In wake of Pallas study, Multaq hopes fade

Earlier this year, a study of Sanofi's atrial fibrillation treatment Multaq was halted because patients on the drug were dying--and suffering strokes and heart failure--at higher rates than placebo patients were. The full study, released at this week's American Heart Association meeting, shows just how much of a disappointment Multaq has become.

As Bloomberg points out, doctors had hoped Multaq would avoid the safety issues that have plagued previous heart-rhythm drugs. And when tested in patients with temporary forms of AF, Multaq certainly seemed promising. It cut the rate of death, stroke and hospitalizations. The FDA approved that use, and Sanofi ($SNY) looked toward extending Multaq to patients with permanent AF, a much bigger market.

But the Pallas study in permanent AF patients, published in the New England Journal of Medicine, found double the risk of death, strokes and heart failure in the Multaq arm. In the 3,236-patient study, 21 subjects on Multaq died from cardiovascular causes, while 10 placebo patients died. The FDA began a safety review.

"We have had a healthy suspicion of anti-arrhythmic drugs for many years, but we had thought this drug didn't have the same risks," lead researcher Stuart Connolly told Bloomberg. "We are now getting the message that this drug has the potential to harm as well. It seems this drug acts very differently depending on which type of patient receives it."

Some cardiologists said the Pallas study shouldn't affect Multaq's use in temporary AF patients. Others say it's an open question whether anyone should use it. Even under the new best-case scenario, the drug won't pan out to be the big seller that Sanofi was hoping for as it faces generic rivals for Lovenox and the loss of exclusivity on megablockbuster Plavix. "Multaq isn't dead but it won't be the drug we were hoping for," Aurel BGC analyst Pierre Corby told the news service. No doubt Sanofi officials agree.

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