PURPOSE: In this randomized, double-blind, placebo controlled phase 2 study we 
investigated tanezumab, a humanized monoclonal antibody that specifically 
inhibits nerve growth factor as a treatment for interstitial cystitis pain.
MATERIALS AND METHODS: Patients with interstitial cystitis received a single 
intravenous dose of 200 μg/kg tanezumab or placebo. Patients recorded daily pain 
scores (on an 11-point numerical rating scale) 7 days before attending study 
visits and completed a urinary symptom diary for 3 of those days. Patients also 
completed the Interstitial Cystitis Symptom Index questionnaire and a global 
response assessment. The primary end point was change in average daily numerical 
rating scale pain score from baseline to week 6. Secondary end points included 
global response assessment, Interstitial Cystitis Symptom Index score, 
micturition and urgency episode frequency per 24 hours, and mean voided volume 
per micturition. The incidence of adverse events was also assessed.
RESULTS: A total of 34 patients received tanezumab and 30 received placebo. At 
week 6 tanezumab produced a significant reduction from baseline in average daily 
pain score vs placebo (treatment difference [LS mean, 90% CI] was -1.4 [-2.2, 
-0.5]). A significantly higher proportion of patients on tanezumab responded as 
improved in the global response assessment and tanezumab also significantly 
reduced urgency episode frequency vs placebo. Tanezumab had no significant 
effect on Interstitial Cystitis Symptom Index score, micturition frequency or 
mean voided volume per micturition. The most common adverse events were headache 
(tanezumab 20.6%, placebo 16.7%) and paresthesia (tanezumab 17.6%, placebo 
3.3%).
CONCLUSIONS: Tanezumab has shown preliminary efficacy in the treatment of pain 
associated with interstitial cystitis.