Protocol amendment (version 1.1) for United Kingdom •Required subjects to have participated in a prior seladelpar study for at least 8 weeks. •Required that, in the Investigator’s opinion, subjects had to have derived a net benefit from participation in a prior PBC study with seladelpar. •Required that female subjects of childbearing potential have a serum pregnancy test performed at every On-Treatment Visit, and between On-Treatment Visits, perform a urine pregnancy test at home monthly (every 30 days).

Protocol amendment (version 1.2) for Germany •Required subjects to have participated in a prior seladelpar study for at least 8 weeks. •Required that, in the Investigator’s opinion, subjects had to have derived a net benefit from participation in a prior PBC study with seladelpar. •Required that female subjects of childbearing potential have a serum pregnancy test performed at every On-Treatment Visit.

Protocol Amendment 1 (version 2.0) •Enrollment into the study was expanded to allow subjects who completed PBC Studies CB8025-31735 (double-blind placebo-controlled study) and CB8025-21838 (single dose hepatic impairment study in PBC population). •Clinical data from Phase 1 and Phase 2 studies was updated. •The study design was updated to add partial randomization. •A secondary objective was added to collect data to support pruritis that was also assessed in study CB8025-31735 and to support future population PK analysis. •The composite response endpoint of ALP and total bilirubin and normalization of ALP were added to analyze similar data collected in a Phase 3 study. •Secondary measures were added to include PBC clinical events to be collected to evaluate the long-term effect of seladelpar. •Patient-reported outcome (pruritus NRS) was added to evaluate the effect of seladelpar based on similar data collected in Phase 3 study. •PK of seladelpar and its metabolites and exposure-response relationship to seladelpar were added to expand seladelpar PK profile in PBC population. •Exclusion criteria was modified for consistency with study CB8025-31735 and with other clinical studies. •The 1 mg dose was removed based on the data collected in study CB8025-21629. •Clearer instructions were added on how to handle safety issues when dose down-titration occurred. •Study assessments were modified to align with updated study measures and with data collected in Phase 3 study. Month 1 visit was added to evaluate safety of the subjects after initiation of seladelpar (specifically, for placebo subjects from Phase 3 and for subjects from Study CB8025-21838). •A dose adjustment during the first year was added to protect the blinding of the Phase 3 study. Dose adjustment criteria were updated to match the Phase 3 study. •Clarification on the liver, muscle, and pancreatic safety monitoring, and serum creatinine monitoring were added.