Randomised clinical trial: vancomycin or metronidazole in patients with primary sclerosing cholangitis - a pilot study

Summary Background Emerging data suggest that oral antibiotics may have therapeutic effects in primary sclerosing cholangitis ( PSC ), but published studies are limited. Aims To investigate the safety and efficacy of oral vancomycin and metronidazole in patients with PSC . Methods Thirty‐five patients with PSC were randomised in a double‐blind manner into four groups: vancomycin 125 mg or 250 mg four times/day, or metronidazole 250 mg or 500 mg three times/day for 12 weeks. The primary endpoint was decrease in alkaline phosphatase ( ALK ) at 12 weeks. Secondary end points included serum bilirubin and Mayo PSC risk score; pruritus; and adverse effects ( AE s). Nonparametric tests were used for analysis. Results The primary endpoint was reached in the low‐dose (−43% change in ALK , P = 0.03) and high‐dose (−40%, P = 0.02) vancomycin groups, with two patients in the former experiencing ALK normalisation. Bilirubin decreased significantly in the low‐dose metronidazole group (−20%, P = 0.03) and trended towards significance in the low‐dose vancomycin group (−33%, P = 0.06). Mayo PSC risk score decreased significantly in the low‐dose vancomycin (−0.55, P = 0.02) and low‐dose metronidazole group (−0.16, P = 0.03). Pruritus decreased significantly in the high‐dose metronidazole group (−3.4, P = 0.03). AE s led to medication discontinuation in six patients, four of whom were receiving metronidazole. Conclusions Both vancomycin and metronidazole demonstrated efficacy; however, only patients in the vancomycin groups reached the primary endpoint, and with less adverse effects. Larger, longer‐term studies are needed to further examine the safety and efficacy of antibiotics as a potential treatment for patients with primary sclerosing cholangitis ( clinicaltrials.gov NCT01085760 ).