IMPRESS I & II – demonstrating efficacy and safety1

The effectiveness of Xiapex in helping to straighten the curve of an erection has been demonstrated in 2 large clinical studies involving over 800 men. In 2 large clinical studies, men with Peyronie’s disease who received up to 4 treatment cycles of Xiapex saw a significant improvement in the curve of their erections, compared to men who were not treated with Xiapex.

In the first study, men who received Xiapex had an average reduction in their curve of 35%, compared to 18% in men who didn’t receive Xiapex.

In the second study, men who received Xiapex had an average reduction in their curve of 33%, compared to 22% for men who didn’t receive Xiapex.

These large, double-blind, placebo controlled studies support the efficacy and safety of Xiapex treatment for the physical and psychological aspects of PD. In IMPRESS I and II Xiapex treated men showed a significantly greater percent reduction in the penile curvature abnormality and significantly greater improvement in subject reported PD bother compared with placebo.


Xiapex was not associated with shortening of penile length in clinical trials in the treatment of Peyronie's disease.1


Study design

IMPRESS Study design summary2

  • Co-Primary Endpoints
    • Percent Improvement in Penile Curvature Deformity
    • Improvement in Peyronie’s Disease Questionnaire (PDQ)
  • Bother domain
  • Evaluated 832 men with Peyronie’s disease over the course of 52 weeks
  • Eligble subjects were randomized (in a 2:1 ratio) into 2 treatments groups
    • 551 treated with Xiapex
    • 281 treated with placebo
  • Patients were given up to 4 treatment cycles of Xiapex or placebo at weeks 0, 6, 12 and 18 and were thereafter followed up to 52 weeks
  • Primary efficacy assessed at 6, 12, 18, 24, 42 and 52 weeks


Baseline Demographics

IMPRESS Subject Demographics Baseline1,2

Baseline Demographics


Improvement in curvature deformity

Xiapex – significant mean improvement in curvature deformity vs placebo1

significant mean improvement


average curvature improvement



Reduction in patient-reported bother

Xiapex – significant mean reduction in patient-reported bother versus placebo1

The first and only validated, disease-specific PRO tool for PD is the Peyronie’s Disease Questionnaire (PDQ), which was developed for the clinical development programme for the PD therapy Xiapex, and validated in the target population of PD patients in the Phase III Xiapex trials, IMPRESS I and II. The PDQ quantifies the symptoms and impacts of PD via 3 subscale domain scores, calculated as the sum of all responses within each subscale patient reported bother (0–16), Psychological and Physical Symptoms (score range 0–24), and Penile Pain (0–30).3

The PDQ was developed in close collaboration with patients, HCP´s and FDA guidance.

PDQ Bother domain questions

  • Intercourse performance
  • Intercourse frequency
  • Erection pain
  • Erection appearance
Reduction in patient-reported bother


Stepwise efficacy

Xiapex improving curvature over time - effect apparent after first treatment cycle4

Stepwise efficacy




  1. Xiapex Summary of Product Characteristics.
  2. Gelbard et al. J Urology 2013;190:199-207.
  3. Hellstrom WJG et al. J Urol. 2013;190(2):627-634.
  4. www.ema.europa.eu/docs/en_GB/document_library/EPAR_-_Assessment_Report_-_Variation/human/0