The study has demonstrated a statistically significant increase in mean change in spontaneous bowel movements (SBM) from baseline after one week on treatment (p<0.0001), the study's primary endpoint, for patients taking Amitiza 24 micrograms twice daily versus placebo. Amitiza 24mcg has also demonstrated statistically significant improvement versus placebo for several secondary endpoints, including change in SBM after week two, mean weekly SBM, percentage of patients having first SBM within 24 and 48 hours, degree of straining and stool consistency, abdominal bloating, abdominal discomfort, global assessment of severity of constipation, global assessment of treatment efficacy as well as a quality of life evaluation of treatment satisfaction. A lower dose level of Amitiza, 16mcg twice daily, also demonstrated statistically significant improvements over placebo in the primary endpoint and some of the secondary endpoints. The randomized, parallel group, double-blind, placebo-controlled, multi-center Phase IIb dose-ranging study compared the dose response of oral Amitiza with that of placebo in Japanese patients diagnosed with chronic idiopathic constipation. The study evaluated 170 patients who were randomized to one of three twice-daily doses of Amitiza (8, 16 or 24mcg) or placebo. In general, Amitiza was well-tolerated. Gayle Dolecek, senior vice president of R&D at Sucampo, said: "Based on these results, we plan to commence Phase III clinical trials in Japan by mid-2009, moving Sucampo closer to our milestone of filing for marketing authorization for Amitiza in Japan for chronic idiopathic constipation."