What happened

Shares of 89bio (ETNB 0.12%) closed Tuesday's trading session down by more than 37%. The healthcare company didn't release any news, but its peer, Akero Therapeutics, released disappointing trial data for a nonalcoholic steatohepatitis (NASH) therapy that is similar to one that 89bio is developing. 89bio's stock price is now down by more than 20% year to date.

So what

89bio is a clinical-stage biotech that focuses on liver and cardiometabolic diseases. It recently was granted a Breakthrough Therapy Designation by the Food and Drug Administration (FDA) for pegozafermin as a potential treatment for patients with NASH, which is a progressive form of non-alcoholic fatty liver disease involving scarring of the liver.

On Tuesday, Akero released phase 2b trial data on efruxifermin that showed the therapy had not reached its primary endpoint toward treating NASH. In the study, the drug was 24% effective, at a dose of 50 milligrams, in showing at least a one-stage improvement in liver fibrosis, with no worsening of NASH, compared to 14% for a placebo. Only 4% of patients in each dose group showed a two-stage or three-stage improvement in fibrosis with no worsening of NASH.

What does that mean for 89bio? The concern is that pegozafermin, like efruxifermin, imitates FGF21, a metabolic hormone that regulates energy use and glucose and lipid metabolism. Pegozafermin, because it also acts to reduce triglycerides, is also being studied as a treatment for severe  hypertriglyceridemia (SHTG). 

Now what

There are enough differences between the two drugs that it's probably too early to throw in the towel on 89bio. The company is planning phase 3 trials of pegozafermin as a treatment for NASH and SHTG. However, there is cause for concern because of the therapy's similarity to efruxifermin, and also because it is the only drug in 89bio's pipeline.

In the second quarter, 89bio had no revenue, a net loss of $34.9 million, and ended the period with $478 million in cash. At its current burn rate, the company should be able to fund operations for at least another three years.