Continuing Collagenase Clostridium Histolyticum Injections Among Initial Nonresponders Results in Significant Curvature Improvements in the Majority of Peyronie's Disease Men

Abstract

It is currently unclear if men with Peyronie's Disease (PD) who achieve minimal benefits with the first 2 series of Collagenase Clostridium Histolyticum (CCH) injections should continue with additional injections. To analyze curvature improvements from the final two series of CCH injections based on amount of improvement during the first 2 series. A prospective registry was analyzed of all men undergoing CCH injections for PD at a single institution. Men were included if they had completed a full 4 series (8 injections) of CCH and had baseline, interval (after 2 series), and/or final (after 4 series) curvature assessments available. Men were stratified into cohorts using baseline-to-interval assessments of ≤10° (or ≤20%) and >10° (or >20%), and improvements were compared using interval-to-final assessments. The primary outcome was interval-to-final curvature improvements stratified by ≤10°/>10° or ≤20%/>20% improvements achieved during the baseline-to-interval period. Secondary outcomes included analyses of demographic and pathophysiologic variables to determine associations with significant improvements during the final 2 CCH series. A total of 296 PD men were identified as receiving at least one CCH injection, of whom 175 had baseline-to-interval, 84 interval-to-final, and 115 with baseline-to-final measurements. Mean age was 56.6, PD duration 28.6 months, baseline curvature 63.4°, hourglass deformity 36.2%, and calcification 20%. Mean overall curve improvement was -21.5° (33.1%). Among men who experienced ≤20% improvements after 2 series, the mean subsequent curvature change was -24.6% during the final two series (vs +4.3% of those with >20% initial improvement, P< .001), and they were 2.7x more likely to experience >20% subsequent curve improvements. Thirty-one percent of those who achieved >10° during the first 2 series experienced benefits during the final 2 series compared to 70% of men who had ≤10° improvement initially. No demographic or pathophysiological variables predicted likelihood for improvements during the final 2 series of injections. Men who fail to achieve significant benefits with 2 series of CCH injections may benefit from completing the final 2 series. Strengths including a relatively large, prospective series. Limitations include a single center, nonrandomization, nonblinded assessments, and restriction to men who completed eight injections. In the current series, approximately 2/3 of men who fail to achieve >10° or 20% curve improvements with an initial 2 series of CCH injections achieved >10° or 20% improvements with the subsequent 2 series.