FDA Approves Treatment for Anemia in Adults with Rare Inherited Disorder

FDA announced on Feb. 17, 2022 that Pyrukynd (mitapivat) tablets are approved to treat hemolytic anemia, a disorder in which red blood cells are destroyed faster than they can be made, in adults with pyruvate kinase (PK) deficiency

PK is a rare and inherited disorder that causes premature red blood cell destruction, which leads to anemia (a decreased number of red blood cells.) PK deficiency is frequently misdiagnosed or undiagnosed. Patients with PK deficiency can experience a range in severity of symptoms, which can include fatigue, unusually pale skin, jaundice (yellowing of skin and eyes), shortness of breath, and a fast heart rate.

Mitapivat’s effectiveness was evaluated in two studies; one randomized, double-blind, placebo-controlled clinical study of 80 adults with PK deficiency who did not receive regular blood transfusions, and one single-arm study of 27 adults with PK deficiency who received regular blood transfusions. The randomized study rated the treatment’s effectiveness on hemoglobin (a measure of the amount of red blood cells that are not destroyed) response, while the single-arm study based its effectiveness on reduction in transfusion burden, defined as at least a 33% reduction in the number of red blood cell units transfused during the last 24 weeks of treatment compared with the historical transfusion burden on the individual participant (standardized to 24 weeks).

At the end of the randomized study, 40% of participants receiving mitapivat had a hemoglobin response compared with no participants receiving placebo. At the end of the single-arm study, 33% of participants receiving mitapivat experienced the reduction in transfusion burden, including 22% of participants who did not require any transfusions during the last 24 weeks of treatment.

Source: FDA