Sucampo Pharmaceuticals and Abbott have said that lubiprostone capsules have been proven effective in Japanese chronic idiopathic constipation patients during a Phase III clinical study.

Lubiprostone is an activator of chronic idiopathic constipation-2 chloride channels in cells lining the small intestine, increasing fluid secretion into the intestinal tract. This softens the stool, facilitating intestinal motility and bowel movements. It is marketed under the brand name Amitiza.

The study enrolled 124 patients for a clinical efficiency trial and 209 patients for a safety trial with fewer than three spontaneous bowel movements per week.

Patients taking lubiprostone met the primary endpoint, a change from baseline in the number of spontaneous bowel movements, as well as secondary endpoints.

Patient “global assessment of treatment effectiveness” was also improved for lubiprostone-treated patients compared to placebo-treated patients.

Abbott Japan vice-president Gary Winer said the combined results of the Phase III efficacy trial and the long-term safety study highlight an important new treatment for people in Japan suffering from chronic idiopathic constipation.

Common adverse reactions seen with the use of the drug include nausea, diarrhoea, headache, abdominal pain, abdominal distention and flatulence.