Biogen shares pop as it completes filing for Alzheimer's drug aducanumab

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Closeup of X-ray photography of human brain

Biogen’s share price was up sharply on Wednesday after the big pharma completed its filing of its Alzheimer’s Disease (AD) drug aducanumab with the FDA. 

Shares in the company have fluctuated wildly according to the fortunes of aducanumab, which the company thought had failed in two phase 3 studies earlier last year. 

But the company shocked the pharma world in October by announcing aducanumab appeared to work at a higher dose after re-analysing the results from the EMERGE and ENGAGE trials which showed the drug “reduced clinical decline in patients with early AD”. 

The renaissance was due to greater exposure to a higher dose of the anti-amyloid antibody in a larger data set, which was not available to the independent committee that initially concluded the trials were unlikely to slow cognitive decline. 

Biogen, which developed aducanumab with Eisai, began putting together an FDA filing, which is now complete. 

The company has asked for a faster, six-month review of the data from the phase 3 trials and the phase 1b PRIME study. 

If approved, aducanumab would become the first therapy to reduce the clinical decline of AD, and would also be the first drug to show that targeting amyloid can have a positive impact on the disease. 

That would be a truly extraordinary outcome, given that dozens of other anti-amyloid therapies have failed in trials. 

Biogen and Eisai point to statistically significant improvements on symptoms like memory, orientation, and language, and benefits on daily activities like “conducting personal finances, performing household chores such as cleaning, shopping, and doing laundry, and independently traveling out of the home.” 

It said EMERGE met its primary endpoint with patients treated with a high dose of aducanumab showing a statistically significant reduction of 22% versus placebo in clinical decline from baseline, as measured by a standard score. 

There was also a significant reduction when measured using different examinations used as secondary endpoints. 

This was backed up with imaging data showing that amyloid plaque burden was reduced in patients taking the higher dose – it is thought that these plaques are linked with or responsible for the cognitive decline that is the hallmark of AD. 

While ENGAGE did not meet its primary endpoint, Biogen believes a subset of data from ENGAGE are supportive of the outcome in EMERGE. 

Stephen Salloway, director of the Butler Hospital Memory and Aging Program at Brown University said: “If we can help slow the progression from one stage to the next, this could preserve independence, which, in turn, could have truly meaningful benefits for people living with the disease and their loved ones. Aducanumab represents a potential breakthrough that we hope will provide a treatment foothold in the fight against Alzheimer’s disease.” 

A string of clinical trial failures have meant there have been no new Alzheimer’s drugs approved by the FDA since 2003 – Forest Labs’ Namenda (memantine) – and what drugs are available only help to manage symptoms rather than slow, halt or even reverse the cognitive decline it causes.