An interventional study of Probiotics and Placebo in HER2-positive Breast Cancer, Diarrhea Caused by Drug and Neratinib, sponsored by Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University. Recruiting at 1 site in China. Open to female participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-17.
Sponsored by Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University · Not applicable, Interventional, and Treatment
This study aims to evaluate the efficacy and safety of probiotics for the prevention of diarrhea in patients with breast cancer receiving the tyrosine kinase inhibitor (TKI) Neratinib.
Study Design: This is a prospective, randomized controlled clinical trial. Participants will be randomly assigned to either a probiotics intervention group or a placebo-controlled group. Both groups will receive prophylactic loperamide according to the FDA-recommended dosing schedule for neratinib-associated diarrhea.
Primary Objective: To evaluate the efficacy of probiotics in reducing the incidence and severity of diarrhea in patients receiving Neratinib.
Secondary Objectives: This study will also investigate the effects of probiotics on gut microbiota composition and their potential impact on drug efficacy.
Study Duration: Enrollment is planned from August 2025 to June 2027 at Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University. Both the intervention and control groups will receive treatment for a total of six weeks (two cycles of three weeks each). No post-treatment observation period is included.
Eligibility Criteria: Participants must be diagnosed with HER2-positive breast cancer and scheduled to receive Neratinib. Exclusion criteria include patients with severe gastrointestinal disorders or recent probiotic consumption.
Breast cancer patients treated with the tyrosine kinase inhibitor (TKI) Neratinib often experience severe diarrhea, leading to treatment interruptions, dose reductions, or discontinuation. Emerging evidence highlights the role of gut microbiota in drug metabolism and gastrointestinal toxicity. Probiotics have been proposed as a potential intervention to modulate gut microbiota and mitigate diarrhea; however, their efficacy in preventing Neratinib-induced diarrhea remains inconclusive.
This randomized, double-blind, placebo-controlled clinical trial aims to evaluate the efficacy and safety of probiotics in preventing diarrhea in HER2-positive breast cancer patients receiving Neratinib. The study will also explore the impact of probiotics on gut microbiota composition and potential microbiome-mediated mechanisms that may enhance treatment adherence and therapeutic outcomes.
Participants will be randomly assigned in a 1:1 ratio to either a probiotics group or a placebo group. Both groups will receive prophylactic loperamide in accordance with the dosing schedule recommended by the U.S. Food and Drug Administration (FDA) for the prevention of Neratinib-associated diarrhea, ensuring consistency with the approved prescribing information.
Participants will receive treatment for a total of six weeks, corresponding to two treatment cycles.
Metagenomic sequencing and targeted metabolomics will be performed on stool samples to investigate gut microbial composition and metabolic changes. Additional analyses will assess the association between gut-derived metabolites and immune cell activation, aiming to elucidate potential interactions among gut microbiota, metabolites, and immune responses.
Sun Yat-sen Memorial Hospital will serve as the coordinating center for this planned multicenter trial. Currently, it is the only active site, and additional participating centers will be added progressively as they are initiated.
877 studies on the registry are indexed under Diarrhea; 76 are open to participants now.
This study's planned enrollment of 308 is above the median of 137 across 738 interventional studies indexed under Diarrhea.
Browse Diarrhea studies →Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University is the lead sponsor of 483 studies on the registry; 283 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Participants must meet all of the following criteria:
Adequate bone marrow function, defined as:
White blood cell count ≥ 3.0 × 10⁹/L ≥ 1.5 × 10⁹/L count ≥ 100 × 10⁹/L ≥ 90 g/L Serum creatinine ≤ 1.5 × ULN
Exclusion Criteria
Participants will be excluded if they meet any of the following criteria:
Severe cardiovascular diseases that may interfere with study treatment, including but not limited to:
Life-threatening arrhythmias Advanced atrioventricular block Unstable angina pericardial disease Myocardial fibrosis Uncontrolled hypertension
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.
“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
HER2
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CTCAE grade
The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.
“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Dietary Supplement: Probiotics · Drug: Loperamide
Dietary Supplement: Placebo · Drug: Loperamide
Participants in this group will receive a daily dose of probiotics as an adjunct to standard Neratinib therapy. The probiotics will be administered orally as a granule formulation dissolved in water, for a total duration of 6 weeks (two treatment cycles). Loperamide will be administered prophylactically according to the FDA-recommended schedule to prevent Neratinib-associated diarrhea. The aim is to assess the efficacy of probiotics in reducing Neratinib-induced diarrhea and improving quality of life.
Participants in this group will receive a daily dose of a placebo that is identical in appearance, taste, and administration method to the probiotic granules, in addition to standard Neratinib therapy. The placebo will be administered orally as a granule formulation dissolved in water, for a total duration of 6 weeks. Loperamide will also be administered prophylactically to all participants in accordance with FDA recommendations. This group will serve as a control to evaluate the true effect of probiotics on Neratinib-induced diarrhea.
All participants will receive prophylactic loperamide to reduce the risk of Neratinib-induced diarrhea. Loperamide will be administered according to the FDA-recommended schedule: 4 mg TID for the first 14 days of treatment, then 4 mg BID from Day 15 to Day 42. This intervention is implemented as a standard supportive therapy and not as a randomized variable.
Incidence of Grade ≥3 Diarrhea
The incidence of grade 3 or higher diarrhea during the 6-week treatment period, assessed using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.
Time frame: Up to 6 weeks
Incidence of Any Grade Diarrhea
The incidence of diarrhea of any grade during the 6-week treatment period, assessed according to the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0.
Time frame: Up to 6 weeks
Duration of First Episode of Grade 3 Diarrhea
The duration (in days) of the first episode of grade 3 diarrhea experienced by participants during the 6-week treatment period, assessed using the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. Duration is defined from onset to recovery (downgrade to grade ≤2).
Time frame: Up to 6 weeks
Proportion of Participants Hospitalized Due to Diarrhea
The proportion of participants who require hospitalization due to diarrhea-related complications during the treatment period.
Time frame: Up to 6 weeks
Loperamide Usage Patterns
Frequency, total dosage, and compliance of loperamide use during the treatment period, including any dose modifications or discontinuation. Data will be collected through medication records and patient diaries.
Time frame: Up to 6 weeks
Change from Baseline in Overall Quality of Life Assessed by EORTC QLQ-C30
Changes in quality of life assessed using the EORTC QLQ-C30 questionnaire. The tool evaluates overall health status and functioning, including physical, role, emotional, cognitive, and social domains. Higher scores in functional and global health scales indicate better quality of life, while higher scores in symptom scales indicate greater symptom burden.
Time frame: Baseline, Weeks 2, 4, and 6 (End of Study)
Change from Baseline in Diarrhea-Related Quality of Life Assessed by FACT-D
Changes in diarrhea-related quality of life assessed using the FACT-D subscale of the Functional Assessment of Cancer Therapy system. This tool specifically evaluates the severity and impact of diarrhea symptoms on patients' daily life and well-being. Higher scores indicate fewer symptoms and better diarrhea-related quality of life.
Time frame: Baseline, Weeks 2, 4, and 6 (End of Study)
Incidence of Treatment-Related Adverse Events (AEs)
The incidence of treatment-related adverse events (AEs) in participants receiving probiotics plus Neratinib versus the control group. AEs, including nausea, allergic reactions, and other related symptoms, will be assessed according to the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0.
Time frame: Up to 6 weeks
Incidence of Serious Adverse Events (SAEs)
The incidence of serious adverse events (SAEs) associated with probiotics or Neratinib treatment. SAEs, including severe allergic reactions, life-threatening complications, or hospitalizations, will be recorded and summarized to assess potential safety concerns.
Time frame: Up to 6 weeks
Rate of Treatment Discontinuation Due to Adverse Events
The proportion of participants who discontinue Neratinib treatment due to adverse events. The outcome will compare discontinuation rates between the probiotic and placebo groups to evaluate tolerability.
Time frame: Up to 6 weeks
Gut Microbiota Composition Changes
Analysis of stool samples collected at baseline, week 3, and week 6 to assess changes in gut microbiota composition in response to probiotic intervention. The goal is to determine whether probiotics modulate the intestinal microbiota and exert a protective effect against Neratinib-associated diarrhea.
Time frame: Baseline, Week 3, and Week 6
Correlation Analysis of Gut Microbiota-Metabolite-Immune Axis
Integrated analysis of gut microbiota composition, blood and gut microbial metabolites, and immune response markers. This study aims to explore potential mechanistic links between gut microbiota, metabolite changes, and immune function.
Time frame: Baseline, Week 3, and Week 6
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