Arthritis trial deaths hurt Pfizer shares

New York: New data raising safety concerns for Pfizer's experimental arthritis drug sent its shares down 3 per cent, while lifting shares of rival drugmaker Abbott Laboratories, analysts said.

Wells Fargo analyst Larry Biegelsen in a research report on Thursday said four deaths were seen in one late-stage study of tofacitinib, Pfizer's oral drug for rheumatoid arthritis, which has been considered a potential rival to Abbott's big-selling Humira.

It is not clear from a brief description of the study, called an abstract, that the drug caused the deaths, Biegelsen said. But the report of the fatalities spooked investors.

A Pfizer spokeswoman had no immediate comment.

The abstract from a 792-patient study to be presented at a meeting of the European League against Rheumatism said four patients who had been taking the 10mg dose of the Pfizer drug had died, including one from heart failure.

The pill, from a new class of medicines called JAK inhibitors, has shown great promise in clinical trials as a potential alternative to widely-used injectable treatments. Some analysts have been forecasting multi-billion-dollar sales for tofacitinib, which is well ahead of similar drugs in development, if approved.

Scrutiny

"Now that you're doing longer trials and you see some deaths, the cardiovascular scrutiny here is going to be really tight because the FDA obviously doesn't want another Vioxx issue," said Hapoalim Securities analyst Jon Lecroy, referring to the widely used Merck & Co pain drug that was pulled from the market after it was found to increase the risk of heart attacks.

Pfizer had released partial data from the study saying its drug was successful in significantly reducing symptoms of rheumatoid arthritis and that "no new safety signals" had emerged from the trial.

JP Morgan analyst Christopher Schott, in a research note, called the Pfizer sell-off an overreaction. He noted that only two of the four deaths happened while patients were taking the Pfizer drug.