The archaic follow of eradicating blood from the physique to deal with a variety of sicknesses lives on as we speak as a regular therapy for sure blood problems. The trendy model of this strategy, known as therapeutic phlebotomy, can handle these circumstances however nonetheless comes with limitations and complication dangers. A drug from companions Protagonist Therapeutics and Takeda Pharmaceutical affords the promise of a therapeutic intervention for considered one of these uncommon blood illnesses, polycythemia vera.
One-year knowledge for the drug, rusfertide, have been offered Saturday through the annual assembly of the American Society of Hematology in Orlando, Florida. Past displaying the overwhelming majority of research individuals reached some extent the place they now not wanted phlebotomy, outcomes additionally confirmed enhancements on high quality of life measures, such because the persistent fatigue that’s the commonest grievance of polycythemia vera sufferers, stated Dr. Andrew Kuykendall, affiliate member within the division of hematology at Moffit Most cancers Middle and lead investigator in rusfertide’s pivotal research.
“There may be this want to maneuver past, transfer out of the darkish ages to some extent, and substitute therapeutic phlebotomy with one thing else that may reliably keep and management blood cell counts within the secure vary with out actually exacerbating iron deficiency and [also] selling symptom enchancment,” Kuykendall stated in an interview.
Polycythemia vera is a uncommon blood most cancers that results in overproduction of crimson blood cells. Consequently, blood turns into thicker and clots extra simply, placing sufferers in danger for cardiovascular occasions akin to coronary heart assault or stroke. Therapeutic phlebotomy brings crimson blood cell counts nearer to regular ranges however requires common scientific visits for the process. Antagonistic results embody fluid shifts within the physique that go away sufferers feeling dizzy, Kuykendall stated. Therapeutic phlebotomy additionally exacerbates the iron deficiency that these sufferers have already got as a result of the physique is utilizing iron to make crimson blood cells.
In an interview earlier this 12 months, Takeda President of Analysis & Growth Andrew Plump described therapeutic phlebotomy as “very medieval.” Moreover, whereas it’s might be efficient, over time, many sufferers who routinely endure this process develop iron deficiency. Rusfertide is a peptide that Protagonist designed to face in for hepcidin, a hormone that regulates how iron is absorbed, saved, and distributed within the physique.
“Mainly what it’s doing is it’s trapping iron in its pure shops and making it much less out there to the bone marrow,” Plump stated. “So it’s lowering manufacturing of crimson blood cells. It’s a really physiologically related pathway, and what we’ve seen in Part 2b [clinical testing] is actually functionally curing [of] these sufferers.”
The placebo-controlled Part 3 check of rusfertide evaluated 293 sufferers with polycythemia vera over the course of 156 weeks. Knowledge from the primary 32 weeks, which confirmed 76.9% of sufferers achieved a scientific response, have been offered earlier this 12 months through the annual assembly of the American Society of Medical Oncology.
The most recent knowledge offered on the ASH assembly are from sufferers who’ve acquired the once-weekly injectable drug for 52 weeks. These outcomes present 61.9% of sufferers handled with rusfertide continued to not want phlebotomy. The research drug was secure and effectively tolerated. The most typical adversarial results have been injection web site reactions, anemia, and fatigue.
Few medication can be found for polycythemia vera. Medicines used to cut back blood counts are one possibility for individuals who can’t tolerate phlebotomies. Incyte’s oral small molecule Jakafi, which was initially accredited in 2011 for myelofibrosis, expanded its FDA approval to polycythemia vera in 2014. On this indication, the Incyte drug is accredited as second-line possibility for a slender section of sufferers, Kuykendall stated. PharmaEssentia’s Besremi, accredited by the FDA in 2021, affords a first-line therapy alternative. This drug is an engineered model of interferon alfa, a protein that prompts and regulates the immune response.
Interferon medication aren’t used for sufferers with a historical past of temper problems or these with a historical past of autoimmune circumstances, Kuykendall stated. It additionally takes time for interferon medication to work, and even once they work in polycythemia vera, sufferers should want phlebotomies to keep up illness management. That leaves an unmet want for sufferers who can’t tolerate current medication or want higher illness management, he stated.
Final 12 months, Takeda paid $300 million to start a partnership with Protagonist. Newark, California-based Protagonist remains to be answerable for the Part 3 research and an FDA submission; the 2 corporations will share in U.S. commercialization of the drug. The deal gave Takeda the rights to commercialize rusfertide in the remainder of the world. With the constructive Part 3 outcomes now out there, Protagonist and Takeda stated they’re making ready a regulatory submission for the drug.
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