Gut Microbiome Changes During Abemaciclib Therapy in Breast Cancer

NCT07406594 | Not Yet Recruiting DMC

• 1 other identifier: MICRO-VERZ
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

Abemaciclib (Verzenio) is a commonly used treatment for hormone receptor-positive breast cancer, but it can cause gastrointestinal side effects such as diarrhea, which may affect quality of life and treatment tolerance. The gut microbiome, which is the collection of bacteria living in the digestive tract, may play a role in these symptoms. The purpose of this study is to examine how the gut microbiome changes during the early phase of abemaciclib treatment and how these changes relate to gastrointestinal symptoms experienced by patients. Participants will provide stool samples at multiple time points using mailed collection kits and will complete questionnaires about gastrointestinal symptoms while receiving standard-of-care abemaciclib therapy. All study procedures will be conducted remotely. Information gained from this study may help inform future supportive care strategies for breast cancer patients receiving abemaciclib.

Conditions

Breast Cancer; HER-2 Positive Breast Cancer

Keywords

microbiome

Outcome Measures

Primary Outcomes (4)

• Recruitment rate

  Feasibility will be assessed by the proportion of eligible participants who enroll in the study out of those approached for participation.

  From study opening through completion of enrollment (approximately 12 months)

• Participant retention

  Feasibility and acceptability will be assessed by the proportion of enrolled participants who complete the intervention period and final study assessments.

  Through end of intervention (6 weeks)

• Supplement adherence

  Feasibility will be assessed by participant adherence to the assigned supplement, measured as the proportion of prescribed doses taken during the intervention period.

  During the 6-week intervention

• Completion of study procedures

  Feasibility will be assessed by the proportion of participants who complete protocol-specified stool sample collections and questionnaires.

  Baseline through end of intervention (6 weeks)

Secondary Outcomes (3)

• Change in Gut Microbial Community Composition During Early Abemaciclib Therapy

  Baseline through Week 6 of abemaciclib therapy

• Correlation between gut microbiome diversity and gastrointestinal symptom severity

  Baseline through Week 6 of abemaciclib therapy

• Differences in Gut Microbial Community Composition Between Resistant Starch and Placebo Groups

  Baseline through Week 6 of abemaciclib therapy

Study Arms (2)

Resistant Starch Intervention

EXPERIMENTAL

Participants randomized to this arm will receive resistant starch powder as a dietary supplement during early abemaciclib therapy. The supplement will be taken orally as a powder mixed with a beverage, according to instructions provided. Participants will continue to receive abemaciclib as standard of care and will complete study procedures including stool sample collection and symptom questionnaires.

Dietary Supplement: Resistant Potato Starch

Placebo Supplementation (Control Arm)

PLACEBO COMPARATOR

Participants randomized to this arm will receive a placebo powder as a dietary supplement during early abemaciclib therapy. The placebo will be taken orally as a powder mixed with a beverage, according to instructions provided. Participants will continue to receive abemaciclib as standard of care and will complete study procedures including stool sample collection and symptom questionnaires.

Dietary Supplement: Placebo control

Interventions

Resistant Potato Starch DIETARY_SUPPLEMENT

Participants randomized to the resistant starch intervention will receive a resistant starch dietary supplement administered orally. The supplement will be taken during early abemaciclib therapy according to study instructions. Abemaciclib is administered as standard of care and is not altered by study participation.

Resistant Starch Intervention

Placebo control DIETARY_SUPPLEMENT

Participants randomized to the placebo intervention will receive a placebo dietary supplement administered orally as a powder mixed with a beverage. The supplement will be taken during early abemaciclib therapy according to study instructions. Abemaciclib is administered as standard of care and is not altered by study participation.

Placebo Supplementation (Control Arm)

Eligibility Criteria

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

You may qualify if:

• Age ≥ 18 years.
• Histologically confirmed hormone receptor-positive, HER2-negative breast cancer.
• Planned initiation of adjuvant abemaciclib (Verzenio) as part of standard clinical care, with enrollment occurring prior to or within 7 days of starting abemaciclib.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
• Women of child-bearing potential must agree to use contraception prior to study entry, for the duration of study participation, and for 90 days following completion of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.
• A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria:
• Has not undergone a hysterectomy or bilateral oophorectomy; or
• Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months).
• Ability to understand and the willingness to sign a written informed consent.

You may not qualify if:

• Concurrent participation in another interventional clinical trial that, in the opinion of the investigator, would interfere with study participation or interpretation of results.
• Known gastrointestinal conditions that would significantly interfere with study procedures or interpretation of results, including but not limited to inflammatory bowel disease, short bowel syndrome, or chronic diarrheal disorders.
• Known allergy or intolerance to resistant starch or any component of the study supplement.
• Pregnant or breastfeeding individuals.
• Any medical, psychiatric, or social condition that, in the judgment of the investigator, would limit the participant's ability to comply with study procedures.

Sponsors & Collaborators

• University of Vermont Medical Center: lead

Study Sites (1)

University of Vermont

Burlington, Vermont, 05401, United States

Location

MeSH Terms

Conditions

Breast Neoplasms

Condition Hierarchy (Ancestors)

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

Central Study Contacts

Tracy Smith, PhD

CONTACT

1 (802) 656-2021; tracy.smith@med.uvm.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: SUPPORTIVE CARE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Faculty Scientist

Study Record Dates

• First Submitted: January 27, 2026
• First Posted: February 12, 2026
• Study Start (Estimated): October 1, 2027
• Primary Completion (Estimated): October 1, 2031
• Study Completion (Estimated): October 1, 2031
• Last Updated: February 12, 2026

Record last verified: 2026-02

Locations

US (1)