InDex Pharmaceuticals has enrolled the first participant in the Phase III CONCLUDE clinical trial of cobitolimod to treat ulcerative colitis patients.

Cobitolimod is a Toll-like receptor 9 (TLR9) agonist that can induce the anti-inflammatory effect in the large intestine.

The double-blind, randomised, placebo-controlled trial will assess the safety and efficacy of the therapy in patients with moderate to severe left-sided ulcerative colitis.

Designed in consultation with the US Food and Drug Administration and the European Medicines Agency, the induction study will recruit nearly 440 patients at several clinics in more than 30 countries.

InDex Pharmaceuticals CEO Peter Zerhouni said: “The Phase III programme will form the basis for marketing approval of cobitolimod in moderate to severe ulcerative colitis, where great importance is put on patient safety, as current treatment options are associated with serious side effects.

“Given cobitolimod’s outstanding combination of efficacy and safety, the annual global peak sales at a successful commercialisation are estimated to have the potential to reach more than $1bn.”

The Phase III CONCLUDE clinical trial will investigate dose strengths of 250mg and 500mg given at baseline and at week three.

Clinical remission at week six will be the trial’s primary endpoint. It is the same endpoint as used in the Phase IIb CONDUCT study, which was successful.

The company stated that patients who respond to cobitolimod will continue in a one-year maintenance trial.

In this study, subjects will be given either cobitolimod or placebo once every three weeks.

In August 2019, InDex reported positive results from the Phase IIb CONDUCT trial of cobitolimod. The dose optimisation study enrolled 213 patients with left-sided moderate to severe active ulcerative colitis.