Metformin and Simvastatin Use in Bladder Cancer

Official Title

A Window of Opportunity Study to Evaluate the Role of the Combination of Metformin and Simvastatin as a Neoadjuvant Therapy in Invasive Bladder Cancer


A single arm, single centre window of opportunity trial of using a combination of metformin and simvastatin as a neoadjuvant treatment for patients with invasive bladder cancer who are to undergo cystectomy. The study will assess the feasibility of conducting window of opportunity trials in invasive bladder cancer the drug combination's affects on a variety of important clinicopathologic variables.

The goal is to enroll 44 patients within 18 months. An interim analysis will be conducted at 12 months, and the study will be prematurely closed if fewer than 10 patients have been enrolled at that time. Patients will be administered 850mg of metformin twice daily along with 20mg of Simvastatin. Patients will be enrolled following the formal diagnosis of invasive bladder cancer or at first visit following referral to the London Health Sciences Centre (LHSC). Patient's will receive metformin and simvastatin from the time of enrollment until the night prior to their operation in the absence of safety or tolerability concerns.

Trial Description

Primary Outcome:

  • Bladder tumour proliferation rate
  • Feasibility of performing neoadjuvant window of opportunity trials using drugs with potential bioactivity against invasive bladder cancer
Secondary Outcome:
  • Toxicity in patients who participate in the treatment regimen of Metformin and Simvastatin therapy
  • Level of apoptosis observed in tumour cells of patients who undergo Metformin and Simvastatin therapy before cystectomy.
  • Impact of Metformin and Simvastatin therapy on the signalling pathways involved in invasive urothelial carcinoma.
This is a single centre window of opportunity trial. A total of 44 patients with a diagnosis of invasive bladder cancer diagnosed by pathologic evaluation of transurethral resection of bladder tumour (TURBT) specimens and meeting all eligibility criteria will be enrolled in the study. Study participants will receive Metformin 850mg twice daily and simvastatin 20mg once daily until the night before of their scheduled cystectomy, which is a time period which will last approximately 12 weeks or less. Pre-treatment TURBT tissue samples and the Cystectomy post-therapy tissue samples will be analyzed and compared. Samples will be analyzed for cell proliferation markers and to determine whether or not the combination of metformin and simvastatin is able to produce a synergistic effect that will result in the decrease of the growth of these aggressive cancer cells. The anticipated recruitment period will be approximately 18 months. Participants in this study will be asked to attend the following clinic visits for this study: Baseline Visit: During this visit, the study doctor will conduct a physical exam and take vital signs as well as height and weight measurements. Blood will also be drawn for analysis and research purposes. Females that are of child bearing potential will have a pregnancy test to confirm that they are not pregnant. Pregnant women will be removed from the study. We will also be collecting blood samples. Clinic Visits Participants will have follow-up clinic visits or phone interviews scheduled every 4 weeks until the time of their surgery. At least 1 visit will be in person before surgery. At these times they will have blood drawn for analysis, have their medication reviewed, and confirm that they are taking the medication in adherence with the study protocol. Day of Surgery On the day of surgery, the participants will have their height and weight measured, have blood drawn for analysis and research purposes, and drug compliance will be assessed. This is a feasibility study, and an interim analysis of enrollment is planned at 12 months after the first patient is enrolled. The trial will be prematurely closed if it fails to enroll 10 patients by the 12 month time point. A preliminary pathological analysis will be performed following the completion of 12 months from the time of study initiation. In the event that the enrolled patient underwent a TURBT for diagnosis prior to referral, either tissue will be obtained from the peripheral centre where the TURBT was performed or they will be consented for repeat TURBT, or withdrawn from the study. Based upon the documentation at the time of TURBT, an attempt will be made, where possible, to obtain tissue sections from the same tumour contained in the cystectomy sections. Where this is not possible, representative slides will be obtained from another tumour, if available. Study Objectives The aim of this study is to evaluate feasibility of window of opportunity neoadjuvant trials for invasive bladder cancer in our centre, and to determine the effect of the combination of metformin and simvastatin on clinicopathologic markers of drug activity in our patient cohort. Primary Objectives
  • Feasibility and Tumour Proliferation Rate The primary endpoint of this trial will be the assessment of the tumour proliferation rate. This will be investigated through the analysis of the change in Ki67 tissue staining between the TURBT tissue samples and the cystectomy tissue. Marker of cell proliferation; 1. Ki67 staining This trial is also designed to establish the framework and evaluate the feasibility of performing neoadjuvant window of opportunity trials using drugs with potential bioactivity against invasive bladder cancer at the London Health Sciences Centre. The goal is to accrue 44 patients within 18 months to the trial. A midterm analysis at 12 months will be performed, at which time the trial will be prematurely closed if there have been fewer than 10 patients enrolled. 2. Feasibility
  • goal to accrue 44 patients in 18 months. Secondary Objectives This study will assess the rate of grade 3 or higher toxicity as defined by the CTCAE 4.03 (Common Terminology Criteria for Adverse Events). If 41 patients are enrolled and complete the study, the study will have an 85% power at an of 0.05 to detect if the toxicity rate is >20% with an assumed baseline of ≤5%. 1. Toxicity The following parameters will be investigated through the analysis of any differences in their tissue staining between the TURBT tissue samples and the cystectomy tissue. This should aid in the delineation of any therapeutic effects of the combination of metformin and simvastatin therapy on urothelial carcinoma (UC). Marker of Apoptosis; 2. Terminal deoxynucleotidyl Transferase-mediated deoxy uridine triphosphate (dUTP) nick end labeling (TUNEL) staining Phosphoinositide-3 kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway readouts; 3. p-mTOR staining 4. p-Akt staining 5. survivin Metformin stimulates activation; 6. phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK) The following parameters will be investigated through the analysis of their tissue staining in the cystectomy sample, as they are assumed to be dependent on the underlying tumour biology and will not be affected by metformin therapy: PI3K/Akt/mTOR pathway regulator, frequently mutated in UC, could affect metformin response; 7. Phosphatase and tensin homolog (PTEN) staining Cell cycle regulator, frequently inactivated in invasive UC, affects metformin response; 8. p53 staining Tertiary Endpoints The following parameters will be investigated through the analysis of any differences in either their values between the time of enrollment and the day of surgery or differences in the frequency between the treatment and control groups. Between time of enrollment and date of surgery; 1. Serum Insulin 2. Fasting glucose levels 3. Body mass index 4. Changes in serum prostate specific antigen (PSA) Clinical Marker of efficacy, has been shown to affect prognosis: 5. Pathologic T0 rate at cystectomy vs. historical rates Potential Novel Biomarkers: 6. Number of circulating tumour cells or tumour microparticles before and after treatment with metformin The following additional stratification analyses of the data will be performed in order to assess our results in light of prior research findings: Stratification of Pathologic Markers; 7. Stratification of pAKT and Survivin expression levels by the presence or absence of PTEN expression 8. Stratification of TUNEL and Ki67 by the status of p53 staining 9. Stratification of pathologic markers by the use or absence of administration of neoadjuvant chemotherapy

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