In a study of intralesional collagenase clostridium histolyticum, mean curvature was reduced most dramatically after the first cycle, researchers reported.
Findings of a retrospective review of men receiving intralesional collagenase clostridium histolyticum (CCH; Xiaflex) for Peyronie’s disease may help inform therapeutic decisions on number of cycles.
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Conducted by researchers at Tulane University School of Medicine in New Orleans, the study analyzed serial and total changes in penile curvature in 77 men, of whom 41 (53%) completed four cycles of CCH treatment (eight total injections). The findings were presented at the AUA annual meeting in San Diego.
Overall, mean curvature decreased significantly from 58.2° at baseline to 41.0° after the last cycle of injections. Comparing men who achieved a ≥20° change from baseline to those with less curvature reduction based on a number of variables showed the two groups differed significantly only in the amount of curvature reduction achieved after the first treatment cycle (–16.2° vs. –5.9°, respectively; p<.001).
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Analysis of change in penile curvature after each injection cycle was done using a repeated measures model. It showed mean curvature was reduced most dramatically after the first cycle (–12.0°), and there was continued improvement between the second and third and third and fourth sets of injections (mean reduction of –4.6° and –4.8°, respectively). However, there was essentially no significant change in penile curvature as a result of the fourth cycle, said first author James Anaissie.
“CCH can be an effective treatment for Peyronie’s disease, but the response is variable, it is expensive, and the injections are painful,” he said.
“Our study indicates that urologists may counsel patients who have a strong response to the first cycle that they are likely to have a better final outcome, so they may feel more confident about continuing. On the other hand, men who had a more modest change in curvature could be told they may still achieve significant benefit with further cycles, but that they are less likely to have a bigger response at the end.”
Senior author Wayne JG Hellstrom, MD, noted that four CCH cycles has become standard of care for treating Peyronie’s disease because it was the regimen used in the large Investigation for Maximal Peyronie's Reduction Efficacy and Safety Studies (IMPRESS). The findings of this retrospective study, however, call the four-cycle protocol into question.
“What constitutes the optimal number of CCH cycles has not been systematically investigated. Our study does not provide conclusive data to state definitively that a fourth cycle is not effective,” Dr. Hellstrom said.
In addition to change in curvature after the first cycle, the variables analyzed as possible predictors of final curvature reduction ≥20° included patient age, duration of Peyronie’s disease, pretreatment curvature, curvature direction, degree of fibrosis, vascular findings from duplex Doppler examination, and number of treatment cycles. Aside from response to the first cycle, none of the factors was found to differ significantly comparing men with a final curvature reduction ≥20° with those having a lesser response.
Dr. Hellstrom was lead investigator for the IMPRESS trials and is a speaker for Endo Pharmaceuticals.
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