Pam Harrison

November 08, 2016

For patients with Peyronie's disease, outcomes are not enhanced when a penis-extending device is added to treatment with the injectable collagenase clostridium histolyticum (Xiaflex, Endo Pharmaceuticals), new research indicates.

Currently, the only medical treatment approved by the US Food and Drug Administration (FDA) for the acquired scarring disorder of the penis is collagenase clostridium histolyticum.

The drug essentially dissolves the scar tissue that causes Peyronie's disease but, according to a phase 2b trial, "if you just injected the drug and didn't do anything else, the injection wouldn't offer any benefit," said Landon Trost, MD, head of andrology and male infertility at the Mayo Clinic in Rochester, Minnesota.

The injections free up that scar tissue, and then the patient "models the penis," which means he "bends the penis in the opposite direction to the curvature or bends it straight out," Dr Trost explained.

"A lot of us wondered if traction would have a bigger impact than manual modeling, because traction gives you continuous pressure on the penis," he told Medscape Medical News.

To answer that question, Dr Trost and his colleagues conducted a study of men treated for Peyronie's disease at the Mayo Clinic from March 2014 to May 2016. He presented the results at the Sexual Medicine Society of North America Fall 2016 Scientific Meeting in Scottsdale, Arizona.

All patients underwent objective curvature assessment prior to therapy, and it was recommended that all undergo final curvature assessment after the discontinuation of therapy or after the completion of four injection series, the researchers report. Final curve assessment was available for 50 patients.

Each of the four series consisted of two injections, given 1 to 3 days apart, followed by a 6-week hiatus, for a total of eight injections.

Dr Trost and his team conducted a retrospective chart review of all recipients of the drug to ascertain patient-reported use of penile traction therapy.

Because the Andropenis penis extender has the most evidence behind it, the researchers recommended this particular device for traction, even though it is not approved by the FDA for this indication.

All patients were instructed to perform manual modeling. In addition, 28 men reported using daily penile traction for a median of 2 hours a day.

At baseline, the median penile curvature was 64.9 degrees. After treatment, the median improvement in penile curvature was a significant 20.0 degrees (P < .0001).

However, there was no significant difference in the median absolute improvement in penile curvature between the men who used traction therapy in addition to manual modeling and the men who did not (22.5 vs 20.0 degrees)

"Additionally, there was no association between penile traction and functional outcomes, including restoration of penetrative intercourse and prevention of surgery after collagenase clostridium histolyticum therapy," Dr Trost reported.

"Based on our data, it doesn't appear that traction, at least with the Andropenis device, has a role to play in Peyronie's disease," he said. "As soon as we saw the data, we changed our practice completely and quit recommending traction to patients."

That said, Dr Trost said that he and his colleagues still recommend traction for restoration of penile length in men who are motivated and interested and in those who are in the acute phase of Peyronie's disease, because there are some data showing a benefit on curvature correction in that specific group.

Sexual Performance

"When we first started doing these injections, we asked our patients whether it was worth going through everything they had to go through, and whether or not treatment restored their ability to penetrate during sex," Dr Trost told Medscape Medical News.

"We found that over 50% of men who could not penetrate before treatment could penetrate after treatment, and were also able to avoid surgery," he said. "That was a pretty significant finding for us."

About the same proportion of men who had an improvement of 0% to 10% in penile curvature with collagenase clostridium histolyticum injections reported that treatment was meaningful, suggesting that there is likely a psychological aspect to treatment that cannot be explained by objective results, the researchers report.

"I was very critical of the drug at first because, when you look at the original trials, you are looking at about a 17 degree improvement in penile curvature with treatment, compared with a 9 degree improvement with placebo," said Dr Trost. "For $50,000 for a series of injections and potential complications, is it really worth it?"

"But we found, and have previously reported, that collagenase clostridium histolyticum reduces the need for surgery and restores penetration in the majority of patients completing four series of injections, and that the majority of patients considered the therapy worthwhile."

More Studies Needed

"Although this study suggests there may be no benefit to penile traction as an adjunct to collagenase clostridium histolyticum, additional multi-institutional studies are needed to settle this important clinical question," said Wayne Hellstrom, MD, chief of andrology at Tulane University in New Orleans.

"The data analysis by the Mayo group suggests that there may be no difference [with the Andropenis device], but modifications to their protocol, which might demonstrate a difference, include increasing the duration of traction therapy to more than 2 hours per day," he told Medscape Medical News.

Future studies involving more patients could reduce the chance of having an underpowered study, Dr Hellstrom noted, pointing out that only 28 patients in this study used traction therapy.

This research was not supported by industry. Dr Trost and Dr Hellstrom have disclosed no relevant financial relationships.

Sexual Medicine Society of North America (SMSNA) Fall 2016 Scientific Meeting: Abstract 002. Presented November 3, 2016.

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