Elan Reports Mixed Alzheimer Results

Patients who are non-carriers of the ApoE4 gene are not at an increased risk for developing Alzheimer's. These "non-carriers" make up between 40% and 70% of the overall population.

In these non-carrier patients, treatment with bapineuzumab compared to placebo resulted in a statistically significant benefit in two measures of cognitive function -- the so-called ADAS-cog test and the Neuropsychological Test Battery, or NTB.

Furthermore, non APoE4 patients reported a statistically significant result compared to placebo on one of two measures of functional benefit -- the Clinical Dementia Rating -- Sum of Boxes (CDR-SB). However, this was only a tertiary functional endpoint of the study. On the prespecified cognitive primary endpoint, the Disability Assessment Scale of Dementia (DAD), there was only a trend in favor of bapineuzumab.

These patients also had less loss of brain volume after treatment with bapineuzumab compared to similar patients treated with placebo.

Elan and Wyeth did not provide any information regarding the numerical magnitude of the functional or cognitive benefit resulting from bapineuzumab treatment, nor did the companies disclose which of the three doses of drug used in the study was the most effective.

Patients who carry the ApoE4 gene have a higher risk for developing Alzheimer's. In these "carrier patients," however, bapineuzumab was ineffective on all cognitive and functional endpoints.

On the safety side of the study, there was a higher rate of brain swelling, or vasogenic edema, reported in ApoE4 carriers treated with bapineuzumab compared to placebo.

Elan and Wyeth began phase III studies of bapineuzumab late last year. Two studies are testing multiple doses of the drug in patients who do not carry the ApoE4 gene, while another two studies are testing a single dose of the drug in patients with the ApoE4 gene. Results are not expected for another two years.