NASH: regulatory considerations for clinical drug development and U.S. FDA approval.

Nonalcoholic fatty liver disease is a growing public health crisis, with phenotypes from nonalcoholic fatty liver to nonalcoholic steatohepatitis, currently known as NASH, which can progress to liver fibrosis and end stage cirrhosis. NASH is associated with an increased risk of cardiovascular disease and Type 2 diabetes mellitus. There are still no U.S. FDA approved drugs or biological treatments for NASH or related liver diseases. Despite official agency guidance, the regulatory pathway to ultimate product approval is unclear, due to both the extra-hepatic factors that contribute to NASH, as well as the organizational structure of FDA, with its traditional separation of therapeutic indications within discrete review divisions. There is hope that continued evolution of the regulatory process will lead to the ability for clinical trial endpoints supporting NASH treatment approval to include both liver-based and traditional metabolic measures, independent of specific FDA division review.