Ropeginterferon Alfa’s Supplemental BLA Moves on as PDUFA Date Issued

The FDA has accepted the supplemental Biologics License Application (BLA) for ropeginterferon alfa-2b-njft (Besremi), a treatment for adult patients with essential thrombocythemia (ET). After undergoing a standard review, the agent was issued a Prescription Drug User Fee Act (PDUFA) date of August 30, 2026.

The FDA has completed its filing review of the Company’s sBLA and determined that the submission is sufficiently complete to proceed with a substantive review. The FDA’s correspondence did not identify any filing review issues, according to a release from the manufacturer.¹

The sBLA under review is supported by statistically significant and clinically meaningful results from the global phase 3 SURPASS-ET clinical trial (NCT04285086) as well as confirmatory evidence from the North American phase 2b EXCEED-ET trial (NCT05482971). The potential final approved indication and changes to the Prescribing Information will be addressed during the review process.

SURPASS and EXCEED-ET

In the SURPASS trial, patients receiving ropeginterferon demonstrated superior efficacy and safety compared with patients who received anagrelide as second-line therapy for ET. Response rates were 42.9% in the treatment arm vs 6.0% in the control arm.²

The EXCEED-ET trial, which reported topline data on January 12, 2026,³ evaluated 91 patients with ET, including 24 patients previously treated with hydroxyurea (HU) and 67 treatment-naïve patients, providing a broad and representative dataset across key ET patient subgroups. The trial results demonstrated a consistent efficacy and treatment response across the overall ET population, with stronger results observed in treatment-naive patients.

In the overall intent-to-treat population, the response rate at 10 and 13 months was approximately 60.2%, based on a modified European LeukemiaNet (ELN) criterion requiring the meeting of 3 components.

The individual component rates were: a reduction in peripheral blood counts (platelets ≤400 × 10⁹/L and white blood cells <9.5 × 10⁹/L) in 63.7% of patients, improvement or no worsening of splenomegaly in 94.5%, and no bleeding or thrombotic events between months 10 and 13 in 100% of patients.³

A key secondary end point, reduction in JAK2V617F allele burden, also showed encouraging results. Investigators reported that the mean allele burden decreased from 22.2% at baseline to 15.4% at month 13.³

Significant Efficacy

The results highlighted a significant efficacy difference based on prior treatment. Among treatment-naïve patients, the overall response rate was 68.0%, compared with 33.4% in patients previously treated with hydroxyurea (HU).

Component-level analysis revealed this disparity:

• 70.7% of treatment-naïve patients achieved the required blood count reduction vs 44.0% of HU-experienced patients
• 100% of treatment-naïve patients showed improvement or no worsening of splenomegaly vs 79.9% in the HU group.
• Both cohorts reported no bleeding or thrombotic events in the assessment window.

“Living with ET can be exhausting—physically and emotionally—for patients who must navigate a chronic cancer with limited treatment choices,” Ruben Mesa, MD, 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, said. “If approved, ropeginterferon alfa-2b-njft could offer clinicians a meaningful new treatment option for their patients with ET.”

REFERENCES

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 USA Corporation. January 13, 2026. Accessed January 20, 2026. https://tinyurl.com/4z36rtb2

2. Mesa R. Ropeginterferon alfa-2b versus anagrelide for the treatment of essential thrombocythemia: Topline results of the phase 3 SURPASS-ET trial. Presented at: 2025 ASCO Annual Meeting. May 30-June 3, 2025. Chicago, IL. Abstract 6500.

3. PharmaEssentia announces positive topline phase 2b data from EXCEED-et study evaluating ropeginterferon alfa-2b-njft for essential thrombocythemia. News release. PharmaEssentia USA Corporation. January 12, 2026. Accessed January 20, 2026. https://tinyurl.com/yuz9bvzv