# EDGAR Filing Document

**Accession Number:** 0001559053
**File Stem:** 0001193125-25-174061
**Filing Date:** 2025-8
**Character Count:** 10863
**Document Hash:** e2a144ba1ba104c9d99ddafd72ca3151
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-174061.hdr.sgml**: 20250806

**ACCESSION NUMBER**: 0001193125-25-174061

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20250806

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20250806

**DATE AS OF CHANGE**: 20250806

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** PROTHENA CORP PUBLIC LTD CO
- **CENTRAL INDEX KEY:** 0001559053
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 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:** 251187784

**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' encoding='ASCII'? 8-K

### 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): August 6, 2025

## PROTHENA CORPORATION PUBLIC LIMITED COMPANY

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

---

| | | |
|:---|:---|:---|
| **Ireland** | **001-35676** | **98-1111119** |
| **(State or other jurisdiction of**<br> **incorporation)** | **(Commission**<br> **File Number)** | **(I.R.S. Employer**<br> **Identification Number)** |

---

---

| |
|:---|
| **77 Sir John Rogerson's Quay, Block C** |
| **Grand Canal Docklands** |
| **Dublin 2, D02 VK60, Ireland** |
| **(Address of principal executive offices including Zip Code)** |

---

#### 011-353-1-236-2500

#### (Registrant's telephone number, including area code)

#### N/A

#### (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:

☐ 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:

---

| | | |
|:---|:---|:---|
| **Title of each class** | **Trading<br>Symbol(s)** | **Name of each exchange**<br> **on which registered** |
| 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 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).

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. ☐

------

---

| | |
|:---|:---|
| **Item 8.01** | **Other Events.**  |

---

On August 6, 2025, Prothena Corporation plc (the "Company") issued a press release announcing that the Company's partner Novo Nordisk announced its decision to advance coramitug into Phase 3 development for ATTR amyloidosis with cardiomyopathy. A copy of that press release is attached 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**  |

---

(d) Exhibits

---

| | |
|:---|:---|
| Exhibit<br>No. | Description |
| 99.1 | [Press Release dated August 6, 2025](d42243dex991.htm) |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) |

---

------

#### 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 hereunto duly authorized.

---

| | | |
|:---|:---|:---|
|  | **PROTHENA CORPORATION PLC** | **PROTHENA CORPORATION PLC** |
| Dated: August 6, 2025 | By: | /s/ Tran B. Nguyen |
|  | Name: | Tran B. Nguyen |
|  | Title: | Chief Strategy Officer and Chief Financial Officer |

---

## Exhibit 99.1

**Exhibit 99.1**![LOGO](g42243g0806012223364.jpg)

**PRESS RELEASE** 

**Prothena Announces that Novo Nordisk Will Advance Coramitug (formerly PRX004) into Phase 3 Development for ATTR Amyloidosis with Cardiomyopathy** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Coramitug is a potential first-in-class amyloid depleter antibody for the treatment of ATTR amyloidosis with cardiomyopathy<sup>1-3</sup>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Novo Nordisk successfully completed a Phase 2 trial with coramitug and is expected to initiate a Phase 3 program
in 2025

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Prothena to earn a clinical milestone payment when prespecified enrollment criteria are met in a Phase 3 clinical
trial by Novo Nordisk

DUBLIN, Ireland, August 6, 2025 — Prothena Corporation plc (NASDAQ:PRTA), announced that Novo Nordisk communicated during their second quarter 2025 earnings call on August 6, 2025 that they expect to advance coramitug, a potential first-in-class amyloid depleter antibody, into a Phase 3 program for ATTR amyloidosis with cardiomyopathy (ATTR-CM) in 2025. Coramitug was initially developed by Prothena and was acquired by Novo Nordisk in July 2021.

"We are excited by Novo Nordisk's decision to advance coramitug into Phase 3 development. There remains a significant unmet need in patients with ATTR amyloidosis with cardiomyopathy, who are at high risk for early mortality and significant morbidity due to amyloid deposition in vital organs," said Gene Kinney, Ph.D., President and Chief Executive Officer, Prothena.

Under the terms of the agreement, Prothena is eligible to receive up to $1.2 billion dollars upon achievement of clinical development and sales milestones, including the $100 million earned to date. Prothena is eligible to earn a clinical milestone payment when prespecified enrollment criteria are met in the Phase 3 clinical trial. Novo Nordisk gained full worldwide rights to the intellectual property and related rights of the ATTR amyloidosis business and pipeline it acquired from Prothena in July 2021.

------

**About Coramitug (formerly PRX004)** 

Coramitug (formerly PRX004) is an investigational antibody designed to deplete amyloid associated with disease pathology in hereditary and wild type ATTR amyloidosis, without affecting the native, normal tetrameric form of the protein<sup>1-3</sup>. Coramitug's proposed mechanism of action is to deplete both the deposited amyloid to improve organ function and circulating non-native TTR to prevent further organ deposition<sup>1-3</sup>. In preclinical studies, coramitug or its murine form demonstrated ability to inhibit amyloid fibril formation, bind soluble aggregate forms of non-native TTR and promote clearance of insoluble amyloid fibrils through antibody-mediated phagocytosis<sup>1,2</sup>. In a Phase 1 clinical study, coramitug was well tolerated in patients with ATTRv amyloidosis and demonstrated potential clinical activity on Global Longitudinal Strain (GLS) and Neuropathy Impairment Score (NIS)<sup>3</sup>. This differentiated depleter mechanism of action could be developed as a monotherapy approach to ATTR amyloidosis and might also complement existing therapeutic approaches which either stabilize or reduce production of the native TTR tetramer<sup>3</sup>.

**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 ATTR amyloidosis with cardiomyopathy, 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 X (formerly Twitter) @ProthenaCorp.

**Forward-Looking Statements** 

This press release contains forward-looking statements. These statements relate to, among other things, the treatment potential, design, and proposed mechanism of action coramitug; plans for ongoing and future clinical trials of coramitug; and amounts we might receive under our agreement with Novo Nordisk. 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 August 4, 2025, and discussions of potential risks, uncertainties, and other important factors in our subsequent filings with the SEC. 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.

**References:** 

<sup>1</sup> Preclinical studies of PRX004 (coramitug) – data on file

<sup>2</sup> Higaki JN et al. *Amyloid*, 2016

<sup>3</sup> Suhr OB et al., *Amyloid*, 2025

------

**Contact:** 

Mark Johnson, CFA, Vice President, Investor Relations

650-417-1974, mark.johnson@prothena.com