A Biogen Inc. drug may be the next best hope in the long and frustrating search for a better Alzheimer’s disease treatment, following Tuesday’s news that another company’s experimental pill for the devastating condition didn’t work in a clinical trial.
The failure of New York startup Axovant Sciences’ drug, called intepirdine, was the latest in a long line of poor results for Alzheimer’s medicines.
Compounding the disappointment, the next chance for a breakthrough won’t come until 2019. That’s when results from three large, late-stage Alzheimer’s trials are expected to read out. Leading that group is Cambridge-based Biogen’s aducanumab, an injected antibody designed to combat the disease by targeting sticky buildups of beta amyloid proteins in the brain.
The amyloid hypothesis has been tough to defend in recent years, and the definitive failure of a drug from Eli Lilly last year didn’t make the case any easier. So the hopes for aducanumab stem from what could be an important difference between the experimental compounds.
Biogen’s drug targets plaques once they have already settled in patients’ brains, while Lilly’s was meant to attack the free-flowing proteins that eventually aggregate and form those sticky clumps. In Lilly’s failed trial, the drug had no relevant effect on actual amyloid levels, suggesting to scientists that Biogen’s approach may yet yield positive results.
In a small, early trial, Biogen’s drug showed signs that its effect on amyloid could actually improve cognition, and many in the Alzheimer’s field consider it the most promising drug in its class.
The other two 2019 contenders are working upstream of Biogen, targeting an enzyme called BACE that is responsible for the production of amyloid. The idea, in essence, is to stem the flow of amyloid before toxic buildups can set in.
The first is, called verubecestat, comes from Merck, and it already has a mixed track record. Earlier this year, Merck halted a 2,200-patient verubecestat study after determining it had “virtually no chance” of meeting its goals in patients with mild forms of Alzheimer’s.
But a second study, enrolling only patients in the earliest stages of disease, has better odds of success, scientists say.
Partners Lilly and AstraZeneca are making a similar bet with their lanabecestat, a BACE inhibitor now in phase 3. Like Merck, the companies are treating patients with early Alzheimer’s in hopes of showing a benefit.
Each contender is racing to commercialize the first-ever therapy that can modify the course of Alzheimer’s rather than just treat its symptoms.
The field has a daunting rate of failure, with more than 99 percent of therapies coming up short in the past decade. But the rapid growth of Alzheimer’s, which now affects an estimated 5 million Americans, has presented a multibillion-dollar market opportunity for whoever can finally beat the odds.