Advisors to the US Food and Drug Administration are supporting the approval of Vertex’ cystic fibrosis combination Orkambi, which targets the most common form of the illness.

The FDA’s Pulmonary-Allergy Drugs Advisory Committee voted 12 to 1 to recommend a green light for Orkambi (lumacaftor/ivacaftor) for use in CF patients ages 12 and older who carry two copies of the F508del mutation.

If approved, Orkambi will be the first and only medicine to treat the underlying cause of CF for these patients, which number about 8,500 in the US, the firm noted.

The news will certainly come as a relief to Vertex given that briefing documents posted to the Agency’s website ahead of the Committee meeting threw a small shadow of doubt over the clinical validity of the combination, questioning whether treatment with ivacaftor alone would have shown a similar benefit.

The FDA is not bound by the Committee's recommendation but often follows its advice. In any case, a final decision is expected by July 5.