Stemline Therapeutics Inc.'s Elzonris became the first medicine to be approved by the U.S. Food and Drug Administration to treat a rare blood disease that affects the bone marrow and multiple organs.
The New York-based biopharmaceutical company's drug Elzonris, or tagraxofusp-erzs, treats blastic plasmacytoid dendritic cell neoplasm, or BPDCN, an aggressive and rare disease that progresses with bone marrow causing a decrease in red and white blood cells and platelet counts.
BPDCN also affects multiple organs, lymph nodes and the skin. The disease, which is more common in men than women and in patients 60 years and older, often has symptoms similar to leukemia or evolves into acute leukemia — a type of cancer in which the bone marrow produces abnormal white blood cells that do not function properly.
The FDA's approval was based on positive data from a trial that included two groups of patients. In the first arm, seven out of the 13 patients — who had never been treated for BPDCN — showed no signs of cancer or were disease-free with a skin abnormality not indicative of active ailment.
In the second group, which consisted of 15 patients whose cancer had returned or were unresponsive to treatment, one patient showed no signs of cancer while another was disease-free with a skin abnormality not indicative of active disease.
The U.S. regulator, however, issued a boxed warning alerting to the increased risk of capillary leak syndrome — a condition in which fluid and proteins leaking out of tiny blood vessels into surrounding tissues — which may be life-threatening or fatal to patients receiving the drug.
The U.S. regulator granted priority review to Elzonris in June and was expected to take a decision by Feb. 21, 2019. Elzonris already received the FDA's breakthrough and orphan-drug designations.
The European Medicines Agency has granted accelerated assessment to Elzonris, which will speed up the time taken by the Committee for Medicinal Products for Human Use to review the company's application for treating the rare form of cancer.