PharmaEssentia Announces Japanese Approval of BESREMi (Ropeginterferon alfa-2b) for Essential Thrombocythemia (ET)

1. Date of Event: 2025/08/24

2. Name or Code of the New Drug: BESREMi (ropeginterferon alfa-2b, also known as P1101)

3. Indications: (1) Essential Thrombocythemia (ET) (2) Polycythemia Vera (PV) in adult patients for whom existing therapies are inadequate or not applicable

4. All Planned Development Stages: Not applicable.

5. Current Development Stage: (1) Status of Application Submission/Approval/Rejection, Clinical Trial Results (including interim analyses), or Other Major Events Impacting Drug Development: BESREMi (ropeginterferon alfa-2b), a new drug developed by the company, has been approved by Japan's Ministry of Health, Labour and Welfare for the treatment of essential thrombocythemia (ET).

(2) Risks and Mitigation Measures if Approval is Denied, Clinical Trial Results are Not Statistically Significant, or Other Major Events Occur: Not applicable.

(3) Future Business Direction Following Regulatory Approval, Statistically Significant Trial Results, or Other Major Events: The company's Japanese subsidiary will officially launch the commercialization of BESREMi (ropeginterferon alfa-2b) in Japan's ET market and initiate planned marketing activities across the country.

(4) Cumulative R&D Expenditure Incurred: In consideration of future marketing strategies and to protect the interests of the company and investors, this information will not be disclosed at this time.

6. Next Development Stage (including expected completion date and obligations): (1) Expected Completion Date: Not applicable. (2) Expected Obligations: None.

7. Market Overview: Essential thrombocythemia (ET) is a type of myeloproliferative neoplasm (MPN), with a patient population comparable to that of polycythemia vera (PV). According to market research, Japan has approximately 63,000 ET patients. Current standard treatments include hydroxyurea (HU) and anagrelide (ANA).

8. Other Matters to be Disclosed: (1) Ropeginterferon alfa-2b was approved by Japan's Ministry of Health, Labour and Welfare in March 2023 for the treatment of adult polycythemia vera patients who respond inadequately to or are ineligible for existing therapies, and was included in the national health insurance reimbursement list in May of the same year.

(2) Ropeginterferon alfa-2b-njft is a next-generation, long-acting interferon independently developed and manufactured by the company. It has been approved in approximately 50 countries worldwide, including major pharmaceutical markets such as the United States, Japan, China, and the European Union, for the treatment of adult polycythemia vera. It is also approved in Taiwan and Macau for adult ET patients who are resistant or intolerant to hydroxyurea therapy.

9. Drug development involves long timelines, high investment costs, and no guarantee of success, which may expose investors to risks. Investors are advised to carefully assess and make prudent investment decisions.

Keyword: Material Information