Biogen cans plan to test aducanumab in Alzheimer's prevention

Biogen continues to list Alzheimer’s and dementia as a key growth area. (Biogen)

Biogen has decided against (PDF) starting a phase 3 trial of aducanumab in the prevention of Alzheimer’s disease. The study was the one option for further development of aducanumab that Biogen left open when it revealed the failure of its main pivotal program last month.

Upon learning that aducanumab had failed in patients with mild Alzheimer’s, Biogen and its partner Eisai shut down two phase 3 trials and two earlier-phase trials. However, the partners opted against making a quick decision about a planned study to assess whether aducanumab can delay or prevent the clinical onset of Alzheimer’s.

Now, that proposed trial has landed on the scrapheap, too. Having analyzed data from the failed phase 3 program, Biogen has decided against initiating the planned study, at least “at this time.” The decision means that when Biogen finishes the closeout of studies it said it would end last month there will be no active clinical trials of aducanumab listed on 

Biogen’s analysis of the aducanumab data linked the drug to a dose- and time-dependent reduction in cerebral amyloid deposition, as assessed by amyloid-PET imaging. But this failed to translate into improvements in cognitive and functional impairment that were strong enough for the trials to clear a futility analysis. 

In shutting down the aducanumab program, Biogen expects to reduce its operating expenses for 2019 by around $125 million. The closeout of the phase 3 studies cost Biogen around $45 million in the first quarter, though, reducing the net annual saving from the actions to roughly $80 million. 

Those figures are small compared with the money Biogen could have made if aducanumab had succeeded in phase 3. And the drug’s failure to move the needle in the studies has deprived Biogen of a possible growth driver, albeit one that was always unlikely to come to fruition given the very high rate of failure in Alzheimer’s. 

In the absence of aducanumab, Biogen is left to talk up the prospects of other clinical programs. By the end of 2020, Biogen expects to release data on drugs in progressive supranuclear palsy, amyotrophic lateral sclerosis, Parkinson’s disease, pain, cognitive impairment associated with schizophrenia, epilepsy, stroke and lupus. But it only has three assets in phase 3, one of which is another Alzheimer’s drug, elenbecestat.

Despite being burned by aducanumab, Biogen continues to list (PDF) Alzheimer’s and dementia as a key growth area. Elenbecestat, a BACE inhibitor, is the most advanced of Biogen’s remaining Alzheimer’s assets. 

BAN2401, another amyloid-beta antibody, is set to join elenbecestat in phase 3. Biogen said it will use the analysis of the aducanumab phase 3 and BAN2401 phase 2 to inform its remaining programs targeting beta-amyloid. But previous attempts to improve the chances of success in Alzheimer’s by learning from prior studies have failed to lead to positive late-phase data. 

A new approach may have more success, and Biogen is active in some emerging areas. The big biotech has moved anti-tau antibodies BIIB076 and BIIB092 into phase 1 and 2, respectively, and has the Ionis-partnered antisense drug BIIB080 in early-phase development.