Vertex Pharmaceuticals issued a statement on Monday 15th August that it is ending a clinical study testing a two-drug combination therapy on a small group of cystic fibrosis patients after an independent board concluded the experimental treatment wasn’t showing meaningful benefit.

Executives had previously warned that the late-stage clinical study combining its drug candidate, called VX-661, with its approved drug Kalydeco might not prove effective for about 150 patients enrolled in the study. Each of those patients has two separate genetic mutations linked to CF.

In a statement, Vertex chief medical officer Jeffrey Chodakewitz said that this CF population has “a form of the disease that is particularly difficult to treat.” But he said Vertex remains hopeful those patients will be able to benefit from a three-drug combination -- including VX-661 and Kalydeco -- that Vertex is also developing.

Background Note: Vertex have two approved drugs, Kalydeco and Orkambi, which treat CF patients with certain mutations. Kalydeco has been approved and is reimbursed in Ireland. Orkambi is not yet available in Ireland, except on compassionate grounds as the price is currently being negotiated. These are the first drugs that treat the underlying cause of CF