Summit’s Ridinilazole Preserves Microbiome During Treatment of C. Diff


Sign up online today & collaborate

or click here to find out more

Summit’s Ridinilazole Preserves Microbiome During Treatment of C. Difficile Infection


Oxford, UK – Summit Therapeutics plc, the drug discovery and development company advancing therapies for Duchenne muscular dystrophy and Clostridium difficile infection (‘CDI’), announces the presentation of further clinical trial data showing ridinilazole outperformed the standard of care, vancomycin, in the preservation of the gut microbiome of patients during treatment for CDI. These data were derived from the Phase 2 CoDIFy trial and are being presented today during ASM Microbe 2016 in Boston, MA, US.

Ridinilazole is part of a novel structural class of antibiotics with potential for broad use in the treatment of CDI. As previously reported, in a Phase 2 clinical trial called CoDIFy, ridinilazole demonstrated substantial clinical benefit over vancomycin, including a large numerical reduction in recurrent disease. Recurrence of CDI, and consequent failure to achieve a sustained response after treatment, is a major issue in the management of the condition and is promoted by disruption of the gut microbiome, which occurs with current mainstay treatments such as vancomycin.

“Ridinilazole is a shining example of translational medicine, where its high selectivity in the lab has read through to a preserved microbiome in trial patients, ultimately resulting in significantly more sustained clinical responses in a Phase 2 trial compared to the standard of care,” said Dale Gerding, MD, Research Physician, Hines Veterans Affairs Hospital, Professor of Medicine, Loyola University Stritch School of Medicine. “These and additional supporting data presented at ASM Microbe show the broad potential of ridinilazole as a novel treatment for CDI, and I look forward to its continued clinical development.”

In the presentation entitled “Ridinilazole Preserves Major Components of the Intestinal Microbiota During Treatment of Clostridium difficile Infection,” stool samples were obtained from 82 patients enrolled in the CoDIFy Phase 2 trial evaluating the efficacy of ridinilazole compared to vancomycin. These samples were analysed on study entry, days five and ten of treatment, days 25 and 40 post-entry as well as at the time of any recurrence for five specific bacterial groups associated with a healthy gut microbiome (Bacteroides, Prevotella, EnterbactericeaeC. coccoides and C. leptum) and also for total bacteria present. Treatment with vancomycin resulted in a significant decrease (p<0.001) in four of the five bacterial groups (Bacteroides, PrevotellaC. coccoides and C. leptum) at days five and ten, and also resulted in a significant decrease in total bacteria. In contrast, treatment with ridinilazole did not significantly decrease these specific bacterial groups nor the total bacteria. These data suggest ridinilazole may have advantages compared to vancomycin in preserving a healthy gut microbiome during treatment for CDI.

A new analysis from the CoDIFy study evaluating rates of sustained clinical response in prospectively defined subgroups of patients at high risk for recurrence is also being presented at the meeting. Consistent with findings from the entire modified intent-to-treat patient population, where ridinilazole achieved statistical superiority over vancomycin in sustained clinical responses (66.7% vs 42.4%), there were trends favouring ridinilazole in most of these groups, including older patients, those with severe disease and those with previous CDI episodes. Notably, among patients aged 75 and over, 83% (5/6) of patients on ridinilazole had sustained clinical responses compared with 22% (2/9) on vancomycin.

Other posters on ridinilazole presented today report biomarker findings from CoDIFy, data on susceptibility of C. difficile isolates from the trial to antimicrobial agents, and in vitro studies of resistance development.

Copies of all the posters are available from Summit’s website, In addition, a video featuring leading CDI experts, Professor Mark Wilcox of the University of Leeds and Dr Dale Gerding of Hines Veterans Affairs Hospital and Loyola University Stritch School of Medicine, discussing the promise of ridinilazole in the treatment of CDI is available on Summit’s homepage

CompanySummit Therapeutics plc
Company Website

© Catalyst Innovation Portal 2019