Oral vancomycin is not associated with meaningful changes in liver-related endpoints among adults with primary sclerosing cholangitis: A randomized, placebo-controlled trial

INTRODUCTION: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease without approved medical therapies. We examined the efficacy and safety of oral vancomycin (OV) in those with PSC. METHODS: In this phase 3, 18-month, double-blind, placebo-controlled trial, we randomly assigned adults with PSC and a serum alkaline phosphatase (SAP) greater than 1.5 times the upper limit of normal to placebo or oral vancomycin (OV) with dosages ranging from 125-375 mg four times daily pending biochemical response. The primary endpoint was normalization of SAP. RESULTS: Of the 82 patients who underwent randomization, 73 individuals had at least one outcome assessment. Individuals who withdrew early were less likely to rate their baseline health as excellent or very good (23.4% vs 54.5%, p<0.01) despite having similar PSC prognostic features to those who completed the study. SAP normalization rates were similar (5% placebo, 6.7% OV, p=1.00) after 18 months. Those who received OV had greater reduction in SAP (+1.2% placebo, -21.9% OV, p=0.03). There were no differences in the changes in either the Mayo PSC risk score (-0.1 placebo, -0.1 OV, p=0.88) or liver stiffness values (+0.1 kPa placebo, -4.0 kPa OV, p=0.15). Discoloration of the teeth and tongue was the most common side effect of OV (17.5%). CONCLUSIONS: OV was not associated with clinically significant reductions in markers of PSC disease severity. Impairments in quality of life may influence patient retention in clinical trials.