# EDGAR Filing Document

**Accession Number:** 0001559053
**File Stem:** 0001559053-23-000002
**Filing Date:** 2023-2
**Character Count:** 28116
**Document Hash:** b7d0055827b8d7ca0b6359572db1fd25
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001559053-23-000002.hdr.sgml**: 20230223

**ACCESSION NUMBER**: 0001559053-23-000002

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20230223

**ITEM INFORMATION**: Results of Operations and Financial Condition

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20230223

**DATE AS OF CHANGE**: 20230223

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** PROTHENA CORP PUBLIC LTD CO
- **CENTRAL INDEX KEY:** 0001559053
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **IRS NUMBER:** 000000000
- **STATE OF INCORPORATION:** L2
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-35676
- **FILM NUMBER:** 23659704

**BUSINESS ADDRESS:**
- **STREET 1:** 77 SIR JOHN ROGERSON'S QUAY, BLOCK C
- **STREET 2:** GRAND CANAL DOCKLANDS
- **CITY:** DUBLIN 2
- **STATE:** L2
- **ZIP:** D02 VK60
- **BUSINESS PHONE:** 011-353-1-236-2500

**MAIL ADDRESS:**
- **STREET 1:** 77 SIR JOHN ROGERSON'S QUAY, BLOCK C
- **STREET 2:** GRAND CANAL DOCKLANDS
- **CITY:** DUBLIN 2
- **STATE:** L2
- **ZIP:** D02 VK60

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Prothena Corp plc
- **DATE OF NAME CHANGE:** 20121102

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Neotope Corp Ltd
- **DATE OF NAME CHANGE:** 20120926

?xml version="1.0" ? prta-20230223

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**WASHINGTON, D.C. 20549**

_______________________________________________________

**FORM 8-K** 

_______________________________________________________

**CURRENT REPORT**

**Pursuant to Section 13 or 15(d) of the**

**Securities Exchange Act of 1934**

**Date of Report (Date of earliest event reported): February 23, 2023** 

_______________________________________________________

**PROTHENA CORPORATION PUBLIC LIMITED COMPANY**

**(Exact name of registrant as specified in its charter)**

_______________________________________________________

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Ireland** | **001-35676** | **001-35676** | **001-35676** | **98-1111119** |
| **(State or Other Jurisdiction<br>of Incorporation)** | **(Commission<br>File Number)** | **(Commission<br>File Number)** | **(Commission<br>File Number)** | **(IRS Employer<br>Identification No.)** |
|  | **77 Sir John Rogerson's Quay, Block C** | **77 Sir John Rogerson's Quay, Block C** | **77 Sir John Rogerson's Quay, Block C** |  |
|  | **Grand Canal Docklands** | **Grand Canal Docklands** | **Grand Canal Docklands** |  |
|  | **Dublin 2,** | **D02 VK60,** | **Ireland** |  |
| **(Address of principal executive offices, including Zip Code)** | **(Address of principal executive offices, including Zip Code)** | **(Address of principal executive offices, including Zip Code)** | **(Address of principal executive offices, including Zip Code)** | **(Address of principal executive offices, including Zip Code)** |

---

**Registrant's telephone number, including area code: 011-353-1-236-2500**

___________________________________________________

**(Former Name or Former Address, if Changed Since Last Report.)** 

___________________________________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (*see* General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

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| | | |
|:---|:---|:---|
| <u>Title of Each Class</u> | <u>Trading Symbol</u> | <u>Name of Each Exchange on Which Registered</u> |
| Ordinary Shares, par value $0.01 per share | PRTA | The Nasdaq Global Select Market |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Emerging growth company ☐

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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. ☐

------

---

| | |
|:---|:---|
| **Item 2.02.** | **Results of Operations and Financial Condition.** |

---

*&nbsp;&nbsp;&nbsp;&nbsp;The information in Item 2.02 of this Current Report on Form 8-K and Exhibit 99.1 attached hereto shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section. It may only be incorporated by reference in another filing under the Exchange Act or the Securities Act of 1933, as amended, if such subsequent filing specifically incorporate by reference the information furnished pursuant to Item 2.02 (including Exhibit 99.1) of this Current Report.*

&nbsp;&nbsp;&nbsp;&nbsp;On February 23, 2023, Prothena Corporation plc issued a press release announcing its financial results for the fourth quarter and fiscal year ended December 31, 2022. A copy of that press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

---

| | |
|:---|:---|
| **Item 9.01.** | **Financial Statements and Exhibits** |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) <u>Exhibits</u>.

---

| | |
|:---|:---|
| **<u>Exhibit No.</u>** | **<u>Description</u>** |
| 99.1 | <u>[Press Release dated](exhibit991q42022earningsre.htm)[February 23, 2023](exhibit991q42022earningsre.htm)</u> |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) |

---

**SIGNATURES**

&nbsp;&nbsp;&nbsp;&nbsp;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 hereunto duly authorized.

---

| | | | |
|:---|:---|:---|:---|
| Date: | February 23, 2023 | **PROTHENA CORPORATION PLC** | **PROTHENA CORPORATION PLC** |
|  |  | By: | /s/ Tran B. Nguyen |
|  |  | Name: | Tran B. Nguyen |
|  |  | Title: | Chief Financial Officer and Chief Strategy Officer |

---

## Exhibit 99.1

**Exhibit 99.1**

**&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**

![prothenargbfullcolora19a.jpg](prothenargbfullcolora19a.jpg)

**PRESS RELEASE**

**Prothena Reports Fourth Quarter and Full Year 2022 Financial Results, and Provides Financial Guidance and Business Highlights**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*•* Net cash used in operating and investing activities was $5.1 million in the fourth quarter and $109.3 million for the full year of 2022; quarter-end cash and restricted cash position was $712.6 million

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Advanced potential best-in-class Alzheimer's Disease portfolio in 2022: received FDA clearance for IND application and Fast Track designation granted for PRX012, an investigational anti-Aβ antibody therapy; initiated Phase 1 SAD and MAD study for PRX012; completed Phase 1 SAD and initiated MAD study for PRX005, an investigational tri-epitopic antibody that specifically binds within the MTBR-tau

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Strengthened leadership position in the amyloidosis community with the ongoing enrollment of the confirmatory Phase 3 AFFIRM-AL study of birtamimab in patients with Mayo Stage IV AL amyloidosis and multiple 2022 scientific publications and presentations, including data presented at ASH

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Received $40 million milestone payment from Novo Nordisk in December 2022 for advancement of NNC6019 (formerly PRX004) in a Phase 2 study for potential treatment of ATTR cardiomyopathy

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Raised net proceeds of $172.4 million in December 2022 through an underwritten public follow-on offering of 3,250,000 ordinary shares

DUBLIN, Ireland, February 23, 2023 -- Prothena Corporation plc (NASDAQ:PRTA), a late-stage clinical biotechnology company with a robust pipeline of investigational therapeutics built on protein dysregulation expertise, today reported financial results for the fourth quarter and full year 2022. In addition, the Company provided 2023 financial guidance and business highlights.

"In 2022 we meaningfully advanced our protein dysregulation portfolio as we continue our transition to a fully integrated commercial company. The foundation we established in 2022 has positioned the next 24 months as a transformational period for Prothena, with many significant clinical milestones expected across six different programs in areas of high unmet patient need," said Gene Kinney, Ph.D., President and Chief Executive Officer Prothena. "For PRX012, we received clearance from the FDA for our IND application and Fast Track designation was granted. We also initiated the Phase 1 SAD and MAD study for PRX012 and completed the Phase 1 SAD and initiated the MAD study for PRX005. Additionally, we presented key data on birtamimab and PRX123 at ASH and AD/PD, respectively. As we grew our organization's capabilities to prepare for the future, we also added significant strategic depth to our board of directors through the appointment of an established biotech leader, Helen S. Kim, MBA."

------

**<u>2022 Business Highlights and Upcoming Milestones</u>**

**Neurodegenerative Diseases Portfolio**

*Alzheimer's Disease (AD)*

**PRX012**, a potential best-in-class, next-generation subcutaneous antibody for the treatment of AD, that targets a key epitope at the N-terminus of amyloid beta (Aβ) with high binding potency

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Received clearance from the U.S. Food and Drug Administration (FDA) in March 2022 for the investigational new drug (IND) application

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• FDA granted Fast Track designation in April 2022

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Initiated Phase 1 single ascending dose (SAD) and multi ascending dose (MAD) studies in healthy volunteers and patients with AD

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Significant presence at upcoming International Conference on Alzheimer's and Parkinson's Diseases (AD/PD) in March/April 2023 highlighted by oral presentation of preclinical data showing superior binding characteristics of PRX012 and a symposium featuring key thought leaders

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Ongoing Phase 1 SAD and MAD studies; topline data expected year end 2023

**PRX005**, a potential best-in-class antibody, for the treatment of AD that specifically targets a key epitope within the microtubule binding region (MTBR) of tau, a protein implicated in diseases including AD, frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), chronic traumatic encephalopathy (CTE), and other tauopathies. PRX005 is part of a global neuroscience research and development collaboration with Bristol Myers Squibb

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Topline data from Phase 1 SAD study announced January 2023 showing single doses of PRX005 across three dose cohorts were generally safe and well tolerated, meeting the primary objective of the study; results expected from the Phase 1 SAD study at an upcoming medical conference

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Ongoing Phase 1 MAD study; topline data expected year end 2023

**PRX123**, a potential first-in-class dual Aβ/tau vaccine, for the treatment and prevention of AD, that is a dual-target vaccine targeting key epitopes within the N-terminus of Aβ and MTBR-tau to promote amyloid clearance and blockade of pathogenic tau

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Oral presentation on preclinical data at AD/PD 2022 demonstrated that Prothena's dual Aβ/tau vaccine generated anti-Aβ and anti-MTBR-tau antibodies to enable clearance of Aβ and to inhibit cell-to-cell transmission of pathogenic tau species

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Investigational new drug (IND) application filing expected by year end 2023

*Parkinson's Disease (PD)*

**Prasinezumab**, a potential first-in-class antibody, for the treatment of PD, that is designed to target key epitopes within the C-terminus of alpha-synuclein and is the focus of a worldwide collaboration with Roche

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Oral presentation by partner Roche at AD/PD 2022 of the Phase 2 PASADENA study further supports a potential effect on delaying motor progression in patients with early PD

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Ongoing Phase 2b PADOVA trial in patients with early PD is being conducted by Roche (NCT04777331); topline data expected in 2024

------

**<u>Rare Peripheral Amyloid Diseases Portfolio</u>**

*AL Amyloidosis*

**Birtamimab**, a potential best-in-class amyloid depleter antibody, for the treatment of AL amyloidosis, that is designed to directly neutralize soluble toxic aggregates and promote clearance of amyloid that causes organ dysfunction and failure

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Poster presented at the XVIII International Symposium on Amyloidosis (ISA) in September 2022 titled: Birtamimab in Patients with Mayo Stage IV AL Amyloidosis: Rationale for Confirmatory AFFIRM-AL Phase 3 trial

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Oral presentation at the 2022 American Society of Hematology (ASH) Annual Meeting and Exposition in December 2022: Consistent Survival Benefit Observed with Birtamimab in Mayo Stage IV AL Amyloidosis Patients in Phase 3 VITAL Study

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Published data on in-hospital mortality in amyloid light chain amyloidosis in *Journal of Comparative Effectiveness Research*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Confirmatory Phase 3 AFFIRM-AL trial ongoing (NCT04973137); topline data expected in 2024

*ATTR Amyloidosis*

**NNC6019** (formerly PRX004), a potential first-in-class antibody, for the treatment of ATTR cardiomyopathy, that is designed to deplete the pathogenic, non-native forms of the transthyretin (TTR) protein and is being developed by Novo Nordisk as part of their up to $1.2 billion acquisition of Prothena's ATTR amyloidosis business and pipeline

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Received $40 million milestone payment from Novo Nordisk in December 2022 related to the continued advancement of NNC6019 in a Phase 2 study

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Ongoing Phase 2 study in patients with ATTR cardiomyopathy is being conducted by Novo Nordisk (NCT05442047); topline data expected in 2024

**2022 Organizational and Corporate Highlights**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Announced the appointment of Helen S. Kim, MBA, to its Board of Directors. With the appointment of Ms. Kim, Prothena expanded its Board to 10 directors

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Raised net proceeds of $172.4 million through an underwritten public follow-on offering of 3,250,000 ordinary shares in December 2022

**Upcoming Investor Conferences**

Members of the senior management team will present and participate in investor meetings at the following upcoming investor conferences:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• **Oppenheimer 33rd Annual Healthcare Conference** on Monday, March 13, 2023; a fireside chat will be held at 10:00 AM ET

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• **Jefferies Biotech on the Bay Summit** on Thursday, March 16, 2023; 1 on 1 investor meetings will be held

**Fourth Quarter and Full Year of 2022 Financial Results**

For the fourth quarter and full year of 2022, Prothena reported a net income of $6.3 million and a net loss of $116.9 million, respectively, as compared to a net loss of $33.2 million and a net income of $67.0 million for the fourth quarter and full year of 2021, respectively. Net income per share on a diluted basis was $0.12 for the fourth quarter of 2022 and net loss per share of for the full year of 2022 was $2.47, as

------

compared to net loss per share of $0.71 and net income per share on a diluted basis of $1.38 for the fourth quarter and full year of 2021, respectively.

Prothena reported total revenue of $49.9 million and $53.9 million for the fourth quarter and full year of 2022, respectively, as compared to total revenue of $1.2 million and $200.6 million for the fourth quarter and full year of 2021, respectively. Total revenue for the fourth quarter and full year of 2022 included a $40.0 million milestone payment from Novo Nordisk and revenue for fourth quarter and full year of 2022 included BMS collaboration revenue of $9.9 million and $13.9 million, respectively. This compares to total revenue of $1.2 million for the fourth quarter of 2021 from BMS collaboration revenue, and total revenue of $200.6 million for the full year of 2021, which included $79.7 million in collaboration revenue from BMS, a $60.0 million clinical milestone payment from Roche and $60.7 million from the sale of intellectual property and related rights to Novo Nordisk.

Research and development (R&D) expenses totaled $36.9 million and $135.6 million for the fourth quarter and full year of 2022, respectively, as compared to $22.1 million and $82.3 million for the fourth quarter and full year of 2021, respectively. The increase in R&D expense for the fourth quarter and full year of 2022 compared to the same periods in the prior year was primarily due to higher manufacturing costs, higher personnel related expenses, higher clinical trial expenses, higher consulting and other R&D expenses. For the full year of 2022, the higher costs were offset in part by lower collaboration expenses with Roche and lower manufacturing expenses related to the NNC6019 (formerly PRX004) program. R&D expenses included non-cash share-based compensation expense of $3.5 million and $14.8 million for the fourth quarter and full year of 2022, respectively, as compared to $2.9 million and $9.5 million for the fourth quarter and full year of 2021, respectively.

General and administrative (G&A) expenses totaled $13.1 million and $49.9 million for the fourth quarter and full year of 2022, respectively, as compared to $12.2 million and $46.3 million for the fourth quarter and full year of 2021, respectively. The increase in G&A expenses for the fourth quarter and full year of 2022 compared to the same periods in the prior year was primarily related to higher personnel related and consulting expenses offset in part by lower legal expenses. G&A expenses included non-cash share-based compensation expense of $3.9 million and $16.5 million for the fourth quarter and full year of 2022, respectively, as compared to $4.0 million and $15.1 million for the fourth quarter and full year of 2021, respectively.

Total non-cash share-based compensation expense was $7.4 million and $31.3 million for the fourth quarter and full year of 2022, respectively, as compared to $6.9 million and $24.7 million for the fourth quarter and full year of 2021, respectively.

As of December 31, 2022, Prothena had $712.6 million in cash, cash equivalents and restricted cash, and no debt.

As of February 17, 2023, Prothena had approximately 52.6 million ordinary shares outstanding.

**2023 Financial Guidance** 

The Company expects the full year 2023 net cash used in operating and investing activities to be $213 to $229 million and expects to end the year with approximately $512 million in cash, cash equivalents and restricted cash (midpoint). The estimated full year 2023 net cash used in operating and investing activities is primarily driven by an estimated net loss of $250 to $275 million, which includes an estimated $46 million of non-cash share-based compensation expense.

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**Conference Call Details**

Prothena management will discuss these results and its 2023 financial guidance during a live audio conference call today, Thursday, February 23, 2023, at 4:30 PM ET. The conference call will be made available on the Company's website at www.prothena.com under the Investors tab in the Events and Presentations section. Following the live audio webcast, a replay will be available on the Company's website for at least 90 days.

To access the call via dial-in, please dial +1 (888) 350-3870 (U.S. and Canada toll free) or +1 (646) 960-0308 (international) five minutes prior to the start time and refer to conference ID number 92750. A replay of the call will be available until March 2, 2023, via dial-in at (800) 770-2030 (U.S. toll free) or +00 1 647 362-9199 (international), Conference ID Number 92750.

**About Prothena**

Prothena Corporation plc is a late-stage clinical biotechnology company with expertise in protein dysregulation and a pipeline of investigational therapeutics with the potential to change the course of devastating neurodegenerative and rare peripheral amyloid diseases. Fueled by its deep scientific expertise built over decades of research, Prothena is advancing a pipeline of therapeutic candidates for a number of indications and novel targets for which its ability to integrate scientific insights around neurological dysfunction and the biology of misfolded proteins can be leveraged. Prothena's pipeline includes both wholly-owned and partnered programs being developed for the potential treatment of diseases including AL amyloidosis, ATTR amyloidosis, Alzheimer's disease, Parkinson's disease and a number of other neurodegenerative diseases. For more information, please visit the Company's website at www.prothena.com and follow the Company on Twitter @ProthenaCorp.

**Forward-Looking Statements**

*This press release contains forward-looking statements. These statements relate to, among other things, the sufficiency of our cash position to fund advancement of a broad pipeline; the continued advancement of our discovery, preclinical, and clinical pipeline, and expected milestones in 2023 and beyond; the treatment potential, designs, proposed mechanisms of action, and potential administration of birtamimab, prasinezumab, PRX004, PRX005, PRX012, and PRX123; plans for future clinical studies of birtamimab, prasinezumab, PRX004, PRX005, PRX012, and PRX123 (including the filing of an IND application); the expected timing of reporting data from clinical studies of birtamimab, prasinezumab, PRX004, PRX005, and PRX012; our anticipated net cash burn from operating and investing activities for 2023 and expected cash balance at the end of 2023; and our estimated net loss and non-cash share-based compensation expense for 2023. These statements are based on estimates, projections and assumptions that may prove not to be accurate, and actual results could differ materially from those anticipated due to known and unknown risks, uncertainties and other factors, including but not limited to those described in the "Risk Factors" sections of our Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) on November 3, 2022, discussions of potential risks, uncertainties, and other important factors in our subsequent filings with the SEC, and our Annual Report on Form 10-K to be filed with the SEC for our fiscal year 2022. We undertake no obligation to update publicly any forward-looking statements contained in this press release as a result of new information, future events, or changes in our expectations.*

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**PROTHENA CORPORATION PLC**

**CONSOLIDATED STATEMENTS OF OPERATIONS**

**(unaudited - amounts in thousands except per share data)**

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| | | | | |
|:---|:---|:---|:---|:---|
| | **Three Months Ended <br>December 31,** | **Three Months Ended <br>December 31,** | **Year Ended <br>December 31,** | **Year Ended <br>December 31,** |
| | **2022** | **2021** | **2022** | **2021** |
| Collaboration revenue | $9923 | $1172 | $13855 | $139833 |
| Revenue from license and intellectual property | 40000 |  | 40050 | 60744 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total revenue | 49923 | 1172 | 53905 | 200577 |
| Operating expenses: |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Research and development | 36871 | 22058 | 135562 | 82284 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;General and administrative | 13124 | 12206 | 49900 | 46318 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total operating expenses | 49995 | 34264 | 185462 | 128602 |
| Income (loss) from operations | (72) | (33092) | (131557) | 71975 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other income (expense), net | 3417 | (4) | 5952 | (54) |
| Income (loss) before income taxes | 3345 | (33096) | (125605) | 71921 |
| Provision for (benefit from) income taxes | (3004) | 83 | (8656) | 4946 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Net income (loss) | $6349 | $(33179) | $(116949) | $66975 |
| Basic net income (loss) per ordinary share | $0.13 | $(0.71) | $(2.47) | $1.51 |
| Diluted net income (loss) per ordinary share | $0.12 | $(0.71) | $(2.47) | $1.38 |
| Shares used to compute basic net income (loss) per share | 48960 | 46618 | 47369 | 44228 |
| Shares used to compute diluted net income (loss) per share | 53979 | 46618 | 47369 | 48464 |

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**PROTHENA CORPORATION PLC**

**CONSOLIDATED BALANCE SHEETS**

**(unaudited - amounts in thousands)**

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| | | |
|:---|:---|:---|
| | **December 31,**<br>**2022** | **December 31, 2021**<br>**2021** |
| **Assets** |  |  |
| Cash and cash equivalents | $710406 | $579094 |
| Prepaid expenses and other current assets | 8692 | 5715 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total current assets | 719098 | 584809 |
| Property and equipment, net | 1731 | 2012 |
| Operating lease right-of-use assets | 6277 | 12123 |
| Restricted cash, non-current | 2212 | 1352 |
| Other non-current assets | 28717 | 9070 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total non-current assets | 38937 | 24557 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total assets | $758035 | $609366 |
| **Liabilities and Shareholders' Equity** |  |  |
| Accrued research and development | 10794 | 6351 |
| Deferred revenue, current | 11442 | 7657 |
| Lease liability, current | 6473 | 5940 |
| Other current liabilities | 21438 | 13504 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total current liabilities | 50147 | 33452 |
| Deferred revenue, non current | 85293 | 102933 |
| Lease liability, non-current |  | 6386 |
| Other non-current liabilities | 553 | 553 |
| &nbsp;&nbsp;&nbsp;&nbsp; Total non-current liabilities | 85846 | 109872 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total liabilities | 135993 | 143324 |
| Total shareholders' equity | 622042 | 466042 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total liabilities and shareholders' equity | $758035 | $609366 |

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**Media and Investor Contact:**

Media

Michael Bachner, Senior Director, Corporate Communications

609-664-7308, michael.bachner@prothena.com

Investors

IR@prothena.com

<br>