In the wake of another negative trial with the anti-amyloid drug bapineuzumab, Pfizer and Janssen said they were halting development of the product for mild to moderate Alzheimer's disease.
All ongoing studies with the drug, a monoclonal antibody intended to break up beta amyloid protein plaques, will be discontinued, according to a statement released by Pfizer. This includes extension studies of previous randomized trials.
The decision came after a placebo-controlled phase III trial led by Janssen, known as Study 301, failed to meet its coprimary endpoints involving cognitive and functional performance in patients without the APOE4 genotype.
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In late July, the companies said a companion trial called Study 302 also failed to meet its main endpoints. The 302 trial had enrolled only patients with the APOE4 genotype.
However, the firms' statement left the door open for developing the drug for preclinical Alzheimer's disease, which many researchers believe is a more appropriate target anyway for anti-amyloid drugs. Pfizer and Janssen stopped short of saying that all development efforts would be terminated.
By the time symptoms develop, these scientists reason, the progression of cognitive decline may be too advanced to be affected by halting or reversing accumulation of beta amyloid plaques. Recent imaging studies with amyloid-specific tracers have indicated that plaques develop long before symptoms appear.
Other anti-amyloid strategies have also yielded disappointing results in clinical trials involving patients with established Alzheimer's disease.
Pfizer said results of both studies would be presented at a European neurology meeting in September.