Vertex jumps after-hours on CF data

Vertex Pharmaceuticals Inc. (NASDAQ:VRTX) jumped $28.58 (54%) in early after-hours trading after reporting data from a Phase II trial of VX-661 to treat cystic fibrosis (CF). All VX-661 monotherapy and combination arms met the primary endpoint of reducing mean absolute sweat chloride levels from baseline to day 28 vs. placebo in 128 CF patients homozygous for the delta F508 CFTR mutation. About 46% of worldwide CF patients are homozygous for that mutation and an additional 33% of patients have at least one copy. Vertex's one marketed CF drug, Kalydeco ivacaftor, is approved for CF patients who have one or more copy of the G551D mutation in the CFTR gene -- about 4% of the CF population.

Patients in the Phase II trial received once-daily 10, 30, 100 and 150 mg doses of VX-661 for 28 days as monotherapy or in combination with twice-daily Kalydeco. Vertex reported detailed data for the study's secondary endpoint, mean relative percent predicted forced expiratory volume in 1 second (FEV1) improvements from baseline to day 28. The two combination arms receiving the highest VX-661 doses met the secondary endpoint, with a 9% improvement for once-daily 100 mg VX-661 plus Kalydeco (p=0.01) and a 7.5% improvement for once-daily 150 mg VX-661 plus Kalydeco (p=0.02) vs. a 0.03% improvement for placebo. All of the other treatment arms missed the secondary endpoint. ...