Conditions: Male Erectile Disorder Prostate Cancer Radiation Toxicity
Keywords: radiation toxicity male erectile disorder prostate cancer
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 140
Healthy volunteers: no

Brief summary:
RATIONALE: L-arginine supplements may improve the quality of life and erectile function in men who are prostate cancer survivors.

PURPOSE: This randomized phase II trial is studying how well L-arginine supplementation works with or without enzyme inhibitors in treating erectile function and quality of life of prostate cancer survivors previously treated with radiation therapy.

Detailed description:
OBJECTIVES:

Primary

* To determine the "best dose" (defined as the dose that shows the greatest improvement in the erectile function domain of the International Index of Erectile Function \[IIEF\] after 8 weeks of therapy) of an L-arginine/Korean ginseng/gingko biloba/damiana-based supplement (L-arginine) to be used in a subsequent phase III trial in prostate cancer survivors previously treated with radiotherapy.

Secondary

* Evaluate the toxicity of treatment with L-arginine with or without phosphodiesterase-5 inhibitors.
* Estimate trial accrual, retention, adherence, and variability.
* Assess changes in quality of life (QOL) and sexual function as defined by changes in the QOL of these patients using the Expanded Prostate Cancer Index Composite, changes in the other domains of the IIEF (i.e., orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction), changes in the Sexual Encounter Profile, and changes in the percentage of "yes" (positive) responses to either of the two global efficacy questions.

OUTLINE: Patients are stratified according to age (\< 65 years vs ≥ 65 years) and current use of phosphodiesterase-5 (PDE-5) inhibitors (yes vs no). Patients are randomized to 1 of 3 treatment arms.

* Arm I: Patients receive oral placebo twice daily (total of 6 capsules per day).
* Arm II: Patients receive oral L-arginine and oral placebo twice daily (total of 3 capsules of each per day).
* Arm III: Patients receive oral L-arginine twice daily (total of 6 capsules per day).

In all arms, treatment continues for 8 weeks in the absence of unacceptable toxicity.

Patients may also receive oral sildenafil, tadalafil, or vardenafil (PDE-5 inhibitors).

Patients complete the International Index of Erectile Function and the Expanded Prostate Cancer Index Composite-26 at baseline and at weeks 4 and 8. Patients also complete the Sexual Encounter Profile Questionnaire, FACT-P, and the Global Efficacy Questionnaire at weeks 4 and 8.

Arms:
arm 1: Patients receive oral placebo twice daily (total of 6 capsules per day). arm 2: Patients receive oral L-arginine and oral placebo twice daily (total of 3 capsules of each per day). arm 3: Oral L-arginine twice daily = 6 capsules per day.

Interventions: intervention 1: Placebo intervention 2: Oral L-Arginine intervention 3: Oral L-Arginine
Intervention descriptions: intervention 1: Given orally intervention 2: Given orally 3 capsules ArginMax and 3 Placebo capsules intervention 3: Patients will take 6 capsules of ArginMax twice daily

Protocol document: