BESREMi wins FDA approval for essential thrombocythemia, becoming the first new FDA-approved ET treatment in nearly 30 years.
Written By: Mayuri Vaja, PharmD
Reviewed By: Pharmacally Editorial Team
The U.S. Food and Drug Administration has approved BESREMi® (ropeginterferon alfa-2b-njft) for adults with essential thrombocythemia, expanding the drug’s existing U.S. indication in polycythemia vera. The approval covers patients regardless of genotype or disease status, including those newly diagnosed who have not previously received cytoreductive therapy.
The decision gives clinicians a new treatment option for ET, a chronic myeloproliferative neoplasm in which abnormal bone marrow activity drives excessive platelet production. Patients face increased risks of thrombosis and bleeding, including stroke, myocardial infarction, and pulmonary embolism.
Long-Acting Interferon Targets Disease Biology
BESREMi is a long-acting interferon-based therapy that uses monopegylation to extend exposure to ropeginterferon alfa-2b. Unlike therapies that primarily focus on reducing platelet counts and controlling symptoms, interferon treatment can act on abnormal hematopoietic cells involved in the disease process.
The formulation also supports subcutaneous administration every two weeks, with the dosing interval potentially extending to once every four weeks after sustained hematologic stability.
Like other interferons, BESREMi carries warnings for potential neuropsychiatric, autoimmune, ischemic, and infectious disorders, requiring periodic monitoring during long-term therapy.
Phase 3 SURPASS ET Supported FDA Approval
The FDA approval is based on the global Phase 3 SURPASS ET trial (NCT04285086), which compared BESREMi with anagrelide in adults with essential thrombocythemia.
BESREMi demonstrated superior durable response rates on the study’s modified European Leukemia Net (ELN) response measure and showed durable hematologic control. The primary modified ELN response assessments were conducted at Months 9 and 12, providing a measure of sustained treatment response rather than short-term blood-count changes.
The trial also reported a reduction in thromboembolic events over 12 months of treatment.
Together, these findings support the potential role of ropeginterferon alfa-2b in sustained ET disease management, extending beyond short-term platelet reduction and symptom control.
Clinicians Gain a New Long-Term Treatment Option
Ruben Mesa, M.D., principal investigator of SURPASS ET, said the approval addresses a longstanding need for therapies that can control blood counts while acting on the underlying disease process.
For PharmaEssentia, the ET approval expands BESREMi’s role across myeloproliferative neoplasms. The company retains global rights to the product and has previously secured ET approvals in Japan and Taiwan.
U.S. Availability Expected Immediately
BESREMi is expected to become available in the United States immediately following the FDA approval. The expanded indication adds ET to the drug’s established U.S. use in adults with polycythemia vera.
The regulatory decision represents the first new FDA-approved treatment for ET in nearly 30 years and gives physicians an additional long-acting interferon option for managing a disease that can require prolonged cytoreductive treatment and carries persistent thrombotic and bleeding risks.
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About the Writer
Mayuri Vaja (Linkedin) is a Pharm.D professional with a strong interest in clinical research, pharmacovigilance, and medical writing, supported by certifications in pharmacovigilance and academic projects exploring AI in healthcare and drug safety.
With a growing focus on evidence-based healthcare and scientific communication, she is developing expertise in clinical research and translating healthcare evidence into clear, meaningful content.
As a Pharmacally healthcare writer, Mayuri is committed to creating accurate, research-driven, and clinically relevant healthcare content while continuously strengthening her professional skills.