Oral Impotence Therapy Effective In Phase III Trial

Texas, USA-based Zonagen has cleared a major hurdle on its way togetting an oral treatment for male impotence on the market. Positive data has now been reported from the company's first Phase III trial of Vasomax, an orally-active formulation of phentolamine mesylate.

Phentolamine is approved by the US Food and Drug Administration for the treatment of hypertension and as a diagnostic for certain tumors of the adrenal gland, and has been widely used by urologists, both in combination with other drugs (eg papaverine and alprostadil) and alone, as a penile injection therapy for the treatment of erectile dysfunction. An oral form has obvious advantages, and there does not seen to be any trade-off in efficacy; Vasomax can restore normal penile function within 15 to 30 minutes of each administration. In addition, the drug appears to result in an erectile response only in the presence of appropriate stimuli.

The Phase III study was conducted at 20 centers across the USA and involved 435 men with erectile dysfunction caused by a range of factors, although those with a history of radical prostatectomy or spinal cord injury were excluded. All had been impotent for at least six months, and the average age was 59.