(036) EFFICACY AND SAFETY OF COLLAGENASE <i>CLOSTRIDIUM HISTOLYTICUM</i> IN TREATING PRIMARY HOURGLASS DEFORMITIES IN ATYPICAL PEYRONIE’S DISEASE PATIENTS

Abstract Introduction Peyronie's disease (PD) typically presents with penile curvature due to a palpable penile plaque. Atypical presentations of PD - including hourglass deformity - are less common but more challenging to treat. Hourglass deformity is characterized by a circumferential indentation along the shaft of the penis, and can make sexual activity difficult and painful. Traditional noninvasive treatment approaches have shown limited efficacy in managing these complex cases. Collagenase clostridium histolyticum (CCH) is a well-studied intralesional treatment for PD, targeting collagen deposits within the penile plaque and reducing curvature/improving penile function. Despite its approval and growing use, the effectiveness of CCH specifically for atypical PD remains under-researched. Objective We aim to retrospectively evaluate the effectiveness/safety of CCH in patients with atypical PD characterized primarily by hourglass deformity at a single center. To our knowledge, there are no studies evaluating the effectiveness of CCH in patients with a primary concern of hourglass deformity. Methods We retrospectively reviewed patients with PD characterized by hourglass deformity as the primary/co-primary concern who had undergone/completed treatment with CCH with appropriate follow up. CCH was administered according to the FDA-approved regimen of up to four treatment cycles per round. Each treatment cycle consists of two injection procedures separated by 1-7 days, followed by penile modeling, with approximately six weeks between each cycle. The duration of PD prior to treatment was recorded. After completing their treatment course, patients were asked to subjectively rate their hourglass deformity on a scale of 1 to 5 (1 = complete resolution, 2 = minimal hourglass left, 3 = partial resolution, 4 = minimal improvement, 5 = no improvement). The primary outcome measure was the post-treatment rating of the hourglass deformity. Results Twenty-five hourglass deformity patients were identified, with eleven meeting inclusion criteria. The mean age was 60.7 years. Average duration of PD prior to treatment was 16.8 months. Patients underwent an average of 3.4 cycles of CCH treatment (SD = 1.0). The mean rating of the hourglass deformity after treatment was 2.0 (SD = 1.0), indicating significant reduction in deformity for most patients. Eight patients (73%) reported either complete resolution of the hourglass deformity or minimal persistent hourglass deformity (ratings of 1 or 2). Plaque location did not impact the effectiveness of CCH as measured by the rating of the hourglass deformity. Additionally, there was no statistically significant correlation between the number of CCH cycles or the duration of Peyronie’s disease and the post-treatment improvement in hourglass deformity rating. Other than expected bruising, no adverse events were reported. Conclusions Intralesional CCH for treatment of hourglass deformity in PD patients safely demonstrated a significant reduction in deformity for most patients. With a mean post-treatment rating of 2, 73% of patients reported either complete resolution or minimal persistent hourglass deformity. The effectiveness of CCH treatment for hourglass deformities was not influenced by plaque location, number of CCH cycles, or the duration of PD. Limitations include the small sample size and reliance on patient-reported outcomes - a prospective multicenter study and objective measurements can be considered in future research. Disclosure Yes, this is sponsored by industry/sponsor: Endo. Clarification: Industry funding only - investigator initiated and executed study.