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

Prospective Evaluation of the Gut Microbiome and a Pilot Dietary Intervention in Patients With HR+/HER2- Breast Cancer Receiving Abemaciclib (GEMMA)

Status
Not yet recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07553234
Acronym
GEMMA
Enrollment
20
Registered
2026-04-27
Start date
2026-12-27
Completion date
2030-05-03
Last updated
2026-05-04

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Breast Cancer

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.

Interventions

OTHERStool Sampling

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

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.

Sponsors

University of Chicago
Lead SponsorOTHER

Study design

Allocation
NON_RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
SUPPORTIVE_CARE
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* 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

Exclusion criteria

* 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.

Design outcomes

Primary

MeasureTime frameDescription
Stool Sampling Feasibility2 yearsProportion of enrolled participants who provide serial stool samples during the baseline and on-treatment periods, as recorded by device data and study records.

Secondary

MeasureTime frameDescription
Baseline Microbiome-Diarrhea Associations2 yearsCorrelation between baseline gut microbiome composition and incidence of grade ≥2 diarrhea during abemaciclib therapy, as defined by CTCAE v6.0.
Microbiome Dynamics and Diarrhea2 yearsCorrelation between longitudinal changes in gut microbiome composition during abemaciclib therapy and incidence and severity of grade ≥2 diarrhea, as defined by CTCAE v6.0.

Countries

United States

Contacts

CONTACTClinical Trials Intake
cancerclinicaltrials@bsd.uchicago.edu855-702-8222
CONTACTRita Nanda
rnanda@bsd.uchicago.edu
PRINCIPAL_INVESTIGATORRita Nanda

University of Chicago

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: May 5, 2026