Secondary Endpoint Results in IMPRESS I:
- Improvement from baseline in percentage of global responders and the percentage of composite responders (Intent to Treat analysis) showed statistical significance vs. placebo.
- Improvement from baseline in the PDQ psychological and physical symptoms and IIEF overall satisfaction, showed trends toward improvement vs. placebo.
Secondary Endpoint Results in IMPRESS II:
- Improvement from baseline in percentage of global responders showed statistical significance vs. placebo.
- Improvement from baseline in PDQ psychological and physical symptoms, IIEF overall satisfaction, percentage of composite responders (Intent to Treat analysis), plaque consistency, and penile length showed trends toward improvement vs. placebo.
A post-hoc meta-analysis of both identical IMPRESS studies' co-primary and secondary endpoints is also presented in the manuscript as each IMPRESS study was not individually powered to meet statistical significance for the secondary endpoints. The meta-analysis was performed to increase the statistical power for evaluation of those secondary endpoints. In the meta-analysis, the algorithm for calculating p-values for the co-primary and first family of secondary endpoints was essentially the same as that observed in the two individual studies.
Post-hoc Meta-Analysis – Combination of Identical IMPRESS I and II Studies:
- Co-primary endpoints maintain statistical significance.
- The following secondary endpoints met statistical significance, compared to placebo, based on the multiple comparison algorithm within the meta-analysis:
- Percentage of global responders
- Improvement in Peyronie's disease physical and psychological symptom domain
- Improvement in IIEF overall satisfaction domain
- Percentage of composite responders (ITT analysis)
- Improvement in penile plaque consistency
- Improvement in penile length and penile pain were not statistically different from placebo.
"The clinical outcomes demonstrated by XIAFLEX in the IMPRESS trials offer great hope and optimism for patients suffering from Peyronie's disease and suggest patients may be successfully treated non-surgically," said
Martin K. Gelbard
, MD, IMPRESS investigator and clinical faculty member of UCLA School of Medicine, Department of Urology. "Currently, urologists have no clinically proven treatment for Peyronie's disease other than surgical intervention, which often is performed as a last resort due to the potential for complications, including decreased penile length or erectile dysfunction. The potential ability, if FDA approved, to offer an effective in-office medical therapy in XIAFLEX would represent a significant evolution in the standard of care for physicians who treat Peyronie's disease."
The most common adverse events reported in the double-blind, placebo-controlled IMPRESS phase III trials were hematoma, pain and swelling at the treatment site. These adverse events were comparable to the previous trials: most AEs were mild or moderate in severity and resolved within 14 days.
There were three serious adverse events of corporal rupture (penile fracture) and three serious adverse events of hematomas related to XIAFLEX reported in IMPRESS I and II. All three corporal ruptures resolved following intervention and two of three hematomas resolved with intervention, with the third hematoma resolving without intervention.