A new treatment approach

The U.S. Food and Drug Administration approved Mimrylo (rusfertide) for adults with polycythemia vera whose disease has not been adequately controlled with existing therapy. The August 28 approval introduces the first treatment for the condition designed to mimic hepcidin, the hormone that regulates iron availability in the body.

Polycythemia vera is a rare chronic blood disorder in which the body produces too many red blood cells. The resulting increase in blood thickness can raise the risk of blood clots, stroke and heart attack. A central treatment goal is to keep hematocrit—the proportion of blood made up of red blood cells—below 45 percent.

How rusfertide works

Red blood cell production depends on iron. By mimicking hepcidin and limiting the iron available for that process, rusfertide is intended to reduce excess red blood cell production and help patients maintain hematocrit control.

The medicine is administered by subcutaneous injection once weekly. According to the FDA announcement, treatment in the pivotal study began at 19 mg and was adjusted to maintain hematocrit below the target level. The approval was granted to Takeda Pharmaceuticals America following priority review.

Results from the VERIFY trial

The FDA based its decision on the VERIFY trial, a randomized, double-blind, placebo-controlled Phase 3 study involving 293 adults who continued to require frequent phlebotomies despite standard-of-care therapy. Participants received either Mimrylo or placebo over 32 weeks.

The primary measure assessed the proportion of patients who did not meet criteria for phlebotomy during the evaluation period. The FDA reported that 76.9 percent of patients receiving Mimrylo required no phlebotomies, compared with 32.9 percent of patients receiving placebo. The most commonly reported adverse reactions were injection-site reactions and anemia.

The approval is notable both for patients with polycythemia vera and for the broader development of peptide-based medicines. It demonstrates how a targeted biological mechanism can move from research through controlled clinical trials and formal regulatory review into an approved treatment with defined use, dosing and safety information.

Original source  U.S. Food and Drug Administration — FDA Approves First Drug of Its Kind for Polycythemia Vera, a Rare Blood Disorder

Editorial note  This article summarizes the FDA’s public announcement. Patients should consult a qualified healthcare professional regarding diagnosis and treatment.