The Metformin Active Surveillance Trial (MAST) Study (MAST)
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The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT01864096 |
Recruitment Status :
Recruiting
First Posted : May 29, 2013
Last Update Posted : April 19, 2021
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
Prostate Cancer | Drug: Metformin Drug: Placebo | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 408 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Triple (Participant, Care Provider, Investigator) |
Primary Purpose: | Treatment |
Official Title: | A Randomized, Double-Blind, Placebo-Controlled Trial of Metformin in Reducing Progression Among Men on Expectant Management for Low Risk Prostate Cancer: The MAST (Metformin Active Surveillance Trial) Study |
Study Start Date : | October 2013 |
Estimated Primary Completion Date : | August 2023 |
Estimated Study Completion Date : | August 2024 |

Arm | Intervention/treatment |
---|---|
Experimental: Metformin |
Drug: Metformin
One month run-in of 850mg metformin once daily, followed by 850mg twice daily of metformin for 35 months. Total time is 36 months.
Other Name: Metformin hydrochloride |
Placebo Comparator: Placebo |
Drug: Placebo
One month run-in of placebo tablet once daily, followed by twice daily for 35 months. Total time is 36 months.
Other Name: Placebo tablet |
- Time to progression [ Time Frame: 3 years ]
Time to progression - progression is defined as the earliest of the following events:
- Primary therapy for prostate cancer (e.g. prostatectomy, radiation, hormonal therapy)
- Pathological progression as defined as one of the following:
i. >1/3 of total amount of cores involved ii. At least 50% of any one core involved iii. Gleason pattern 4 or higher
- Time to primary therapy for prostate cancer [ Time Frame: 3 years ]Length of time before the participants move on to more radical treatment options (prostatectomy, radiation and/or hormonal therapy)
- Time to pathological progression [ Time Frame: 3 years ]
- Change from baseline in disease-related patient anxiety [ Time Frame: 3 years ]Measured by the Memorial Anxiety Scale for Prostate Cancer (MAX-PC)
- Change from baseline in decisional satisfaction and decisional conflict [ Time Frame: 3 years ]Measured by the Decisional Regret scale
- Change from baseline in prostate cancer diagnosis at repeat biopsy [ Time Frame: 3 years ]
- Change in Gleason Score at repeat biopsy [ Time Frame: 3 years ]
- Change in clinical stage of prostate cancer based on digital rectal examination [ Time Frame: 3 years ]
- Assess the prognostic and predictive value of prostate cancer biomarkers [ Time Frame: 3 years ]Using biomarkers in tissue, blood and urine samples
- To determine the safety and incidence of (serious) adverse events from the administration of 36 months of metformin to men with early stage prostate cancer [ Time Frame: 3 years ]

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Ages Eligible for Study: | 18 Years to 79 Years (Adult, Older Adult) |
Sexes Eligible for Study: | Male |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Must be male > 18 and < 80 years of age
- Have biopsy proven, low-risk, localized prostate cancer choosing expectant management as primary treatment ≤ 1year. [For the purposes of assessing subject eligibility a diagnostic biopsy must have included at least 10 cores, ≤1/3 of total number of cores sampled and < 50% of any one core positive) and must have been obtained within 6 months of screening]. Initial diagnosis of T1a/T1b obtained during a TURP is not allowed
- Gleason score ≤ 6 [Gleason pattern 4 or above must not be present on any biopsy (initial or entry)]
- Clinical stage T1c-T2a
- Serum PSA ≤10 ng/mL (prior to biopsy)
- Life expectancy greater than 5 years, as judged by the treating clinician/urologist
- Able to swallow and retain oral medication
- Hemoglobin A1c < 6.5%
- Able and willing to participate in the full 3 years of the study
- Able to understand instructions related to study procedures
- Able to read and write (health outcome questionnaires are self-administered), understand instructions related to study procedures and give written informed consent
Exclusion Criteria:
-
Subject that has ever been treated for prostate cancer with any of the following:
- Radiotherapy (external beam or brachytherapy)
- Chemotherapy
- Hormonal therapy (e.g., megestrol, medoxyprogesterone, cyproterone)
- Oral glucocorticoids
- GnRH analogues (e.g., leuprolide, goserelin, degarelix)
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Current and/or previous use of the following medications:
- Use of 5α-reductase inhibitors (eg. Finasteride, Dutasteride) within the past 6 months of screening
- Drugs with antiandrogenic properties (e.g., flutamide, bicalutamide, ketoconazole, progestational agents) within 6 months prior to screening
- Previous or current diagnosis of type 1 or type 2 diabetes
- Exposure to metformin within 12 months of screening
- Planned or concurrent use of metformin hydrochloride, sulfonylureas, thiazolidinediones, or insulin for any reason
- Known hypersensitivity or intolerance to metformin hydrochloride
- Any condition associated with increased risk of metformin hydrochloride-associated lactic acidosis (e.g. congestive heart failure defines as NYHA class III or IV, history of any type of acidosis, habitual intake of ≥ 4 alcoholic beverages per day)
- Subject has had prior prostatic surgery including TUNA, TURP, TUIP, laser treatment, thermotherapy, balloon dilatation, prosthesis, and ultrasound ablation within 3 months of screening
- Participation in any investigational or marketed drug trial within 30 days prior to screening or anytime during the study period. This includes any interventional or exercise trials
- Any unstable serious co-existing medical condition(s) including, but not limited to, myocardial infarction, coronary bypass surgery, unstable angina, cardiac arrhythmias, clinically evident congestive heart failure, or cerebrovascular accident within 6 months prior to Screening visit
-
Abnormal liver function test:
- Total bilirubin > 1.8 X institutional upper limit of normal (ULN)
- Aspartate aminotransferase (AST) > 1.8 X institutional ULN
- Alanine aminotransferase (ALT) > 1.8 X institutional ULN
- Alkaline phosphatase (ALP) > 1.8 X institutional ULN
- Serum creatinine > 1.8 X ULN
- History of other malignancies, with the exception of adequately treated nonmelanoma skin cancer, stage I melanoma, NMIBC or other solid tumors curatively treated with no evidence of disease for at least 5 years
- History or current evidence of substance abuse, as defined in DSM-IV, within 12 months of screening
- History of any illness (including psychiatric) that, in the opinion of the investigator, might confound the results of the study or pose additional risk to the subject
- No other concurrent metformin hydrochloride, sulfonylureas, thiazolidinediones, or insulin for any reason

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01864096
Contact: Miran Kenk, PhD | 416-946-4501 ext 3431 | miran.kenk@uhn.ca | |
Contact: Heidi Wagner, BSc, PA (ASPC) | (416) 946-4501 ext 2354 | heidi.wagner@uhn.ca |
Canada, Manitoba | |
Manitoba Cancer Care Centre | Recruiting |
Winnipeg, Manitoba, Canada, R3E 0V9 | |
Principal Investigator: Darrel Drachenberg, MD | |
Canada, Nova Scotia | |
CDHA - Victoria Site | Recruiting |
Halifax, Nova Scotia, Canada, B2H 1Y6 | |
Principal Investigator: Ricardo Rendon, MD | |
Canada, Ontario | |
McMaster Institute of Urology-St .Joseph's Healthcare | Recruiting |
Hamilton, Ontario, Canada, L8N 4A6 | |
Principal Investigator: Bobby Shayegan, MD | |
Centre for Appled Urologic Research, Kingston General Hospital | Recruiting |
Kingston, Ontario, Canada, K7L 3J7 | |
Principal Investigator: Michael Leveridge, MD | |
London Health Sciences Centre-Victoria Hospital | Recruiting |
London, Ontario, Canada, N6A 5W9 | |
Principal Investigator: Jonathan Izawa, MD | |
Ottawa Hospital Research Institute (The Ottawa Hospital) | Recruiting |
Ottawa, Ontario, Canada, K1H 8L6 | |
Principal Investigator: Rodney Breau, MD | |
Sunnybrook Research Institute | Recruiting |
Toronto, Ontario, Canada, M4N 3M5 | |
Principal Investigator: Laurence Klotz, MD | |
Princess Margaret Cancer Centre | Recruiting |
Toronto, Ontario, Canada, M5G 2M9 | |
Principal Investigator: Neil Fleshner, MD | |
Principal Investigator: Anthony Joshua, MD | |
Canada, Quebec | |
Centre L'Hopitalie de l'Universite de Montreal | Recruiting |
Montreal, Quebec, Canada, H2L 4M1 | |
Principal Investigator: Fred Saad, MD | |
MUHC - Montreal General Hospital | Recruiting |
Montreal, Quebec, Canada | |
Principal Investigator: Simon Tanguay | |
Centre de Recherche du CHUS | Recruiting |
Sherbrooke, Quebec, Canada, J1J 3H5 | |
Contact: Elsie Morneau, BSN 819-346-1110 ext 12827 emorneau.chus@ssss.gouv.qc.ca | |
Principal Investigator: Patrick Richard, MD | |
Canada | |
Alberta Urology Institute | Recruiting |
Edmonton, Canada | |
Contact: Adrian Fairey, FRCSC, MD, MSc. |
Principal Investigator: | Neil Fleshner, MD, MPH, FRCSC | University Health Network: Department of Surgical Oncology (Urology) | |
Principal Investigator: | Anthony Joshua, MD | University Health Network: Department of Surgical Oncology (Urology) |
Responsible Party: | University Health Network, Toronto |
ClinicalTrials.gov Identifier: | NCT01864096 |
Other Study ID Numbers: |
MAST 01 |
First Posted: | May 29, 2013 Key Record Dates |
Last Update Posted: | April 19, 2021 |
Last Verified: | April 2021 |
localized prostate cancer metformin active surveillance |
Prostatic Neoplasms Genital Neoplasms, Male Urogenital Neoplasms Neoplasms by Site Neoplasms |
Prostatic Diseases Metformin Hypoglycemic Agents Physiological Effects of Drugs |