Elan Corporation, plc and Wyeth announced that the companies will discontinue the highest of three dosing regimens, 2.0 mg/kg, in the two ongoing phase-3 studies of bapineuzumab in patients with mild to moderate Alzheimer's disease (AD) who do not carry the Apolipoprotein E4 (ApoE4) allele (non-carriers). ApoE4 is a known genetic risk factor for development of AD. The 0.5 mg/kg and 1.0 mg/kg doses in these two trials will continue as planned.

This decision has no impact on two other ongoing studies, which are testing a single 0.5 mg/kg dose of bapineuzumab in patients who carry the ApoE4 allele (carriers). No changes are planned for these two carrier studies. The phase-3 programme for bapineuzumab is the largest clinical programme ever initiated in Alzheimer's disease. It is expected that approximately 4,000 patients will be included across all four studies.

The decision of the companies to discontinue the 2.0 mg/kg dose was made in concurrence with the study's independent Safety Monitoring Committee (SMC), following its review of vasogenic edema (VE) in the ongoing phase-3 clinical programme. The SMC also reviewed unblinded data regarding VE from the 0.5 mg/kg and 1.0 mg/kg dose cohorts in the non-carrier studies and does not have concerns about these cohorts at this time.

"Alzheimer's disease is a devastating condition and the development of new therapies that have the potential to slow progression of the illness is critical," said Elan president Carlos Paya. "Our review of the safety data and the feedback from the Safety Monitoring Committee made it clear that continued development of the highest dose was not advisable. The decision to remove the highest dose from development reduces risk to patients and it also helps to reduce risk to the overall development effort."

Moving forward, newly enrolled patients will be randomized to either the 0.5 mg/kg or the 1.0 mg/kg dose cohorts or to placebo. In consultation with the SMC, the companies plan to amend the protocols to allow patients who are currently receiving the 2.0 mg/kg dose to be reassigned to the 1.0 mg/kg dose.

Wyeth and Elan's decision to modify the dosing regimen for two of the four ongoing phase-3 studies is being communicated to study investigators and the Boards of Health where the clinical trials are being conducted.

Elan Corporation, plc is a neuroscience-based biotechnology company committed to making a difference in the lives of patients and their families by dedicating itself to bringing innovations in science to fill significant unmet medical needs that continue to exist around the world.