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C. difficile (CDI) Treatment Summit Therapeutics Has Reported Outstanding Results In the Phase II Trial of Ridinilazole

Summit Therapeutics  has reported ‘outstanding’ results in the phase II trial of ridinilazole, its new C.difficile (CDI) treatment.

During the trial, the new oral antibiotic significantly outperformed vancomycin, the current standard prescription, which was the primary objective said Summit.

Over two-thirds (66.7%) of those treated showed a sustained clinical response (SCR) against 42.4% for vancomycin.

The statistical superiority was driven by a large numerical reduction in recurrent disease compared with vancomycin, which Summit said was key as recurrence is one of the hardest things to stop.

C.difficile or CDI is a growing danger for patients in hospital, care homes and the wider community.

Annually, there are between 450,000 and 700,000 cases in the US alone, with the elderly and sick especially vulnerable.

One study has suggested it costs US$4.8bn to treat these people.

“The healthcare community is acutely aware of the major threat CDI poses, particularly given widespread antibiotic use and our aging population,” said Glyn Edwards, Summit’s chief executive.

The biggest unmet need in CDI treatment is reduce recurring cases, he added and the results from the latest trial had exceeded its ‘wildest expectations’.

“These outstanding clinical data from CoDIFy strongly support the profile of ridinilazole as a narrow spectrum antibiotic.

“There is a vital need for potent new antibiotics, and the potential of ridinilazole has attracted great interest.

Edwards added that the results from the CoDIFy trial were exceptionally encouraging and the aim no is to advance ridinilazole into Phase 3 clinical trials.

Here, the company would evaluate partnership opportunities against the benefit of it forward itself, he added.

Professor Mark Wilcox, at Leeds University and Public Health England’s lead consultant on C.difficile added that the latest data indicated ridinilazole could become an important new treatment option for CDI with the potential to reduce the high rates of recurrent disease that remain a key clinical challenge.

CoDIFy was a double blind, randomised, active controlled, multicentre, Phase II clinical trial that evaluated the efficacy of ridinilazole against vancomycin in 100 patients in the US and Canada.

Results from a second CoFIFy trail are due next year, though Edwards said the results announced today would provide the bulk of the quantitative data.

Ridinilazole has already received Qualified Infectious Disease Product, or QIDP, designation and has been granted Fast Track status from the US Food and Drug Administration


*Please note – The C Diff Foundation does not endorse this product or any product and this posting is strictly for informational purposes only.

C. diff. Research and Development Community; November/December 2014

Here’s the latest from the

C. diff. Research Community:


Animal models of Clostridium difficile infection (CDI) are essential for the better understanding of this disease. The historical animal model for studying CDI was the Golden Syrian hamster, and the murine model for CDI has been described by Dr. Ciaran Kelly’s group in 2008. In this current study, Koenigsknecht et al. have used the antibiotic-treated murine model to describe in great detail the early dynamics of CDI in mice from ingestion and colonization, germination and colitis.


The role of host microbiota in the development of C. diff. infection (CDI) has been studied in great detail. In the current issue of Cell Host Microbe, two studies have looked at two different pathogens and their interactions with host microbiota.

In the first study, by Ferreyra et al, the authors show that following antibiotic treatment                 C. difficile uses host microbiota produced succinate to colonize the gut and cause diarrhea.

In the second study, Curtis et al. show that Bacteroides thetaiotaomicron enhances the expression of virulence genes of enterohemorrhagic Escherichia coli (EHEC) leading to EHEC colonization. B.thetaiotaomicron leads to increased levels of succinate which in turn is sensed by transcription factor Cra, which then leads to the enhanced expression of virulence genes in EHEC.

Although commensal microbiota often prevents pathogens from gaining a foothold in the gut by providing colonization resistance, gut pathogen have evolved in ways so that they can exploit metabolites produced by commnesals to use for their own advantage.



Several journal articles in December have been published looking at the efficacy of LFF571 in treateing CDI. LFF571 is a novel semi-synthetic thiopeptide antibacterial that inhibits bacterial protein synthesis.

The first article includes results from a Phase 2 exploratory study where the authors compared the safety and efficacy (based on a non-inferiority analysis) of LFF571 to vancomycin in adults with primary episodes or first recurrences of moderate C. difficile. Results show that based on protocol-specified definition, rates of clinical cure for LFF571 were non-inferior to those of vancomycin, recurrences were lower for LFF571 and LFF571 was generally safe and well-tolerated.
The second article compares the pharmacokinetics (PK) of LFF571 and vancomycin in patients with  a C. difficile infection (CDI) as part of an early efficacy study. Patients were randomized to receive 200 mg of LFF571 or 125 mg of vancomycin four times daily for 10 days. The highest LFF571 serum concentration was 41.7 ng/mL. This is in comparison to peak vancomycin serum level at 2.73 μg/mL. CDI patients had high fecal concentrations and low serum levels of LFF571 which is similar to healthy volunteers.



Chandrabali Ghose-Paul,MS,PhD, Chairperson of C. diff. Research and Development