BERKELEY, CA (UroToday.com) - Since the FDA approval of XIAFLEX® for the treatment of Peyronie's disease (PD) in 2013, collagenase has represented a promising treatment option. The first study to describe the use of collagenase clostridium histolyticum (CCh) in the treatment of PD was conducted by Gelbard in 1985. This study concluded that CCh appeared to be an effective treatment for PD. However, it was not until 2012 that Gelbard published results of pivotal studies of the drug, defining key issues such as recommended dose, dosage (number of cycles and interval between cycles), and the immune response of patients after injection.
Regarding analysis of the methodology, the pivotal studies of the drug presented a suitable design. The 2b study was a randomized, double-blind, placebo-controlled trial which included a reasonable number of patients. Derived from the results of 2b study, it was demonstrated that penile modeling after CCh injection statistically and significantly improved the results in terms of curvature reduction, so in phase 3 studies (Impress I and II), all patients were treated with modeling. With respect to the phase 3 studies, we found 2 identical, prospective, randomized, multicenter, double-blind, placebo-controlled studies, conducted in 64 cities in the United States and Australia during a one-year period, and they included 417 and 415 patients, respectively. The results, as in the previous study, showed a statistically significant decrease in penile curvature compared to placebo (34º vs.18º p < 0.0001) and an increased percentage of composite responders (patients with improvement of curvature > 20° and decreased PDQ bother score of more than 1 point) of 46%.
The main limitation of these studies was the short follow-up period, which in no case exceeded one year, and the lack of documentation of possible late adverse effects after drug administration (such as the formation of new plaques in those patients who had had ecchymosis or bruising at the injection site). Currently it is not possible to ascertain if changes in penile curvature, evidenced at 52 weeks, were maintained or whether they declined over time. More studies will be needed with larger follow-up periods in order to clarify these issues.
María Alejandra Egui Rojo, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Urology Department, Hospital Universitario de Fuenlabrada. Madrid, Spain