Frequently Asked Questions

In studies done in a scientific laboratory, ridinilazole killed C. difficile by stopping the bacteria from reproducing. Ridinilazole is highly specific for C. difficile.

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 trail 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 trail 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.

Ridinilazole is being tested in two global Phase 3 clinical trials.

Sites are currently active in North America, Australia, Asia, Europe and South America. Please see the maps above for further information.

While no personal benefit can ever be guaranteed by participation in a clinical trial, there are other potential benefits, including allowing you to play an active role in your healthcare and helping others by contributing to the better understanding of CDI.

You can contact one of the actively enrolling sites to inquire about participating in the trials. The trail doctors will review inclusion and exclusion criteria with you to help decide whether you would be eligible for the trials.

You can find more information at and, or by signing up for our email list below.

If the Phase 3 clinical trial results are positive, we expect to file for regulatory approval in the US in 2022. Timing to market would be dependent upon regulatory review. Ridinilazole does have the potential to receive priority review with the US Food and Drug Administration, which shortens the review time to six months. However, this is not guaranteed.

Running clinical trials that can support regulatory approvals is the best way to ultimately ensure wide access for patients to our drug candidates. All of our efforts are therefore focused on conducting rigorous clinical trials to establish the safety and potential clinical benefits ridinilazole may have. At this point in the development, we cannot support any use of ridinilazole, or any of our product candidates, outside of our clinical trials.