An observational study in Breast Cancer, Drug-Related Side Effects and Diarrhea, sponsored by Hubei Cancer Hospital. Recruiting at 1 site in China. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-07-16.
Sponsored by Hubei Cancer Hospital · Observational
Background:
Pyrotinib is an effective targeted drug for HER2-positive breast cancer, but it very frequently causes diarrhea, which can be severe enough to disrupt treatment and reduce patients' quality of life. The reason why some patients develop diarrhea while others do not is not well understood. Recent research suggests that the community of bacteria in the gut (gut microbiota) may play a key role in this side effect.
What is the purpose of this study? This is an observational study (Phase 1) that aims to understand the relationship between pyrotinib treatment, changes in gut bacteria, and the occurrence of diarrhea. The main goal is to compare the gut bacteria of patients who develop diarrhea while taking pyrotinib with those who do not. Researchers hope to identify specific bacteria that might protect against diarrhea, which could lead to new ways to prevent or treat this side effect in the future.
What will happen in the study? Patients with HER2-positive breast cancer who are being treated with pyrotinib will be invited to participate. They will be divided into two groups: those who experience diarrhea and those who do not. Participants will provide stool samples at specific time points (e.g., 2 and 4 weeks after starting pyrotinib). They will also allow researchers to collect information from their medical records about their clinical condition and diarrhea symptoms. No experimental intervention will be administered in this phase of the study; all patients will receive standard medical care.
Potential Benefits:
Participants will not receive any direct benefit from this observational phase of the study. However, the information gathered may help scientists better understand pyrotinib-induced diarrhea and develop future strategies to help other breast cancer patients manage this side effect more effectively.
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
This study's planned enrollment of 60 is below the median of 184 across 3,235 observational studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →Hubei Cancer Hospital is the lead sponsor of 25 studies on the registry; 17 are open to participants now.
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The study population consists of adult patients (aged 18-75) diagnosed with HER2-positive breast cancer who are currently undergoing treatment with pyrotinib (either as monotherapy or in combination). This is a prospective observational cohort study where participants are not assigned to an intervention but are instead grouped based on the natural outcome of whether they develop drug-induced diarrhea during the observation period. This creates two primary cohorts for comparison: the 'Diarrhea Group' and the 'Non-Diarrhea Group'. All participants will continue their standard pyrotinib treatment and clinical care throughout the study.
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.
Exclusion Criteria:
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.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
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.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
This cohort consists of HER2-positive breast cancer patients receiving pyrotinib treatment who develop diarrhea (graded as ≥ Grade 1 according to CTCAE v5.0) during the observation period. Participants in this group will provide stool samples and clinical data for comparison with the non-diarrhea group. No study intervention is administered; all patients receive standard medical care.
This cohort consists of HER2-positive breast cancer patients receiving pyrotinib treatment who do not develop diarrhea (Grade 0 according to CTCAE v5.0) during the observation period. Participants in this group will provide stool samples and clinical data, serving as a control for comparison with the diarrhea group. No study intervention is administered; all patients receive standard medical care.
Difference in gut microbiota β-diversity between the Diarrhea group and the Non-diarrhea group.
Beta diversity (e.g., using UniFrac distance) of the gut microbiota will be compared between the two groups based on metagenomic sequencing data. A statistically significant difference (P \< 0.05) is expected.
Time frame: Through study completion, an average of 6 months.
Identification of specific bacterial species enriched in the Non-diarrhea group.
Metagenomic sequencing data will be analyzed to identify bacterial species that are significantly more abundant in the Non-diarrhea group compared to the Diarrhea group, using statistical methods such as LEfSe (Linear Discriminant Analysis Effect Size) with a threshold of LDA Score \> 2 and P \< 0.05.
Time frame: Through study completion, an average of 6 months.
Difference in gut microbiota α-diversity between groups.
Alpha diversity indices (e.g., Shannon index, Chao1 index) of the gut microbiota will be compared between the Diarrhea and Non-diarrhea groups.
Time frame: Through study completion, an average of 6 months.
Differences in metagenomic functional pathways between groups.
Metagenomic sequencing data will be annotated using databases like KEGG. The abundance of functional pathways (e.g., KEGG Level 2 or 3) will be compared between the two groups to identify differentially abundant metabolic or functional modules.
Time frame: Through study completion, an average of 6 months.
Differences in serum inflammatory cytokine levels between groups.
Levels of systemic inflammatory cytokines (e.g., IL-6, TNF-α, CRP) measured in serum samples by ELISA or other assays will be compared between the Diarrhea and Non-diarrhea groups.
Time frame: Through study completion, an average of 6 months.
Differences in serum metabolomic profiles between groups.
Metabolomic profiling of serum samples will be performed (e.g., by mass spectrometry). The metabolic profiles will be compared between the two groups to identify differentially abundant metabolites.
Time frame: Through study completion, an average of 6 months.
Predictive potential of baseline gut microbiota for pyrotinib-induced diarrhea risk.
An exploratory analysis to assess whether the composition and features of the gut microbiota before starting pyrotinib treatment (baseline) can predict the subsequent risk of developing diarrhea during treatment. Metagenomic sequencing data from baseline stool samples will be used to build predictive models.
Time frame: Through study completion, an average of 6 months.
Plan to share: No — The Individual Participant Data (IPD) collected in this study will not be made publicly available. The primary reasons are to protect patient privacy and confidentiality, as the dataset contains detailed genetic (metagenomic) and clinical information that could potentially be used to identify individuals. Furthermore, the data is integral to ongoing and future research by the investigative team, including the development of synthetic probiotics, which may involve intellectual property considerations.
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Hubei Cancer Hospital