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BackgroundPrimary sclerosing cholangitis (PSC) is frequently associated with pruritus, which significantly impairs quality of life. Maralixibat is a selective ileal bile acid transporter (IBAT) inhibitor that lowers circulating bile acid (BA) levels and reduces pruritus in cholestatic liver diseases. This is the first proof-of-concept study of IBAT inhibition in PSC.MethodsThis open-label study evaluated the safety and tolerability of maralixibat ≤10mg/d for 14 weeks in adults with PSC. Measures of pruritus, biomarkers of BA synthesis, cholestasis, and liver function were also assessed.ResultsOf 27 enrolled participants, 85.2% completed treatment. Gastrointestinal treatment-emergent adverse events (TEAEs) occurred in 81.5%, with diarrhea in 51.9%. TEAEs were mostly mild or moderate (63.0%); 1 serious TEAE (cholangitis) was considered treatment related. Mean serum BA (sBA) levels decreased by 16.7% (-14.84µmol/L; 95% CI, -27.25 to -2.43; p = 0.0043) by week 14/early termination (ET). In participants with baseline sBA levels above normal (n = 18), mean sBA decreased by 40.0% (-22.3µmol/L, 95% CI, -40.38 to -4.3; p = 0.004) by week 14/ET. Liver enzyme elevations were not significant; however, increases of unknown clinical significance in conjugated bilirubin levels were observed. ItchRO weekly sum scores decreased from baseline to week 14/ET by 8.4% (p = 0.0495), by 12.6% (p = 0.0275) in 18 participants with pruritus at baseline, and by 70% (p = 0.0078) in 8 participants with ItchRO daily average score ≥3 at baseline.ConclusionsMaralixibat was associated with reduced sBA levels in adults with PSC. In participants with more severe baseline pruritus, pruritus improved significantly from baseline. TEAEs were mostly gastrointestinal related. These results support further investigation of IBAT inhibitors for adults with PSC-associated pruritus. ClinicalTrials.gov: NCT02061540.

Background Pruritus, a common symptom of psoriasis, negatively affects quality of life; however, treatment of lesional skin does not consistently alleviate psoriatic itch. Objective To examine the effects of serlopitant, an oral, once-daily neurokinin 1 receptor antagonist, for treatment of psoriatic pruritus in a phase 2, randomized clinical trial (NCT03343639). Methods Patients (n = 204) were randomized to receive serlopitant, 5 mg, or placebo daily for 8 weeks. Eligible adult patients had plaque psoriasis for ≥6 months, plaques covering ≤10% of body surface area, pruritus for ≥4 weeks, and Worst Itch Numeric Rating Scale (WI-NRS) score ≥7 at the initial screening. Results Participants (54.2% women) had a mean age of 47.5 years and 85.2% were white. Mean baseline WI-NRS scores were 8.3 for serlopitant and 8.1 for placebo. The WI-NRS 4-point response rate at 8 weeks (primary end point) was 33.3% for serlopitant vs 21.1% for placebo (P = .028); at 4 weeks the rates were 20.8% for serlopitant vs 11.5% for placebo (P = .039). Treatment-related adverse events were reported for 4.9% of serlopitant-treated and 4.0% of placebo-treated patients. Limitations This was a phase 2 study with a small study population. Patients with severe psoriasis were excluded. Conclusion Serlopitant significantly reduced pruritus associated with mild to moderate psoriasis, supporting continued development of serlopitant for this patient population.