Ridinilazole Reduces C difficile Infection Recurrence More Effectively Than Vancomycin

Treatment with ridinilazone was found to significantly decrease the rate of recurrent Clostridioides difficile infection (CDI) compared with vancomycin, according to study results presented at IDWeek 2022, held from October 19 to 23, in Washington, DC.

Researchers conducted a randomized, double-blind, phase 3 trial to compare the efficacy and safety of ridinilazole with vancomycin among patients with CDI. Patients (N=759) were randomly assigned in a 1:1 fashion to receive a 10-day course of either ridinilazole (200 mg) twice daily or vancomycin (125 mg) 4 times daily. The primary endpoint was sustained clinical response, defined as the absence of recurrent CDI 30 days following treatment completion.

A total of 745 patients were included in the modified intention-to-treat analysis, of whom 370 received ridinilazone and 375 received vancomycin. Of the patients in the ridinilazone and vancomycin groups, 73.0% and 70.7% achieved a sustained clinical response (P =.4672). In addition, patients in the ridinilazole group demonstrated significantly reduced rates of recurrent CDI compared with those in the vancomycin group (8.1% vs 17.3%, respectively; P =.0002).

The association between ridinilazone and reduced CDI recurrence was more significant among patients who were not receiving additional antibiotics, with CDI recurrence rates of 6.7% and 16.5% observed among those in the ridinilazone and vancomycin groups, respectively (P =.0005).

Patients in the ridinilazole group presented with increased microbiome diversity compared with those in the vancomycin group at both 10 (P <.0001) and 30 (P ≤.0007) days following treatment completion.

Further comparisons between the groups showed that patients who received ridinilazole also demonstrated reduced abundance and concentrations of fecal secondary bile acids at treatment completion (P <.0001) and at 30 days following treatment completion (P =.0203).

Both increased microbiome diversity and decreased concentrations of secondary bile acids correlated with higher rates of sustained clinical response achievement and lower CDI recurrence rates.

Approximately 36.4% of patients who received ridinilazole and 35.5% of those who received vancomycin experienced at least 1 treatment-related adverse event. The rate of treatment discontinuation related to adverse events was decreased among patients in the ridinilazole vs vancomycin groups (0.8% vs 2.9%).

“RDZ [ridinilazole] was effective for sustained clinical response and safe for the treatment of patients with CDI,” the researchers concluded.