Expanding the role of injectable collagenase clostridium histolyticum for the treatment of active phase Peyronie’s disease

Collagenase clostridium histolyticum (CCH) (Xiaflex TM) has recently become the mainstay and gold standard of minimally invasive management of Peyronie's disease. Approved by the FDA in 2013 after phase III studies demonstrated efficacy and safety, collagenase is a popular and promising, albeit expensive treatment option. With the exception of phase II and phase III study data, there is a dearth of published outcomes and safety data. At present, Yang and Bennett's single-provider, prospectively collected series of 49 patients undergoing Xiaflex injections, is only the second published series cataloging efficacy and safety (1). Yang and Bennett detail their experience with intralesional collagenase injections over a 17-month period. They demonstrate a mean curvature reduction of 15.4° or 32.4% after intralesional therapy. The authors performed a subset analysis on patients who received the full treatment course of four cycles of injection and found that these patients had a 17.7° or 45.7% improvement in curvature. These findings are in keeping with the IMPRESS I & II trials which reported a 34% improvement in penile curvature (2). They further note a 29.1% improvement in their patients' ability to engage in vaginal intercourse after treatment. This compares to Ziegelmann et al., who report that 52% of their patients were able to achieve intromission after therapy (3). The authors note a higher than expected rate of adverse events in 5 patients (10.2% of patients). They report four penile hematomas, all managed conservatively, and one corporal rupture, requiring operative intervention. The corporal rupture occurred 31 days after completion of the second injection cycle. Upon surgical exploration, the tunical defect was noted contralateral to injection location. This rate of adverse events is similar to that reported by Ziegelmann et al., where 7/69 (10%) of patients experienced penile hematomas, and no patients experienced corporal ruptures (3). Phase III studies reported an incidence of corporal rupture of 0.3%, with only one patient reported to have suffered corporal rupture. In this cohort, two patients had penile hematomas requiring treatment, and 80% of patients reported penile ecchymosis (2). The ideal time to initiating intralesional therapy is unknown. Based on the IMPRESS phase II and III clinical trial data, required 1 year of stable disease prior to initiation of intralesional collagenase injections, the AUA Guidelines for Peyronie's disease recommend that the clinician start therapy during the stable phase of disease, after pain has subsided, and when there is " non-progression of curvature " (4). …