Surotomycin versus vancomycin for Clostridium difficile infection: Phase 2, randomized, controlled, double-blind, non-inferiority, multicentre trial

Clostridium difficile infection (CDI) is a major public health concern. Treatment with commonly prescribed antibiotics is associated with high rates of recurrence after initial cure. Here, we present the efficacy and safety of surotomycin, an orally administered, minimally absorbed, selective bactericidal cyclic lipopeptide, compared with vancomycin, in patients with CDI. In this Phase 2, randomized, controlled, double-blind, non-inferiority, multicentre trial, participants received surotomycin 125 mg twice daily, surotomycin 250 mg twice daily or vancomycin 125 mg four times daily for 10 days. The primary efficacy outcome was clinical response at end of treatment. The registration number of the study on clinicaltrials.gov is NCT01085591. Clinical cure rates were similar among treatment groups (92.4% for surotomycin 125 mg twice daily, 86.6% for surotomycin 250 mg twice daily and 89.4% for vancomycin). Recurrence rates were 27.9% for surotomycin 125 mg twice daily, 17.2% for surotomycin 250 mg twice daily and 35.6% for vancomycin. The lower recurrence rate with surotomycin 250 mg twice daily versus vancomycin was statistically significant (P=0.035). Recurrence rates were statistically similar between the surotomycin dose groups (P=0.193). Rates of sustained clinical response at end of study were 66.7% for surotomycin 125 mg twice daily, 70.1% for surotomycin 250 mg twice daily and 56.1% for vancomycin. Incidence of adverse events was similar among treatment arms. Recurrence rates of CDI were lower with surotomycin with higher sustained clinical response rates compared with vancomycin, both of which may offer potential clinical benefits.