Actelion’s bid to get a new use approved for Gaucher disease drug Zavesca has suffered a setback after regulators in the USA asked more information on the drug as a treatment for a rarer condition.

The Swiss firm has received a complete response letter from the US Food and Drug Administration for its supplemental New Drug Application for Zavesca (miglustat) for the treatment of Niemann-Pick type C disease, a rare, neurodegenerative genetic disorder. The latter symptoms are caused by the storage of some lipids within certain tissues in the body, including the brain. NP-C, which has only about 500 confirmed cases worldwide, is “invariably progressive” and most patients die within five to ten years of diagnosis.

There is no specific drug therapy approved in the USA to treat NP-C disease and there will not be for some time yet. The FDA has requested “additional preclinical and clinical information” and Actelion has given no details of what this specifically involves.

This is a blow for Actelion, seeing as how the agency’s Endocrinologic and Metabolic Drugs Advisory Committee voted 10 to three in favour of the benefit/risk profile of Zavesca for this disease in January. Nevertheless, chief executive Jean-Paul Clozel said “we remain committed to bringing an approved treatment to patients suffering from NP-C disease and in this spirit we will continue the dialogue with the FDA”.

The FDA's decision comes just a week or so after Actelion’s shares took a battering after the company announced that a clinical trial aimed at expanding the indications for its flagship drug, the pulmonary arterial hypertension therapyTracleer (bosentan) had failed to meet its primary endpoint as a treatment for idiopathic pulmonary fibrosis.