A phase 2 multiple ascending dose trial of bapineuzumab in mild to moderate Alzheimer disease

Background: Bapineuzumab, a humanized anti-amyloid-beta (A beta) monoclonal antibody for the potential treatment of Alzheimer disease (AD), was evaluated in a multiple ascending dose, safety, and efficacy study in mild to moderate AD. Methods: The study enrolled 234 patients, randomly assigned to IV bapineuzumab or placebo in 4 dose cohorts (0.15, 0.5, 1.0, or 2.0 mg/kg). Patients received 6 infusions, 13 weeks apart, with final assessments at week 78. The prespecified primary efficacy analysis in the modified intent-to-treat population assumed linear decline and compared treatment differences within dose cohorts on the Alzheimer's Disease Assessment Scale-Cognitive and Disability Assessment for Dementia. Exploratory analyses combined dose cohorts and did not assume a specific pattern of decline. Results: No significant differences were found in the primary efficacy analysis. Exploratory analyses showed potential treatment differences (p < 0.05, unadjusted for multiple comparisons) on cognitive and functional endpoints in study completers and APOE epsilon 4 noncarriers. Reversible vasogenic edema, detected on brain MRI in 12/124 (9.7%) bapineuzumab-treated patients, was more frequent in higher dose groups and APOE epsilon 4 carriers. Six vasogenic edema patients were asymptomatic; 6 experienced transient symptoms. Conclusions: Primary efficacy outcomes in this phase 2 trial were not significant. Potential treatment differences in the exploratory analyses support further investigation of bapineuzumab in phase 3 with special attention to APOE epsilon 4 carrier status. Classification of evidence: Due to varying doses and a lack of statistical precision, this Class II ascending dose trial provides insufficient evidence to support or refute a benefit of bapineuzumab. Neurology (R) 2009; 73: 2061-2070