Pfizer has reported that co-primary clinical endpoints, change in cognitive and functional performance compared to placebo, were not met in Phase 3 trial of intravenous (IV) bapineuzumab in patients with mild-to-moderate Alzheimer’s disease who do not carry the ApoE4 (apolipoprotein E epsilon 4) genotype (Study 301).

Study 301 was led by Janssen Alzheimer Immunotherapy (Janssen AI) under the Alzheimer’s Immunotherapy Program (AIP) in which Janssen AI and Pfizer are partners.

The Janssen AI and Pfizer Joint Steering Committee for the AIP has decided to discontinue all other bapineuzumab IV studies in patients with mild-to-moderate Alzheimer’s disease, based on the topline results of Study 301 along with a Janssen AI-led Phase 3 study in patients who carry the ApoE4 genotype (Study 302).

Pfizer global primary care business unit medicines development group head, senior vice president Steven Romano said the outcomes of the trial are disappointing.

"Yet these data, and the subgroup and biomarker analyses underway, will further inform our understanding of this complex disease and advance research in this field," Romano added.

The discontinued studies include all follow-on extension studies in patients with mild-to-moderate Alzheimer’s disease receiving bapineuzumab IV in addition to the Pfizer-led Phase 3 studies (Study 3000 and Study 3001).

All patients in the discontinued studies will have a follow-up evaluation and Janssen Al and Pfizer will conduct final data analyses, according to Pfizer.

Study 301 did not report any new safety concerns while the most commonly observed serious adverse events which occurred in bapineuzumab-treated patients more than in placebo-treated patients were pneumonia, amyloid-related imaging abnormalities-edema or effusion, syncope, hip fracture and convulsion. These had an incidence of at least 1% in the combined 0.5 mg/kg and 1.0 mg/kg group.