Efficacy and safety of fixed-dose and dose-optimization regimens of sublingual apomorphine versus placebo in men with erectile dysfunction. The Apomorphine Study Group.

OBJECTIVE

A sublingual (SL) formulation of apomorphine has been developed and found effective in penile erectile dysfunction (ED). This study assessed the efficacy and safety of several doses of apomorphine SL in a dose-optimization schedule compared with placebo.

METHODS

In this 8-week, multicenter, double-blind clinical trial, 569 patients were randomized to four groups: a dose-optimization group in which patients began with 2 mg, increased or decreased the dosage as needed for 4 weeks, and thereafter maintained an optimal dose for 4 weeks; two fixed-dose groups of either 5 or 6 mg; and a placebo group. Efficacy was assessed by patient and partner responses to home-use questionnaires about sexual function and activity and by responses to the International Index of Erectile Function and the Brief Sexual Function Inventory.

RESULTS

In all apomorphine SL groups, a significantly higher percentage of patients compared with the placebo group achieved and maintained an erection firm enough for intercourse (48% to 53% versus 35% for placebo, P < or =0.001) and a significantly higher percentage of attempts resulted in intercourse (45% to 51% versus 33%, P < or =0.001). The responses to the questionnaires completed by the patients and partners were similar. Apomorphine SL was well tolerated; nausea, the most common side effect, was dose related and diminished substantially during the second 4-week period at all doses. The dose-optimization schedule resulted in fewer adverse events without impacting efficacy.

CONCLUSIONS

Apomorphine SL is an effective and safe treatment for ED, with 2 and 4 mg providing the most acceptable therapeutic index.