US regulators have approved Vertex’ Symdeko, a combination of Kalydeco (ivacaftor) and tezacaftor, to treat certain patients with cystic fibrosis (CF).

The decision allows use of the therapy in patients who have two copies of the F508del mutation or one mutation that is responsive to the treatment, expanding the reach of the firm’s CF offering.

The submissions include data from the 24-week, Phase III EVOLVE study, which evaluated the treatment in people who have two copies of the F508del mutation, and showed a mean absolute improvement in ppFEV1 (a measure of lung function) through 24 weeks of 4.0 percentage points from baseline compared to placebo.

The second Phase III study, EXPAND, looked at the combination in those carrying who have one mutation that results in residual CFTR function and one F508del mutation.

This also met the primary endpoints of absolute change in ppFEV1 from baseline to the average of the Week 4 and Week 8 measurements, with the tezacaftor/ivacaftor combination treatment demonstrating a mean absolute improvement of 6.8 percentage points compared to placebo and the ivacaftor monotherapy group demonstrating a mean absolute improvement of 4.7 percentage points compared to placebo.

Across both studies, Symdeko was generally well tolerated, the most common adverse events - regardless of treatment group - being infective pulmonary exacerbation and cough.

“The approval of Symdeko, our third disease-modifying CF medicine, offers many patients an important new treatment option," said Jeffrey Leiden, Vertex' chairman, president and chief executive officer.

"This approval is an important milestone in our journey to treat every person with CF, and we remain committed to urgently advancing our efforts to develop new medicines that treat the underlying cause of CF for the many people still waiting."

The therapy, which has a list price in the US of $292,000 a year, is also currently under review in Europe.