Completed

Phase II Clinical Trial of Soy Isoflavones Prior to Radical Prostatectomy

0 criteria met from your profileSee at a glance how your profile meets each eligibility criteria.
What is being tested

soy isoflavones

+ neoadjuvant therapy
+ Placebo
Dietary Supplement
Procedure
Other
Who is being recruted

Urogenital Diseases
+7

+ Genital Diseases
+ Genital Diseases, Male
Over 18 Years
See all eligibility criteria
How is the trial designed

Prevention Study

Phase 2
Interventional
Study Start: November 2001
See protocol details

Summary

Principal SponsorBarbara Ann Karmanos Cancer Institute
Last updated: January 14, 2026
Sourced from a government-validated database.Claim as a partner
Study start date: November 1, 2001Actual date on which the first participant was enrolled.

OBJECTIVES: * Compare blood/prostate biomarkers of oxidative stress and prostate cancer risk in patients with stage I or II adenocarcinoma of the prostate treated with 3 different dose levels of soy isoflavones before radical prostatectomy. * Compare prostatic tissue biomarkers of proliferation and apoptosis in patients treated with these regimens. * Determine the potential response, in terms of tumor and prostatic intraepithelial neoplasia grade and volume, extraprostatic extension, and serum prostate-specific antigen level, in patients treated with soy isoflavones and in those treated with placebo. * Determine the safety of soy isoflavone supplementation in these patients. OUTLINE: This is a randomized, double-blind, placebo-controlled, parallel-group study. Patients are stratified according to tumor stage (T1c vs T2). Patients are randomized to 1 of 4 treatment arms. * Arm I (control group): Patients receive oral placebo once daily. * Arm II: Patients receive oral soy isoflavones and oral placebo once daily. * Arm III: Patients receive a higher dose of oral soy isoflavones and oral placebo once daily. * Arm IV: Patients receive a higher dose (higher than arm III) of oral soy isoflavones once daily. In all arms, treatment continues for 2-6 weeks (depending on the time from study entry to planned surgery) in the absence of unacceptable toxicity. All patients then undergo radical prostatectomy. Patients are followed at 1 week. PROJECTED ACCRUAL: A total of 100 patients (25 per treatment arm) will be accrued for this study within 12.5 months.

Official TitlePhase II Clinical Trial of Soy Isoflavones Prior to Radical Prostatectomy 
NCT00078923
Principal SponsorBarbara Ann Karmanos Cancer Institute
Last updated: January 14, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details
32 patients to be enrolledTotal number of participants that the clinical trial aims to recruit.
Prevention Study
Prevention studies aim to stop a disease from developing. They often involve people at risk and test things like vaccines, lifestyle changes, or preventive medications.

How participants are assigned to different groups/arms
In this clinical study, participants are placed into groups randomly, like flipping a coin. This ensures that the study is fair and unbiased, making the results more reliable. By assigning participants by chance, researchers can better compare treatments without external influences.

Other Ways to Assign Participants
Non-randomized allocation: Participants are assigned based on specific factors, such as their medical condition or a doctor's decision.
None (Single-arm trial): If the study has only one group, all participants receive the same treatment, and no allocation is needed.

How treatments are given to participants
Participants are divided into different groups, each receiving a specific treatment at the same time. This helps researchers compare how well different treatments work against each other.

Other Ways to Assign Treatments
Single-group assignment: Everyone gets the same treatment.
Cross-over assignment: Participants switch between treatments during the study.
Factorial assignment: Participants receive different combinations of treatments.
Sequential assignment: Participants receive treatments one after another in a specific order, possibly based on individual responses.
Other assignment: Treatment assignment does not follow a standard or predefined design.

How the effectiveness of the treatment is controlled
In a non placebo-controlled study, no participants receive an inert substance (placebo) to compare outcomes. Instead, all participants receive either the experimental treatment or an alternative treatment (often the Standard of Care). This method allows researchers to compare the effects of the experimental treatment with those of a different active intervention, rather than a placebo.

Other Options
Placebo-Controlled: A placebo is used to compare the effects of the experimental treatment with those of an inert substance, isolating the true treatment effect.

How the interventions assigned to participants is kept confidential
Everyone involved in the study knows which treatment is being given. This is typically used when it's not possible or necessary to hide the treatment details from participants or researchers.

Other Ways to Mask Information
Single-blind: Participants do not know which treatment they are receiving, but researchers do.
Double-blind: Neither participants nor researchers know which treatment is given.
Triple-blind: Participants, researchers, and outcome assessors do not know which treatment is given.
Quadruple-blind: Participants, researchers, outcome assessors, and care providers all do not know which treatment is given.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria
MaleBiological sex of participants that are eligible to enroll.
Over 18 YearsRange of ages for which participants are eligible to join.
Healthy volunteers not allowedIf individuals who are healthy and do not have the condition being studied can participate.
Conditions
Pathology
Urogenital Diseases
Genital Diseases
Genital Diseases, Male
Genital Neoplasms, Male
Neoplasms
Neoplasms by Site
Prostatic Diseases
Prostatic Neoplasms
Urogenital Neoplasms
Male Urogenital Diseases
Criteria

DISEASE CHARACTERISTICS: * Histologically confirmed adenocarcinoma of the prostate * Stage T1c or T2 * Disease confined to the prostate gland * Planning to undergo radical prostatectomy within the next 3-4 weeks PATIENT CHARACTERISTICS: Age * 18 and over Performance status * Not specified Life expectancy * Not specified Hematopoietic * Not specified Hepatic * ALT and AST less than 2 times upper limit of normal (ULN) * Alkaline phosphatase less than 2 times ULN Renal * Not specified Other * Fertile patients must use effective barrier contraception * Medically cleared for surgery * No concurrent thyroid disease PRIOR CONCURRENT THERAPY: Biologic therapy * No prior biological therapy for prostate cancer * No concurrent biological agents Chemotherapy * No prior chemotherapy for prostate cancer * No concurrent chemotherapy Endocrine therapy * No prior hormonal therapy for prostate cancer * No concurrent thyroid hormone replacement medication * No concurrent hormonal therapy Radiotherapy * Not specified Surgery * See Disease Characteristics Other * At least 3 months since prior high-dose nutritional supplements * No concurrent regular use (more than once weekly) of soy products greater than 50 g of soy protein or 50 mg of soy isoflavone * No concurrent high-dose nutritional supplements * Standard-dose single multivitamin tablet (e.g., Centrum™) allowed * No concurrent herbs * No concurrent soy foods * No other concurrent isoflavone supplements * No other concurrent antineoplastic agents

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives
4 intervention groups 

are designated in this study

This study does not include a placebo group 

Treatment Groups
Group I
Experimental
Arm IV: Arm III: Patients receive oral soy isoflavones (PTI G-2535) 600 mg genistein capsules by mouth daily for 3 weeks.

Group II
Experimental
Arm III: Patients receive oral soy isoflavones (PTI G-2535) 300 mg genistein capsules + 2 placebo capsules by mouth daily for 3 weeks.

Prostatectomy or Brachytherapy

Arm I: 4 placebo capsules Arm II: 3 placebo capsules Arm III: 2 placebo capsules
Group III
Experimental
Arm II: Patients receive oral soy isoflavones (PTI G-2535) 150 mg genistein capsules + 3 placebo capsules by mouth daily for 3 weeks.

Prostatectomy or Brachytherapy

Arm I: 4 placebo capsules Arm II: 3 placebo capsules Arm III: 2 placebo capsules
Group IV
Experimental
Arm I (control group): Patients receive 4 placebo capsules by mouth daily for three weeks.

Prostatectomy or Brachytherapy

Arm I: 4 placebo capsules Arm II: 3 placebo capsules Arm III: 2 placebo capsules
Study Objectives
Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.
This study has 1 location
Suspended
Barbara Ann Karmanos Cancer InstituteDetroit, United StatesSee the location
CompletedOne Study Center
;