Purpose: The aim of this study was to investigate the effect of potassium paraaminobenzoate (Potaba) in Peyronie's disease in a prospective, randomized, double-blind, placebo-controlled, multicentre study during a 12-months period of treatment.
Patients and methods: 103 patients with Peyronie's disease and a history <12 months, non-calcified plaques and without pre-treatment were included. 51 were randomized to potassium paraaminobenzoate, 52 to placebo receiving 4 x 3g/day for 12 months. Follow-up was performed during the treatment period. Response has been defined as regression in plaque-size and/or reduction in penile curvature of at least 30%. Data analysis was focussed on 75 patients who completed the study [valid-cases (VC)].
Results: No severe adverse events occurred. Response rates were 74.3% on potassium paraaminobenzoate and 50.0% on placebo (p=0.016). Mean plaque-size decreased from 259 mm(2) to 142 mm(2) in the treatment arm. In the placebo group, plaque-size aggravated from 259 mm(2) to 303 mm(2) after 6 months but improved slightly to 233 mm(2) after 12 months. Differences between the groups were significant (p=0.042). Pre-existing curvature did not improve under the drug (p=0.066) but comparing the development of new curvature or deterioration of pre-existing curvature under potassium paraaminobenzoate penile deviation remained stable. However, under placebo penile curvature deteriorated significantly in 32.5% of the cases (p<0.001). No significant differences concerning decrease of pain could be observed between the two groups (82.6% vs. 77.3%).
Conclusions: The results of this study indicate a significant plaque-related effect of potassium paraaminobenzoate. There was no relevant difference with regard to improvement of pre-existing penile deviation. However, under potassium paraaminobenzoate a significant protective effect on deterioration of penile curvature could be demonstrated. Potassium paraaminobenzoate appears to be useful to stabilize the disorder and prevent progression of penile curvature.