L-Arginine Supplementation With or Without Enzyme Inhibitors Treating Erectile Function of Prostate Cancer Survivors

Phase 2

Completed

Conditions: Male Erectile Disorder
Prostate Cancer
Radiation Toxicity

Interventions: Drug: Oral L-Arginine
Other: Placebo

Registration Number: NCT01105130

Lead Sponsor: Wake Forest University Health Sciences

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.

Recruitment & Eligibility

Status: COMPLETED

Sex: Male

Target Recruitment: 140

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Arm III - high dose	Oral L-Arginine	Oral L-arginine twice daily = 6 capsules per day.
Arm I - Placebo	Placebo	Patients receive oral placebo twice daily (total of 6 capsules per day).
Arm II - low dose	Oral L-Arginine	Patients receive oral L-arginine and oral placebo twice daily (total of 3 capsules of each per day).
Arm II - low dose	Placebo	Patients receive oral L-arginine and oral placebo twice daily (total of 3 capsules of each per day).

Primary Outcome Measures

Name	Time	Method
International Index of Erectile Function (IIEF)	8 weeks	The International Index of Erectile Function (IIEF) questionnaire consists of 15 questions, each of which is scored on a 0 to 5 or 1 to 5 scale. It is comprised of five domains, each scored as the sum of 2 to 5 questions. Erectile function is the sum of six questions with a range from 1 to 30. Higher scores indicate better functioning.

Secondary Outcome Measures

Name	Time	Method
Retention	8 weeks	Retention is the percentage of participants who complete the 8 week visit.
Adherence	8 weeks	Adherence is the percentage of prescribed pills taken by the participants
Assessment of Quality of Life	8 weeks	Quality of life is quantified by the Functional Assessment of Cancer Therapy - Prostate (FACT_P) questionnaire. The FACT questionnaire is comprised of four subscales - social, emotional, functional, and physical. Each subscale is obtained by summing over 6-7 items, each of which is coded on a 0 to 4 scale. Negatively worded questions are reverse scored and higher scores for each subscale indicate better HRQOL. The social, functional, and physical subscales range from 0 to 28 while the emotional subscale ranges from 0 to 24. The overall score (FACT-G) is the sum over the four subscales and ranges from 0 to 108. Patients also completed 12 questions related to prostate cancer, and the prostate subscale score is the sum of those responses (with some items reverse scored). Scores range from 0 to 48, and as with the other FACT subscales higher scores indicate better HRQOL. FACT-P is the sum of FACT-G and the prostate subscale. This questionnaire was added half-way through the study.