal Financial and Accounting Officer) |

---

## Exhibit 31.1

**EXHIBIT 31.1**

**CERTIFICATION OF PERIODIC REPORT UNDER SECTION 302 OF**

**THE SARBANES-OXLEY ACT OF 2002**

I, Faheem Hasnain, certify that:

1. I have reviewed this quarterly report on Form 10-Q of Gossamer Bio, Inc.;

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;

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;

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)) for the registrant and have:

&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;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;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;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

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;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;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: May 15, 2026

---

| |
|:---|
| /s/ Faheem Hasnain |
| Faheem Hasnain |
| *President and Chief Executive Officer* |
| (Principal Executive Officer*)* |

---

## Exhibit 31.2

**EXHIBIT 31.2**

**CERTIFICATION OF PERIODIC REPORT UNDER SECTION 302 OF**

**THE SARBANES-OXLEY ACT OF 2002**

I, Bryan Giraudo, certify that:

1. I have reviewed this quarterly report on Form 10-Q of Gossamer Bio, Inc.;

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;

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;

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)) for the registrant and have:

&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;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;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;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

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;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;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: May 15, 2026

---

| |
|:---|
| /s/ Bryan Giraudo |
| Bryan Giraudo |
| *Chief Financial Officer and Chief Operating Officer* |
| (Principal Financial and Accounting Officer*)* |

---

## Exhibit 32.1

**EXHIBIT 32.1**

**CERTIFICATION PURSUANT TO**

**18 U.S.C. SECTION 1350**

**AS ADOPTED PURSUANT TO SECTION 906**

**OF THE SARBANES-OXLEY ACT OF 2002**

I, Faheem Hasnain, President and Chief Executive Officer of Gossamer Bio, Inc. (the "Company"), do hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the accompanying Quarterly Report on Form 10-Q of the Company for the quarter ended March 31, 2026 (the "Report"), as filed with the Securities and Exchange Commission, fully complies with the requirements of Section 13(a) or Section 15(d), as applicable, of the Securities Exchange Act of 1934, as amended; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company for the periods presented therein.

Date: May 15, 2026

---

| |
|:---|
| /s/ Faheem Hasnain |
| Faheem Hasnain |
| *President and Chief Executive Officer* |
| (Principal Executive Officer*)* |

---

## Exhibit 32.2

**EXHIBIT 32.2**

**CERTIFICATION PURSUANT TO**

**18 U.S.C. SECTION 1350**

**AS ADOPTED PURSUANT TO SECTION 906**

**OF THE SARBANES-OXLEY ACT OF 2002**

I, Bryan Giraudo, Chief Financial Officer and Chief Operating Officer of Gossamer Bio, Inc. (the "Company"), do hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the accompanying Quarterly Report on Form 10-Q of the Company for the quarter ended March 31, 2026 (the "Report"), as filed with the Securities and Exchange Commission, fully complies with the requirements of Section 13(a) or Section 15(d), as applicable, of the Securities Exchange Act of 1934, as amended; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company for the periods presented therein.

Date: May 15, 2026

---

| |
|:---|
| /s/ Bryan Giraudo |
| Bryan Giraudo |
| *Chief Financial Officer and Chief Operating Officer* |
| (Principal Financial and Accounting Officer*)* |

---

<br>