NCT07624617 · University of Minnesota
Fast-Her: Fasting Effects on Breast Cancer Treatment
What this study is about
We hypothesize that promoting a fasting state will strengthen the anti-cancer effects of PI3K inhibitors in metastatic breast cancer (MBC) treatment. The primary objective of this study is to assess acceptability of prolonged fasting in this population.
View original scientific description
We hypothesize that promoting a fasting state will strengthen the anti-cancer effects of PI3K inhibitors in metastatic breast cancer (MBC) treatment. The primary objective of this study is to assess acceptability of prolonged fasting in this population.
Interventions
BEHAVIORAL
Normal Eating
During the normal eating intervention period, participants will follow their usual eating pattern. Participants will continue their prescribed PI3K inhibitor dosing, with medications taken at standardized times to ensure consistent pharmacokinetic measurements.
BEHAVIORAL
Prolonged Fasting
During the prolonged fasting intervention period, participants will eat only once daily (dinner), with water, black coffee, and tea permitted during fasting hours. Participants will continue their prescribed PI3K inhibitor dosing, with medications taken at standardized times to ensure consistent pharmacokinetic measurements.
Primary outcome measures
Effect of plasma from fasting in patients on PI3K inhibitors on cell viability
Time frame: Week 2 of prolonged fasting
We will culture 2D/3D breast cancer models using plasma from patients in the fed and fasted states. We will assess tumor cell viability by measuring cell proliferation, apoptosis, and cell cycle distribution.
mechanisms by which fasting might enhance PI3K inhibitor efficacy through complementary molecular and cellular studies
Time frame: Week 7
We will culture 2D/3D breast cancer models using plasma from patients in the fed and fasted states and perform metabolomic and proteomic analyses to evaluate the effects on insulin and PI3K pathways.
Identify biomarkers/patient characteristics predicting the enhancement of PI3K inhibitor efficacy with fasting.
Time frame: Week 7
We will evaluate biomarkers that may predict the influence of fasting on PI3K inhibitor efficacy. Using serial plasma samples, we will analyze PI3K inhibitor pharmacokinetics, metabolic markers (e.g., insulin, glucose), circadian markers (melatonin, cortisol), and tumor-specific markers (circulating tumor DNA).
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Age ≥18 years
- Histologically confirmed metastatic breast cancer
- Menopausal or medically ovarian suppressed
- Currently receiving capivasertib therapy (2 tablets twice daily, 4 days per week)
- Stable on current capivasertib regimen for at least 2 weeks
- an ECOG performance status of 0-1
- BMI ≥25kg/m2
- Able to provide informed consent
- Willing to comply with study procedures including CGM wear, food tracking by mCC app and dietary modifications
- Access to smartphone or tablet for mobile application use
Exclusion criteria
- Type 1 diabetes mellitus
- Uncontrolled type 2 diabetes (HbA1c \>9.0%)
- History of severe hypoglycemia
- Eating disorders or contraindications to fasting
- Pregnancy or breastfeeding
- Significant gastrointestinal disorders affecting food absorption
- Unable to fast for medical reasons
- Concurrent participation in other dietary intervention studies
- A history of significantly abnormal lab results within 4 weeks of consent date, such as hematologic (Hgb \< 10.0, platelets \< 100), hepatic (LFTs \> 2X nl), renal (Cr \> 1.5)
Where
- Minneapolis, Minnesota
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Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 8, 2026 · Source of record for eligibility and locations