Effects of tadalafil treatment after bilateral nerve-sparing radical prostatectomy: quality of life, psychosocial outcomes, and treatment satisfaction results from a randomized, placebo-controlled phase IV study

BACKGROUND This multicenter, randomized, double-blind, double-dummy, placebo-controlled trial primarily evaluated the efficacy of tadalafil once-daily (OaD) or on-demand ("pro-re-nata"; PRN) treatment, started early post-nsRP. Secondary outcome-measures on quality-of-life (QoL) and treatment satisfaction are reported. METHODS Patients, aged <68 yrs, with adenocarcinoma of the prostate (Gleason ≤ 7, normal preoperative erectile function [EF]) were randomized post-nsRP 1:1:1 to 9-month treatment with tadalafil 5 mg OaD, tadalafil 20 mg PRN, or placebo, followed by 6-week drug-free washout and 3-month open-label tadalafil OaD treatment (OLT). The main outcome measures were Changes in Expanded Prostate Cancer Index Composite (EPIC-26), Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS), and Self-Esteem and Relationship (SEAR) questionnaires (mixed-model-for-repeated-measures, including terms for treatment, visit, treatment-by-visit interaction, age-group, country, baseline-score). LS means with 95% confidence interval (CI) are reported. RESULTS 423 patients were randomized to 3 treatment-groups: tadalafil OaD (N = 139), PRN (N = 143), or placebo (N = 141). In each group, 57 (41.0%), 58 (40.6%), and 50 (35.5%) patients were aged 61-68 yrs. At the end of double-blind treatment (DBT), patients' EPIC sexual domain-scores improved significantly with tadalafil OaD versus placebo (treatment effect [95% CI]: 9.6 [3.1,16.0]; p = 0.004); comparisons of PRN versus placebo at end of DBT, and comparisons of tadalafil OaD and PRN versus placebo after OLT were not significant. Only in older patients (61-68 yrs; age-by-treatment p ≤ 0.1), EPIC urinary incontinence domain-scores also improved significantly with tadalafil OaD versus placebo (overall treatment effect across all visits, 8.3 [0.4,16.1]; p = 0.040). Treatment satisfaction increased significantly in both tadalafil groups, EDITS total-scores increased significantly with OaD and PRN versus placebo during DBT (p = 0.005 and p = 0.041, respectively). At the end of OLT, improvement was significant for tadalafil OaD versus placebo only (p = 0.035). No significant differences were observed for SEAR. CONCLUSIONS These results suggest that chronic dosing of tadalafil improves QoL of patients post-nsRP. The improvement of urinary incontinence in elderly patients randomized to tadalafil OaD may contribute to this effect. TRIAL REGISTRATION www.clinicaltrials.gov , NCT01026818.