Vertex black box warning for Alyftrek ‘somewhat a surprise,’ says Barclays

After Vertex Pharmaceuticals (VRTX) announced early FDA approval of Alyftrek in cystic fibrosis ahead of a PDUFA deadline on January 2, Barclays notes that the label was broad, but adds that the black box warning for liver toxicity “came as somewhat a surprise,” with requirement for regular monitoring. The firm had expected initial uptake in about 6,000 patients who discontinued Trikafta, but says the black box warning and requirement for liver enzymes monitoring “could present some challenges for rapid broader uptake,” as it reiterates an Equal Weight rating on Vertex shares.