Summary of “Predictors of Curvature Improvement in Men With Peyronie’s Disease Treated With Intralesional Collagenase Clostridium Histolyticum”

The following is a summary of an article recently published in the Journal of Sexual Medicine.  We provide these summaries in the hopes that they will help patients keep up to date on the latest research published on the topics of PD and male infertility.  This particular study’s goal was to define the factors that could predict penile curvature improvement in men with PD treated with CCH therapy.


The American Urological Association and the European Association of Urology PD guidelines recommend Collagenase Clostridium Histolyticum (CCH) injections to treat Peyronie’s disease (PD) in men that have lateral or dorsal curvatures between 30 and 90 degrees. Typical CCH therapy recommends 4 cycles of 2 injections each cycle (0.58 mg) 3 days apart, although, this varies between studies.

Study Methods

The data collected for this study was taken between January 2014 and December 2020 (114 patients). The following information was collected on men who had been treated with CCH therapy: PD duration, patient age, smoking status, ability to penetrate during sexual relations, comorbidities, partnered status, presence of subjective penile length loss, number of CCH cycles completed, and penile curvature assessment data (baseline and post-treatment). This information was taken at baseline and after the second and fourth CCH cycles. Treatment success was considered curvature improvement of ≥10 degrees and/or ≥20% (whichever was larger). For this study, the patients had up to 8 injections (4 cycles). Each cycle had 2 injections separated by 1 week. After a cycle was completed, there was a 6-week break before the next cycle. If after cycle 2 (4 injections) there was no curvature improvement, it was recommended the patient stop CCH therapy. If there were significant improvements and the patient was happy with the improvements, no further treatment was recommended to the patient. If there were significant improvements and the patient was still not happy with the improvements, they recommended the treatments continue. In addition to the CCH injections, it was recommended that the patients use penile traction at home 7 days after the last injection in each cycle for at least 2 hours (no more than 6 hours) a day.

Study Results

Of the 114 patients, the median age was 57 years old with a median PD duration of 11 months. 33% had dyslipidemia, 5% diabetes, 22% hypertension, 71% were former smokers, and 8% were current smokers. 26% of the patients at baseline had the inability to penetrate during sexual relations and 54% had loss of length. Baseline mean curvature was 47 ± 19 degrees. 19% had indentation, 65% had dorsal curvature with 53% having it at the mid-shaft location, and 15% had calcification. 57% had some instability during curve assessment. Only 44% of the patients underwent all 4 CCH cycles. The mean post-CCH curve results were 40 ± 20 degrees. In 39% of the patients, there was no change in curvature; however, in 44% of the patients, improvements were measured while 17% had worsening of the curvature. Of those men with penile curvature improvement after CCH injections, the mean curvature decreased by 22 ± 13 degrees/41 ± 15%. Interestingly, men with higher baseline curvatures noticed the greatest improvements post therapy. Men with baseline curvature of ≤30 degrees saw a successful CCH response of 29%. Men with baseline curvature of 31-59 degrees, saw a successful response of 43%. Finally, men with curvature ≥60 degrees, saw a successful response of 60%. Overall, 29% of patients who started with a curvature of ≤30 degrees showed improvement. 40% with 31-50 degrees of baseline curvature improved, 50% improved with baseline curvatures of 51-60 degrees, and 60% of patients improved with baseline curvatures of ≥60 degrees.

Summary and Conclusions

All in all, this study found that the only predictor of penile curvature improvement after CCH therapy was the baseline curvature. The greater the starting curvature, the greater the improvements under CCH therapy. Furthermore, rates of improvement after CCH therapy were seen as high as 60% in men with a baseline curvature of ≥60 degrees. Therefore, men with PD are more likely to see a higher rate of improvement when they start with a greater degree of curvature.

Comment from Dr. Landon Trost

This is an excellent study which was performed by a well-recognized and well-respected team in the field of PD.  The authors found that baseline curve was the only finding which predicted outcomes: men who had larger curvatures more likely to experience greater improvements (makes sense).  We also have looked at our data and will be presenting findings on potential predictors at the upcoming SMSNA meeting in a few weeks.  Our study reviewed a total of 476 men who had undergone CCH injections and found that baseline curve, direction of curve, calcification, and indentation/hourglass deformity were all predictors of long-term outcomes.  Our team proposed a new scoring system to consider each of these variables, and the final model ended up doubling the predictiveness of baseline curve alone.  These types of studies are helpful because it provides more information for patients and allows providers the ability to better predict potential outcomes. 


Flores, J.M., Nascimento, B., Punjani, N., Salter, C.A., Bernie, H.L., Taniguchi, H., Miranda, E., Terrier, J.-E., Schofield, E., Jenkins, L., and Mulhall, J.P. (2022). Predictors of Curvature Improvement in Men With Peyronie’s Disease Treated With Intralesional Collagenase Clostridium Histolyticum. J Sex Med, S1743-6095(22)01573-9. DOI: 10.1016/j.jsxm.2022.08.001

Scroll to Top