Calorie Restriction With or Without Metformin in Triple Negative Breast Cancer (BREAKFAST)
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ClinicalTrials.gov Identifier: NCT04248998 |
Recruitment Status :
Active, not recruiting
First Posted : January 30, 2020
Last Update Posted : January 18, 2023
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Condition or disease | Intervention/treatment | Phase |
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Triple-negative Breast Cancer | Dietary Supplement: Fasting-mimicking diet Drug: Metformin Drug: Preoperative chemotherapy | Phase 2 |
Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, and is associated with the lowest cure rates in the limited-stage disease setting, as well as with the lowest overall survival in the metastatic setting. Preclinical studies indicate that cycles of fasting or calorie-restricted, low-carbohydrate, low-protein diets, also known as fasting-mimicking diets (FMDs), have synergistic cytotoxic effects when combined with chemotherapy agents, such as doxorubicin or cisplatin, in several in vitro and in vivo tumor models, including murine TNBC models. More recently, intermittent fasting has demonstrated highly synergistic antitumor effects when combined with metformin; of note, these effects are mediated through the concomitant inhibition of glycolysis (via fasting-induced hypoglycemia) and metformin-induced inhibition of mitochondrial oxidative phosphorylation (OXPHOS). Finally, small reports published so far indicate that cyclic fasting and FMDs are well tolerated in cancer patients, and can be safety combined with standard antitumor treatments.
Based on these data, the BREAKFAST trial was designed to investigate the antitumor activity of cyclic FMD, alone or in combination with metformin, in patients with localized TNBC. In this study, 90 patients with stage I-III TNBC will be randomized in a 1:1 ratio to receive approximately 6 months of standard preoperative anthracycline plus taxane chemotherapy in combination with eight triweekly cycles of 5-day FMD (Arm A), or the same chemotherapy-FMD regimen plus daily metformin (Arm B). The primary objective of the study is to demonstrate that one or both experimental treatments increase the rate of pCR from 45% (historical data) to 65%
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 30 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | Targeting Triple Negative BREAst Cancer Metabolism With a Combination of Chemotherapy and a Diet Mimicking FASTing Plus/Minus Metformin in the Preoperative Setting: the BREAKFAST Trial |
Actual Study Start Date : | May 5, 2020 |
Estimated Primary Completion Date : | May 1, 2024 |
Estimated Study Completion Date : | May 1, 2024 |

Arm | Intervention/treatment |
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Experimental: Chemotherapy plus Fasting-Mimicking Diet (FMD)
Experimental Arm A will consist of 6 months of standard anthracycline-taxane preoperative chemotherapy in combination with triweekly cycles of 5-day FMD. Chemotherapy will consist of:
The FMD will consist of a triweekly 5-day regimen of a plant-based, calorie-restricted (600 KCal on day 1; 300 KCal on days 2-5), low-carbohydrate, low-protein diet. The FMD will be repeated up to a maximum of eight consecutive cycles. |
Dietary Supplement: Fasting-mimicking diet
Cyclic, 5-day, calorie-restricted (600 KCal on day 1; 300 KCal on days 2-5), low-carbohydrate, low protein diet every three weeks Drug: Preoperative chemotherapy Chemotherapy will consist of:
Other Name: doxorubicin+cyclophosphamide and paclitaxel |
Experimental: Fasting-mimicking diet plus metformin plus chemotherapy
Experimental Arm B will consist of 6 months of standard anthracycline-taxane preoperative chemotherapy in combination with triweekly cycles of 5-day FMD and daily metformin Chemotherapy will consist of:
The FMD will consist of a triweekly 5-day regimen of a plant-based, calorie-restricted (600 KCal on day 1; 300 KCal on days 2-5), low-carbohydrate, low-protein diet. The FMD will be repeated up to a maximum of eight consecutive cycles. Metformin will be administered at an initial dosage of 850 mg/dya, and then escalated to the maximum dosage of 1700/day (two 850 mg tablets) if well tolerated. Metformin will be interrupted 7 days before surgery. |
Dietary Supplement: Fasting-mimicking diet
Cyclic, 5-day, calorie-restricted (600 KCal on day 1; 300 KCal on days 2-5), low-carbohydrate, low protein diet every three weeks Drug: Metformin Metformin 850 mg twice a day
Other Name: Metforal Drug: Preoperative chemotherapy Chemotherapy will consist of:
Other Name: doxorubicin+cyclophosphamide and paclitaxel |
- pCR rate [ Time Frame: 36 months ]Rate of pathologic complete responses (pCRs)
- Severe adverse events [ Time Frame: 36 months ]Incidence of severe (grade 3 or 4) adverse events according to CTCAE v 5.0
- Safety of the experimental treatments [ Time Frame: 36 months ]Incidence of treatment-related adverse events (AEs)
- Compliance with the experimental treatment [ Time Frame: 36 months ]Patients' ability to adhere to the prescribed FMD regimen and pharmacological treatment according to the analysis of daily food diaries and diaries related to metformin intake
- RFS [ Time Frame: 60 months ]Relapse-free survival
- DMFS [ Time Frame: 60 months ]Distant metastasis-free survival
- OS [ Time Frame: 60 months ]Overall Survival
- Short-term modifications of plasma glycemia (mg/dl) [ Time Frame: 30 months ]Short-term modifications of plasma glucose levels, as defined as changes in peripheral blood venous plasma glucose concentration before and after each FMD cycle
- Long-term modifications of plasma glycemia (mg/dl) [ Time Frame: 30 months ]Long-term modifications of plasma glucose concentration, as defined as changes in peripheral blood venous plasma glucose concentration measured before consecutive FMD cycles
- Short-term modifications of serum insulin concentration (µU/ml) [ Time Frame: 30 months ]Short-term modifications of serum insulin concentration, as defined as changes in peripheral blood venous serum insulin concentration before and after each FMD cycle
- Long-term modifications of serum insulin concentration (µU/ml) [ Time Frame: 30 months ]Long-term modifications of serum insulin concentration, as defined as changes in peripheral blood venous serum insulin concentration measured before consecutive FMD cycles
- Short-term modifications of serum IGF-1 concentration (ng/ml) [ Time Frame: 30 months ]Short-term modifications of serum IGF-1 concentration, as defined as changes in peripheral blood venous serum IGF-1 concentration before and after each FMD cycle
- Long-term modifications ofserum IGF-1 concentration (ng/ml) [ Time Frame: 30 months ]Long-term modifications of blood IGF-1 concentration, as defined as changes in serum IGF-1 concentration measured before consecutive FMD cycles
- Short-term modifications of blood lipid profile by UPLC-MS and HPLC-ELDS [ Time Frame: 30 months ]Short-term modifications of blood lipid profile, as defined as changes in plasma lipids before and after individual FMD cycles
- Long-term modifications of blood lipid profile by UPLC-MS and HPLC-ELDS [ Time Frame: 30 months ]Long-term modifications of blood lipid profile, as defined as changes in plasma lipids assessed before consecutive FMD cycles
- Clinical tumor response [ Time Frame: 30 months ]To estimate clinical tumor responses, as assessed through Magnetic Resonance Imaging (MRI) evaluations according to RECIST 1.1 criteria before surgery
- Gene expression profiles [ Time Frame: 36 months ]To correlate baseline metabolic gene expression, as assessed through RNA-seq analysis, with patient probability to achieve a pCR. In particular, the expression of genes encoding for catalytic, regulatory and scaffolding subunits of PP2A will be evaluated.
- Mutational analyses [ Time Frame: 36 months ]To correlate mutational tumor profiles, as assessed through whole-genome sequencing analysis, with patient probability to achieve a pCR. In particular, the expression of genes encoding for catalytic, regulatory and scaffolding subunits of PP2A will be evaluated.
- Short-term modifications of plasma amino acid profile by UPLC-QDa Mass detector system (Waters) [ Time Frame: 30 months ]Short-term modifications of plasma amino acid profile, as defined as changes in plasma amino acids before and after individual FMD cycles
- Long-term modifications of plasma amino acid profile by UPLC-QDa Mass detector system (Waters) [ Time Frame: 30 months ]Long-term modifications of plasma amino acid profile, as defined as changes in plasma amino acids assessed before consecutive FMD cycles

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Ages Eligible for Study: | 18 Years to 75 Years (Adult, Older Adult) |
Sexes Eligible for Study: | Female |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
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Patients eligible for inclusion in this study must meet all of the following criteria:
- Female sex
- Age ≥ 18 and ≤ 75 years.
- Evidence of a personally signed and dated informed consent document (ICD) indicating that the patient has been informed of all pertinent aspects of the study before enrollment
- Willingness and ability to comply with the prescribed FMD regimen, metformin intake, the scheduled visits, treatment plans, laboratory tests and other procedures.
- Histologically confirmed diagnosis of invasive TNBC candidate to neoadjuvant chemotherapy and subsequent curative surgery. On the basis of International Guidelines, TNBC is defined by absent or minimal (<1%) expression of oestrogen and progesterone receptors at IHC, and absence of HER2 over-expression or amplification, as defined as an IHC score of 0, 1+, or an IHC score of 2+ with in situ hybridization (ISH) analysis excluding HER2 gene amplification.
- Patients with localized disease (clinical stage I-III according to TNM). Patients with Stage I TNBC will be included only if the primary tumor is at least 10 mm in greatest dimension (clinical T1c as determined through baseline MRI assessment).
- Presence of an Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1.
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Presence of adequate bone marrow and organ function as defined by the following laboratory values:
- ANC ≥ 1.5 x 103/l
- platelets ≥ 100 x 103/l
- hemoglobin ≥ 9.0 g/dl
- calcium (corrected for serum albumin) within normal limits or ≤ grade 1 according to NCI-CTCAE version 5.0 if not clinically significant
- potassium within the normal limits, or corrected with supplements
- creatinine < 1.5 ULN
- blood uric acid < 10 mg/dl
- ALT and AST ≤ 2 x ULN
- total bilirubin < 1.5 ULN except for patients with Gilbert syndrome who may only be included if the total bilirubin is < 3.0 x ULN or direct bilirubin < 1.5 x ULN
- Fasting glucose ≤ 250 mg/dl.
- Female patients of childbearing potential must agree to sexual abstinence or to use two highly effective methods of contraception throughout the study and for at least six months after the end of the FMD. Abstinence is only acceptable if it is in line with the preferred and usual lifestyle of the patient. Examples of contraceptive methods with a failure rate of < 1% per year include tubal ligation, male sterilization, hormonal implants, established, proper use of combined oral or injected hormonal contraceptives, and certain intrauterine devices. Alternatively, two methods (e.g., two barrier methods such as a condom and a cervical cap) may be combined to achieve a failure rate of < 1% per year. Barrier methods must always be supplemented with the use of a spermicide. A patient is of childbearing potential if, in the opinion of the Investigator, she is biologically capable of having children and is sexually active.
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Female patients are not of childbearing potential if they meet at least one of the following criteria:
- Have undergone a documented hysterectomy and/or bilateral oophorectomy
- Have medically confirmed ovarian failure
- Achieved post-menopausal status, defined as: ≥ 12 months of non-therapy-induced amenorrhea or surgically sterile (absence of ovaries) and have a serum FSH level within the laboratory's reference range for postmenopausal females.
Exclusion Criteria:
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Patients eligible for this study must not meet any of the following criteria:
- Prior systemic treatment for breast cancer or other malignancies within 5 years of treatment enrollment.
- Prior treatment with anthracyclines
- Diagnosis of other malignancies in advanced stages (unresectable, locally advanced or metastatic), or that required systemic (neo)adjuvant chemotherapy in the previous 5 years. Other malignancies diagnosed more than 5 years before the diagnosis of breast cancer must have been radically treated without evidence of relapse at the moment of patient enrollment in the trial.
- Body mass index (BMI) < 20 kg/m2.
- History of alcohol abuse.
- Non-intentional weight loss ≥ 5% in the previous 3 months, unless the patient has a BMI > 22 kg/m2 and weight loss has been lower than 10% at the time of enrollment in the study; or non-intentional weight loss of ≥ 10% in the previous 3 months, unless the patients has a BMI > 25 kg/m2 and weight loss has been lower than 15% at the time of the enrollment in the study. In both cases, weight must have been stable for at least one month before study enrollment.
- Active pregnancy or breast feeding.
- Known active B or C hepatitis or human immunodeficiency virus (HIV) infection, or occasional finding of active hepatitis B/C infection during screening tests before chemotherapy initiation, as defined as positive polymerase chain reaction (PCR) testing for HBV-DNA and HCV-RNA and qualitative PCR for HIV-RNA, or requiring active treatment at study enrollment.
- Serious infections in the previous 4 weeks before the FMD initiation, including, but not limited to, potential hospitalizations for complications of infections, bacteriemia or serious pneumonitis.
- Active autoimmune diseases requiring systemic treatments (e.g. systemic steroids or immune suppressants).
- Active chronic therapy with systemic steroids at a dose ≥ 10 mg per day of prednisone or equivalent at study enrollment.
- Known recent diagnosis of hypothyroidism requiring systemic replacement hormonal therapy and without stabilization of hormonal profile (fT3, fT4 and TSH within the normal range).
- Diagnosis of type 1 or 2 diabetes mellitus requiring pharmacologic therapy (including, but not limited to, insulin, secretagogues and metformin). A diagnosis of type 2 diabetes mellitus not requiring pharmacological treatments based on the judgment of a diabetologist, is compatible with patient enrollment in the trial.
- Active gastric or intestinal ulcerative disease, uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome, small intestine resection.
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Anamnesis of clinically significant heart disease including:
- angina pectoris, coronary bypass, symptomatic pericarditis, myocardial infarction in the previous 12 months from the beginning of experimental therapy;
- congestive heart failure (NYHA III-IV).
- Anamnesis of clinically meaningful cardiac arrhythmias, such as ventricular tachycardia, chronic atrial fibrillation, complete bundle branch block, high grade atrio-ventricular block like bi-fascicular block, type II Mobitz and third grade atrio-ventricular block, nodal arrhythmias, supra-ventricular arrhythmia.
- Left ventricular ejection fraction lower than 50% at the cardiac scan with radionuclides or at echocardiography.
- Previous episodes of symptomatic hypotension leading to loss of consciousness.
- Baseline plasma fasting glucose ≤ 60 mg/dL.
- Medical or psychiatric comorbidities rendering the patient not candidate to the clinical trial, according to the investigator's judgement.
- Other cardiac, liver, lung or renal comorbidities, not specified in the previous inclusion or exclusion criteria, but potentially exposing the patient to a high risk of lactic acidosis.

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): NCT04248998
Italy | |
Fondazione IRCCS Istituto Nazionale Tumori | |
Milano, Italy, 20133 |
Principal Investigator: | Filippo de Braud, Professor | Fondazione IRCCS Istituto Nazionale dei Tumori, Milano | |
Principal Investigator: | Claudio Vernieri, M.D. PhD | Fondazione IRCCS Istituto Nazionale dei Tumori, Milano |
Responsible Party: | Fondazione IRCCS Istituto Nazionale dei Tumori, Milano |
ClinicalTrials.gov Identifier: | NCT04248998 |
Other Study ID Numbers: |
INT 192/19 2019-003093-13 ( EudraCT Number ) |
First Posted: | January 30, 2020 Key Record Dates |
Last Update Posted: | January 18, 2023 |
Last Verified: | January 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Triple-negative breast cancer Fasting-Mimicking Diet Metformin Tumor Metabolism Cytotoxic Chemotherapy |
Breast Neoplasms Triple Negative Breast Neoplasms Neoplasms by Site Neoplasms Breast Diseases Skin Diseases Metformin Paclitaxel Cyclophosphamide Doxorubicin Antineoplastic Agents, Phytogenic Antineoplastic Agents Tubulin Modulators Antimitotic Agents |
Mitosis Modulators Molecular Mechanisms of Pharmacological Action Immunosuppressive Agents Immunologic Factors Physiological Effects of Drugs Antirheumatic Agents Antineoplastic Agents, Alkylating Alkylating Agents Myeloablative Agonists Hypoglycemic Agents Antibiotics, Antineoplastic Topoisomerase II Inhibitors Topoisomerase Inhibitors Enzyme Inhibitors |