'Trick or treat?' Analysts react to Biogen's aducanumab surprise

When Biogen’s Alzheimer’s med aducanumab failed a futility analysis earlier this year, RBC analysts called it a “transformative failure” for the Big Biotech’s pipeline. Biogen transformed the candidate yet again on Tuesday, resurrecting it for an FDA filing early next year and surprising analysts across the board. 

“Does this mean the mother of all FOMO trades is back on?! We’re left somewhat speechless by news this morning that Biogen’s Alzheimer’s drug candidate aducanumab is back from the dead,” wrote J.P. Morgan analyst Cory Kasimov Tuesday morning in a note titled, “Shocking, Simply Shocking – Adu is Back...” 

RELATED: Biogen resurrects aducanumab, arguing expanded data set supports FDA filing in Alzheimer's 

But despite the "speechless" claim, Kasimov and his fellow analysts had plenty to say about the move throughout the day on Tuesday. 

“Trick or treat? At this point, who seriously knows,” Kasimov wrote Tuesday afternoon in a note detailing “what we know and what we don’t know about the resurrection of aducanumab.” He raised key regulatory questions, including whether the FDA would overlook the fact that one of Biogen's trials, called Engage, failed and whether the agency would require another confirmatory study to take place before or after approval. 

Cantor Fitzgerald analyst Alethia Young continued the Halloween theme in a more confident note titled, “Aducanumab Filing Looks Like More of a Treat Than a Halloween Trick.” 

“We are more inclined to believe that there is reasonably strong evidence for the company to move forward with a BLA filing. It seems that the futility analysis was wrong and didn't fully consider the complexity of the trial amendments around dosing of aducanumab,” Young wrote after Biogen’s third-quarter earnings call Tuesday morning. 

“We are currently reviewing our model based on today's news but think that the big stock move is warranted as investors probably at least move to 50-60% confidence for a potential approval of aducanumab,” Young wrote.

RELATED: Biogen, Eisai throw out remaining Alzheimer's BACE hope

"We believe adu, if approved, has the potential to completely change the profile of the company," wrote Guggenheim analyst Yatin Suneja in another spooky note titled, "Just In Time for Halloween, Aducanumab Has Risen from the Dead"

"The market potential for a drug in AD could be significant (>$10B+ in sales)... We note the clinically meaningfulness of these data are debatable and likely to be the key focus for investors and how they assign value to adu. We also note that prior to aducanumab the stock was trading in the $300-360 range and we would not be surprised if the stock re-rated itself in that range until we get final FDA decision," Suneja wrote.