A mixed bag: Biogen's & Lilly's hotly anticipated Alzheimer's data are inconclusive
- Biogen and Eli Lilly on Wednesday released data on investigational Alzheimer's drug candidates that have been closely watched by the industry and investors, with many hoping that one (or both) would prove to be the first true therapeutic game-changer for the degenerative condition.
- But if industry watchers were hoping for a clear signal affirming a bull thesis on Wednesday, they were disappointed. Both Biogen's and Lilly's candidates (aducanumab and solanezumab, respectively) were widely regarded to show a mixed bag of results. More trial data will be necessary to fully evaluate the drugs' efficacies.
- The companies will make their full presentations to the ongoing Alzheimer's Association International Conference (AAIC) conference in Washington, D.C. later on Wednesday.
Here's the breakdown: Biogen's aducanumab, whose early trial data sent the biotech's shares soaring back in March after demonstrating a sharp slowdown in cognitive decline and a reduction of amyloid plaque in Alzheimer's patients, especially at the highest doses, needed to prove that it was effective at a safer, yet still strong, dosing level. At the highest (and most effective) doses, 55% of patients experienced brain swelling in the data released in March—a dangerous adverse event.
However, the data released today for a 6 mg/kg dose was a mixed bag. While aducanmuab did reduce amyloid plaque at this level, its effect on slowing down cognitive decline was not nearly as pronounced as many had hope for and expected given the much more clear-cut effect on cognitive decline in the 3 mg and 10 mg phase I results from March. Biogen executives still hailed the data as promising and largely in line with expectations, at least when it comes to plaque reduction (it also proved more effective than placebo and a 1 mg dose on at least one cognitive decline metric).
Lilly's solanezumab will also require further scrutiny down the line. Researchers announced that the patients who took the investigational compound at an earlier stage of disease progression fared better when it came to cognitive decline compared to patients who began taking it later in the trial. This improved cognition effect was maintained for two years. But even Lilly spokespeople admitted that it will take data from a larger and separate ongoing trial (which won't end until late 2016) to truly prove the drug's efficacy.
None of this is necessarily devastating news. It's entirely possible that continued trials, and other dosing regimens, will hit the sweet spot between plaque reduction, slowdown in cognitive impairment, and acceptable adverse event risk profiles. But it is a bit of a letdown against the context of the (potentially inappropriately) outsize expectations surrounding the drugs, particularly Biogen's. And the big question now is whether these two drugs will give us a definitive answer on whether or not targeting amyloid plaque is truly the most effective method for tackling Alzheimer's and the main reason for cognitive decline.
Biogen and Lilly shares were both down about 3% in morning trading.