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Biogen surges as FDA reviewers appear supportive of Alzheimer’s drug approval

Food and Drug Administration scientists appear more supportive than expected of a controversial Alzheimer’s drug from Biogen, documents made public Wednesday show, boosting the biotech company’s market value by more than $15 billion in a dramatic stock upswing.

Biogen’s drug, called aducanumab, is currently under review by the FDA, and on Friday will face a panel of independent experts convened by the agency to debate the merits of the drugmaker’s clinical trial data. The documents released Wednesday share the views of FDA review teams, as well as the case Biogen plans to make.

Aducanumab initially failed the two large studies meant to test whether the drug can slow Alzheimer’s inexorable progression for patients early on in their disease, a setback that Biogen later revisited, declaring one trial an outright success and the other supportive after collecting and analyzing more data.

The unprecedented revival, and the FDA’s subsequent agreement to review Biogen’s application, have brought aducanumab closer to a potential approval than any other drug of its type before it, all of which failed in testing. But researchers remain divided on whether or not the drug works as well as Biogen claims, making Friday’s meeting a crucial test.

The FDA is not required to follow the recommendations of its advisory panels, but usually does.

Wednesday’s documents show the agency as willing to accept Biogen’s argument, which hinges on the claim that the divergent study results are due in large part to differing levels of exposure to a high dose of aducanumab.

In their review, FDA staff agreed with Biogen that, given the differences between the trials, the two studies could be considered separately, rather than as conflicting.

Kevin Krudys, the lead FDA clinical reviewer, described aducanumab’s effect in the positive study as “robust and exceptionally persuasive,” while concluding further analyses of the failed study don’t “meaningfully detract” from that conclusion.

Not all the agency’s staff appeared united in that view, however, a potential fissure that could make Friday’s advisory committee discussion even more consequential for aducanumab’s fate.

The statistical review, conducted by an FDA official named Tristan Massie, found significant issues with the evidence presented by Biogen, sharply questioning whether the available evidence could prove a benefit to aducanumab.

“There is only one positive study at best and a second study which directly conflicts with the positive study,” Massie wrote, concluding “there is no substantial evidence of treatment effect or disease slowing.”

As a result, Massie recommended the agency require Biogen to run another trial.

The FDA won’t formally ask its advisory panel that question on Friday, pointing the committee experts instead to consider the positive study on its own merits, and whether it alone could support the conclusion that aducanumab is effective.

Made up of ten researchers and statisticians, the panel will hear from both Biogen and the FDA, as well as the general public, before making its recommendations.

While there may be disagreement among the FDA staff, investors seem to have a clear consensus on the briefing documents. Biogen shares jumped as high as $363 apiece Wednesday morning, equating to almost $17 billion in added market value. Company shares haven’t traded at such prices since mid-2018.

Biogen’s gains also appeared to lift other drugmakers that have invested heavily in would-be Alzheimer’s drugs. Shares in Eli Lilly, which saw its drug solanezumab fail several major trials, rose by nearly 14%, while Roche, which has made several attempts to develop an Alzheimer’s treatment, climbed by 6%.

Merck & Co., Amgen and AstraZeneca are among the other companies to report high-profile Alzheimer’s drug failures in recent years. That track record has put the principal scientific hypothesis behind aducanumab in significant doubt, spurring calls for researchers and drugmakers to consider other approaches.

FDA staff, however, seem to view aducanumab as different from the drugs that came before it, indicating in the documents published Wednesday they don’t view past setbacks as a “class failure.”

The stock lift and relatively positive feedback from FDA staff come at a critical moment for Biogen. The storied biotech has had trouble overcoming several threats to its business in the last couple years — namely, greater competition to both its top-selling drug, Tecfidera, and its biggest growth driver, Spinraza. Biogen recently lowered its 2020 revenue expectations by at least $400 million, and warned that Tecfidera could face “significant erosion” at the same time that Spinraza loses patients to newer treatments.