Translarna, a Novel CF Therapy, Advances in 2nd Clinical Trial

PTC Therapeutics Inc. has announced the completion of patient enrollment in its second Phase 3 clinical trial of the experimental cystic fibrosis therapy Translarna™.

The clinical trial, named ACT CF, is a placebo controlled study designed to evaluate the efficacy of Translarna (ataluren) in patients, age 6 or older, with nonsense mutation cystic fibrosis (nmCF) who are not receiving chronic inhaled aminoglycosides. The study’s primary endpoint is lung function, as measured by relative change in percent predicted FEV1 (forced expiratory volume in 1). Full enrollment has been reached at 88 worldwide sites. These patients are also eligible to participate in an open-label extension study after completing the 48 weeks of treatment, and extension enrollment has already begun.

Cystic fibrosis caused by a nonsense mutation results from an interruption in the genetic code that leads to little or no CFTR (cystic fibrosis transmembrane conductance regulator) production. Nonsense mutations are categorized as Class I mutations, which are very difficult to treat due to the almost complete, or complete, absence of CFTR. Patients with these mutations  experience more severe symptoms, both in the lung and pancreas, and have a shorter life expectancy. About 10%  of patients have CF due to Class I nonsense mutations and their available treatments, such as inhaled antibiotics, address disease symptoms but not the defect that is its cause.

Translarna is a protein restoration therapy, designed to allow the production of complete and functioning proteins in patients with nonsense mutations.

“We are very pleased by the enthusiastic response from our clinical investigators and strong interest from patients to participate in our ACT CF study,” said Dr. Stuart Peltz, Chief Executive Officer of PTC Therapeutics, in a press release. “Based on the results from our previous Phase 3 study, we believe that Translarna has the potential to meaningfully improve lung function and decrease pulmonary exacerbations in nonsense mutation cystic fibrosis patients by targeting the underlying cause of the disease.”

News of the trial’s full enrollment comes on the heels of the  European Medicines Agency’s (EMA) validation — on Sept. 30 — of the company’s submission of a new indication for Translarna as a treatment for nmCF. Translarna, an investigational drug in the U.S., received marketing authorization in Europe in August 2014 for the treatment of nonsense mutation Duchenne muscular dystrophy (nmDMD) in ambulatory patients age 5 or older.