Biogen, Eisai sink as much-awaited Alzheimer’s results raise more questions
Investors still have questions about the sucess of an experimental drug from Biogen and Japanese partner Eisai.
The drug, dubbed BAN2401, was shown to slow the declines in memory and clear thinking associated with Alzheimer’s disease in a clinical trial.
At a higher dose over 18 months patients showed a significant clearance of amyloid plaque buildups in the brain, of 93 percent
While the high dose showed a 30 percent improvement on a composite endpoint of cognition measures — one made up of several better-known scales — it didn't meet statistical significance on one more common measure.
The 30 percent slowing of Alzheimer's progression in the results released Wednesday was measured by a scale called the Alzheimer's Disease Composite Score, or ADCOMS, a combination of commonly used endpoints that gauge cognition, or the ability to remember things and think clearly. On a more common measure of cognition, known as ADAS-cog, the highest dose of BAN2401 slowed progression by 47 percent compared with placebo.
On another well-known measure, known as the Clinical Dementia Rating, or CDR, the difference between the highest dose and placebo was 26 percent, but that result didn't meet statistical significance. That metric is particularly important because it's the primary goal of Biogen's ongoing aducanumab trial, Piper Jaffray analyst Chris Raymond wrote in a note to investors Wednesday evening.
There were also questions about the lower doses, which didn't appear to work. And, later, the reveal that the highest dose group, which performed so well, had significantly fewer patients with a genetic mutation known as APOE4 associated with Alzheimer's disease than the other groups. While it's not known whether patients with this mutation decline faster than those without it, analysts and investors raised questions about whether that could account for the more positive result in the high-dose group.
"And the one on APOE is obvious and very fair. We have to follow through on that."