VX-661: Phase II data

A double-blind, placebo-controlled Phase II trial in 18 CF patients ages >=12 with both the delta F508 CFTR mutation and G551D CFTR mutation showed that once-daily 100 mg VX-661 plus patients' ongoing stable Kalydeco ivacaftor treatment led to a mean reduction in sweat chloride levels of 7.02 mmol/L at day 28 compared to baseline (p=0.053). Additionally, VX-661 plus Kalydeco led to a mean absolute improvement in percent predicted FEV1 of 4.6% and a mean relative improvement in percent predicted FEV1 of 7.3% at day 28 compared to baseline (p=0.012 for both). Vertex said the trial was not powered to detect statistical significance vs. placebo and did not report data from the placebo arm. VX-661 plus Kalydeco was generally well tolerated. The most common adverse events were cough, pulmonary exacerbation, headache and upper respiratory tract infection. There was 1 serious adverse event of arthritis in the VX-661 arm that was deemed unrelated to VX-661 or Kalydeco. There were 14 patients in the VX-661 arm and 4 patients in the placebo arm.

Vertex is evaluating VX-661 plus Kalydeco in a 12-week Phase II trial in CF patients with 2 copies of the delta F508 CFTR mutation. The company declined to disclose a time frame for when data from the 12-week trial are expected. Pending data from the 12-week trial, Vertex said it plans to discuss with worldwide regulatory authorities the approval pathway for VX-661 in combination with Kalydeco. VX-661 plus Kalydeco has breakthrough therapy designation from FDA to treat CF in patients with 2 copies of the delta F508 CFTR mutation. ...