(Alliance News) - Summit Therapeutics PLC on Monday presented new data explaining the result of its phase 2 ridinilazole antibiotic trial in c difficile infection.
Shares in Summit were down 4.1% at 26.86 pence in London in early afternoon trading.
C diff bacteria infect the colon, causing toxins that result in inflammation, as well as severe diarrhoea and even death. Infection usually takes hold after the use of a broad-spectrum antibiotic, which kills the body's natural gut bacteria and allows c diff to take hold.
At present, the most common treatment for c diff is to administer another broad-spectrum antibiotic, which again kills natural gut bacteria. As such, c difficile often recurs after treatment. Ridinilazole, meanwhile, is designed to kill c diff without destroying the rest of the patient's microbiome as well.
The two key findings of the trial were that ridinilazole was superior in efficacy to the antibiotic vancomycin, with a 60% lower rate of disease recurrence, and that ridinilazole preserved gut microbiome diversity.
Tufts University collaborated with Summit to assess the trial results and found that the two facts, the superiority and the microbiome diversity, "are connected mechanistically by bile acids".
Bile acids come in various forms and can inhibit or promote c diff regrowth and it turns out that vancomycin kills the bacteria that turn pro-c diff bile acids into anti-c diff acids. By sparing these bacteria, ridinilazole, lets them continue to convert the more dangerous acids into safer ones.
David Roblin, president of Research & Development at Summit, said: "The damaging effect of broad-spectrum antibiotics in the treatment of [c difficile infection] is far-reaching from the make-up and function of the gut microbiome through the poor clinical outcomes seen in one third of patients, driven by a high rate of disease recurrence.
"Ridinilazole has the potential to be a targeted CDI treatment that could result in significantly better patient outcomes for the over half million US patients per year who have an episode of CDI. These latest data help to put the science behind the function of a healthy microbiome into context and highlight its importance in sustaining CDI cures."
By Anna Farley; annafarley@alliancenews.com
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