Beyond the Abstract - Efficacy and safety of tadalafil 20 mg on demand vs. tadalafil 5 mg once-a-day in the treatment of post-radiotherapy erectile dysfunction in prostate cancer men: A randomized phase II trial, by Patrizia Ciammella, MD, JD

BERKELEY, CA ( - Our primary study objective was to look at changes in erectile function while comparison of other sexual function aspects, treatment compliance, and safety were taken as secondary objectives.

Eligible patients were men with histological proven PC treated by three-dimensional conformal radiotherapy (3DCRT) at least 6 months before study entry. All patients claimed normal erectile functioning before radiotherapy, which was confirmed by an EF domain score of the IIEF questionnaire (retrospectively administered) ≥25, and all had experienced progressive ED after treatment at least 3 months before enrolling in the study (EF domain <25). To be enrolled, patients were required to have a stable sexual relationship and not be on any treatment for ED.

From September 2008 to June 2009, 86 patients reporting ED during a follow-up visit, showed interest in the study and entered the screening phase. Fifty-two out of 86 screened patients were randomized in a 1:1 ratio to receive 12 weeks of treatment of on-demand-20-mg tadalafil (Arm A; n=27)) or once-a-day 5-mg tadalafil (Arm B; n=25). Three patients were lost to follow-up, three discontinued treatment because of adverse events, and two patients because of personal choice. Then, forty-four patients were evaluable for efficacy. The overall dropout rate was 15.3% and equally distributed between two arms. No statistically significant differences in baseline characteristics were found between the two arms.

A significant improvement in all domains of the IIEF was observed in both arms (p=0.0001) with mean EF domain scores values of 25 and 27.1 for the 20 mg and 5 mg tadalafil, respectively (p=0.19). Then, mean value of the EF domain scores did not significantly differ between the two arms, but a greater variability between values was evident for Arm A. The end of treatment EF domain score was normalized in 63% and 87% of patients in Arm A and Arm B, respectively (p=0.07).

SEP 2 and 3 positive response rates increased from 0% in both arms at baseline to 81 and 70% in the 20 mg Arm and 90 and 73% in the 5 mg Arm respectively at the end of treatment (p=0.27). End of treatment GEQ positive answers were 86% in the 20 mg arm and 95% in the 5 mg arm (p=0.27). Twenty patients had been using some sort of temporary hormonal manipulation, with a mean duration of 14 months. For most of them, it consisted in an LH-RH analogue in association with radiation treatment. Any previous use of androgen deprivation therapy was not found related to post-treatment EF domain score (p>0.05). ED duration, but not age, testosterone level, and ED severity were found significantly related to an overall higher post-treatment EF domain score.

Higher treatment compliance was shown in Arm B (100%) as compared to Arm A (86%). Few severe adverse events, including headache and dyspepsia, were observed in the two arms, but did not result in drug discontinuation. There was a non-statistically significant trend towards fewer side effects in favor of the 5 mg daily dose arm.



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Patrizia Ciammella, MD, JD as part of Beyond the Abstract on This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Efficacy and safety of tadalafil 20 mg on demand vs. tadalafil 5 mg once-a-day in the treatment of post-radiotherapy erectile dysfunction in prostate cancer men: A randomized phase II trial - Abstract Prostate Cancer Section

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