Recently, Pfizer Inc voluntarily withdrew the drug Mylotarg (gemtuzumab ozogamicin) from the U.S. market. Mylotarg is used to treat patients with acute myeloid leukemia, a bone marrow cancer. Pfizer withdrew the drug at the request of the Federal Food and Drug Administration (FDA) since a new clinical trial yielded both new safety concerns and lack of benefit to patients.
Mylotarg was approved by the FDA in 2000 to treat patients 60 years or older who had recurring acute myeloid leukemiaand were not candidates for chemotherapy. The drug originally obtained "accelerated approval", which allows the FDA to approve drugs for serious illnesses with little alternative treatment options. based on solely a laboratory measurement or physical sign. The laboratory measurement or physical sign are used in place of a clinical trial which directly measures the drug's effect on a patient's health. Usually drugs with accelerated approval are required to conduct clinical trials after approval to properly measure health benefit.
After Mylotarg's clinical trial was completed, it was observed that no benefit occurred, and a greater number of deaths occurred in patients receiving the drug than those receiving just chemotherapy.