This phase III trial aims to evaluate if metformin (Glucophage) can delay the time to progression in men with low-risk prostate cancer. The main outcome to be investigated is disease progression based on the need for treatment or biopsy results. The trial is recruiting in several locations in Canada.
The details
Metformin is a drug commonly used in the management of diabetes. Metformin works by suppressing glucose production in the liver and increasing the body's sensitivity to insulin. Recent studies have suggested that metformin may also affect the progression of certain cancers.
This trial will examine the effectiveness of metformin in delaying disease progression in men undergoing active surveillance for low-risk prostate cancer. Disease progression will be measured by regular biopsies (tissue samples) from the prostate gland and the time until primary treatment is needed. Disease progression will be monitored over the course of 3 years.
Who are they looking for?
The study will recruit about 408 men with localized prostate cancer, who have not yet undergone any treatment, and who are candidates for active surveillance. Participants should have low-risk prostate cancer. Participants should have a life expectancy of at least 5 years.
Previous treatment for prostate cancer is not permitted (including any prostate surgery, hormone therapy, chemotherapy, radiation therapy, and oral steroids). The use of medication for urinary symptoms (such as finasteride, dutasteride, flutamide, and bicalutamide) must be stopped at least 6 months before taking part. Previous exposure to metformin within 12 months of taking part is not permitted. Participants should not have a history of diabetes, substance abuse, heart or blood vessel disease, or abnormal liver functioning. Participants should not present with any other cancers that were active within the last 5 years (with the exception of treated skin cancer), or present with any significant or uncontrolled medical or psychiatric illnesses.
How will it work
Participants will be randomly allocated to either undergo treatment with metformin or placebo (a control substance with no effect on the body). 850 mg of metformin will be administered once daily for one month, followed by 850 mg of metformin twice daily for 35 months.
Disease progression will be monitored over the course of 3 years. Regular biopsies will measure any changes in Gleason score and the number of positive samples (tissue that contains cancer cells). The length of time until treatment needs to be initiated will also be recorded in both treatment groups. Questionnaires will keep a record of the patients’ disease-related anxiety and treatment satisfaction. Regular rectal examinations and blood tests will be carried out, as will a record of the number of side effects associated with metformin.
