FDA Grants Breakthrough Therapy Designation for Primary Biliary Cholangitis Therapy

Officials with the FDA granted Breakthrough Therapy Designation to seladelpar for the treatment of early stage primary biliary cholangitis (PBC), in combination with ursodeoxycholic acid (UDCA), according to a press release.

Seladelpar is an orally administered selective peroxisome proliferator-activated receptor delta being developed by CymaBay Therapeutics. The therapy has also received an orphan designation from the FDA. If approved, seladelpar will be indicated in combination with UDCA for adult patients with an inadequate response to UDCA or as monotherapy in adults unable to tolerate UDCA.

PBC is a serious, potentially life-threatening autoimmune disease of the liver characterized by impaired bile flow and accumulation of toxic bile acids, according to CymaBay. The disease can result in inflammation and destruction of the intrahepatic bile ducts, which can progress to fibrosis, cirrhosis, and liver failure.

The designation was granted based on preliminary data from the ongoing phase 2 clinical trial. According to the preliminary results, patients treated with seladelpar demonstrated substantial improvement compared with those treated with existing therapy based on a reduction in alkaline phosphatase. The study included data from patients with PBC randomized to seladelpar 10 mg/day, seladelpar 5/10 mg/day (starting treatment at 5 mg with the possibility to escalate dose to 10 mg after 6 months), or a placebo.

In the 26-week analysis from the phase 2 study, composite responder rates for the 5 mg/10 mg and 10 mg seladelpar groups were 59% and 71%, respectively. Median changes of pruritis for each of the groups as measured by the visual analog scale was -50% and -55%, respectively. These data indicate that seladelpar is not associated with drug-induced pruritis and that the drug may decrease pruritis in patients with PBC, according to CymaBay.

The therapy is currently being evaluated in the phase 3 ENHANCE clinical trial. To be eligible for the study, patients must experience an inadequate response to UDCA or an intolerance to UDCA. The primary outcome measure is the responder rate after 52 weeks. Other key outcomes of efficacy will compare the rate of normalization of AP and the level of pruritis at 6 months.

CymaBay is also conducting a phase 2b proof-of-concept study of seladelpar for patients with nonalcoholic steatohepatitis, according to the release.

References

CymaBay Therapeutics Announces Seladelpar Granted Breakthrough Therapy Designation by the FDA for the Treatment of Primary Biliary Cholangitis [news release]. CymaBay Therapeutics. https://ir.cymabay.com/press-releases/detail/446/cymabay-therapeutics-announces-seladelpar-granted-breakthrough-therapy-designation-by-the-fda-for-the-treatment-of-primary-biliary-cholangitis. Accessed February 18, 2019.

CymaBay Therapeutics Announces Additional Positive Results from its Ongoing Phase 2 Study of Seladelpar in Patiens with PBC will be Presented During the Late-Breaking Session at The Liver Meeting [news release]. CymaBay Therapeutics. https://ir.cymabay.com/press-releases/detail/439/cymabay-therapeutics-announces-additional-positive-results-from-its-ongoing-phase-2-study-of-seladelpar-in-patients-with-pbc-will-be-presented-during-the-late-breaking-session-at-the-liver-meeting. Accessed February 18, 2019.