Some positive results seen in early review of IBS therapy

Top-line results from a phase 2 study of Lexicon Pharmaceuticals LX1033 drug candidate for the treatment of diarrhea-predominant irritable bowel syndrome did not meet the primary endpoint, a company news release said.

The randomized analysis of 373 patients treated for 28 days with placebo or one of three doses of LX1033 —1,000 mg twice daily, 500 mg twice daily or 500 mg three times daily — was intended to determine changes in baseline stool consistency, but all treatment groups, including placebo, demonstrated significant improvements, the release said. The differences between placebo and LX1033 did not meet statistical significance.

Researchers then re-examined the data to adjust for early terminations that may have resulted in a heightened placebo response rate. The cohort assigned 500 mg LX1033 three times daily demonstrated favorable stool-consistency results vs. placebo (P<.05), the release said.

“While LX1033 showed similar improvements in stool consistency as compared to the placebo patients who completed the study, there were positive effects on abdominal pain in the treated group that warrant further study,” Pablo Lapuerta, MD, Lexicon’s chief medical officer, said in the release. “While this initial phase 2a study was under way, we completed long-term toxicology studies which would allow us to conduct a phase 2b study at doses informed by the current results and with a duration of 12 weeks, a treatment period that has historically been important to identify clinically meaningful changes as compared to placebo.”