Gilead Highlights Phase III Results for Liver Drug Before PDUFA Date

Gilead Sciences announced that Seladelpar, a key asset from its $4.3 billion acquisition of CymaBay in February 2024, demonstrated positive interim results in a late-stage trial for treating primary biliary cholangitis (PBC). The Phase III ASSURE study evaluated this once-daily selective peroxisome proliferator-activated receptor (PPAR) delta agonist and found it effective in reducing pruritus, a common symptom of PBC.

Participants in the trial were adults with PBC who had previously taken part in a seladelpar study and either did not respond adequately or could not tolerate ursodeoxycholic acid (UDCA), the currently FDA-approved first-line treatment for PBC. The interim results showed that 70% of the 148 patients who completed 12 months of treatment achieved a clinically significant composite response endpoint. Additionally, 37% of the patients experienced normalization of alkaline phosphatase (ALP) levels, with an average ALP reduction of 44% from the baseline.

For the subset of 20 patients who finished 24 months of treatment, 70% reached the composite response endpoint, and 25% saw their ALP levels return to normal. Furthermore, the treatment reduced other liver injury biomarkers, including total bilirubin by 9%, alanine aminotransferase by 25%, and gamma-glutamyl transferase by 36%.

Merdad Parsey, Gilead's Chief Medical Officer, emphasized that these initial findings reinforce the efficacy and safety profile of seladelpar observed throughout its development. He noted that the drug has the potential to become a best-in-class therapy, significantly impacting the lives of those with PBC by addressing both disease progression and challenging symptoms like pruritus.

The study reported no serious adverse events, and the drug was generally well tolerated, with only 4.6% of patients discontinuing treatment due to adverse effects. These results did not include patients from the separate Phase III Response study, which will have its findings reported independently.

The Bank of Montreal's investor note highlighted that seladelpar represents a promising opportunity for Gilead to expand and diversify its liver disease treatment portfolio. The drug has an upcoming PDUFA date set for August 14, 2024, and is also under review by the European Medicines Agency (EMA) and the U.K.’s Medicines and Healthcare Products Regulatory Agency.