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Population dose-response model for tadalafil in the treatment of male erectile dysfunction

Staab A, Tillmann C, Forgue ST, Mackie A, Allerheiligen SR, Rapado J, Trocóniz IF

Pharmaceutical research, 2004

212 participants

Abstract

PURPOSE: To determine the population dose-response relationship for tadalafil during on-demand (as-needed) administration for treatment of erectile dysfunction (ED).

METHODS: A total of 212 male patients with mild, moderate, or severe ED participated in a multicenter, randomized, double-blind, placebo-controlled, parallel-group study. Patients were randomized to receive placebo or 2, 5, 10, or 25 mg tadalafil, taken on demand over an 8-week period. Efficacy was assessed on the basis of questions 2 and 3 of the Sexual Encounter Profile (SEP) and questions 3 and 4 of the International Index of Erectile Function (IIEF) questionaires. These scores were modeled using logistic regression. A fifth patient response, the IIEF EF (erectile function) domain score, was modeled as a continuous variable.

RESULTS: The dose-response relationship for each efficacy variable was best described with an Emax model, in which maximum effect increased with ED severity at baseline. Response scores increased substantially between 10 and 25 mg tadalafil doses, and the dose-response parameter estimates suggested possibly higher responses at even higher doses.

CONCLUSIONS: Population dose-response modeling of all five oucome measures indicated that efficacy in all ED severity groups in the studied population generally increased across the 2 to 25 mg tadalafil dose range. Estimates of maximal improvement (Emax) in the IIEF EF domain score were 7.5, 11.4, and 16.3 points for patients with mild, moderate,…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 212 participants or records.

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