BURLINGTON, Mass., August 31, 2026

PharmaEssentia announced that the U.S. Food and Drug Administration (FDA) has approved BESREMi® (ropeginterferon alfa-2b-njft) for the treatment of adults with essential thrombocythemia (ET), expanding the approved use of the company’s long-acting interferon therapy beyond polycythemia vera. The decision makes BESREMi the first new FDA-approved treatment for ET in nearly three decades, marking a significant regulatory milestone for PharmaEssentia and the rare blood cancer community. The approval covers adults with ET regardless of genotype or disease status, including newly diagnosed patients who have not previously received cytoreductive therapy. The company said BESREMi is expected to be available in the United States immediately, providing physicians with another treatment option for long-term management of this chronic myeloproliferative neoplasm.

BESREMi Expands Treatment Option for ET

PharmaEssentia’s FDA approval addresses an important treatment need in essential thrombocythemia, a chronic blood cancer in which the bone marrow produces excessive numbers of platelets. Persistent disease activity can increase the risk of serious thrombotic complications, including heart attacks, strokes and pulmonary embolism, making long-term disease management an important part of patient care. BESREMi is a long-acting interferon-based therapy designed to provide sustained treatment while targeting disease-driving cells in the bone marrow. The therapy uses PharmaEssentia’s monopegylation technology to extend its half-life, supporting prolonged pharmacologic activity. The company positions BESREMi as a differentiated approach to ET management because its mechanism is intended to address disease biology in addition to reducing elevated blood counts and disease burden.

Phase 3 SURPASS ET Data Support FDA Decision

The FDA approval of BESREMi for ET is supported by results from the global Phase 3 SURPASS ET trial, which evaluated BESREMi against anagrelide in adults with essential thrombocythemia. According to PharmaEssentia, the study demonstrated superior durable modified European Leukemia Net (ELN) response rates and durable hematologic control with BESREMi. The trial also reported a reduction in thromboembolic events over 12 months of treatment. These findings provided the clinical foundation for expanding BESREMi’s U.S. label into ET and strengthen the product’s position within PharmaEssentia’s broader myeloproliferative neoplasm (MPN) portfolio. The company said the approval follows recent regulatory clearances for ET in Japan and Taiwan, further extending the geographic reach of BESREMi.

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PharmaEssentia Expands BESREMi’s MPN Role

PharmaEssentia now has an expanded opportunity to establish BESREMi across the ET treatment landscape, building on its existing commercial use in adults with polycythemia vera. The company described the approval as an important step in its strategy to advance biologic treatments for challenging diseases in hematology, oncology and immunology. With ET patients potentially requiring years of ongoing disease management, the addition of an FDA-approved long-acting interferon option could broaden therapeutic choices for clinicians and patients. BESREMi’s approval in ET also represents a major commercial and regulatory expansion for PharmaEssentia in the U.S. market, while the company continues to develop its broader pipeline and international presence in myeloproliferative neoplasms.

Source: PharmaEssentia press relese