Peyronie’s disease (PD) is a sexual health condition that affects up to 13% of the adult men in the United States. In men with PD, plaques of scar tissue form under the skin of the penis, causing it to curve or take on a deformity when it is erect. This can lead to painful erections, erectile dysfunction (ED), low self-esteem, mental health issues, and relationship difficulties.
Intralesional collagenase clostridium histolyticum injection therapy (Xiaflex) is an FDA-approved treatment for PD. The medication, which is injected into the penis by a trained health care professional, works by breaking down some of the components of the plaques that are causing the penis to bend.
Previous clinical trials for Xiaflex have outlined the protocol as follows: 8 injections divided into 4 treatment cycles of 2 injections separated by a few days. Results from one such study showed an average improvement in curve deformity of 34% after the patients received all 8 injections.
According to the experts, clinical improvement is defined as a 20% decrease in penile curvature after treatment. However, patients who don’t reach clinical improvement after 1 round of Xiaflex may question whether additional rounds of treatment would be beneficial.
A recent study sought to answer this question by analyzing the results of all patients receiving Xiaflex injections at a single institution between October 2015 and December 2020. Some of the patients who completed 1 round of treatment opted to complete additional rounds of treatment, receiving either 16 or 24 injections overall.
For this study, the authors had access to the pre- and posttreatment erect penile curvature measurements of 229 patients who completed 1 round of treatment, 80 who completed 2 rounds of treatment, and 18 who completed 3 rounds of treatment.
In total, 57 of the 80 patients who had a second round of treatment and 8 of the 18 who had a third did not achieve clinical improvement after their previous round. Ultimately, 42.8% (98/229), 38.6% (22/57), and 12.5% (1/8) of patients achieved clinical improvement after 1, 2, and 3 rounds of therapy, respectively.
Furthermore, the average percentage of penile curvature improvement was 16.4% after 1 round, 16.8% after 2 rounds, and 8.1% after three rounds. The most frequent side effect was bruising, but swelling and penile blood blisters were also common.
Given these results, the researchers concluded that for patients who do not reach clinical improvement after 1 round of treatment, an additional round may be beneficial. On the other hand, a third round showed no significant improvements.