Educated Patient® MPN Summit On The Horizon For PV Management Presentation: May 20, 2023

The debate between phlebotomy (blood removal) and chemotherapy for the treatment of patients with polycythemia vera should be over, explained Dr. Jerry Spivak, who said that in most instances, chemotherapy use may not be appropriate and phlebotomy continues to help manage blood levels in this patient population.

In CURE®’s Educated Patient® MPN Summit, Spivak, an emeritus professor of medicine at Johns Hopkins University School of Medicine, discussed what’s on the horizons for the treatment of polycythemia vera, a type of myeloproliferative neoplasm (MPN).

Spivak explained that patients with polycythemia vera have elevated hematocrit (red blood cell) levels due to the JAK2 mutation that instructs the body to create more red and white cells, as well as platelets. In doing so, the body absorbs more iron. In fact, Spivak mentioned that patients with polycythemia vera tend to absorb about twice the amount of iron as the general population. This can lead to the risk of thrombosis (blood clots).

Since iron is accumulated in red blood cells throughout the body, phlebotomy is essential in preventing thrombosis.

“If you lower the hematocrit levels below 45 in men, you essentially eliminate thrombosis risk,” Spivak said during his presentation. “For women, we tend to forget that women are not small men. They don’t make androgens and they have smaller blood volumes, and you must bleed them below 42. But quite frankly, I bleed everyone according to their symptoms because these are only generalities.”

For patients dependent on phlebotomy, PTG-300 (rusfertide) — a subcutaneous drug that is currently being investigated for patients with polycythemia vera — may help decrease the amount of blood removal a patient needs, as it blocks excess iron from entering the blood.

“This could be very exciting… but I want to make the point that this does not take the iron out, it prevents it from getting in, so you’ll still need phlebotomy,” Spivak said.

Other drugs, such as Jakafi (ruxolitinib) and Besremi (ropeginterferon-alfa-2b-njft) are also being used to treat patients with polycythemia vera but they — like all other cancer drugs — come with their own set of side effects and potential complications.

“I should point out for patients who are (Jakafi) intolerant that we have Inrebic (fedratinib), which will treat patients who are refractory to (Jakafi) and we also have pacritinib, which will treat patients who are refractory to Inrebic or Jakafi,” Spivak said. “What's exciting to me because interferon is not the whole answer, and (Jakafi) is not the whole answer. But perhaps together we can get better effects than we get with one or the other.”

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