How many clinical trials of ridinilazole have you completed and what have you found in these trials?
Ridinilazole has been tested in one Phase 1 clinical trial and two Phase 2 clinical trials.
Our Phase 1 clinical trial was conducted in 56 healthy male volunteers. In this study ridinilazole was well-tolerated, retained in the gastrointestinal tract (the site of CDI) and selective for Clostridia family bacteria with minimal impact on other gut bacteria.
Our Phase 2 clinical trial called CoDIFy enrolled 100 patients, half of which received vancomycin and the other half of which received ridinilazole. This study showed that 66.7% of patients treated with ridinilazole had a sustained clinical response compared to 42.4% of patients treated with vancomycin. A sustained clinical response means that patients were cured after the end of treatment (days 12-14), defined as ≤3 unformed bowel movements in 24 hours or <200ml of unformed stool in rectal collection devices, and did not have a recurrence in the 30 days following treatment. Sustained clinical response was the primary endpoint, or main measure of success. Ridinilazole was shown to be statistically superior to vancomycin in this measure. The difference between ridinilazole-treated patients and vancomycin-treated patients was driven by a reduction in recurrence rate – 14.3% of patients on ridinilazole had a recurrence, whereas 34.8% of patients on vancomycin had a recurrence. Ridinilazole was well tolerated, with an adverse event profile similar to that of vancomycin. Of all participants, 82% in the ridinilazole group and 80% in the vancomycin group reported treatment-emergent adverse events, the most common ((≥ 10% of patients) of which for ridinilazole were nausea, abdominal pain, abdominal distension, vomiting and decreased appetite and for vancomycin were abdominal pain, nausea, abdominal distension, vomiting, diarrhea, nasopharyngitis, headache and dizziness.
A second exploratory Phase 2 clinical trial was conducted in 27 patients, in that trial, ridinilazole was found to be well-tolerated.