Altimmune (ALT) said Thursday that its phase 2b trial of its product candidate pemvidutide has met its primary endpoint with "statistically significant" metabolic dysfunction-associated steatohepatitis, or MASH, resolution.

The company said pemvidutide showed significant MASH effects and weight loss at 24 weeks.

An intent-to-treat analysis showed that MASH resolution without worsening of fibrosis was achieved in 59.1% and 52.1% of participants treated with 1.2 mg and 1.8 mg, respectively, compared with 19.1% of participants treated with placebo, Altimmune said.

An additional intent-to-treat analysis showed that 31.8% and 34.5% of participants treated with pemvidutide 1.2 mg and 1.8 mg improved their fibrosis without worsening their MASH, compared with 25.9% in the placebo group, with "differences not significant," the company said.

The average weight loss in patients treated with pemvidutide at 24 weeks was 5% and 6.2% for the 1.2 mg and 1.8 mg doses, respectively, compared with 1% in placebo, Altimmune said.

Shares of Altimmune were down 63% in recent Thursday premarket activity.