Effects of fasting and exercise on fatigue in women with advanced breast cancer

Prolonged Overnight Fasting and/or Exercise on Fatigue and Other Patient Reported Outcomes in Women With Hormone Receptor Positive Advanced Breast Cancer (FastER)

Not applicable Interventional University of Miami · NCT06123988

This study is testing whether fasting, exercise, a mix of both, or health education can help reduce fatigue in postmenopausal women with advanced breast cancer who are starting hormone therapy.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment260 (estimated)
Ages18 Years and up
SexFemale
SponsorUniversity of Miami Academic / other
Drugs / interventionstrastuzumab, pertuzumab
Locations3 sites (Phoenix, Arizona and 2 other locations)
Trial IDNCT06123988 on ClinicalTrials.gov

What this trial studies

This study investigates the impact of four different interventions on fatigue in women with hormone receptor-positive advanced breast cancer. Participants will be assigned to one of four groups: prolonged overnight fasting, moderate-intensity exercise, a combination of both, or general health education sessions. The aim is to determine which approach, if any, can effectively reduce fatigue in patients receiving CDK4/6 inhibitors. The study will include women who are postmenopausal and have recently started endocrine therapy.

Who should consider this trial

Good fit: Ideal candidates are postmenopausal women with hormone receptor-positive advanced breast cancer who are starting treatment with a CDK4/6 inhibitor.

Not a fit: Patients who are already engaging in significant physical activity or structured fasting may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide effective non-pharmacological strategies to alleviate fatigue in women undergoing treatment for advanced breast cancer.

How similar studies have performed: While there is ongoing research into lifestyle interventions for cancer-related fatigue, this specific combination of fasting and exercise in this patient population is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Women
2. Able to provide written informed consent
3. Able to speak, read, and understand English or Spanish
4. Postmenopausal (including concurrent use of ovarian suppression)
5. Diagnosis of ER+ and/or PR+, hormone estrogen receptor-2 (HER-2)- or HER-2+ metastatic or locally advanced unresectable breast cancer
6. Initiation of first-line or second-line endocrine therapy in combination with a CDK4/6 inhibitor (e.g., palbociclib, ribociclib, or abemaciclib), with or without hormone estrogen receptor-2 (HER2)-directed therapy (e.g., trastuzumab ± pertuzumab), or in combination with both a CDK4/6 inhibitor and a Phosphoinositide 3-kinase (PI3K) inhibitor, within the past 90 days.

   1. Prior use of a CDK4/6 inhibitor in the adjuvant setting is permitted; participants must be enrolled within 90 days of starting a CDK4/6 inhibitor for the first or second time in the metastatic or locally advanced setting.
   2. Participants who switch from one CDK4/6 inhibitor to another due to toxicity or insurance constraints remain eligible, provided enrollment occurs within 90 days of initiating the first or second-line CDK4/6 inhibitor in the metastatic or locally advanced setting.
7. Having not consistently (not equal to or more than 50% of the time) engaged in more than 90 minutes of moderate or 45 minutes of vigorous physical activity per week over the past 3 months
8. Having not consistently engaged in resistance training 2 or more days per week over the past 3 months
9. Having not consistently (not equal to or more than 50% of the time) engaged in structured fasting (i.e., not regularly fasting for ≥12hr/night) for the past 3 months
10. Approval from a medical oncology provider to participate.

Exclusion Criteria:

1. Unable to provide consent
2. Unable to read or understand English or Spanish
3. Oxygen dependent
4. Unstable cardiac disease
5. Insulin-dependent diabetes
6. Unable to walk 2 blocks without assistance (excluding canes)
7. Regularly maintaining a shiftwork schedule, i.e. working evening shifts, night shifts, or rotating shifts in the last 3 months
8. History of a clinical eating disorder
9. Unstable bone metastases
10. More than 90 days since initiation of first- or second-line endocrine therapy in combination with 1) a CDK4/6 inhibitor, with or without HER2-directed therapy, or 2) a CDK 4/6 inhibitor in combination with a PI3K inhibitor, in the metastatic or locally advanced.
11. Presence of a severe medical condition or psychiatric condition or medications that would preclude participation of the study intervention.

Where this trial is running

Phoenix, Arizona and 2 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions HER2-positive Breast CancerAdvanced Breast Cancer
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.