Kalydeco targets the underlying cause of cystic fibrosis.\
Kalydeco targets the underlying cause of cystic fibrosis.
Yoon S. Byun/Globe staff

Vertex Pharmaceuticals Inc., a Cambridge biotechnology company, said that its Kalydeco cystic fibrosis drug has been granted approval by Australian regulators to treat a small segment of the patient population.

Kalydeco, which was approved by US regulators in February 2012, targets the cause of the disease in about 4 percent of the US patient population. Those patients have a genetic mutation in a particular protein that sits at the surface of cells and regulates the flow of water and salt. The Vertex drug binds to the protein and works to restore its normal function, helping patients make mucus that lets them absorb and digest food and gain weight.

Cystic fibrosis is a rare, life-threatening genetic disease affecting approximately 70,000 people worldwide, including 3,000 people in Australia, 30,000 in the United States, 35,000 in Europe and 4,000 in Canada.

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In its press release, Vertex said that about 250 people in Australia have this genetic mutation.

In any case, Australia’s Therapeutic Goods Administration has approved Kalydeco for people with cystic fibrosis ages 6 and older who have at least one copy of the G551D mutation in the cystic fibrosis transmembrane conductance regulator gene.

Australian approval and reimbursement of a new medicine is a multi-step process, Vertex’s press release noted. Once a new medicine receives approval from the Therapeutic Goods Administration, it is assessed for effectiveness and cost-effectiveness by the Pharmaceutical Benefits Advisory Committee for listing on the Pharmaceutical Benefits Scheme. Additional information regarding the reimbursement of Kalydeco in Australia is expected to be available later in 2013.

In April, investors bid up Vertex shares to a record high after the company released clinical trial data that appeared to dramatically improve the prospects of its plan to build a portfolio of cystic fibrosis drugs, a Globe story noted then.

In the coming years, Vertex is planning to relocate much of its operations from Cambridge to Boston’s so-called Innovation District.