Leukemia drug Mylotarg taken off the market over safety, effectiveness concerns

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For patients with a diagnosis of the blood cancer acute myeloid leukemia, or AML, the search for a drug that can effectively treat a recurrence of leukemia has been elusive. So the withdrawal from the market Monday of the AML drug gemtuzumab ozogamicin, marketed as Mylotarg, comes as another disappointment to those hoping for a cure.

Pfizer, which makes Mylotarg, withdrew the drug after a clinical trial raised concerns about its safety and effectiveness. Early trials had spurred hopes that Mylotarg would induce remission -- meaning the absence of leukemia in the bone marrow -- in almost a third of patients who took it. But the drug, which promised reduced side effects because it appeared to home in only on cancerous cells, has been associated with a serious and sometimes fatal liver condition call veno-occlusive disease.

Although Mylotarg received accelerated FDA approval in 2000, the agency required an additional clinical trial to demonstrate its safety and effectiveness. That trial, which began in 2004, has shown higher levels of liver toxicity in patients than seen in early trials, with no benefits to patients. In fact, compared with AML patients on standard chemotherapy alone, those on Mylotarg were more likely to die.

The FDA said that patients who have begun treatment with Mylotarg may complete their therapy, but that patients with new recurrences of AML will not be permitted to start on the medication.

Remember that some patients with AML can be treated -- and cured -- with a bone marrow transplant, but they need an excellent match for a good outcome. Joining the bone marrow registry is easy and painless, and you could be the match that saves someone’s life. Find out why and how to register as a prospective bone marrow donor here.

-- Melissa Healy