FDA Clears Pen Device for Interferon Therapy in Polycythemia Vera

The FDA has approved a prefilled pen device for ropeginterferon alfa-2b-njft (BESREMi Pen), giving adults with polycythemia vera a second self-injection option alongside the existing prefilled syringe.¹

The pen will be commercially available in the United States within the coming weeks. It does not change the drug's indication, dosing, or safety profile; the approval pertains to the delivery device itself, which the manufacturer said is intended to simplify subcutaneous self-administration for patients on long-term therapy.

Ropeginterferon alfa-2b-njft is a monopegylated interferon alfa-2b formulation administered by subcutaneous injection, typically once every 2 weeks during dose titration and once monthly during maintenance in patients who achieve hematologic control. It was first approved by the FDA in November 2021 for adults with polycythemia vera and has since received marketing authorization in more than 40 countries, according to the company. The drug previously received FDA orphan drug designation for this indication.²

Polycythemia vera is a chronic myeloproliferative neoplasm arising from a mutated hematopoietic stem cell, most often driven by an acquired JAK2 mutation, that results in excessive production of red blood cells along with variable increases in white blood cells and platelets. The disease carries an elevated risk of arterial and venous thrombosis and can progress over time to myelofibrosis or acute leukemia, underscoring the importance of sustained disease control.

“I’m very excited to see the FDA approval of the BESREMi Pen™ as a new option for patients,” said John Mascarenhas, MD, director of the Center of Excellence for Blood Cancers and Myeloid Disorders at Mount Sinai in New York City, in a news release.¹ “Treatment consistency is critical for managing [polycythemia vera], and this device has the potential to make a meaningful positive impact on patients’ lives by simplifying self-administration and supporting better adherence.”

The original efficacy and safety evidence supporting ropeginterferon alfa-2b-njft in polycythemia vera came from the phase 1/2 PEGINVERA study (NCT01193699) and the phase 3 PROUD-PV trial (NCT01949805) with its extension, CONTINUATION-PV (NCT02218047). In long-term follow-up of PROUD-PV and CONTINUATION-PV, patients treated with ropeginterferon alfa-2b showed durable hematologic responses and reductions in JAK2 V617F allele burden compared with those receiving hydroxyurea or best available therapy. The trials demonstrated a reduction in JAK2 allele burden, a surrogate marker associated with lower risk of thrombosis and disease progression over time, although the overall rate of clinical events during the study period was low, meaning longer follow-up will be needed to confirm differences in progression rates between treatment arms. The National Comprehensive Cancer Network lists ropeginterferon alfa-2b-njft as a preferred first-line cytoreductive option for adults with polycythemia vera regardless of risk category or treatment history.

The drug carries a boxed warning, shared by other interferon alfa products, for serious or fatal neuropsychiatric, autoimmune, ischemic, and infectious disorders; the label recommends periodic clinical and laboratory monitoring and discontinuation if severe or worsening symptoms occur. Contraindications include current or past severe depression, suicidal ideation, or suicide attempt; hypersensitivity to interferons; moderate-to-severe hepatic impairment; active untreated autoimmune disease; and a history of organ transplantation with immunosuppressive therapy. Additional warnings address cardiovascular, endocrine, pulmonary, hepatic, renal, ophthalmologic, and dermatologic toxicity, as well as cytopenias, pancreatitis, colitis, and hyperlipidemia, each requiring specific monitoring or dose adjustment as detailed in the full prescribing information.

Clinicians prescribing either device should continue to follow the same baseline and on-treatment monitoring recommendations, including complete blood counts at baseline, every two weeks during dose titration, and every 3 to 6 months during maintenance therapy. PharmaEssentia said dosing and administration technique for the pen are intended to mirror those of the prefilled syringe, though prescribers and patients should consult the device-specific instructions for use once available.

REFERENCES

1. PharmaEssentia Announces FDA Approval and U.S. Launch of BESREMi Pen™ (ropeginterferon alfa-2b-njft) for Polycythemia Vera. News release. PharmaEssentia USA Corporation. June 26, 2026. Accessed June 26, 2026. https://tinyurl.com/yry749n9

2. U.S. FDA Approves Besremi® (ropeginterferon alfa-2b-njft) as the only interferon for adults with polycythemia vera. News release. PharmaEssentia Corporation. November 12, 2021. Accessed June 26, 2021. https://bwnews.pr/3CdLudY