• Trials Aim to Show Superiority of Ridinilazole Over Standard of Care Treatment Vancomycin
  • Health Economic Outcomes Included to Support Commercialisation

OXFORD, UK, and CAMBRIDGE, MA, USA I February 13, 2019 I Summit Therapeutics plc (NASDAQ: SMMT, AIM: SUMM), a leader in new mechanism antibiotic innovation, today announces it has dosed the first patient in the global Phase 3 clinical trials of its precision oral antibiotic, ridinilazole, for C. difficile infection (‘CDI’). The trials aim to show superiority of ridinilazole over the standard of care, vancomycin, in a measure that combines CDI cure and recurrence called sustained clinical response (‘SCR’). Ridinilazole achieved statistical superiority over vancomycin in SCR in a Phase 2 clinical trial.

“Starting our Phase 3 programme is an important milestone for Summit,” commented Mr Glyn Edwards, Chief Executive Officer of Summit. With positive results, we believe ridinilazole could be positioned as the drug of choice in the front-line treatment of CDI, which potentially provides patients with sustained cures and hospitals with compelling cost savings.”

“Ridinilazole is the trail-blazer in our growing pipeline of innovative product candidates targeting serious infectious diseases,” added Dr David Roblin, President of R&D of Summit. “Our Phase 3 programme exemplifies our broader strategy of demonstrating significant advantages over current standards of care by gathering a carefully considered package of clinical and economic data to address the needs of physicians, regulators, healthcare providers, payors and, above all, patients.”

The Phase 3 clinical programme comprises two global, randomised, double-blind, active-controlled clinical trials called Ri-CoDIFy 1 and Ri-CoDIFy 2. The trials will be run concurrently with each expected to enrol approximately 680 patients at sites in North America, Latin America, Europe, Australia and Asia. Upon confirmation of a positive CDI toxin test, patients will be randomised to receive either ridinilazole (200mg twice a day) or vancomycin (125mg four times a day) for ten days. The primary endpoint of both clinical trials will test for superiority in SCR, defined as cure at the end of treatment and no recurrence of CDI within 30 days post-treatment. Secondary endpoints include cure at the end of treatment and SCR at 60 days and 90 days post-treatment. Additional endpoints will evaluate the impact of ridinilazole and vancomycin on the gut microbiome, which is known to protect against CDI. The Phase 3 clinical trials also include health economic outcome measures, such as readmission rates and length of hospital stay, to help support the commercialisation of ridinilazole, if approved.

Top-line data from the Phase 3 programme are expected to be reported in the second half of 2021.

The clinical and regulatory development of ridinilazole is being funded in part with Federal funds from the US Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority (‘BARDA’), under Contract No. HHS0100201700014C. Summit is eligible to receive up to $62 million in funding from BARDA to support the clinical and regulatory development of ridinilazole.

About C. difficile Infection
C. difficile infection is a serious healthcare threat in hospitals, long-term care homes and increasingly in the wider community with over one million estimated cases of CDI annually in the United States and Europe. CDI is caused by an infection of the colon by the bacterium C. difficile, which produces toxins that cause inflammation and severe diarrhoea, and in the most serious cases can be fatal. Patients typically develop CDI following the use of broad-spectrum antibiotics that can cause widespread damage to the natural gastrointestinal (gut) flora and allow overgrowth of C. difficile bacteria. The vast majority of patients are treated with broad-spectrum antibiotics, which cause further damage to the gut flora and are associated with high rates of recurrent disease. Reducing disease recurrence is the key clinical issue in CDI as repeat episodes are typically more severe and associated with an increase in mortality rates and healthcare costs. The economic impact of CDI is significant with one study estimating annual acute care costs at $4.8 billion in the US. 

About Ridinilazole
Ridinilazole is an oral small molecule new mechanism antibiotic that is designed to selectively kill C. difficile, thereby preserving patients’ protective gut microbiome and leading to sustained CDI cures. In a Phase 2 proof of concept trial in CDI patients, ridinilazole showed statistical superiority in sustained clinical response (‘SCR’) rates compared to the standard of care, vancomycin. In that trial, SCR was defined as clinical cure at end of treatment and no recurrence of CDI within 30 days of the end of therapy. Ridinilazole was also shown to be highly preserving of the gut microbiome in the Phase 2 proof of concept trial, which was believed to be the reason for the improved clinical outcome for the ridinilazole-treated patients. In addition, ridinilazole preserved the gut microbiome to a greater extent than the marketed narrow-spectrum antibiotic fidaxomicin in an exploratory Phase 2 clinical trial. Ridinilazole has received Qualified Infectious Disease Product (‘QIDP’) designation and has been granted Fast Track designation by the US Food and Drug Administration. The QIDP incentives are provided through the US GAIN Act and include a potential extension of marketing exclusivity for an additional five years upon FDA approval.

About Summit Therapeutics
Summit Therapeutics is a leader in antibiotic innovation. Our new mechanism antibiotics are designed to become the new standards of care for the benefit of patients and create value for payors and healthcare providers. We are currently developing new mechanism antibiotics for infections caused by C. difficile, N. gonorrhoeae and ESKAPE pathogens and are using our proprietary Discuva Platform to expand our pipeline. For more information, visit www.summitplc.com and follow us on Twitter @summitplc.

SOURCE: Summit Therapeutics