Clinical Cases in Pharmacology Clinical Cases  ·  Urology Vol. II  ·  Andrology  ·  Peyronie's Disease and the Choice to Inject: Collagenase Against Watching and Waiting
Urology Vol. II, Case 9 — Andrology

Peyronie's Disease and the Choice to Inject: Collagenase Against Watching and Waiting

A single patient with stable-phase Peyronie's disease, intact erectile function, and no pain — the textbook candidate for collagenase by guideline criteria. The disagreement is whether “can still have intercourse” makes active treatment optional rather than indicated.

Abbreviations, terms, and other agents mentioned in this case CCH — collagenase clostridium histolyticum  ·  IMPRESS — Investigation for Maximal Peyronie's Reduction Efficacy and Safety Studies  ·  AUA — American Urological Association  ·  Tunica albuginea — the fibrous sheath surrounding the erectile tissue of the penis
Presentation

Nathaniel B., a 55-year-old bakery owner married for twenty-two years, noticed a curve developing in his penis about fourteen months ago — gradual enough that he assumed it would pass, then worried enough about it that he waited another several months before mentioning it to anyone. It has held steady at forty-five degrees, measured on two visits six weeks apart, with a single palpable dorsal plaque and no calcification. His erectile function is intact and there’s no pain; the actual complaint, which he describes more matter-of-factly than distressed, is that intercourse has become mechanically more difficult than it used to be.

That combination — stable disease, curvature between 30 and 90 degrees, intact erectile function — is precisely what the AUA guideline names as the profile for offering collagenase clostridium histolyticum, based on the IMPRESS I and II trials that support its approval. Across those two trials, men treated with collagenase saw their curvature improve by a mean of 34 percent, against an 18 percent improvement in men on placebo — a real, statistically significant difference, though a modest one in absolute terms given that even placebo-treated men saw meaningful change, likely reflecting natural variability in how curvature gets measured over time. Symptom-bother scores improved more clearly with treatment. The treatment isn’t free of risk: among the 551 men randomized to collagenase across the two trials, six had a serious treatment-related complication — three corporal ruptures, every one of them requiring surgical repair, and three penile hematomas, two of which needed intervention — a rare but real possibility the guideline doesn’t minimize even while endorsing the drug for exactly Nathaniel’s profile. A standard course runs up to four treatment cycles spaced six weeks apart — roughly six months end to end — each cycle pairing two injections with manual modeling of the plaque — a real time and cost commitment against a benefit whose average size, however statistically genuine, isn’t enormous.

Nathaniel B. · 55 Stable Phase, 4 Months
History
Runs a family bakery; married 22 years; noticed dorsal penile curvature developing over 14 months, stable for the last 4
Curvature
45 degrees dorsal, measured on two visits 6 weeks apart
Erectile function
Intact, no pain
Palpable plaque
Single dorsal plaque, no calcification on exam
Functional impact
Reports intercourse is mechanically more difficult, not painful
Prior treatment
None

In the andrology clinic, discussing options

Urologist/Andrologist Opening

Offer collagenase. He meets every criterion the AUA guideline names — stable disease, curvature in the 30 to 90 degree range, intact erectile function — and IMPRESS supports a real curvature reduction with symptom improvement. This is exactly the patient this drug was studied in and approved for.

Clinical Pharmacologist Response

I'd slow down before presenting it as the obvious next step. Thirty-four percent against eighteen percent is a real difference, but it's a sixteen-point absolute gap, not a transformation — and he can still have intercourse today, even if it's harder than it used to be. Weighing that modest average benefit against a rare but serious rupture risk, in a man who isn't in acute distress, is a genuinely close call, not a formality.

Framing this as 'the guideline-endorsed option' undersells how much of that endorsement rests on group averages that may not map cleanly onto how much this particular difficulty actually bothers him.

Reconstructive Urologist Final

There's a third path neither of you has named: surgical correction, plication or grafting depending on his anatomy, done once rather than across an eight-injection course spread over roughly six months. For a man whose complaint is purely mechanical and who values a definitive fix, a single procedure may suit him better than committing to collagenase's incremental, modest-average result.

I'm not arguing against collagenase — I'm arguing it shouldn't be presented as the only real option on the table. He deserves to hear both modalities described honestly before choosing.

Regimen selected
Collagenase Clostridium Histolyticum
Collagenase · Intralesional, per IMPRESS protocol
The only FDA-approved intralesional therapy for Peyronie's disease; IMPRESS I/II showed a mean 34% curvature improvement against 18% with placebo, with three corporal ruptures among 551 treated men — all surgically repaired — disclosed as part of informed consent.
Where this was left

Agreed: proceed with collagenase given Nathaniel meets the AUA guideline’s eligibility criteria and prefers a non-surgical option once all three paths were explained, with the corporal rupture risk named explicitly and in plain terms as part of consent.

Not agreed: whether surgical correction should have been presented with equal weight from the outset rather than raised as a counterpoint partway through the visit. The reconstructive urologist felt collagenase was framed as the default too quickly; the andrologist felt the guideline’s own specific endorsement for this profile justified leading with it.

Educational content only — a composite teaching case, not a real patient encounter or a substitute for clinical guidance. About These Cases →