Peyronie's disease: what the evidence says the treatments can and can't do

Peyronie's disease is a wound-healing disorder in which a plaque of scar tissue forms in the penis and pulls it into a curve, often with pain, and it affects a small but real share of adult men [s4]. The one drug the US Food and Drug Administration has approved for it, an injected enzyme called collagenase, straightens the average man's curvature only modestly more than a placebo does in randomised trials — genuinely better, but well short of a cure [s1][s3].

That gap between what the condition needs and what the treatments deliver is the honest headline, and it is worth stating before the specifics.

How common it is

Estimates depend heavily on how the disease is defined. A US population-based survey of 7,711 adult men found that 57 of them, or 0.7%, had a definitive diagnosis of Peyronie's disease, while a further 850, or 11.0%, met criteria for probable disease based on symptoms such as penile curvature or a palpable plaque [s4]. The authors note that the prevalence of diagnosed disease in the US had previously been put at about 0.5% of adult men [s4]. The spread between 0.5–0.7% diagnosed and roughly 11% with suggestive symptoms tells you the condition is substantially under-recognised, likely because men are reluctant to raise it [s4].

The one approved drug, and what it does

Collagenase clostridium histolyticum — marketed as Xiaflex — is an enzyme that breaks down the collagen the plaque is made of. The FDA first approved the product in February 2010 for Dupuytren's contracture, a hand condition, and cleared it for Peyronie's disease in a supplemental approval on 6 December 2013, making it the first and, still, the only drug the agency has approved for the condition [s3].

Approval rested on the two IMPRESS trials — Investigation for Maximal Peyronie's Reduction Efficacy and Safety Studies — identical phase 3, randomised, double-blind, placebo-controlled studies enrolling 417 and 415 men respectively [s1]. Men received up to eight injections of 0.58 mg collagenase over a maximum of four treatment cycles, each cycle pairing two injections with penile "modelling", and were randomised 2:1 in favour of the drug [s1]. The co-primary outcomes were the percentage change in penile curvature and the change in a symptom-bother score, measured from baseline to 52 weeks [s1].

The results were positive but measured. A pooled analysis of the two trials found men on collagenase had a mean 34% improvement in curvature — an average change of −17.0 degrees per man — compared with a mean 18.2% improvement, or −9.3 degrees, in the placebo group (p<0.0001) [s1]. The symptom-bother score improved more with the drug than with placebo as well (−2.8 versus −1.8, p=0.0037) [s1]. On safety, three men in the trials suffered a serious adverse event — corporeal rupture — that required surgical repair, a reminder that the injections are a clinical procedure with real risks, not a casual fix [s1].

The placebo response is the part most coverage omits. A curvature improving by roughly 18% on placebo means much of what a man notices after any treatment is not necessarily the treatment working — which is exactly why the randomised comparison, not the before-and-after, is what counts [s1].

Where surgery and the oral remedies sit

The American Urological Association's guideline, built on a systematic review of 303 peer-reviewed articles, frames Peyronie's treatment as a menu matched to the individual rather than a single answer, grading each option by the strength of its evidence from A down to C [s2]. Surgical correction — plication, plaque incision or grafting, or a penile prosthesis in men who also have erectile dysfunction — is the most reliable way to straighten a stable, well-established curve, at the cost of being irreversible and carrying its own risks [s2].

The guideline is most useful for what it discourages. Many widely sold oral treatments for Peyronie's — vitamin E and other supplements among them — are not supported by the evidence the panel reviewed, and the AUA advises against several of them [s2]. That places Peyronie's alongside a familiar pattern in men's health: a real condition surrounded by remedies that outrun their proof.

Because Peyronie's frequently coexists with erectile dysfunction, the two are often assessed together; our review of erectile dysfunction and heart risk covers that overlap. For a related male condition where the evidence and the marketing also diverge, see gynecomastia.

This article is informational and is not medical advice. Peyronie's disease should be assessed by a clinician, who can weigh curvature, stability and erectile function before any treatment.