Sucampo Pharmaceuticals and Abbott reported positive data from a two-year Phase III safety and efficacy trial evaluating Amitiza® (lubiprostone) in Japanese patients with chronic idiopathic constipation (CIC). Sucampo said it will submit the new data to the Japanese regulatory authorities as an update to its existing marketing authorization application for the drug, which was filed in September. Amitiza was approved by FDA in 2006 for the treatment of CIC in adults. The U.S. regulatory subsequently cleared the drug in 2008 for the treatment of irritable bowel syndrome with constipation (IBS-C) in women aged 18 and over.
The reported trial involved 209 patients,173 of whom completed year-long treatment, and 163 of whom completed the whole 48 weeks of therapy with lubiprostone. The resulting data showed that 66.4% of lubiprostone-treated patients achieved a spontaneous bowel movement (SBM) within 24 hours of their first dose, and 81.3% achieved an SBM within two days. There was also a statistically significant increase from baseline in the number of SBMs at the end of the first week of treatment, with this beneficial effect being maintained throughout the treatment period, Sucampo notes. Additional benefits of lubiprostone therapy included a reduction in the use of rescue medications, and improvements in all parameters of the IBS-QOL-J patient self-assessment questionnaire.
Abbott negotiated Japanese commercialization rights to lubiprostone in February 2009 for the treatment of CIC. The firm also has the right of first refusal to any additional indications for which lubiprostone is developed in Japan. Under terms of the deal Sucampo received an up-front payment of $10 million, and was eligible to receive additional milestone payments based on specified development and commercialization goals.
Sucampo is responsible for the development and regulatory filing of lubiprostone in Japan. Following marketing authorization and pricing approval Abbott will purchase the finished product from Sucampo for distribution in Japan. Sucampo also retains the right to co-promote lubiprostone in Japan.
It claims Amitiza has a novel mechanism of action that works by activating ClC-2 chloride channels to increase fluid secretion in the small intestine, Additional development of the drug is ongoing for a range of gastrointestinal disorders, including a Phase IV study for CIC in pediatric patients, a safety study in patients with hepatic impairment, and Phase III pivotal trials for opioid-induced bowel dysfunction.