CDCA’s safety and efficacy in CTX highlighted in Phase 3 study
Chenodeoxycholic acid (CDCA) plays a critical role in managing cerebrotendinous xanthomatosis (CTX) by controlling aberrant bile acid synthesis and preventing the toxic buildup of metabolites, according to results from the RESTORE Phase 3 study presented at 2024 National Lipid Association Conference that confirmed CDCA’s safety and efficacy.
Cataracts play a significant role in the clinical presentation of CTX, often appearing early in the disease, contributing to visual impairment and reducing the quality of life for affected individuals. The presence of cataracts, alongside other manifestations such as chronic diarrhea, tendon xanthomas, and progressive neurological deterioration, underscores the systemic nature of CTX.
The RESTORE study is the first randomized, double-blind, placebo-controlled trial to evaluate the effects of CDCA withdrawal in patients with CTX. CDCA has been the standard treatment for CTX since 1984, although it has yet to receive FDA approval in the United States.
The study enrolled adult patients with a confirmed CTX diagnosis. Participants underwent 2 open-label periods and 2 double-blind periods, during which they received either CDCA or a placebo. Rescue medication was available for those exhibiting significant symptoms or biomarker increases. The primary objective was to assess the efficacy, safety, and tolerability of CDCA in controlling CTX biomarkers.
The study found a 20-fold increase in urine 23S-pentol levels upon CDCA withdrawal in the placebo group, which normalized upon resumption of CDCA treatment. Plasma cholestanol and 7αC4 levels also saw significant increases upon withdrawal, indicating heightened bile acid synthesis. A significant portion of participants on placebo required rescue CDCA during the study, underscoring the necessity of continuous treatment.
CDCA was well tolerated, with most adverse events being mild or moderate. Common side effects included diarrhea and headache, with no severe liver function abnormalities reported.
The study’s results support the need for continuous CDCA treatment and pave the way for potential FDA approval in the United States.
Reference
Duell PB, et al. Evaluation of Chenodeoxycholic Acid Treatment in Adult Patients with Cerebrotendinous Xanthomatosis: A Phase 3 Study. Poster session presented at: 2024 National Lipid Association Conference; June 2, 2024; Las Vegas, Nevada.
