US regulators have placed Shire's SHP626 (volixibat) on a fast-track regulatory pathway in the hope of potentially accelerating access to the experimental liver disease drug.

Shire is developing volixibat for the treatment of adults who have nonalcoholic steatohepatitis (NASH) with liver fibrosis, a serious, chronic liver disease for which there are currently no approved drugs.

NASH is a type of nonalcoholic fatty liver disease characterised by inflammation and the accumulation of fat in the liver.

Shire's experimental therapy is a once daily, orally-administered inhibitor of the apical sodium dependent bile acid transporter (ASBT), a protein which is primarily responsible for recycling bile acids from the intestine to the liver.

The drug has already been evaluated in preclinical and Phase I studies looking at its safety, tolerability and preliminary activity compared to placebo, and a Phase II trial is due to kick off imminently.

"Shire's development plan for SHP626 is designed to address the unmet need in the treatment of adult patients who have NASH with liver fibrosis," said Philip Vickers, head of R&D at the firm. "This Fast Track designation is further recognition of the critical need to develop new, effective therapeutic options for patients with this serious condition."