Maralixibat response in PFIC may be dependent on subtype

Depending on progressive familial intrahepatic cholestasis subtype (PFIC), treatment with maralixibat may produce rapid and sustained reductions in serum bile acid (sBA)levels, according to a study.

In this open-label, Phase 2 long-term study, 33 patients with either FIC1 deficiency (n = 8) or BSEP deficiency (n = 25) received oral once daily maralixibat 266 μg/kg from baseline to Week 72; after Week 72, twice-daily dosing was permitted. Of those with BSEP, 6 had biallelic, protein truncating mutations (t)-BSEP, and 19 had ≥1 nontruncating mutation (nt)-BSEP.

A sBA response, defined as a reduction in sBAs of >75% from baseline or concentrations <102.0 μmol/L, was achieved in 6 patients with nt-BSEP while receiving once-daily dosing and 1 patient while receiving twice-daily dosing. Overall, sBA responders had marked reductions in sBAs and pruritus and increases in height, weight, and Quality of life; all were liver transplant-free after >5 years.

Patients with FIC1 deficiency or t-BSEP deficiency did not have an sBA response.

Overall, treatment was considered well-tolerated.

Reference
Loomes KM, Squires RH, Kelly D, et al. Maralixibat for the treatment of PFIC: Long-term, IBAT inhibition in an open-label, Phase 2 study. Hepatol Commun. 2022;doi: 10.1002/hep4.1980. Epub ahead of print. PMID: 35507739.