Biogen's Aduhelm headache returns as appeals court revives part of investor lawsuit

For more than a year, Biogen has been working to turn the page from its Aduhelm fiasco and focus on its newer Eisai-partnered Alzheimer's disease medicine Leqembi. But a new ruling from the U.S. Court of Appeals for the First Circuit will make that effort a little tougher.

After Biogen last year won the dismissal of an investor lawsuit surrounding disclosures into its Aduhelm research, the appeals court has reversed the ruling—in part—by focusing on one statement made by Biogen's former chief medical officer Al Sandrock.

Specifically, the appeals court flagged Sandrock's statement from the company's second-quarter earnings call in 2020. During the call, Sandrock stated that "[Y]ou really need to get to the higher dose," adding, "I think our data are all consistent with that."

The court dubbed this the "all data" statement and painstakingly broke down the context behind the remark.

To refresh readers' memory, Biogen in March 2019 announced that two pivotal trials on the drug were being discontinued, citing findings from a futility analysis conducted by an independent data monitoring committee. 

Later in 2019, Biogen said its own analysis and discussions with the FDA had supported the decision to file an approval application with the agency. A barrage of public statements about the company's analysis followed, and the plaintiffs in the investor lawsuit took issue with some of them.

The investors claim Biogen wasn't completely forthright with all of the data on aducanumab as it sought FDA approval.

At the time, Biogen noted that one of the drug's pivotal trials, Emerge, met its primary endpoint in reducing clinical decline. The company said it believed a subset of data from patients in the other study—who'd received a high dose of the drug—supported that readout.

In the end, the appeals court found that the investor lawsuit "plausibly alleges" that not "all data" supported the company's argument about a dose-response correlation, noting that "some patients did better on a lower dose and others experienced the same lack of clinical benefit whether they were on the higher dose or not."

With the decision, the case may proceed to litigate that single statement from Sandrock.

Despite winning a controversial FDA approval in 2021, Aduhelm never gained much steam because of payer doubts about the data.

While Aduhelm is a headache the company might want to forget, Biogen is in quite a different situation these days. The company has a new CEO in Chris Viehbacher and is busy with the launch of another Alzheimer's disease drug, Leqembi.

It also recently acquired Reata and the potential blockbuster Skyclarys.

Sandrock, for his part, is no longer with Biogen and is instead leading Voyager Therapeutics.