Study to Understand Relationship Between Gut Health and Toxicities of Hormonal Breast Cancer Treatment

NCT07553234 | Not Yet Recruiting

• 1 other identifier: IRB25-2098
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

This study will be conducted in 2 sequential parts. The first part will be a prospective, observational study. This will be followed by a small interventional, pilot study involving use of fiber supplement (chia seeds). The study aims to evaluate the relationship between the gut microbiome (a diverse ecosystem of microorganisms that affects your health and well-being) and treatment-related gastrointestinal toxicities in patients with HR+/HER2- breast cancer receiving abemaciclib plus endocrine therapy.

Conditions

Breast Cancer

Outcome Measures

Primary Outcomes (1)

• Stool Sampling Feasibility

  Proportion of enrolled participants who provide serial stool samples during the baseline and on-treatment periods, as recorded by device data and study records.

  2 years

Secondary Outcomes (2)

• Baseline Microbiome-Diarrhea Associations

  2 years

• Microbiome Dynamics and Diarrhea

  2 years

Study Arms (2)

Observational Cohort

EXPERIMENTAL

Enrolled patients with early or advanced HR+/HER2- breast cancer starting abemaciclib as per standard of care to characterize the baseline composition and longitudinal dynamics of the gut microbiome before and during treatment. Stool samples will be collected continuously using the GutLab platform, alongside clinical toxicity assessments, with a focus on identifying microbial signatures associated with the development and severity of diarrhea. No intervention will be administered.

Other: Stool Sampling

Dietary Intervention Cohort

EXPERIMENTAL

Enrolled patients with early-stage HR+/HER2- breast cancer. A 2-week chia seed intervention will be administered prior to initiation of abemaciclib. The goal of this high fiber intervention is to favorably modulate the gut microbiome by supporting a more diverse microbiome and reducing the risk of inflammation and dysbiosis.

Other: Stool Sampling; Other: Chia Seeds

Interventions

Stool Sampling OTHER

Stool samples will be collected continuously (during as many bowel movements as possible) using the GutLab device (BiomeSense, Inc.).

Dietary Intervention Cohort; Observational Cohort

Chia Seeds OTHER

In the Fiber Study cohort (Part 2), participants will be advised to consume a standardized daily serving of chia seeds (25g/day) and provided with guidance on how to integrate this into their usual diet.

Dietary Intervention Cohort

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Be willing and able to provide written informed consent for the trial
• Be a male or female subject 18 years of age on day of signing informed consent.
• Histologically proven infiltrating carcinoma of the breast on core needle biopsy that is:
• HER2 negative in primary tumour pre-treatment by local pathology assessed according current American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines: In situ hybridization non-amplified (ratio of HER2 to CEP17 \< 2.0 or single probe average HER2 gene copy number \< 4 signals/cell), OR Immunohistochemistry (IHC) 0 or IHC 1+.
• Estrogen receptor (ER) and progesterone receptors (PR) positive in primary tumour pre-treatment defined as \>1% of cells expressing hormonal receptors via IHC analysis by local laboratory assessment.
• Planned to undergo standard of care therapy with abemaciclib and endocrine therapy, in the adjuvant or metastatic setting (Part 1) or the adjuvant setting (Part 2).
• Be willing to provide mandatory stool samples at baseline and on treatment.
• The Eastern Cooperative Oncology Group (ECOG) 0-2

You may not qualify if:

• Patients who are pregnant or breast-feeding
• Current use of any investigational agents
• Uncontrolled Ulcerative Colitis, Crohn's Disease, Malabsorption syndrome or any disease significantly affecting gastrointestinal function
• History or current evidence of any condition, therapy, lab abnormality or other circumstance that in the opinion of the investigator might expose the subject to risk by participating in the trial, confound the results of the trial, or interfere with the subject's participation for the full duration of the trial.

Sponsors & Collaborators

• University of Chicago: lead

Study Sites (1)

The University of Chicago Medicine Comprehensive Cancer Center

Chicago, Illinois, 60637, United States

Location

MeSH Terms

Conditions

Breast Neoplasms

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Study Officials

• Rita Nanda

  University of Chicago

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Clinical Trials Intake

CONTACT

855-702-8222; cancerclinicaltrials@bsd.uchicago.edu

Rita Nanda

CONTACT

rnanda@bsd.uchicago.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: SUPPORTIVE CARE
• Intervention Model: SEQUENTIAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 2, 2026
• First Posted: April 27, 2026
• Study Start (Estimated): December 27, 2026
• Primary Completion (Estimated): May 3, 2030
• Study Completion (Estimated): May 3, 2030
• Last Updated: May 4, 2026

Record last verified: 2026-04

Locations

US (1)