A randomized controlled trial of precision bezlotoxumab treatment for Clostridioides difficile infection.

Summary

The two-stage BEYOND program developed a multi-omic risk score and then ran a double-blind RCT in high-risk CDI. Adding bezlotoxumab to standard care reduced the composite of organ dysfunction, relapse, and/or death from 72.7% to 31.8% (p=0.015).

Key Findings

• The BEYOND score integrating hemoglobin, urea, IL-8, rs2091172 genotype, and specific stool taxa achieved 84.6% sensitivity and 95.8% specificity for unfavorable outcomes.
• In a double-blind RCT of 44 high-risk patients, standard care plus bezlotoxumab reduced the composite endpoint to 31.8% vs 72.7% with placebo (p=0.015).
• Predictive enrichment was feasible, suggesting precision allocation of bezlotoxumab may improve outcomes in CDI.

Clinical Implications

If externally validated, the BEYOND score could guide selective bezlotoxumab use to prevent organ dysfunction, relapse, and death in high-risk CDI. Implementation will require assay availability (IL-8, microbiome), workflow integration, and cost-effectiveness evaluation.

Limitations

• Small RCT sample size (n=44) limits generalizability and precision of effect estimates.
• External validation of the BEYOND score and feasibility of IL-8/microbiome assays in routine care are needed.

Future Directions

Conduct multicenter RCTs powered for hard clinical endpoints, externally validate BEYOND score across settings, and assess cost-effectiveness and implementation strategies.