FDA Approves PV Treatment That May Reduce Need for Blood Draws

Written by Ted Samson

Posted on September 22, 2026

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The U.S. Food and Drug Administration (FDA) has approved rusfertide (Mimrylo) for adults with polycythemia vera (PV). The drug treats erythrocytosis, or too many red blood cells.

Mimrylo is the first FDA-approved treatment for PV designed to act like hepcidin, one of the hormones that regulates iron in the body. For some people whose PV isn’t well controlled with existing therapies, it provides another treatment option.

Keeping hematocrit — the percentage of blood made up of red blood cells — below 45 percent is a key goal in PV care. That often involves phlebotomy, a procedure that removes blood to help bring red blood cell levels down.

🗳️ How frequently do you typically need phlebotomy (blood draw) for your polycythemia vera?

Once a month or more often

Every two to three months

Less frequently than every three months

I don’t receive regular phlebotomies.

Some people need frequent phlebotomies to control their hematocrit. Symptoms of erythrocytosis can include headaches, blurry vision, and itching.

What Is Rusfertide?

Rusfertide acts like hepcidin and blocks ferroportin, a protein involved in moving iron through the body. With less iron available for red blood cell production, hematocrit levels can fall.

Rusfertide is given by an injection under the skin on a weekly dosing schedule.

What Did the Phase 3 Study Show?

One key study behind the FDA approval included 293 adults with PV who needed frequent phlebotomies despite standard treatment. For the first 32 weeks, participants continued their existing therapy and received either rusfertide or a placebo (an inactive treatment).

The main outcome was not meeting the study’s criteria for needing a phlebotomy from week 20 through week 32.

Key findings included:

76.9 percent of people who received rusfertide met the response goal, compared with 32.9 percent who received a placebo.
62.6 percent of people who received rusfertide met the study’s measure for maintaining hematocrit below 45 percent from week 0 through week 32, compared with 14.4 percent who received a placebo. The study allowed one hematocrit reading at or above 45 percent.
The study estimated an average of 0.53 phlebotomies, compared with 1.82 with a placebo, during the first 32 weeks.

What Are the Possible Side Effects?

Like all treatments, rusfertide can cause side effects. In the phase 3 study, the most common were injection-site reactions (56 percent) and anemia (16 percent).

The prescribing information also warns that Mimrylo may cause new or worsening thrombocytosis (high platelet counts) and may harm a baby during pregnancy.

Why Does This Approval Matter for People With PV?

For some people with PV, repeated blood draws are a burden. Rusfertide offers a new way to target red blood cell overproduction and may reduce the need for phlebotomy for adults who meet the treatment criteria.

Clinical trials measured hematocrit control, fatigue, and phlebotomy eligibility. They were not designed to determine whether rusfertide prevents blood clots, stroke, or heart attack.

If you’re living with PV, talk with your healthcare provider about your treatment goals, how well your current care plan is working, and whether other options may be appropriate for you.

Never start, stop, or change treatment without medical guidance.

References