Completed

Phase II Clinical Trial of Soy Isoflavones Prior to Radical Prostatectomy

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What is being tested

soy isoflavones

+ neoadjuvant therapy

+ Placebo

Dietary SupplementProcedureOther
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, 2001

Actual 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 enrolled

Total 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.



Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria

Male

Biological sex of participants that are eligible to enroll.

Over 18 Years

Range of ages for which participants are eligible to join.

Healthy volunteers not allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

Urogenital DiseasesGenital DiseasesGenital Diseases, MaleGenital Neoplasms, MaleNeoplasmsNeoplasms by SiteProstatic DiseasesProstatic NeoplasmsUrogenital NeoplasmsMale 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.

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.

Group IV

Experimental
Arm I (control group): Patients receive 4 placebo capsules by mouth daily for three weeks.

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 Institute

Detroit, United StatesSee the location
CompletedOne Study Center