How an Unproven Alzheimer’s Drug Got Approved

The idea of accelerated approval came up briefly toward the end, raised by Dr. Rick Pazdur, head of F.D.A.’s oncology center, who was not a council member. It was not discussed in detail, but after the meeting, given the council’s rejection of standard approval, accelerated approval appeared to be the only way to make the drug available.

On April 26, Dr. Patrizia Cavazzoni, Dr. Dunn’s boss and director of the Center for Drug Evaluation and Research, led a smaller meeting about accelerated approval, which had never been used for Alzheimer’s drugs.

In fact, the F.D.A.’s most recent guidance for Alzheimer’s drugs, issued by Dr. Dunn in 2018, says “the standard for accelerated approval” had not yet been met for the disease, “despite a great deal of research.” The guidance says that is because “there is unfortunately at present no sufficiently reliable evidence” that attacking amyloid plaques or other biomarkers of Alzheimer’s “would be reasonably likely to predict clinical benefit.”

And at the November advisory committee meeting, Dr. Dunn said that in considering whether to approve aducanumab, “we’re not using the amyloid as a surrogate for efficacy.”

Under accelerated approval, while a drug is on the market, a company must conduct an additional trial, a costly undertaking. Biogen said its goal was standard approval, which it believed its data warranted.

At the April 26 meeting, Dr. Cavazzoni invited two officials not involved with neurological drugs who had used accelerated approval frequently: Dr. Pazdur and Dr. Peter Marks, the top vaccine regulator. They and Dr. Cavazzoni voted to grant such approval to aducanumab, as did Dr. Issam Zineh, director of the Office of Pharmacology, and Dr. Jacqueline Corrigan-Curay, who led the internal review of the F.D.A-Biogen collaboration.

The director of the office of translational sciences, Dr. ShaAvhrée Buckman-Garner — who supervises both the pharmacology and biostatistics offices — did not vote yes or no, saying she understood both arguments. The only clear no vote, F.D.A. documents say, was the director of the office of biostatistics, Dr. Sylva Collins, “stating her belief that there is insufficient evidence to support accelerated approval or any other type of approval.”