Syndax Pharmaceuticals Inc. won U.S. FDA approval – the company’s second this year – for menin inhibitor Revuforj (revumenib) with a black box warning for differentiation syndrome. “We’ve long expected that would be the case,” said CEO Michael Metzger. For “the last six years or so” the agency has had a “heightened awareness” of the problem, and he predicted all drugs in the class would bear similar cautionary language. But there’s also a warning about QT prolongation and a requirement for monitoring.