FDA Accepts Besremi Application for Essential Thrombocythemia

The U.S. Food and Drug Administration (FDA) has accepted a supplemental biologics license application for Besremi (ropeginterferon alfa-2b-njft) for the treatment of adults with essential thrombocythemia, a rare blood cancer, according to a news release from PharmaEssentia USA Corporation, marking a key regulatory step aimed at expanding treatment options for patients with cancer who have this chronic condition.

The application was accepted under a standard review classification, with a user target date of Aug. 30, 2026, as the company seeks to broaden access of the therapy for patients with essential thrombocythemia.

What Evidence Supports the FDA Submission?

The supplemental application is supported by statistically significant and clinically meaningful results from the global phase 3 SURPASS-ET clinical trial as well as confirmatory evidence from the North American phase 2b EXCEED-ET clinical trial. According to the company, these data formed the basis of the submission and were sufficient for the FDA to complete its filing review and determine that the application was complete enough to move forward with a substantive review. The FDA’s correspondence did not identify any filing review issues.

Essential thrombocythemia is described by the company as a rare blood cancer driven by excessive platelet production. Patients with cancer who have this condition face increased risks that can include blood clots, abnormal bleeding, enlarged spleens and serious complications such as organ damage and stroke. Despite these risks, the company noted that no new therapies have been approved by the FDA for essential thrombocythemia in more than two decades, underscoring the potential significance of a new treatment option for this patient population.

If approved, Besremi could become an additional option for clinicians caring for adults with essential thrombocythemia. The company stated that the potential final approved indication and any changes to the Prescribing Information will be addressed during the FDA review process.

Which Trials Are Informing the FDA Review?

The supplemental biologics license application is based primarily on results from the SURPASS-ET trial, a global phase 3 study registered as NCT04285086, along with confirmatory evidence from the EXCEED-ET trial, a North American phase 2b study registered as NCT05482971. Dr. Ruben Mesa, principal investigator of the SURPASS-ET trial and president of Advocate Health’s Cancer National Service Line, noted that living with essential thrombocythemia can be physically and emotionally exhausting for patients with cancer who must manage a chronic disease with limited treatment choices. He said that, if approved, Besremi could offer clinicians a meaningful new option for their patients with essential thrombocythemia.

Besremi is already FDA-approved for the treatment of adults with polycythemia vera. PharmaEssentia plans to seek a label expansion to include essential thrombocythemia and has submitted this supplemental application to support that goal. Besremi holds orphan drug designation in the United States for the treatment of adults with polycythemia vera and has received regulatory approval in more than 40 countries, including approvals from the European Medicines Agency in 2019, the FDA in 2021 and Japan’s Pharmaceuticals and Medical Devices Agency in 2023.

What Safety Information Should Patients Know?

The safety profile discussed in the press release reflects the important safety information for Besremi. Interferon alfa products, including Besremi, carry a warning for the risk of serious disorders. These therapies 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, and 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.

Besremi is contraindicated in patients with a history of severe depression, suicidal ideation or suicide attempt; hypersensitivity to interferons or any inactive ingredients; moderate or severe hepatic impairment; active serious or untreated autoimmune disease; or a history of transplantation while receiving immunosuppressant agents.

Warnings and precautions include the need to closely monitor patients for depression and suicidal symptoms, endocrine toxicity that cannot be medically managed, cardiovascular toxicity in those with severe or unstable cardiovascular disease and decreases in peripheral blood counts, which require regular monitoring. Other potential risks include hypersensitivity reactions, pancreatitis, colitis, pulmonary toxicity, ophthalmologic toxicity, hyperlipidemia, hepatotoxicity, renal toxicity, dental and periodontal toxicity and dermatologic toxicity. Patients are advised to have eye examinations before and during treatment, maintain good oral hygiene with regular dental care and avoid driving or operating machinery if they experience dizziness, somnolence or hallucinations.

Reference

1. “FDA Confirms a PDUFA Goal Date of August 30, 2026 for the sBLA Submission of Ropeginterferon Alfa-2b-njft in Essential Thrombocythemia (ET).” News Release. PharmaEssentia. Jan. 13, 2025.

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