Good Tidings for Gilead

The FDA didn't concur. However, Tracleer's label contains the same safety warning and requirement for regular liver monitoring, signaling that the FDA views the risk of liver damage as belonging to the entire class of drugs -- endothelin receptor antagonists -- that includes both Tracleer and Letairis.

The agency did OK a Letairis label that gives the Gilead sales force a lot to work with. Significantly, it includes safety data demonstrating a relatively low incidence of liver toxicity compared to a placebo, as well as a lack of interactions with other drugs used to treat PAH patients. These data should give Letairis a leg up on Tracleer when doctors consider treatment for newly diagnosed PAH patients.

The FDA also allowed Gilead to include data from a recently concluded study showing that Letairis is effective and safe in patients who had to stop taking Tracleer or Thelin because of liver toxicity. This will help Gilead convince doctors to switch patients from Tracleer to Letairis.

Gilead is pricing Letairis at parity with Tracleer
-- about $3,940 per month -- and will launch the drug this week.

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