Recruiting

Phase 2

WBF-038 with Aromatase Inhibitor5-strain Probiotic Formulation in HR-positive Breast Cancer Receiving Aromatase Inhibitor to Prevent Bone Loss

Sponsor:

Mayo Clinic

Code:

NCT07044310

Conditions

Anatomic Stage 0 Breast Cancer AJCC v8

Anatomic Stage I Breast Cancer AJCC v8

Anatomic Stage II Breast Cancer AJCC v8

Anatomic Stage III Breast Cancer AJCC v8

Hormone Receptor-Positive Breast Carcinoma

Eligibility Criteria

Sex: Female

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Biospecimen Collection

Bone Mineral Density Test

Questionnaire Administration

WBF-038

Study Details

Brief summary:

This phase II trial tests how well a probiotic, WBF-038, works in preventing bone loss in patients with early-stage hormone receptor-positive breast cancer who are starting treatment with aromatase inhibitors. Aromatase inhibitors are a drug that blocks the activity of an enzyme called aromatase, which the body uses to make estrogen in the ovaries and other tissues. Blocking aromatase lowers the amount of estrogen made by the body, which may stop the growth of cancer cells that need estrogen to grow. Aromatase inhibitors are used to treat some types of breast cancer or to keep it from coming back. Aromatase inhibitors can affect bone health, weight, blood sugar, and waist size. WBF-038 is a combination of both prebiotics and probiotics, designed to improve metabolic health. Giving WBF-038 may improve bone turnover, bone health, blood sugar, weight, and waist circumference in patients with early-stage hormone receptor-positive breast cancer starting on adjuvant endocrine therapy with an aromatase inhibitor.

Conditions

Anatomic Stage 0 Breast Cancer AJCC v8

Anatomic Stage I Breast Cancer AJCC v8

Anatomic Stage II Breast Cancer AJCC v8

Anatomic Stage III Breast Cancer AJCC v8

Hormone Receptor-Positive Breast Carcinoma

Study ID

NCT07044310

Start date

Jul 25, 2025

Status verified date

Aug, 2026

Completion date

Jul 25, 2027

Anticipated

Primary completion date

Jul 25, 2027

Anticipated

Eligibility Criteria

Sex: Female

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

Female age ≥ 18 years
Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2
Histologically confirmed anatomical stage 0-III hormone receptor-positive breast cancer
Will be starting on an aromatase inhibitor (letrozole, anastrozole, or exemestane) ± ovarian function suppression (OFS) per treating physician's discretion
Absolute neutrophil count (ANC) ≥ 1000/mm\^3 (prior to registration)
Platelet count ≥ 75,000/mm\^3 (prior to registration)
Hemoglobin ≥ 9.0 g/dL (prior to registration)
Creatinine ≤ 2 x upper limit of normal (ULN) (prior to registration)
Serum glutamic-oxaloacetic transaminase (SGOT) (aspartate aminotransferase \[AST\]) ≤ 2 x ULN (prior to registration)
Albumin ≥ 3 g/dL (prior to registration)
Willing and able to provide research stool and blood samples
Negative serum pregnancy test done ≤ 7 days prior to registration, for women of childbearing potential only (< 60 years old with intact uterus)
Capable of providing valid informed consent
Willing to return to enrolling institution for all study visits (blood draws, etc)

Exclusion Criteria:

Requires prolonged systemic antibiotic therapy for other conditions and recent systemic antibiotic ≤ 14 days prior to registration
Fecal microbiota transplant (FMT) ≤ 6 months prior to registration
FMT with an associated serious adverse event related to the FMT product or procedure
Co-morbid systemic illnesses or other severe concurrent diseases which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of over-the-counter probiotics
Immunocompromised patients including patients known to be HIV positive or those on chronic steroids > 20 mg prednisone a day or prednisone-equivalent. Note: Must be off systemic steroids ≥ 90 days prior to registration. However, topical steroids, inhalants, or steroid eye drops are permitted
History of inflammatory bowel disease (IBD), e.g., ulcerative colitis, Crohn's disease, or microscopic colitis
History of chronic diarrhea
History of celiac disease
Currently has a colostomy
Intraabdominal surgery related to gastrointestinal tract ≤ 60 days prior to registration
Evidence of active, severe colitis
History of short gut syndrome or motility disorders
Requires the daily use of medications to manage bowel hypermotility, such as imodium or lomotil
Active autoimmune disease that has required systemic treatment in the ≤ 30 days (i.e., with the use of disease-modifying agents, corticosteroids, or immunosuppressive products) prior to registration. Note: Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment. Patients with vitiligo, Graves' disease, or psoriasis not requiring systemic treatment ≤ 30 days prior to registration are not excluded
History of osteoporosis or hyperparathyroidism
History of untreated vitamin D deficiency
Receiving or will receive bisphosphonates during study period (alendronate, risedronate, ibandronate, pamidronate, or zolendronic acid) or denosumab
Patients who received oral bisphosphonate within ≤ 12 weeks, intravenous (IV) zoledronic acid (Reclast) ≤ 52 weeks, or denosumab ≤ 24 weeks will also be excluded
Known hypersensitivity to any component of study product (including known inulin intolerance)
Known hypersensitivity to > 4 first-line antimicrobial therapies against akkermansia muciniphila, clostridium beijerinckii, clostridium butyricum, anaerobutyricum hallii, including penicillin, piperacillin, tetracycline, amoxicillin, or ampicillin
Known hypersensitivity to > 4 first line antimicrobial therapies against bifidobacterium infantis Bi-26TM, including gentamicin, kanamycin, streptomycin, tetracycline, erythromycin, clindamycin, ampicillin, vancomycin
Received an experimental product ≤ 30 days prior to registration
Receiving or will receive CDK 4/6 inhibitor (abemaciclib, ribociclib, or palbociclib)
Received chemotherapy ≤ 30 days prior to registration

Study Design

Enrollment

38 participants

Anticipated

Intervention Model

Single group

Primary purpose

Supportive Care

Interventions and Outcome Measures

Arms

experimental: Supportive care (WBF-038)

Patients receive WBF-038 PO QD for 365 days in the absence of disease progression or unacceptable toxicity. Patients also undergo blood sample collection and BMD test at screening and on study.

Interventions

Biospecimen Collection

Undergo blood sample collection

Bone Mineral Density Test

Undergo BMD

Questionnaire Administration

Ancillary studies

WBF-038

Given WBF-038 PO

Primary outcome measure

Change in C-terminal telopeptide of type 1 collagen (CTx) [ Time Frame: Baseline; 90 days after start of AI therapy (before beginning WBF-038); 14 days after start of WBF-038; 90 days after start of WBF-038; 180 days after start of WBF-038; 365 days after start of WBF-038; 90 days after stopping WBF-038 ]

Central Contacts and Locations

Central contacts

Clinical Trials Referral Office

855-776-0015 mayocliniccancerstudies@mayo.edu

Locations

Mayo Clinic in Florida

Recruiting

Jacksonville, Florida, United States, 32224-9980

Contacts

Clinical Trials Referral Office

855-776-0015 mayocliniccancerstudies@mayo.edu

Principal Investigator:

Saranya Chumsri, MD

More Information

Sponsor

Mayo Clinic

Last update posted

Aug 10, 2026

Last verified

Aug, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Mayo Clinic on 2026-08-10.