Trial · NCT01101438

A Phase III Randomized Trial of Metformin vs Placebo in Early Stage Breast Cancer

NCT01101438, Phase 3, Completed, Canadian Cancer Trials Group; results first posted 2022-10-18

3 sourcestrials-2026-11-12-0.5.0

Cite this record

ConductScience Library. A Phase III Randomized Trial of Metformin vs Placebo in Early Stage Breast Cancer. Trials, record NCT01101438. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT01101438

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: A Phase III Randomized Trial of Metformin vs Placebo in Early Stage Breast Cancer
NCT number: NCT01101438
Status: Completed
Phases: Phase 3
Enrollment: 3,649 participants, actual
Lead sponsor: Canadian Cancer Trials Group
Conditions: Breast Cancer
Interventions: metformin hydrochloride, placebo
First posted: 2010-04-12
Last updated: 2023-09-13
Results first posted: 2022-10-18

Source ClinicalTrials.gov

Registered outcomes5

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Invasive Disease-free Survival in Hormone Receptor (ER and PgR) Positive Sub-groups	5 years	Invasive disease-free survival (IDFS) is defined as percentage of patients without documented development of ipsilateral and contralateral invasive breast tumour, local/regional invasive recurrence, distant recurrence, death from any causes. If a subject has not had invasive disease or died at the time of data cut-off for this final analysis, IDFS was censored on the date of last follow-up.
Primary	Invasive Disease-free Survival	5 years	Invasive disease-free survival (IDFS) is defined as the percent of patients without documented development of ipsilateral and contralateral invasive breast tumour, local/regional invasive recurrence, distant recurrence, death from any causes. If a subject has not had invasive disease or died at the time of data cut-off for this final analysis, IDFS was censored on the date of last follow-up.
Secondary	Overall Survival	10 years	Number of patients who died from any causes.
Secondary	Distant Relapse-free Survival	5 years	Distant Relapse Free Survival (DRFS) is defined as the percentage of patients without any documented distant recurrence, death from breast cancer, death from a non breast cancer cause or death from an unknown cause. If a subject has not had distant DRFS event nor died at the time of data cut-off for this analysis, DRFS will be censored on the date of last disease assessment.
Secondary	Breast Cancer-specific Mortality	10 years	Patients who died from breast cancer

Source ClinicalTrials.gov

Outcomes5

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Invasive Disease-free Survival in Hormone Receptor (ER and PgR) Positive Sub-groups	5 years		percentage of patients without event	NUMBER
PRIMARY	Invasive Disease-free Survival	5 years	All randomized patients will be analyzed according to the arm that they were randomized to (intent to treat population).	percentage of patients without event	NUMBER
SECONDARY	Overall Survival	10 years	Intent to treat	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Distant Relapse-free Survival	5 years		percentage of patients without event	NUMBER
SECONDARY	Breast Cancer-specific Mortality	10 years	Intent to treat	Participants	COUNT_OF_PARTICIPANTS

Source ClinicalTrials.gov

Results by group12

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Category	Value	Spread	Units
Invasive Disease-free Survival in Hormone Receptor (ER and PgR) Positive Sub-groups	Metformin		86.5	95% Confidence Interval 84.5 to 88.5	percentage of patients without event
Invasive Disease-free Survival in Hormone Receptor (ER and PgR) Positive Sub-groups	Placebo		85.9	95% Confidence Interval 83.9 to 87.9	percentage of patients without event
Invasive Disease-free Survival	Metformin		84.9	95% Confidence Interval 83.2 to 86.6	percentage of patients without event
Invasive Disease-free Survival	Placebo		84.1	95% Confidence Interval 82.4 to 85.8	percentage of patients without event
Overall Survival	Metformin	Patients who died	201		Participants
Overall Survival	Placebo	Patients who died	198		Participants
Overall Survival	Metformin	Patients who alive	1623		Participants
Overall Survival	Placebo	Patients who alive	1627		Participants
Distant Relapse-free Survival	Metformin		88.7	95% Confidence Interval 87.2 to 90.2	percentage of patients without event
Distant Relapse-free Survival	Placebo		87.8	95% Confidence Interval 86.3 to 89.3	percentage of patients without event

1 to 10 of 12Source ClinicalTrials.gov

See all 12 results by group

Participant flow6

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	Metformin	1,824
Overall Study	STARTED	Placebo	1,825
Overall Study	COMPLETED	Metformin	1,816
Overall Study	COMPLETED	Placebo	1,816
Overall Study	NOT COMPLETED	Metformin	8
Overall Study	NOT COMPLETED	Placebo	9

Source ClinicalTrials.gov

Adverse events80

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Abdominal pain	Gastrointestinal disorders	Metformin	191	1,816
other	Abdominal pain	Gastrointestinal disorders	Placebo	146	1,816
other	Bloating	Gastrointestinal disorders	Metformin	179	1,816
other	Bloating	Gastrointestinal disorders	Placebo	151	1,816
other	Constipation	Gastrointestinal disorders	Metformin	288	1,816
other	Constipation	Gastrointestinal disorders	Placebo	226	1,816
other	Diarrhea	Gastrointestinal disorders	Metformin	819	1,816
other	Diarrhea	Gastrointestinal disorders	Placebo	354	1,816
other	Dyspepsia	Gastrointestinal disorders	Metformin	174	1,816
other	Dyspepsia	Gastrointestinal disorders	Placebo	141	1,816

1 to 10 of 80Source ClinicalTrials.gov

See all 80 adverse events

Adverse event totals6

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Metformin	201	1,824
Total, all-cause mortality	Placebo	198	1,825
Total, other adverse events	Metformin	1,707	1,816
Total, other adverse events	Placebo	1,670	1,816
Total, serious adverse events	Metformin	1	1,816
Total, serious adverse events	Placebo	3	1,816

Source ClinicalTrials.gov

Papers6

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as	Source
25740979	BACKGROUND	PubMed
35608580	RESULT	PubMed
37695982	DERIVED	PubMed
42063220	DERIVED	PubMed
42137612	DERIVED	PubMed
42360727	DERIVED	PubMed

Grants1

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

Project	Title	Principal investigators	Organization	Funder	Fiscal years
U10CA077202	Canadian Contribution to NCI Intergroup Program	EISENHAUER, ELIZABETH	QUEEN'S UNIVERSITY AT KINGSTON	NATIONAL CANCER INSTITUTE	1998 to 2013

Source NIH RePORTER

Trial comparisons3

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

Comparison	Source
Arm I vs Arm II: Breast Cancer-specific Mortality	Trial comparisons
Metformin vs Placebo: deaths from any cause	Trial comparisons
Metformin vs Placebo: serious adverse events	Trial comparisons

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

For software

Read this trial from software.

The record and each of its lists are JSON, twenty rows a page. No key.

GET https://conductscience.org/api/trials/v1/NCT01101438

GET https://conductscience.org/api/trials/v1/NCT01101438/events?page=2

API reference For AI assistants