Patients with chronic, non-cancer pain, excluding those taking methadone, received lubiprostone 24mcg capsule or placebo capsule twice daily for 12 weeks.
The overall spontaneous bowel movement (SBM) response rate was the primary endpoint of the study.
In the placebo-controlled double-blinded trial, the response rate for lubiprostone-treated patients was 26.9% (n=219) versus 18.6% (n=220) for placebo-treated patients (p=0.035).
SPI chairman and CEO Ryuji Ueno said they expect to submit the sNDA to the US Food and Drug Administration (FDA) in the first half of 2012.
"If approved, lubiprostone could be the first orally-administered medicine with the indication for OBD, providing another option for patients who need it and further differentiating lubiprostone from the competition," Ueno added.