RETRACTED: A double-blind placebo-controlled study of the efficacy and safety of pentoxifylline in early chronic Peyronie's disease (Retracted article. See vol. 115, pg. E10, 2015)

OBJECTIVE To analyse the safety and efficacy of pentoxifylline sustained-release (PTX-SR) treatment in patients with early chronic Peyronie's disease (PD). PATIENTS AND METHODS In all, 228 patients with a mean (sd) age of 51 (9) years who had early chronic PD were randomized to receive 400 mg PTX-SR (Apo-Pentoxifylline, Apotex Inc., Toronto, Canada) twice daily (group 1, 114) or similar regimen of placebo (group 2, 114) for 6 months. A medical history was taken and the men had a complete physical examination. The following variables were assessed before and after therapy: penile curvature and penile artery spectral traces (end-diastolic velocity, EDV, peak systolic velocity, PSV, and resistivity index, RI, of the right and left cavernous arteries assessed with dynamic penile duplex ultrasonography), plaque characteristics (assessed by penile X-ray and penile ultrasonography), pain (assessed by visual analogue scale), erectile function (assessed by the International Index of Erectile Function, IIEF questionnaire), treatment satisfaction (assessed by Erectile Dysfunction Inventory of Treatment Satisfaction questionnaire), and side-effects. Patient perception of penile curvature and plaque size, and mean weekly intercourse attempts were also assessed. RESULTS Overall, 36.9% of patients who received PTX-SR reported a positive response, vs only 4.5% in the placebo group. Of patients in PTX-SR group, 12 (11%) had disease progression, vs 46 (42%) in placebo group (P = 0.01). Improvement in penile curvature (P = 0.01), and plaque volume (P = 0.001) was significantly greater in patients treated with PTX-SR than placebo. The increase in IIEF total score was significantly higher in the PTX-SR group (P = 0.02). Mean PSV changes after therapy compared to baseline were statistically significant between PTX-SR (right, +11.4%, left, +11.7%) and placebo-treated (+0.2% and -4.2%, respectively) patients (both P = 0.04). CONCLUSIONS PTX-R was moderately effective in reducing penile curvature and plaque volume in patients with early chronic PD. Further studies with different treatment regimens are needed to better elucidate the beneficial effects of PTX-SR in PD.