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# PharmaEssentia BLA Approved for Blood Disease
- URL: https://www.fdaweb.com/pharmaessentia-bla-approved-for-blood-disease/
- Published: 2021-11-12T12:00:00.000Z
- Updated: 2026-09-14T17:22:12.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5150572

FDA has approved a PharmaEssentia BLA for Besremi (ropeginterferon alfa-2b-njft) injection to treat adults with polycythemia vera, a blood disease associated with red blood cell overproduction, which thickens blood and increases the risk of blood clots.

The interferon therapy is believed to work by “attaching to certain receptors in the body, setting off a chain reaction that makes the bone marrow reduce blood cell production,” an [FDA release](https://www.fda.gov/news-events/press-announcements/fda-approves-treatment-rare-blood-disease?ref=fdaweb.com) says. The long-acting injectable drug is administered under the skin once every two weeks. If Besremi can reduce excess blood cells and maintain normal levels for at least one year, then dosing frequency may be reduced to once every four weeks, FDA says.

Approval is based on data from a 51-patient, single-arm [trial](http://email.prnewswire.com/ls/click?upn=OXp-2BEvHp8OzhyU1j9bSWuxb3W1qN-2FETzRMaRsoUOQ0cH38SgJoovPONn0uK0XQIPJ0Og46CAf4g3p-2FtRx-2F0C9w-3D-3DoMAD%5Ff0D7hj0BJ4b-2F7NuVqzPDs7FGiq8VLIwAX0sPSotqoLJejYqb1dmQHyCXe45PgGWVikAbTXaVmm3Ze6-2BhblAewBqvUhnOPdSuz9E29wdTqlKoTWcusqP6HQY6-2FiAeL-2FScy2W4vDCeffKU9Albe63FIrCf0ZhIY-2FP2Oj4UKi3IuRC3xXi6KX-2FhcTW4ShqpmrZk0ooVFaFnpvH1t19r81zye4JlU5uFlkDN6MUhoh7hQ-2BrhwN4I2sPh3Tv74F0XPmHWEd5lMuO-2FKbJQKk9mk7fpWjSmBlABGfmdAT1SweHEIxDlyR-2BTMl8oskwTAg0dhdfqWY9UD7SsJ7iWoxP0A3nUY9kE9HeICcMZX3RlgoZ2Uqg-3D&ref=fdaweb.com) that lasted 7.5 years. The primary endpoint was complete hematological response, which meant patients had a red blood cell volume of less than 45% without a recent phlebotomy, normal white cell counts and platelet counts, a normal spleen size, and no blood clots, according to the agency. Overall, 61% of patients had the response.

On the safety side, FDA says Besremi can cause liver enzyme elevations, low levels of white blood cells, low levels of platelets, joint pain, fatigue, itching, upper airway infection, muscle pain and flu-like illness.