Eli Lilly has suffered a setback with the news that US regulators are demanding a new study before they will consider approving its non-porcine pancreatic enzyme replacement therapy liprotamase.

The company has received a complete response letter from the US Food and Drug Administration for its New Drug Application for liprotamase, which has been developed for the treatment of exocrine pancreatic insufficiency. Furthermore the agency has "communicated the need for Lilly to conduct an additional clinical trial prior to a re-submission".

The rejection is no great surprise given that the FDA's Gastrointestinal Drugs Advisory Committee voted 9-3 in January that the data submitted did not provide substantial evidence of efficacy of liprotamase, which had the proposed brand name of Solpura, in patients with cystic fibrosis, chronic pancreatitis, pancreatectomy or other conditions. The panel also voted 7-4 (with one abstention) as to whether the therapy's risks outweighed its benefits, and recommended that additional studies be carried out.

Lilly was hoping that liprotamase, developed by its Alnara Pharmaceuticals subsidiary, would be the the first treatment not based on pig enzymes to get the green light to help certain pancreatic patients digest their food. Eiry Roberts, who heads up liprotamase product development, said the company is looking forward to "further discussion with the FDA to address the items outlined in the letter and provide the requested information as quickly as possible", adding that "we are committed to working with the agency and the CF community to make this important treatment option available".