Concerns mount over Biogen Alzheimer's drug

There are mounting concerns over Biogen’s Alzheimer’s drug aducanumab after the company announced tweaks to the design of ongoing phase 3 trials, as the FDA released new guidance designed to help pharma find more treatments after a string of failures.

According to press reports, Biogen told investors in a presentation on Wednesday that it will add about 500 more patients to phase 3 studies of aducanumab.

Biogen has a make-or-break bet on aducanumab, which aims to tackle the amyloid clumps that build up in the brains of people with Alzheimer’s and are thought to play a role in disease progression.

The issue seems to be that the trials need to be bigger to iron out any excessive statistical noise, but the response from investors indicated that there are growing fears over the drug after a series of high-profile Alzheimer’s drug failures.

Having already seen high-profile Alzheimer’s drug failures from Axovant, Boehringer Ingelheim, and Merck & Co in recent months, investors feared the worst and Biogen’s stock fell by as much as 9.1% following the news late on Wednesday, although they have since recovered slightly.

Brian Skoney, an analyst at Robert W Baird & Co, told Bloomberg: “Generally, it’s not a good sign when the way you designed your study isn’t working out appropriately.”

“Aducanumab is considered a very risky pipeline candidate to begin with, just given the history of Alzheimer’s trials.”

Commentators on twitter also expressed concerns that the chances of a successful outcome are receding.

Preliminary results from Biogen’s ENGAGE trial of aducanumab could be available late next year, with results from EMERGE due in early 2020.

https://twitter.com/LiveseyLab/status/963883084331520001

https://twitter.com/RNAiAnalyst/status/963886164104105985

A spokesperson for Biogen countered by saying it has not seen whether the drug is working because the experiment is still in its blinded phase, where clinicians working on the trial do not know whether they are administering a placebo or aducanumab in order to prevent bias.

The FDA is also concerned about the lack of new drugs to treat Alzheimer's, as it has not approved any medicines to treat the disease for around 15 years.

It has changed its standards for approval in patients who have failed to develop outward signs of Alzheimer’s.

If the therapy affects a biological marker of the disease, the FDA said it could fast-track drugs to market. However it would require further trials to confirm that the change leads to benefits such as slowing or staying the decline of cognitive functions.