On June 7th, 2021, the FDA approved Biogen’s Aduhelm (aducanumab) for the treatment of Alzheimer’s disease, the first drug approved to treat Alzheimer’s in 17 years. It is a monthly intraveneous infusion with a list price of $56,000.000 a year, and treatment with it also involves tens of thousands of dollars in costs for associated diagnostic testing and brain imaging.
It wasn’t exactly a traditional, streamlined, or easy approval. It was approved via the FDA’s accelerated approval pathway, available to manufacturers for drugs that provide a “meaningful therapeutic advantage over existing treatments for a serious or life-threatening illness, where there is an unmet need, and where there is an expectation of clinical benefit despite some residual uncertainty regarding that benefit.”
This approval came on the heels a few months ago of the FDA’s Advisory Committee’s vote of 10-1 against approval, indicating that that it was not reasonable to consider the evidence of clinical benefit from one of the two studies submitted in support, as the members opined that there were conflicting results of between the two studies.
The FDA rationalized its ultimate approval by pointing out that with submissions for approval under the accelerated approval pathway, the surrogate endpoint must only be shown to be reasonably likely to predict clinical benefit. The FDA indicated that it concluded that these requirements were met for aducanumab, “with substantial evidence that the drug reduces amyloid beta plaque, and that this reduction is reasonably likely to predict clinical benefit.” The reduction of amyloid beta plaque in the brain is significant, the FDA indicate, as its presence is a hallmark of Alzheimer’s disease. It added that “for drugs approved using the accelerated approval pathway, further study is required to verify anticipated clinical benefits.” Thus, Biogen must conduct a Phase 4 Study and submit the results to the FDA in further support of efficacy.
Although the 2 trials were conducted on a narrow patient population of patients — those with mild cognitive impairment or early-stage Alzheimer’s whose brains contained high-than-normal levels of amyloid — the FDA-approved label fails to restrict the patient population. The label simply says the drug is “for the treatment of Alzheimer’s disease.”
This broad label for a drug that costs Medicare a retail price of about $56,000 per year, is going to add up quickly. That, coupled with the fact that the market is an estimated 5.5 million with Alzheimer’s disease in the U.S., and additional millions more who may be labeled with Alzheimer’s in order to qualify for the drug. More concerning, if Biogen engages in unlawful off-label promotion for uses or conditions other than Alzheimer’s, and there are plenty of close cousins in the elderly, the market of elderly patient population in the U.S. is huge. Accordingly, if the drug may in fact not be helpful in these patient populations, this is going to be a drug promotion that needs to be watched and curtailed. Kudos to the manufacturer for obtaining FDA-approval and for all the patients the Aduhelm will help. We just hope that any off-label promotion is kept in check, and care is taken that patients are not prescribed Aduhelm for which there is no benefit.