Investigation of a Ca2+ Channel α2δ Ligand for the Treatment of Interstitial Cystitis: Results of a Randomized, Double-Blind, Placebo Controlled Phase II Trial

Purpose: We investigated PD-0299685, a Ca2+ channel alpha 2 delta ligand, for interstitial cystitis pain in a randomized, double-blind, placebo controlled phase IIa study. Materials and Methods: Patients with interstitial cystitis/bladder pain syndrome received 30 or 60 mg PD-0299685 daily or placebo for 12 weeks. Primary end points were change in average daily worst pain severity score (on an 11-point numerical rating scale) and change in Interstitial Cystitis Symptom Index score from baseline to week 12. Secondary end points included global response assessment, micturition and urgency episode frequency per 24 hours and mean voided volume per micturition. Incidence of adverse events was also assessed. Results: Of 161 patients 54 received 30 mg PD-0299685 daily, 55 received 60 mg PD-0299685 daily and 52 received placebo. At week 12 the 60 mg dose produced a clinically significant reduction in daily worst pain severity score from baseline compared to placebo (treatment difference [90% CI] -0.82 [-1.72, 0.08]). A greater proportion of patients taking 60 mg PD-0299685 daily demonstrated improvement in global response assessment. PD-0299685 had no clinically significant effect on the Interstitial Cystitis Symptom Index score or urinary end points. More patients discontinued due to treatment related adverse events with 30 or 60 mg PD-0299685 daily than with the placebo. Conclusions: PD-0299685 failed to demonstrate positive proof of concept for the treatment of pain and other urinary end points associated with interstitial cystitis/bladder pain syndrome.