Alternative C Difficile Treatment Non-Inferior to Vancomycin

Ridinilazole is a non-inferior alternative to vancomycin in treating patients with Clostridium difficile, according to a recent study.

Between June 26, 2014, and August 31, 2015, the phase 2 non-inferiority study recruited 100 participants in the United States and Canada with signs and symptoms of C difficile and a positive diagnostic test. Infection was confirmed by the presence of free toxin in stool.
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Over the course of 10 days, 50 participants received 200 mg oral ridinilazole every 12 hours, and the remaining 50 received 125 mg oral vancomycin every 6 hours.

The primary endpoint was achievement of a sustained clinical response, which the researchers had defined as clinical cure at the end of treatment and no recurrence of C difficile within 30 days. Primary efficacy analysis was conducted on all participants.

The primary efficacy analysis included 69 patients, with 36 receiving ridinilazole and 33 receiving vancomycin. A total of 24 (66.7%) patients receiving ridinilazole had a sustained clinical response, compared with 14 (42.4%) of those receiving vancomycin.

Not only was ridinilazole non-inferior to vancomycin, but ridinilazole demonstrated statistical superiority at the 10% level, according to the researchers

Ridinilazole was well tolerated by participants and had an adverse event profile similar to that of vancomycin. About 82% of patients receiving ridinilazone reported adverse events, compared with 80% of patients receiving vancomycin. Although some patients discontinued treatment, there were no adverse events related to ridinilazole that led to discontinuation.

“Ridinilazole is a targeted-spectrum antimicrobial that shows potential in treatment of initial C difficile infection and in providing sustained benefit through reduction in disease recurrence,” the researchers concluded. “Further clinical development is warranted.”

—Christina Vogt

Reference:

Vickers RJ, Tillotson GS, Nathan R, et al. Efficacy and safety of ridinilazole compared with vancomycin for the treatment of Clostridium difficile infection: a phase 2, randomised, double-blind, active-controlled, non-inferiority study. Lancet Infect Dis. 2017;17(7):735-744. doi:10.1016/S1473-3099(17)30235-9.