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Round Two: FDA Approves Pfizer’s Previously Withdrawn Cancer Drug

Published onNov 01, 2017
Round Two: FDA Approves Pfizer’s Previously Withdrawn Cancer Drug

The FDA recently approved a new version of a previously withdrawn drug for the treatment of acute myeloid leukemia. Mylotarg, produced by Pfizer, Inc., was voluntarily withdrawn from the market in 2010 after studies showed the drug failed to provide clinical benefits and carried certain safety concerns, such as a high number of deaths.

Mylotarg hit the market in 2000 as part of the FDA’s Accelerated Approval program. First instituted in 1993, this program allows drugs for serious conditions that fill an unmet medical need to be approved based on a surrogate endpoint. In 2012, Congress passed the Food and Drug Administration Safety Innovations Act (FDASIA). This amended the Food, Drug, and Cosmetic Act (FD&C Act) to allow the FDA to base approval of such drugs on whether the drug influences a surrogate or intermediate endpoint. The FDA defines a surrogate endpoint as a measure or marker that is thought to predict a clinical benefit but is not itself a measure of a clinical benefit. An intermediate endpoint is a measure of a therapeutic effect that is considered reasonably likely to predict the clinic benefit of a drug. Studies that attempt to demonstrate a surrogate or intermediate clinical endpoint must be “adequate and well controlled.”

Once the FDA approves a drug under this program, the drug can be sold to the market per usual. However, the drug company is still required to continue studies to show whether the surrogate or intermediate clinical endpoint verified a clinical benefit, called a phase 4 confirmatory trial. If the studies show that the drug does not have a clinical benefit, or if the drug poses risks that outweigh any benefit, the drug may be withdrawn.

Some experts question the merit of the Accelerated Approval method, posing that the FDA is accepting “weaker than usual” evidence of the drug’s efficacy. Furthermore, a recent study published in the Journal of the American Medical Association (JAMA) showed that only half of the confirmatory studies the FDA ordered between 2009-2013 had been completed a period of three years later. The confirmatory studies that had been completed often did not differ much in substance from the pre-approval study. Another JAMA published study found that drugs approved through Accelerated Approval were associated with higher rates of post-market safety issues.

The failure by drug companies to complete or perform confirmatory studies in a satisfactory manner could certainly raise liability issues, especially if the drug poses risks to patients not disclosed in black box or other safety warnings. According to the FDA, the new iteration of the Mylotarg has a lower dose, a different dosing schedule, and a new patient population; all which alleviate its prior safety concerns. Safety also carries with it a significantly higher price tag: one course of treatment will cost $24,600. The previous version cost $15,522 per course before it was pulled in 2010.

Gabriela Mejias is a current 2L at Wake Forest University School of Law. She graduated from the University of Georgia in 2016 with a degree in journalism and is originally from Athens, Georgia. She has interned at National Public Radio and The Legal Aid Society and hopes to pursue a career in public interest law.  

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