Experimental drug for IBS falls flat in dose-ranging trial

The novel α₂δ ligand PD-217,014 does not appear to show any benefit in the treatment of patients with irritable bowel syndrome (IBS) or bowel habit subtypes, irrespective of their pain and anxiety levels, according to a study.

A total of 330 adults with IBS, defined by the Rome II criteria, were randomly assigned to receive 150 mg or 300 mg of PD-217,014 or placebo, administered twice daily for 4 weeks. Of these participants, 322 (98 percent) were included in the intention-to-treat (ITT) population. Within this population, 271 participants (84 percent) completed the study and 51 (16 percent) discontinued from the study.

The primary efficacy endpoint was response, which was defined as achieving adequate relief of abdominal pain/discomfort for at least 50 percent of the active treatment period. Key secondary endpoints included changes in abdominal pain, bloating, stool frequency/consistency, and global assessment of IBS symptoms.

Results showed that the percentage of participants reporting adequate relief of abdominal pain/discomfort did not differ between the 150- and 300-mg dose groups and the placebo group. The results were consistent across the Rome II-defined total cohort or Rome II and IV IBS bowel habit subtypes.

Likewise, similar observations were obtained for the secondary endpoints, with PD-217,014 showing no significant efficacy vs placebo.

In terms of safety, PD-217,014 was generally well tolerated. Treatment-emergent adverse events (AEs) were documented in 70 percent of participants treated with PD-217,014 and 64 percent of those who received placebo. The most common AEs were headache, vertigo, dizziness, fatigue, abdominal pain, and nasopharyngitis. There was one case of malignancy reported. None of the patients died during the study.