Birth Of A Biomarker? FDA Doesn't Define Eosinophilic Asthma, Defers To Docs On Nucala

FDA declined to codify new asthma phenotype in the indication for GSK's Nucala, leaving emerging definition of eosinophilic asthma to the medical community. For FDA's endorsement, it is not enough to show that patients with eosinophilia biomarkers benefit; you also need to show that patients without the biomarker do not benefit.