- Enanta Pharmaceuticals has been looking into whether one of its experimental drugs can treat two different types of liver disease. But after receiving negative clinical trial results, the company said it is narrowing the development focus to just one of those targets: a condition known as NASH.
- Those clinical results, announced Wednesday, found Enanta's drug missed the main goal of a mid-stage study that tested it against placebo in patients with a chronic liver illness called primary biliary cholangitis. The company noted, though, that its drug would have succeeded had the results been based solely on patients who completed the study, rather than on all the patients enrolled.
- Enanta said the PBC trial data will be helpful as it continues to investigate the drug as a potential treatment for NASH, or nonalcoholic steatohepatitis. The fatty liver condition is believed to affect millions of patients in the U.S. alone, yet there are currently no approved treatments for it, in part because drugmakers are still learning about the various ways NASH develops.
While Enanta remains optimistic that its drug, EDP-305, could have a place in NASH treatment, results from the PBC study may be seen as foreboding.
According to company management, the study results suffered from a higher-than-expected number of participants dropping out. Itching, which is a common side effect for some experimental liver drugs, led 3% of patients in the lower dose arm and 18% in the higher dose arm to leave the study early.
Higher dropout rates are more noteworthy when considering PBC is a chronic liver condition that progressively destroys the organ. A former SVB Leerink analyst noted last year that, "PBC patients are very motivated. Their livers are dying, they have to be treated for this. It's not an optional thing."
NASH, while also a progressive disease, can be reversed up until its most advanced stages. As such, there have been concerns among NASH drugmakers and their investors that itching or other noticeable side effects may deter patients from wanting to use them, which in turn could impact not only clinical studies but commercial prospects.
Jay Luly, Enanta's CEO, said on a Wednesday call with investors that his company was "encouraged" by the PBC study data that showed the lower dose of EDP-305 had similar efficacy to the higher dose but was more tolerable to patients.
The company noted that the planned mid-stage trial of EDP-305 in NASH will be evaluating two doses of the drug that fall in between the low and high dose tested in the PBC study. Enrollment for the NASH trial, though, is currently paused due to the coronavirus pandemic.
In a note to clients, analysts at JMP Securities wrote that it was "no surprise" that the PBC trial didn't succeed and that their expectations for the NASH study are low "given the significant competitive landscape and the struggle this compound has with [itching]."
Analysts from other investment banks have too voiced concerns about whether Enanta would be able to compete against rival NASH drugmakers — namely Intercept Pharmaceuticals, which is the only company to have secured positive data in a late-stage NASH study.
For Enanta to hit the PBC study's main goal, an enzyme tied to liver damage needed to drop by 20% or more in a significantly higher proportion of patients receiving EDP-305 as opposed to placebo. Results found that was not the case when looking at all the patients enrolled in the study, though it was true of the patients who completed all 12 weeks of treatment.
Enanta also pointed out that the study found EDP-305 to have statistically significant effects on other enzyme markers of liver health.
Yet, while liver enzymes have been a popular measurement in NASH studies, the Food and Drug Administration has signaled that developers need data showing some level of NASH resolution or fibrosis improvement for the best chances at approval.
Enanta's share price rose about 5% Thursday morning on the heels of the trial readout and a first quarter earnings report. Over the last year, however, shares have fallen close to 40%.