Early termination of a trial of mycophenolate mofetil for treatment of interstitial cystitis/painful bladder syndrome: lessons learned

Purpose: We evaluated the efficacy and tolerability of mycophenolate mofetil in patients with treatment refractory interstitial cystitis/painful bladder syndrome.

Materials and methods: A total of 210 patients with interstitial cystitis/painful bladder syndrome were to be randomized into a multicenter, placebo controlled trial using a 2:1 randomization. Participants in whom at least 3 interstitial cystitis/painful bladder syndrome specific treatments had failed and who had at least moderately severe symptoms were enrolled in a 12-week treatment study. The primary study end point was the global response assessment. Secondary end points were general and disease specific symptom questionnaires, and voiding diaries.

Results: Only 58 subjects were randomized before a black box warning regarding mycophenolate mofetil safety was issued by the manufacturer in October 2007. The trial was halted, and interim analysis was performed and presented to an independent data and safety monitoring board. Six of the 39 subjects (15%) randomized at study cessation were considered responders for mycophenolate mofetil compared to 3 of 19 controls (16%, p=0.67). Secondary outcome measures reflected more improvement in controls.

Conclusions: In a randomized, placebo controlled trial that was prematurely halted mycophenolate mofetil showed efficacy similar to that of placebo to treat symptoms of refractory interstitial cystitis/painful bladder syndrome. The results of this limited study cannot be used to confirm or refute the hypothesis that immunosuppressive therapy may be beneficial to at least a subgroup of patients with interstitial cystitis/painful bladder syndrome. Despite study termination lessons can be gleaned to inform future investigations.