89bio, Inc. announced positive topline results from an open-label expansion cohort of 20 patients (Cohort 7) in the Phase 1b/2a proof-of-concept study evaluating pegozafermin (formerly BIO89-100) for the treatment of NASH. In this single-arm cohort, biopsy-confirmed, fibrosis stage F2 and F3 NASH patients were treated once weekly for 20 weeks with 27 mg of pegozafermin. At baseline, 65% of patients were fibrosis stage F3.

Of the 20 patients enrolled, 19 received an end-of-treatment biopsy and the results from these 19 patients were as follows: 2-point or greater improvement in NAS without worsening of fibrosis(primary endpoint): 63%; 2-point or greater improvement in NAS: 74%; NASH resolution without worsening of fibrosis: 32%; One-stage improvement of fibrosis without worsening of NASH: 26%; ASH resolution or fibrosis improvement: 47% Results also showed clinically meaningful and significant changes across key non-invasive tests (NITs) associated with fibrosis, risk of fibrosis or NASH resolution. In 83 patients treated with pegozafermin across the full Phase 1b/2a study, pegozafermin continues to be generally well tolerated with a favorable safety profile. There have been no drug-related serious adverse events, only one treatment-related discontinuation, no tremors and no hypersensitivity reactions have been observed.

In the open-label histology cohort the most commonly reported treatment-related adverse events were nausea, diarrhea, vomiting and injection site reactions, most of which were graded as mild.