Analysts speculate on approval for Wyeth's, Elan's bapineuzumab

Some analysts suggested that Wyeth's and Elan's investigational Alzheimer's disease drug bapineuzumab may not reach the market, after more detailed Phase II study results were presented on July 29. The findings confirmed that the compound did not meet the trial's primary efficacy endpoints and raised concerns about potential adverse events. Wyeth's shares fell 16 percent after the data were released, while shares of Elan plunged as much as 40 percent.

Results from the 234-patient trial showed that while bapineuzumab did not meet the study's primary endpoints, it might benefit patients who lack the ApoE4 gene. However, the results also demonstrated that 12 patients administered the compound developed vasogenic oedema, compared with none who received placebo. Canaccord Adams analyst Karl Keegan remarked: "The presented data [were] analysed with unexpected additional layers of complexity. Although the oedema resolved upon drug withdrawal, outside of the clinical trial setting we view the potential for a requirement for regular scans to be a significant commercial hurdle.''

Sanford C. Bernstein's Tim Anderson suggested that "negatives with the data include efficacy trends that were weak, and potentially worrisome safety findings that seemed marginally worse than we expected,'' adding that "bapineuzumab has been, and remains, a high-risk, high-reward opportunity.'' Anderson also noted that investors "felt burned'' by the preliminary findings, which had given a more positive impression of the results.

Deutsche Bank's Barbara Ryan predicted that the compound has less than a 50-percent chance of success in Phase III testing. "The last two months of spurious speculation on one small trial demonstrates clearly why we do not make bets on anticipated Phase II data," she commented. John Boris of Citi Investment Research forecast that "the likelihood of Phase III clinical success, regulatory approval and commercial success are extremely low." Late-stage testing on the drug began in North America in December. In all, about 4100 patients are expected to take part in four Phase III trials.

Commenting on the news, Elan CEO Kelly Martin called the stock selloff "unjustified," noting that the company learned more about the compound's efficacy and safety, despite it having missed significant endpoints. The executive stated: "Clearly, there is a gap in knowledge with the marketplace and the investors with the data. A relatively small Phase II Alzheimer's trial is never going to be able to answer all the questions about Alzheimer's that have existed."

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