OP-1 LONG-TERM EFFICACY AND SAFETY OF OPEN-LABEL SELADELPAR TREATMENT IN PATIENTS WITH PRIMARY BILIARY CHOLANGITIS: INTERIM 2-YEAR RESULTS FROM THE ASSURE STUDY

Abstract

Conflict of interest: Yes, Full disclosures sent separately. Introduction and Objectives: Seladelpar reduces biochemical markers of cholestasis and pruritus in patients with primary biliary cholangitis. ASSURE (NCT03301506) is an ongoing, open-label, long-term Phase 3 trial of seladelpar in patients rolling over from Phase 3 RESPONSE (NCT04620733) or legacy studies (NCT03602560, NCT02955602, NCT03301506, and NCT04950764). We report interim 2-year efficacy and safety results. Patients / Materials and Methods: Patients with insufficient response/intolerance to ursodeoxycholic acid could enroll in ASSURE. Key endpoints were composite biochemical response (alkaline phosphatase [ALP] <1.67 × upper limit of normal [ULN], ALP decrease ≥15%, and total bilirubin ≤ULN) and ALP normalization. Pruritus was measured using numerical rating scale (NRS; 0–10). For patients enrolling from RESPONSE, baseline was entry to RESPONSE and analyzed as continuous seladelpar or crossover from placebo; legacy patients were analyzed separately with baseline defined as entry to ASSURE. Results and Discussion: As of 01/2024, 158 RESPONSE and 179 legacy patients received seladelpar 10 mg daily for up to 155 weeks. In RESPONSE, 61.7% of patients met the endpoint at 12 months (M) vs 20% for placebo. In ASSURE, 61.8% (6M) and 72.4% (12M) met the composite endpoint; 75% (6M) and 93.8% (12M) of placebo crossover patients met the endpoint. In RESPONSE, ALP normalized in 25% of seladelpar and 0 placebo patients at 12M. With continued treatment, 33.3% (6M) and 17.2% (12M) had ALP normalization; 26.9% (6M) and 50% (12M) of crossover patients had ALP normalization. In ASSURE, 6-month change from baseline in pruritus NRS was similar to RESPONSE: −3.8 and −3.7 in continuous and crossover patients, respectively. At 12M and 24M, 73.2% and 69.7% of legacy patients met the endpoint in ASSURE; 42.1% and 42.4% achieved ALP normalization, and reduction in pruritus NRS was −3.8 and −3.1, respectively. There were no treatment-related serious adverse events. Conclusions: Seladelpar treatment led to improvements in biochemical markers and pruritus, and was well tolerated with long-term use.