Panhematin (hemin for injection) is an approved medication used to treat acute intermittent porphyria (AIP) related to the menstrual cycle in women when carbohydrate therapy is ineffective. It was developed by Recordati Rare Diseases.
How does Panhematin work?
AIP is a rare genetic disease that results in patients not being able to produce enough of an enzyme called hydroxymethylbilane synthase (HMBS), which is also called porphobilinogen deaminase or PBGD. This enzyme plays a role in the process of making heme, an important part of the molecule hemoglobin which carries oxygen in red blood cells. Without sufficient HMBS, intermediate molecules called porphyrins build up in the body. Also, the body cannot make as much hemoglobin as it needs, so it stimulates the pathway to try to increase the amount of heme produced. Because the body cannot process the intermediates without HMBS, this stimulation increases the amount of porphyrin.
A mutation is not enough to cause AIP. The disease usually appears following stimulation from hormonal changes, drug use, infections, or diet. In women, AIP is associated with the hormonal changes that control the menstrual cycle.
Panhematin works by supplying the heme that the body is unable to make. This “turns off” some of the enzymes that are upstream of HMBS, reducing the amount of porphyrin that the body produces as a result.
Doctors administer Panhematin as an intravenous infusion, usually following a carbohydrates treatment. Panhematin is usually effective for three to 14 days.
Panhematin in clinical trials
The approval of Panhematin by the U.S. Food and Drug Administration was based on the results of five open-label studies, a compassionate-use study, and many case studies that demonstrated the safety and efficacy of the treatment.
In the initial open-label studies, 99 patients with acute porphyrias (including 72 with AIP) were treated with hematin once or twice daily. Patients experienced a clinical response in 86% of treatment courses, which was defined as an improvement of symptoms and a reduction in pain.
A Phase 2 clinical trial (NCT02922413) is currently recruiting patients with acute porphyria to examine the safety and efficacy of Panhematin treatment in preventing acute porphyria attacks. The trial, in Galveston, Texas, is recruiting 20 adult patients who will randomly receive either Panhematin or a placebo. Following one week of treatment, patients will have weekly follow-up visits for four weeks. Researchers will conduct three- and six-month follow-ups by phone. The primary outcome measure will be the number of acute porphyria attacks in the weeks following treatment. Researchers expect to conclude the study in 2023.
Panhematin can cause side effects, including headache, fever, irritation around the infusion site, and elevated iron levels in the blood. It can also cause mild blood-thinning, which can be dangerous if you are on other blood-thinning medications.
Last updated: June 25, 2020
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