FDA staff eyes safety of Novartis' MS drug

WASHINGTON (Reuters) - U.S. regulators expressed concern about potential side effects of Novartis AG's multiple sclerosis pill in patients most at risk for complications.

Food and Drug Administration staff scientists noted on Tuesday a "clear dose-related effect" on the heart after the first dose of the drug, which Novartis aims to sell under the brand Gilenia. If approved, the drug could be the first pill to treat MS.

Side effects include heart problems, but there was little data on more vulnerable patients, the staff said, noting that further safety signals could crop up in those patients.

The "main limitations of this application are the lack of data in patients with pre-existing conditions who would be at risk for developing eye and cardiovascular complications," one reviewer wrote, noting that it is also unclear whether the drug "may be associated with an increased risk of seizure."

Although FDA reviews cast little doubt on the drug's success in relapsing patients, they said further study was needed not only on such vulnerable patients but also on some of the drug's long-term side effects.

Whether such studies are needed before or after the drug's approval will be part of a public discussion on Thursday as the FDA's outside advisors weigh whether to recommend the pill for approval.

The FDA will also ask the committee whether the effect of lower doses of the drug should be evaluated prior to the agency's approval decision, expected by September.

Gilenia, which Novartis licensed from Mitsubishi Tanabe Pharma Corp, aims to be easier to take than injectable rivals while also not causing flu-like symptoms seen with some competing drugs. But clinical trials have linked the drug to skin cancer, heart problems and infections, among other side effects.

If approved, the drug would need a risk management plan, FDA staff said.

Novartis shares were down 0.6 percent in Swiss trading.

FDA posted the agency's review on its website here

(Reporting by Susan Heavey; Editing by Derek Caney)