Updated May 2026 · ClinicalTrials.gov

RECRUITINGPhase 2INTERVENTIONAL

Phase II Study of Oral Metformin for Intravesical Treatment of Non-muscle-invasive Bladder Cancer

Q: What is the NCT03379909 clinical trial studying?

A multi-center, open-label, phase II clinical study of metformin in up to evaluable 49 patients with low-grade NMIBC with the aim to determine the overall response to administration of oral metformin for 3 months in a index papillary NMIBC tumour. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Q: Who can participate in NCT03379909?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

Q: How do I contact the trial site for NCT03379909?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Q: Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Q: Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

Phase II Study of Oral Metformin for Intravesical Treatment of Non-muscle-invasive Bladder Cancer (NCT03379909) is a Phase 2 interventional studying Superficial Bladder Cancer and Bladder Cancer, sponsored by Academisch Medisch Centrum - Universiteit van Amsterdam (amc-UvA). RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Superficial Bladder Cancer and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 49 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

Who May Qualify: - Age \> 18 years. - Patients with primary or recurrent suspectedTa or T1, G1 or G2 (low grade) urothelial carcinoma of the bladder with no suspicion of carcinoma in situ. - Patients must have at least 1 lesion but no more than 5. - There must be one index lesion measuring between 0.5 and 1.0 cm in its greatest dimension. - Bimanual examination immediately following cystoscopyshould be carried out and no mass should be felt. - Adequate renal function (eGFR \>50 ml/min/1.73m2 according to CKD-EPI). (47) - Adequate liver function (bilirubin \<1.5 times upper limit of normal, ALAT or ASAT \<2.5 the upper limit of normal). - Eligible patients must be fully informed of the investigational nature of the study and written signed willing to sign a consent form must be obtained prior to any study specific investigations. - Mentally, physically, and geographically able to undergo treatment and follow up. Who Should NOT Join This Trial: - Patients with positive cytology (suspected for high-grade urothelial carcinoma, TPS 4 or TPS 5) or suspected grade 3 tumours. - Patients with diabetes mellitus receiving metformin or having received metformin in the past 6 months. - Patients who have received intravesical treatment (chemotherapy or immunotherapy) within the last 3 months. - Patients that are currently receiving other anti-cancer therapy. - Patients with existing urinary tract infection or recurrent severe bacterial cystitis. - Patients that need to be treated with a transurethral catheter. - Patients with urogenital tumours with histology other than urothelial carcinoma (i.e. squamous cell or adenocarcinoma) or with urothelial carcinoma involving the upper tract or the prostatic urethra. - Patients with a history of other primary malignancy (other than squamous or basal cell skin cancers or cone biopsied CIS of the uterine cervix or prostate carcinoma treated curatively with normal PSA values at inclusion) in the last five years. ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: * Age \> 18 years. * Patients with primary or recurrent suspectedTa or T1, G1 or G2 (low grade) urothelial carcinoma of the bladder with no suspicion of carcinoma in situ. * Patients must have at least 1 lesion but no more than 5. * There must be one index lesion measuring between 0.5 and 1.0 cm in its greatest dimension. * Bimanual examination immediately following cystoscopyshould be carried out and no mass should be felt. * Adequate renal function (eGFR \>50 ml/min/1.73m2 according to CKD-EPI). (47) * Adequate liver function (bilirubin \<1.5 times upper limit of normal, ALAT or ASAT \<2.5 the upper limit of normal). * Eligible patients must be fully informed of the investigational nature of the study and written signed informed consent must be obtained prior to any study specific investigations. * Mentally, physically, and geographically able to undergo treatment and follow up. Exclusion Criteria: * Patients with positive cytology (suspected for high-grade urothelial carcinoma, TPS 4 or TPS 5) or suspected grade 3 tumours. * Patients with diabetes mellitus receiving metformin or having received metformin in the past 6 months. * Patients who have received intravesical treatment (chemotherapy or immunotherapy) within the last 3 months. * Patients that are currently receiving other anti-cancer therapy. * Patients with existing urinary tract infection or recurrent severe bacterial cystitis. * Patients that need to be treated with a transurethral catheter. * Patients with urogenital tumours with histology other than urothelial carcinoma (i.e. squamous cell or adenocarcinoma) or with urothelial carcinoma involving the upper tract or the prostatic urethra. * Patients with a history of other primary malignancy (other than squamous or basal cell skin cancers or cone biopsied CIS of the uterine cervix or prostate carcinoma treated curatively with normal PSA values at inclusion) in the last five years. * Patients with active, uncontrolled impairment of the renal, hepatobiliary, cardiovascular, gastrointestinal, urogenital, neurologic or hematopoietic systems that, in the opinion of the investigator, would predispose to the development of complications from the administration of metformin. * Patients who are using loop diuretics, cimetidine, ranitidine, cetirizine, trimethoprim, vandetanib, kinidine and/or HIV medication, for which no reasonable alternative is available. * Women who are pregnant or lactating. Individuals of reproductive potential may not participate unless agreeing to use an effective contraceptive method for themselves and/or their sexual partner. * Patients with ECOG-WHO performance status of 3 or 4. * Patients with a known history of alcohol abuse. * Patients with a known hypersensitivity to metformin. * Patients who in the investigator's opinion, cannot comply with provisions of the protocol or do not understand the nature of the study.

Treatments Being Tested

DRUG

Metformin

Metformin orally at doses up to 1500 mg twice daily for 3 months.

Locations (3)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

RadboudUMC

Nijmegen, Gelderland, Netherlands

Sint Franciscus Gasthuis

Rotterdam, South Holland, Netherlands

Academic Medical Center

Amsterdam, Netherlands

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT03379909), the sponsor (Academisch Medisch Centrum - Universiteit van Amsterdam (amc-UvA)), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT03379909 clinical trial studying?

A multi-center, open-label, phase II clinical study of metformin in up to evaluable 49 patients with low-grade NMIBC with the aim to determine the overall response to administration of oral metformin for 3 months in a index papillary NMIBC tumour. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT03379909?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT03379909?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT03379909. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT03379909. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.