A much-anticipated presentation of data from Biogen’s pivotal trials programme for Alzheimer’s disease candidate aducanumab has done little to boost confidence in the drug’s prospects.
A fresh look at the ENGAGE and EMERGE trials at the Clinical Trials on Alzheimer’s Disease (CTAD) didn’t include any new results, but covered the same ground as Biogen’ October update, which resurrected the amyloid-targeting drug – partnered with Eisai – after it was written off earlier in the year.
Biogen reiterated its plans to file for US approval of the drug early next year, as experts tried to decipher the data – pretty much universally described as complex and hard-to-interpret.
EMERGE gave a positive if modest readout for the high-dose aducanumab arm on cognition scores, but ENGAGE didn’t show clinical efficacy for the drug and the general sense seems to be that the dataset doesn’t meet the FDA’s usual criteria for approval.
‘Usual’ is the key word in the last sentence however, as Biogen and others think that mixed data may be enough for a green light from the FDA given the desperate need for new therapies for Alzheimer’s disease.
One key element was the contention that the effects of aducanumab were stronger as exposure to the drug accumulated, which if correct could mean that the divergence from placebo gets stronger with further follow-up.
Dr James Pickett, head of research at Alzheimer’s Society, said after the presentation that from the results presented at CTAD “it’s not possible to be sure whether people in the early stages of Alzheimer’s disease would meaningfully benefit from aducanumab”.
He noted however that Biogen is collecting more data “which may help further answer this question over the coming months”.
Meanwhile, Paul Aisen, director of the Alzheimer’s Therapeutic Research Institute, said the current results were “consistent and positive” in showing a benefit at a high dose, which he maintained represents “a truly major advance” in Alzheimer’s disease.
GlobalData analyst Alessio Brunello said today that key opinion leaders (KOLs) polled by the company “expressed mixed opinion about the potential approval from FDA as its standard of approval is substantial evidence of efficacy and the cumulative data for aducanumab are not really exhaustive to meet this standard”.
That said, he suggested the FDA is “unlikely to turn down aducanumab even if its benefit is modest, given the lack of any therapy that is truly efficacious”.
GlobalData has some pretty high sales expectations for aducanumab if approved, reckoning it could hit almost $4.7bn in the seven largest pharma markets worldwide in 2026, although it has reservations about aducanumab’s intravenous administration which “could be an issue where infusion centres aren’t available”.
The potential approval for aducanumab could also open doors for research into combination therapy with new drugs such as anti tau-therapies, it suggests.