Interim results from an ongoing, open-label, single-arm trial of odevixibat in progressive familial intrahepatic cholestasis

Abstract

Background & aims: PEDFIC 2, an ongoing, open-label, 72-week study, evaluates odevixibat, an ileal bile acid transporter inhibitor, in patients with progressive familial intrahepatic cholestasis.

Methods: PEDFIC 2 enrolled and dosed 69 patients across two cohorts; all received odevixibat 120 μg/kg per day. Cohort 1 comprised children from PEDFIC 1, and cohort 2 comprised new patients (any age). We report data through 15 July 2020, with Week 24 of PEDFIC 2 the main time point analysed. This represents up to 48 weeks of cumulative exposure for patients treated with odevixibat from the 24-week PEDFIC 1 study (cohort 1A) and up to 24 weeks of treatment for those who initiated odevixibat in PEDFIC 2 (patients who received placebo in PEDFIC 1 [cohort 1B] or cohort 2 patients). Primary endpoints for this prespecified interim analysis were change from baseline to Weeks 22-24 in serum bile acids (sBAs) and proportion of positive pruritus assessments (≥1-point drop from PEDFIC 2 baseline in pruritus on a 0-4 scale or score ≤1) over the 24-week period. Safety monitoring included evaluating treatment-emergent adverse events (TEAEs).

Results: In cohort 1A, mean change from PEDFIC 1 baseline to Weeks 22-24 of PEDFIC 2 in sBAs was -201 μmol/L (p <0.0001). For cohort 1B and cohort 2, mean changes from odevixibat initiation to weeks 22-24 in sBAs were -144 and -104 μmol/L, respectively. The proportion of positive pruritus assessments in the first 24-week period of PEDFIC 2 was 33%, 56%, and 62% in cohorts 1A, 1B, and 2, respectively. Most TEAEs were mild or moderate. No drug-related serious TEAEs occurred.

Conclusions: Odevixibat in patients with progressive familial intrahepatic cholestasis was generally well tolerated and associated with sustained reductions in sBAs and pruritus.

Clinical trials registration: This study is registered at ClinicalTrials.gov (NCT03659916).

Impact and implications: Disrupted bile flow is a hallmark feature of patients with progressive familial intrahepatic cholestasis and can result in build-up of bile constituents in the liver with spill over into the bloodstream; other effects that patients can experience include extremely itchy skin, and because not enough bile reaches the gut, patients can have problems digesting food, which may lead to poor growth. Odevixibat is an orally administered medication that shunts bile acids away from the liver. The current study, called PEDFIC 2, suggested that odevixibat can improve the problematic signs and symptoms of progressive familial intrahepatic cholestasis and was generally safe for patients.

Keywords: Bile acids and salts; Clinical trial; Enterohepatic circulation; Liver diseases.

Graphical abstract

Fig. 1

Patient disposition (A) and study design (B). (A) New patients in cohort 2 either did not meet PEDFIC 1 eligibility criteria or presented after closure of that study’s recruitment. ^†One patient withdrew from treatment owing to AEs, but this was not reflected in the termination record at the time of data cut-off. (B) Cohort 2 screening visits occurred during Days 56−35 and 28−7 before the first odevixibat dose. For patients in cohort 1, the first visit of the PEDFIC 2 treatment period coincided with the PEDFIC 1 end-of-treatment visit (there was no interruption of treatment). AE, adverse event.

Fig. 2

Change in serum bile acids during PEDFIC 1 and through PEDFIC 2 Week 24. PEDFIC 1 time points represent all PEDFIC 1 patients (odevixibat group, n = 42; placebo group, n = 20); values shown for PEDFIC 2 time points represent only the patients in PEDFIC 2 (cohort 1A, n = 34; cohort 1B, n = 19; cohort 2, n = 16). Dashed purple line indicates period of placebo administration. In cohort 1A, a significant change was observed in serum bile acids from PEDFIC 1 baseline to PEDFIC 2 weeks 22–24 (mean change: -201 μmol/L; 95% CI: -281 μmol/L, -121 μmol/L; p <0.0001 [one-sample t test]).

Fig. 3

Change in pruritus scores during PEDFIC 1 and through PEDFIC 2 Week 24. PEDFIC 1 time points represent all PEDFIC 1 patients (odevixibat group, n = 42; placebo group, n = 20); values shown for PEDFIC 2 time points represent only the patients in PEDFIC 2 (cohort 1A, n = 34; cohort 1B, n = 19; cohort 2, n = 16). Dashed purple line indicates period of placebo administration. In cohort 1A, a significant change was observed in pruritus score from PEDFIC 1 baseline to PEDFIC 2 weeks 21–24 (mean change: -1.6; 95% CI: -2.0, -1.1; p <0.0001 [one-sample t test]).

Fig. 4

Effects of odevixibat on height (A) and weight (B) from PEDFIC 1 baseline through PEDFIC 2 Week 24. PEDFIC 1 values represent all patients in PEDFIC 1 (odevixibat group, n = 42; placebo group, n = 20); PEDFIC 2 time points represent only patients in PEDFIC 2 (cohort 1A, n = 34; cohort 1B, n = 19; cohort 2, n = 16). Dashed purple lines indicate placebo period. In cohort 1A, significant changes were observed in height and weight Z scores from PEDFIC 1 baseline to PEDFIC 2 Week 24 (mean changes: 0.4 [95% CI: 0.1, 0.7; p = 0.02] and 0.4 [95% CI: 0.0, 0.7; p = 0.03], respectively [one-sample t tests]).