Sunday, November 11, 2012

Donepezil


 

The US Food and Drug Administration (FDA) has rejected a petition by the consumer advocacy group Public Citizen requesting that the agency pull the 23-mg dose of the Alzheimer's disease drug donepezil (Aricept, Eisai/Pfizer) from the market because of safety concerns.
The FDA action comes roughly 2 months after Public Citizen sued the FDA for not responding to its petition, as reported previously by Medscape Medical News.
In a response letter dated November 6, 2012, to Sidney Wolfe, MD, head of Public Citizen's Health Research Group, Janet Woodcock, MD, director of the Center for Drug Evaluation and Research at FDA, said, "Donepezil is 1 of only 2 drugs indicated for treating the severe stage of [Alzheimer's], and the 23 mg dose is shown to produce added cognitive benefits over the 10 mg strength."
"For a disease such as AD, a physician may determine that an improvement in a patient's cognition justifies the risk of additional side effects. FDA stands by its approval decision, and believes that physicians should have the option of prescribing Aricept 23 to those patients who could benefit from it. Thus, after careful consideration...we deny your Petition," the letter reads.
Donepezil was approved in 1996 to treat moderate to severe Alzheimer's disease at a dose of 5 mg or 10 mg once daily. In 2010, the FDA approved a 23-mg version of the drug, a few months before the drug was to lose patent protection.
In May 2011, Public Citizen petitioned the FDA to withdraw donepezil 23-mg tablets and add a warning label to lower-dose forms of the drug, "citing the FDA's medical and statistical reviewers' conclusions that the 23-mg dose has no greater efficacy than the lower doses but has more severe — and potentially life-threatening — side effects," the complaint read.
In a statement responding to the FDA's decision to deny the petition, Dr. Wolfe said allowing the 23-mg dose to stay on the market is "unconscionable."
He charges that Eisai and Pfizer, "with more than $2.4 billion U.S. sales in 2010 were facing a threat to that revenue stream when the patent was set to expire on the lower-dose version of the drug. A study presented to the FDA in 2009 failed to show that Aricept 23 was more effective than the lower-dose drug in improving overall patient function and while showing it to be only minimally more effective in improving cognition."
As previously reported by Medscape Medical News, 2 experts challenged FDA approval of the 23-mg dose in an article in the British Medical Journal in April 2012.
Steven Woloshin, MD, and Lisa Schwartz, MD, both from the Center for Medicine and the Media at the Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, New Hampshire, said the decision "breached the FDA's own regulatory standard" and has led to "incomplete and distorted messages" about the agent.
 

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