A Dietary Supplement (Resistant Potato Starch) for Reducing Musculoskeletal Symptoms in Individuals Planning to Receive Aromatase Inhibitor Therapy, AIMSS-RPS Trial (AIMSS-RPS)

Phase 2 Study of Aromatase Inhibitor-Associated Musculoskeletal Symptom Prevention With Resistant Potato Starch (AIMSS-RPS)

This phase II trial tests the safety and effectiveness of a dietary supplement called resistant potato starch for reducing musculoskeletal symptoms in patients with stage 0-III breast cancer or who are at high risk for breast cancer and are planning to receive treatment with an aromatase inhibitor. Aromatase inhibitors are a type of drug commonly used for the treatment or prevention of breast cancer. Many people who receive aromatase inhibitors experience musculoskeletal symptoms (symptoms relating to bones and muscles, such as joint pain or stiffness). Research has shown there may be an association between reduced levels of beneficial gut bacteria and the development of aromatase inhibitor-associated musculoskeletal symptoms. Resistant potato starch is a plant-based low-digestible carbohydrate that has the potential to promote the growth of beneficial gut bacteria. Taking resistant potato starch while receiving aromatase inhibitor therapy may reduce musculoskeletal symptoms in patients with stage 0-III breast cancer or individuals at high risk of developing breast cancer.

Study Overview

• Status: Recruiting
• Conditions: Anatomic Stage I Breast Cancer AJCC v8; Anatomic Stage II Breast Cancer AJCC v8; Anatomic Stage III Breast Cancer AJCC v8; Anatomic Stage 0 Breast Cancer AJCC v8; Localized Breast Carcinoma
• Intervention / Treatment: Drug: Starch, Potato

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Cancer AnswerLine; Phone Number: 1-800-865-1125; Email: CancerAnswerLine@med.umich.edu

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • Recruiting
      • University of Michigan Rogel Cancer Center
      • Contact: Cancer AnswerLine; Phone Number: 800-865-1125; Email: CancerAnswerLine@med.umich.edu
      • Principal Investigator: Norah L. Henry, M.D.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Patient who is planning to start standard-of-care AI therapy and receive treatment for at least 24 weeks. Can be planning to take AI therapy for stage 0-3 breast cancer or because they are at high risk of developing breast cancer. Concurrent gonadotropin-releasing hormone antagonist (GnRHa) therapy, anti-osteoclast therapy, anti-HER2 therapy, ribociclib, and/or PARP inhibitor are permitted
• Average joint pain 0-6 on a 0-10 scale during the 7 days prior to study enrollment
• Able to take oral medication
• Able to read and understand English
• Aware of the nature of her diagnosis, understands study requirement, and able to sign an informed consent form

Exclusion Criteria:

• Distant metastatic breast cancer
• Current or planned use of abemaciclib during study participation
• Current or planned use of chemotherapy or immunotherapy during study participation
• Pregnant or breast feeding, or planning to become pregnant during study participation
• Known active inflammatory bowel disease
• History of colectomy and/or gastric bypass
• Prior AI therapy except in the context of fertility treatment
• Planned use of prebiotics during study participation
• Use of estrogen supplementation other than vaginal estrogen
• Receipt of another investigational agent concurrent with participation in this trial

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Supportive Care (RPS); Participants receive RPS PO QD for 24 weeks in the absence of unacceptable toxicity.	Drug: Starch, Potato; Given PO

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of patients who took at least 70% of resistant potato starch (RPS) doses per protocol	Will be assessed using patient self-report. The study will be deemed feasible if at least 60% of patients take at least 70% of protocol-directed doses of RPS, as assessed on the treatment logs. Will be evaluated with a 95% confidence interval.	Up to 24 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of adverse events	Will evaluate the frequency and severity of adverse events possibly, probably, or definitely associated with RPS. Safety and tolerability will be assessed using descriptive analysis of adverse event data (adverse events possibly, probably, or definitely associated with RPS) as well as analysis of patient-reported outcomes common terminology criteria for adverse events measures.	Up to 24 weeks
Relative abundance of Bifidobacteria	Will be assessed from stool. Sequencing data will be analyzed using standard protocols to identify butyrate generators. The primary analysis will compare relative abundance of Bifidobacteria at 12 weeks versus baseline, using Wilcoxon signed-rank tests.	At baseline and 12 weeks
Proportion of patients who discontinue initially prescribed aromatase inhibitor medication due to toxicity	Data regarding persistence with initially prescribed AI therapy will be obtained from physician notes in the electronic medical record and from patient-self report about reasons for AI discontinuation. Will estimate the proportion of participants who remain on their initially prescribed AI medication at 6 months, and report this proportion with exact 95% binomial confidence intervals. This estimate will be descriptively compared to the 86% persistence rate observed in a historical cohort.	Up to 24 weeks

Collaborators and Investigators

• Sponsor: University of Michigan Rogel Cancer Center
• Collaborators: The Breast Cancer Research Foundation
• Investigators: Principal Investigator: Norah L Henry, M.D., University of Michigan Rogel Cancer Center

Study record dates

Study Major Dates

• Study Start (Actual): April 22, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): April 1, 2028

Study Registration Dates

• First Submitted: February 23, 2026
• First Submitted That Met QC Criteria: February 24, 2026
• First Posted (Actual): March 2, 2026

Study Record Updates

• Last Update Posted (Actual): April 24, 2026
• Last Update Submitted That Met QC Criteria: April 23, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Neoplasms by Histologic Type; Neoplasms, Glandular and Epithelial; Skin Diseases; Breast Diseases; Carcinoma; Breast Neoplasms; Carcinoma in Situ; Skin and Connective Tissue Diseases; Breast Carcinoma In Situ; Dietary Carbohydrates; Carbohydrates; Polymers; Macromolecular Substances; Polysaccharides; Glucans; Biopolymers; Starch
• Other Study ID Numbers: UMCC 2025.125; NCI-2026-00733 (Registry Identifier: CTRP (Clinical Trial Reporting Program)); HUM00281010 (Other Identifier: University of Michigan Rogel Cancer Center)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Participant demographics and patient-reported outcomes data will be available to researchers upon reasonable request
• IPD Sharing Time Frame: Researchers can request data once the primary analysis has been published
• IPD Sharing Access Criteria: Deidentified data will be available to researchers upon reasonable request
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes