Wyeth: Results mixed on Alzheimer’s trial

Wyeth and its partner, Elan Corp., a biopharmaceutical manufacturer based in Ireland, announced mixed results from a Phase II clinical trial of an experimental Alzheimer's drug, causing investors to dump shares of both companies today.

The companies said they were encouraged by results of the trial among 234 patients, which showed that the drug improved functioning among a subset of trial participants.

But there were no significant benefits for patients who carried a gene found in more than half of all Alzheimer's patients. Equity analysts said the study results also suggested some worrisome safety signals.

Wyeth's shares plunged as much as 18 percent in early trading and recovered slightly to close at $39.74, down nearly 12 percent. Shares in Elan on the London Stock Exchange closed down 33 percent.Wyeth, a Madison, N.J., company, employs more than 5,300 people at its pharmaceutical headquarters in Collegeville.

Both companies' stock had climb after the announcement in June of encouraging findings about the drug, called bapineuzumab.

But with the full presentation of Phase II data at a medical meeting in Chicago last night, analysts began to cast a more skeptical eye toward prospects for the drug, which is aimed at a potential market of millions of people who suffer from the progressive and to date incurable brain disorder.

"Negatives with the data include efficacy trends that were weak and potentially worrisome safety findings that seemed marginally worse than expected," said Tim Anderson, a pharmaceuticals analyst with Sanford C. Bernstein & Co. L.L.C.

The company maintained an outperform rating on Wyeth, but lowered its target price from $53 to $46.

Citi analyst John Boris, saying that chances for final FDA approval and commercial development of the drug were "extremely low," recommended that investors sell Wyeth stock.

Alzheimer's affects about five million people in the United States, primarily the elderly. Over time, it gradually destroys a person's memory and ability to carry out daily activities. While there is medication that can suppress the symptoms, there is no known cure.

Bapineuzumab was developed to clear out spindly clumps of protein that clot the brain and kill nerve cells, affecting mental function.

But the drug did not appear to have a beneficial effect for study participants with the ApoE4 gene, which is present in about 60 percent of Alzheimer's patients.

Still, Wyeth said that in patients who did not have the gene, statistically significant results were achieved in mental functioning. Moreover, favorable effects were also observed in MRIs of those patients in the 18-month study.

"The clinically significant benefit seen with the bapineuzumab treatment in [patients without the gene] is encouraging," said Dale Schenk, Elan's executive vice president and chief scientific officer.

The companies said adverse events were observed in more than 5 percent of the trial participants treated with bapineuzumab, twice the rate of the placebo-treated patients. Adverse reactions included back pain, anxiety, vomiting, brain swelling, hypertension, weight loss and paranoia.

The companies said they planned to forge ahead with Phase III studies involving 4,000 Alzheimer's victims.

The trial results for bapineuzumab underscore the highly speculative nature of the pharmaceutical business. Experimental medications must run a gantlet of tests, and few ever make it through clinical trials to FDA approval, even in cases in which early indications seem promising.