Pfizer has obtained Fast Track designation from the US Food and Drug Administration (FDA) for its investigational combination therapy, ervogastat (PF-06865571) and clesacostat (PF-05221304), to treat non-alcoholic steatohepatitis (NASH) with liver fibrosis.

Ervogastat is an inhibitor of diacylglycerol O-acyltransferase 2 (DGAT2i) while clesacostat is an acetyl-CoA carboxylase inhibitor (ACCi). 

Pfizer believes that ervogastat/clesacostat could potentially offer direct improvements in inflammation and fibrosis.

The latest decision by the regulatory agency is based on the findings from the company’s nonclinical studies and a Phase IIa clinical trial of ervogastat/clesacostat combination therapy.

In the trial, the combination therapy showed to decrease liver fat with a favourable safety and tolerability profile. 

At present, the company is analysing ervogastat/clesacostat in a Phase II trial underway to assess the impact of the combination therapy on NASH resolution or improvement in liver fibrosis.

It also has arms analysing ervogastat as a monotherapy.

This trial is anticipated to complete in 2024 and its findings will inform a potential Phase III development programme.

Pfizer Internal Medicine and Hospital senior vice-president and chief development officer James Rusnak said: “Receiving Fast Track designation from the FDA reinforces Pfizer’s belief in ervogastat/clesacostat as a potential treatment for NASH, a serious, progressive liver disease with no currently approved therapies. 

“We are proud to be advancing this investigational combination as part of our goal to develop innovative medicines to address some of the world’s most widespread health challenges that affect millions of people—including diseases like NASH.”

A progressive type of non-alcoholic fatty liver disease (NAFLD), NASH is caused by the accumulation of fat in the liver. 

Earlier this month, the company entered a definitive agreement to acquire Biohaven Pharmaceutical for nearly $11.6bn.