FDA Sends Cystic Fibrosis Treatment Back for More Study

Megan Brooks


March 19, 2013

The US Food and Drug Administration (FDA) has completed its review of Pharmaxis' New Drug Application (NDA) for its dry powder formulation of mannitol (Bronchitol, Pharmaxis) and has recommended that the company conduct an additional study to obtain marketing approval in the US, Pharmaxis announced today.

"The submitted data do not provide a favorable benefit-risk balance to support the use of inhaled mannitol in patients with cystic fibrosis 6 years of age and older," the FDA said in a complete response letter to the company.

"The determination of efficacy based on the 2 clinical trials conducted to date are not adequate because of the treatment-related frequent early dropouts in trial 301 for which the primary statistical analyses did not account and the lack of statistical significance in trial 302 for the primary endpoint," the agency stated.

In relation to safety, Pharmaxis said the FDA expressed concerns over the occurrence of hemoptysis, particularly in patients younger than 18 years.

Pharmaxis CEO Gary Phillips said the company is "clearly disappointed" in the FDA's decision, but noted that the regulator has provided guidance on the necessary measures to gain approval and that Pharmaxis will meet with the FDA soon to determine appropriate parameters of an additional clinical trial.

The complete response letter follows a unanimous decision January 30 by the FDA's Pulmonary-Allergy Drugs Advisory Committee against approval of Bronchitol for the management of cystic fibrosis in patients aged 6 years and older to improve pulmonary function.

The FDA previously granted Bronchitol orphan drug designation for the treatment of patients with cystic fibrosis.

Bronchitol, which helps facilitate mucus clearance in the lungs of patients with cystic fibrosis, is approved for marketing for patients aged 6 years and older in Australia and for patients aged 18 years and older throughout the European Union.