- Impactful milestone for the ET community, with BESREMi becoming the first FDA-approved treatment for ET in nearly three decades
- FDA approval is based on the global Phase 3 SURPASS ET study demonstrating durable modified European Leukemia Net (ELN) responses and hematologic control
- BESREMi has been approved for adults with ET, regardless of genotype or disease status
BURLINGTON, Mass.--(BUSINESS WIRE)--PharmaEssentia USA Corporation, a subsidiary of PharmaEssentia Corporation (TWSE: 6446) today announced the U.S. Food and Drug Administration (FDA) has approved BESREMi® (ropeginterferon alfa-2b-njft) for the treatment of adults with essential thrombocythemia (ET), making it the first new FDA-approved treatment for ET in nearly three decades. BESREMi has been approved for adults with ET, regardless of their genotype or disease status, including newly diagnosed patients who are naive to cytoreductive therapy. The ET approval expands the BESREMi product label, which has been commercially available for the treatment of adults with polycythemia vera (PV).
This approval marks a major milestone for people living with ET, a rare chronic blood cancer characterized by an overproduction of platelets. Patients with ET often require years of ongoing disease management and remain at risk for serious complications, such as heart attacks, strokes and pulmonary embolism.1 The approval of BESREMi provides a new ET treatment option and offers the potential for durable disease control, addressing a longstanding unmet need in ET care.
BESREMi is a long-acting interferon-based therapy designed to provide sustained disease management for ET. It offers a differentiated treatment option compared with current therapies that primarily focus on controlling platelet counts and symptoms, with limited impact on the underlying disease biology.2 Using novel monopegylation technology and an extended half-life, BESREMi is designed to target disease-driving cells in the bone marrow while reducing elevated platelet counts and disease burden.
“For nearly 30 years, people living with ET and the physicians treating them have had limited treatment innovation,” said Ruben Mesa, M.D., principal investigator of the SURPASS-ET trial and President of Advocate Health’s Cancer National Service Line, which includes Atrium Health Levine Cancer Institute and the Comprehensive Cancer Center at Atrium Health Wake Forest Baptist. “In my experience, patients need treatment options that not only control blood counts but also address the underlying disease. The approval of BESREMi provides an important new treatment option that is supported by strong clinical evidence and that also works at the source of the disease rather than solely managing symptoms.”
The FDA approval of BESREMi is based on clinical data demonstrating durable modified European Leukemia Net (ELN) responses and durable hematologic control in adults with ET. In the global Phase 3 SURPASS ET clinical trial (NCT04285086), BESREMi achieved superior durable response rates compared with anagrelide and reduced thromboembolic events over 12 months of treatment.
“Today’s FDA approval of BESREMi for ET is a significant advancement for patients and reflects PharmaEssentia’s longstanding commitment to advancing innovative therapies for people living with myeloproliferative neoplasms,” said Ko-Chung Lin Ph.D., founder and CEO of PharmaEssentia. “We have been working closely with the FDA, healthcare providers, advocacy organizations and payers to bring this important treatment option to the ET community.”
This announcement follows BESREMi’s recent regulatory approval in Japan and Taiwan for ET and further expands the company’s MPN portfolio. BESREMi for ET is expected to be available in the United States immediately upon approval. Additional information, including Prescribing Information, is available here.
About PharmaEssentia
PharmaEssentia USA Corporation, located in Burlington, Massachusetts, is a subsidiary of PharmaEssentia Corporation (TWSE: 6446). PharmaEssentia Corporation, headquartered in Taipei, Taiwan, is a global and rapidly growing biopharmaceutical innovator. Leveraging deep expertise and proven scientific principles, PharmaEssentia aims to deliver effective new biologics for challenging diseases in the areas of hematology, oncology, and immunology with one approved product and a diversifying pipeline. Founded in 2003 by a team of Taiwanese-American executives and renowned scientists from U.S. biotechnology and pharmaceutical companies, today PharmaEssentia is expanding its global presence with operations in the U.S., Japan, China, and Korea, along with a world-class biologics production facility in Taichung, Taiwan. For more information about PharmaEssentia USA, visit the website, LinkedIn or X (formerly Twitter).
About Essential Thrombocythemia (ET)
Essential thrombocythemia (ET) is a rare blood disorder and type of myeloproliferative neoplasm (MPN). It is characterized by the bone marrow overproducing platelets. Patients with ET are at an increased risk of blood clots, abnormal bleeding and enlarged spleens. ET is often caused by genetic mutations such as a JAK2 genetic mutation.
About BESREMI® (ropeginterferon alfa-2b-njft)
Ropeginterferon alfa-2b-njft is currently FDA-approved and marketed as BESREMi® for the treatment of adults with polycythemia vera (PV) and essential thrombocythemia (ET).
BESREMi® holds orphan drug designation in the United States for the treatment of polycythemia vera and essential thrombocythemia in adults. The product was developed by PharmaEssentia. PharmaEssentia retains full global intellectual property rights across all indications.
INDICATION
BESREMi is indicated for the treatment of adults with essential thrombocythemia.
IMPORTANT SAFETY INFORMATION
WARNING: RISK OF SERIOUS DISORDERS
Interferon alfa products may cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Patients should be monitored closely with periodic clinical and laboratory evaluations. Therapy should be withdrawn in patients with persistently severe or worsening signs or symptoms of these conditions. In many, but not all cases, these disorders resolve after stopping therapy.
CONTRAINDICATIONS
Existence of or history of severe depression, suicidal ideation, or suicide attempt
Hypersensitivity to interferons or any inactive ingredients
Moderate or severe hepatic impairment
History or presence of active serious or untreated autoimmune disease
History of transplantation and receiving immunosuppressant agents
WARNINGS AND PRECAUTIONS
Patients exhibiting the following events should be closely monitored and may require dose reduction or discontinuation of therapy:
- Depression and Suicide: Monitor closely for symptoms and need for treatment.
- Endocrine Toxicity: Discontinue if endocrine disorders occur that cannot be medically managed.
- Cardiovascular Toxicity: Avoid use in patients with severe, acute or unstable cardiovascular disease. Monitor patients with history of cardiovascular disorders more frequently.
- Decreased Peripheral Blood Counts: Perform blood counts at baseline, every 2 weeks during titration, and at least every 3-6 months during maintenance treatment.
- Hypersensitivity Reactions: Stop treatment and immediately manage reaction.
- Pancreatitis: Consider discontinuation if confirmed pancreatitis
- Colitis: Discontinue if signs or symptoms of colitis
- Pulmonary Toxicity: Discontinue if pulmonary infiltrates or pulmonary function impairment
- Ophthalmologic Toxicity: Advise patients to have eye examinations before and during treatment. Evaluate eye symptoms promptly and discontinue if new or worsening eye disorders.
- Hyperlipidemia: Monitor serum triglycerides before BESREMi® treatment and intermittently during therapy and manage when elevated.
- Hepatotoxicity: Monitor liver enzymes and hepatic function at baseline and during treatment. Reduce dose or discontinue depending on severity.
- Renal Toxicity: Monitor serum creatinine at baseline and during therapy. Discontinue if severe renal impairment develops.
- Dental and Periodontal Toxicity: Advise patients on good oral hygiene and to have regular dental examinations.
- Dermatologic Toxicity: Consider discontinuing if clinically significant dermatologic toxicity.
- Driving and Operating Machinery: Advise patients to avoid driving or using machinery if they experience dizziness, somnolence, or hallucination.
Please see full Prescribing Information, including Boxed Warning.
1 PharmaEssentia Corporation. What is ET? Piece Together ET. https://piecetogetheret.com/what-is-et/. Last accessed July 1, 2026.
2 Reeves BN, El Chaer F, Foltz L et al. Ropeginterferon alfa-2b-njft treatment in essential thrombocythemia across different driver mutations: results from a North American, single-arm, multicentre study (EXCEED-ET). Lancet Reg Health Am. 2026 Jun 10;61:101529. doi: 10.1016/j.lana.2026.101529. PMID: 42306077; PMCID: PMC13267617.
3 Mesa R, Gill H, Zhang L et al. Ropeginterferon alfa-2b in hydroxyurea-intolerant or hydroxyurea-refractory essential thrombocythaemia (SURPASS ET): a multicentre, open-label, randomised, active-controlled, phase 3 study. Lancet Haematol. 2025 Nov;12(11):e862-e875. doi: 10.1016/S2352-3026(25)00264-9. PMID: 41193116.
Contacts
Media
Muriel Huang
Director, Investor Relations and Corporate Communications
Muriel_huang@pharmaessentia.com
