Microbiome-preserving antibiotics for the treatment of Clostridioides difficile infection: a systematic review and meta-analysis

Newer antibiotics that specifically target Clostridioides difficile while preserving the host microbiome have emerged to treat C. difficile infection (CDI): cadazolid, fidaxomicin, ridinilazole, and surotomycin. The aim of the present study was to perform a systematic review and meta-analysis of efficacy for each antibiotic.

Only randomized clinical trials of patients being treated for Clostridioides disease infection were included. Studies were sought in MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, ClinicalTrials.gov, and the World Health Organization clinical trials register portal (up to December 9, 2022). Sustained clinical cure was the outcome of treatment comparison, defined as the resolution of diarrhea without recurrence. Vancomycin was the standard treatment comparator. Meta-analysis was performed for each antibiotic. The overall certainty of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE)-classified as either high, moderate, low, or very low.

Fourteen eligible studies were included in the meta-analysis with 4837 patients from 773 sites. Cadazolid did not increase sustained clinical cure relative to vancomycin (risk ratio (RR) 1.04, 95% confidence intervals (CI) 0.96-1.13; moderate-certainty evidence). Fidaxomicin demonstrated a significant increase (RR 1.14, 95% CI 1.07-1.21; low-certainty evidence). In one phase 2 study, ridinilazole demonstrated a significant increase in sustained clinical cure (RR 1.71, 95% CI 1.01-2.91; very low-quality evidence). Surotomycin did not show significant improvement (RR 1.05, 95% CI 0.96-1.14; moderate-certainty evidence).

Fidaxomicin (in seven studies) demonstrated significant improvement in achieving sustained clinical cure. A limitation of this study may that more studies are needed to compare fidaxomicin with other antibiotics.