BioPharma, Pharma

Confirming benefit of Biogen Alzheimer’s disease drug will take 8 years

Biogen is still discussing with the FDA the clinical trial design to confirm the benefit offered by its newly approved Alzheimer’s disease drug, Aduhelm. According to a timeline set by the regulator, that clinical trial is not expected to be complete until 2029.


Biogen’s newly approved Alzheimer’s disease drug, Aduhelm, could start reaching patients in a matter of weeks. As for the clinical trial that could provide data confirming whether the drug actually works, that could take another eight years.

According to the FDA’s approval letter for the drug, Aduhelm, the target completion date for the confirmatory clinical trial is August 2029. But the letter does not specify requirements for the size or design of that study. During a Tuesday conference call to discuss the drug approval, Biogen executives were asked whether the post-marketing study would include a placebo control group. Alfred Sandrock, Biogen’s head of research and development, said the company is still discussing the trial design with the FDA.

“We’ll be disclosing the details of a planned confirmatory trial at a later date,” he said.

The Biogen drug is an antibody designed to clear away amyloid plaques from the brain. The FDA approved Aduhelm under the agency’s accelerated approval pathway, which gets an experimental drug to the market faster based on a sign in clinical trials that a drug might work even though patient benefit hasn’t been confirmed. Confirmation must come from additional clinical studies conducted after the drug reaches the market.

Accelerated approvals are most often used in the review of drugs for cancer and rare diseases, indications where patients have limited treatment options. Drug companies that seek accelerated approval typically submit their applications based on Phase 1 or Phase 2 data. Those submissions may happen even as larger studies that could confirm a drug’s benefit are already underway. That’s not the case with Aduhelm, which had already reached late-stage testing.

Biogen ended two Phase 3 studies in 2019 after an independent body concluded that based on the data to date, the studies were unlikely to be successful. Biogen’s reanalysis of the data found that one of the two Phase 3 studies was successful in slowing cognitive decline in patients given the high dose if the drug. In granting accelerated approval to Aduhelm, the FDA did not base its decision on that clinical trial result. Instead, the agency pointed to the reduction of amyloid protein observed in patients across all of Biogen’s studies.

While amyloid deposits on the brain are characteristic of Alzheimer’s, research has yet to show that removing these plaques slows disease progression. Aduhelm’s confirmatory trial might provide some answers. The approval letter for the drug states that Biogen must submit a draft of its clinical trial protocol by October. The final protocol must be submitted by August of next year, and the study completed by August 2029. The final report of that trial must be submitted within six months of the trial’s completion.

“FDA considers the term final to mean that the applicant has submitted a protocol, the FDA review team has sent comments to the applicant, and the protocol has been revised as needed to meet the goal of the study or clinical trial,” the regulator wrote.

It’s common for an Alzheimer’s clinical trial to take years. These studies are large, enrolling 1,000 or more participants, and finding enough patients can be difficult. Also, the slow progression of the disease means that patients must be tracked for a long period of time to assess a drug’s effect. The two Phase 3 tests of Aduhelm were in their fourth year when they were terminated.

In the near term, Biogen is preparing to launch Aduhelm. The drug is an infusion given over the course of one hour once a month, which requires dosing in a clinical setting. Aduhelm will carry a $56,000 wholesale price, before any rebates or discounts. Biogen does not expect most people will pay anything close to that. Since Alzheimer’s primarily affects the elderly, most patients will be covered by Medicare. Many of those patients also have private insurance that will further limit the out-of-pocket cost, said Alisha Alaimo, president of Biogen’s U.S. operations.

Biogen estimates that there are more than 900 sites now ready to treat patients with Aduhelm. Biogen expects to begin shipping the drug to those sites in about two weeks.

Photo: John Tlumacki/The Boston Globe, via Getty Images