Mylotarg® (gemtuzumab ozogamicin), a drug used for the treatment of acute myeloid leukemia (AML), will be withdrawn from the U.S. market following a recent clinical trial that raised new concerns about safety and failed to demonstrate clinical benefit.
Mylotarg was originally approved in 2000 under the U.S. Food and Drug Administration’s accelerated approval program. This program allows the FDA to approve a drug to treat serious diseases with an unmet need based on a surrogate endpoint (a laboratory measurement or a physical sign used as a substitute for a clinically meaningful endpoint such as survival).
Drugs with accelerated approval must be further tested after approval to confirm a benefit. If the expected benefit is not confirmed, the FDA can withdraw the drug from the market.
Mylotarg was approved to treat patients ages 60 years and older with recurrent AML who were not candidates for other chemotherapy. The surrogate endpoint that prompted accelerated approval was response rate (the percentage of patients whose leukemia decreased or disappeared).
After approval, a confirmatory clinical trial was conducted to determine whether Mylotarg improved survival with AML. The study—which compared treatment with chemotherapy and Mylotarg to treatment with chemotherapy alone—was stopped early when Mylotarg failed to provide a clinical benefit, and after a greater number of deaths occurred among patients treated with Mylotarg.
As a result of the withdrawal, Mylotarg will not be commercially available to new patients in the United States. Patients who are currently receiving the drug may complete their therapy following consultation with their healthcare professional.
Reference: FDA news release. FDA: Pfizer Voluntarily Withdraws Cancer Treatment Mylotarg from U.S. Market. June 21, 2010.