Breast CancerEarly Phase 1NCT07446686
Study on the Safety and Tolerability of Postoperative Radiotherapy Concurrent With CDK4/6 Inhibitors in HR+/HER2- High-Risk Breast Cancer
A Early Phase 1 study testing CDK4/6 inhibitor±endocrine therapy drug±OFS treatment combined with synchronous radiotherapy in people with Breast Cancer, run by Guizhou Provincial People's Hospital.
Trial summary
The investigators combined postoperative radiotherapy with CDK4/6 inhibitors ± endocrine adjuvant therapy to explore the tolerability and safety of this treatment regimen in HR+/HER2- postoperative high-risk breast cancer patients. Read more about this study
- Who is it for?
- Ages 18 to 75 years, women only
- Conditions the study is for
- Breast Cancer
- What is being tested?
- CDK4/6 inhibitor±endocrine therapy drug±OFS treatment combined with synchronous radiotherapy
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- No sites listed yet
- Study dates
- 1 Apr 2026to 30 Jun 2027
- Phase
- Early Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age is 18-75 years old, gender is female
- Postoperative pathological examination confirmed HR+, HER2- invasive breast cancer:
- ER positivity and/or PR positivity is defined as: all positively stained tumor cells The proportion of tumor cells is ≥10%;
- HER2 negativity is defined as: 0/1+ by standard immunohistochemistry (IHC) test; ISH test was negative.
- The time from radical surgery or breast-conserving surgery to randomization shall not exceed 6 months;
- Postoperative pathological examination after radical surgery revealed the presence of lymph nodes in the axilla on the ipsilateral side of the breast lesion.
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- Metastasis (lymph node micrometastases, ipsilateral internal mammary lymph nodes and supraclavicular lymph nodes are allowed) metastasis, but the number of metastases to the ipsilateral internal mammary lymph nodes and supraclavicular lymph nodes is not included in the positive calculation of sexual lymph nodes), the specific requirements are as follows:
- 1) The number of lymph node metastases is ≥ 4; 2) When the number of lymph node metastases is 1 to 3, at least one of the following high-risk factors must be met: i. Postoperative pathological examination shows that the diameter of the primary tumor is ≥5cm; ii. The histological grade of the primary tumor is grade III (excluding grade II-III); iii. There is residual invasive cancer in breast lesions after neoadjuvant treatment; iv. Ki-67≥30%.
- Eastern Cooperative Oncology Group (ECOG) physical status score is 0 -2 points.
- With my consent and having signed the informed consent form, I am willing and able to comply with the planned interview.
- inspections, study treatment plans, laboratory tests, and other research procedures.
Who cannot join
- Pathological examination diagnosed as HER2-positive breast cancer (HER2-positive definition: standard immune Histochemistry (IHC) test is 3+ or ISH test is positive).
- Local or regional recurrence of breast malignant tumors.
- The clinical stage of the tumor is stage IV (metastatic) breast cancer.
- Bilateral breast cancer (including contralateral carcinoma in situ).
- History of serious lung diseases such as interstitial pneumonia.
- Have received CDK4/6 inhibitor treatment or other anti-tumor biological treatments in the past therapy, targeted therapy or tumor immunotherapy.
- Have undergone major surgical operations, any investigational drugs, or others within 4 weeks before randomization Anticancer treatment or use of immunomodulators (excluding surgery, chemotherapy, radiotherapy and endocrine therapy).
- The presence of other serious physical or mental illnesses or laboratory abnormalities that may increase participation The risks of the research, or interference with the research results, and the researcher's opinion that he is not suitable to participate in this research study patients.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
The investigators combined postoperative radiotherapy with CDK4/6 inhibitors ± endocrine adjuvant therapy to explore the tolerability and safety of this treatment regimen in HR+/HER2- postoperative high-risk breast cancer patients. During the study, investigators also utilized PRO scales (FACT-B, FACT-ES, FACT-F) to evaluate patients' multidimensional experiences, such as physical function, emotional state, and treatment-related symptoms, thereby obtaining more authentic and reliable data for symptom assessment and patient benefit.
Read the detailed description
- The screening and evaluation of patients are conducted within 28 days prior to their enrollment, with the investigator screening subjects who meet the inclusion criteria. Prior to initiating any study-specific procedures or assessments, it is mandatory to obtain a signed informed consent form (ICF) from the subjects. Suitable candidates are selected through a series of consultations and examinations, which include inquiries about the patient's personal information, medical history, family history, marital and reproductive history, postoperative pathology, electrocardiogram (ECG), CT scans, complete blood count (CBC), blood biochemistry, and other relevant laboratory tests, to determine whether the subjects are eligible for enrollment in this study.
- The patient is orally administered the CDK4/6 inhibitor determined by the dose escalation model one day before radiotherapy. During radiotherapy, patient visits are conducted weekly (±2 days) to record vital signs, adverse reactions, and related management measures, specifically at the following times: 7 days before the start of radiotherapy, the 10th day of radiotherapy, the 20th day of radiotherapy, and the 30th day of radiotherapy. If the patient's radiotherapy is delayed for any reason, the follow-up time should be postponed according to the actual situation. PRO scale questionnaires (FACT-B, FACT-ES, FACT-F) are assessed one day before radiotherapy, on the 14th day of radiotherapy, and on the 28th day of radiotherapy. Follow-up evaluations and PRO scale questionnaire assessments are conducted 2 weeks and 4 weeks after the completion of the combined treatment regimen. After completing the 4-week follow-up period of the combination therapy, the patient may resume the normal oral dosage of CDK4/6 inhibitor medication.
- Evaluate efficacy and safety through statistical methods to form research conclusions. Conduct data cleaning and preprocessing, safety analysis (incidence and severity of AEs; analysis of the correlation between serious adverse events and treatment), and summarize and report the results.
- Conditions
- Breast Cancer
- Being tested
- CDK4/6 inhibitor±endocrine therapy drug±OFS treatment combined with synchronous radiotherapy
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CDK4/6 inhibitor±endocrine therapy drug±OFS treatment combined with synchronous radiotherapyDrug
After the patient is confirmed to be enrolled, the CDK4/6i dose for the next patient is determined by a dose allocation model (empirical logistic model, obtained using the R dfcrm software package) based on the DLT observed in all previously evaluated patients. The starting dose of CDK4/6i (abexiclib, oral) is 50 mg bid, and other dose levels are: 100 mg bid, 150 mg bid.
| Study group | Role | What they receive |
|---|---|---|
| Radiotherapy with concurrent CDK4/6 inhibitors combined with endocrine therapy | Experimental | After the patient is confirmed to be enrolled, the CDK4/6i dose for the next patient is determined by a dose allocation model (empirical logistic model, obtained using the R dfcrm software package) based on the DLT observed in all previously evaluated patients. The starting dose of CDK4/6i (abexiclib, oral) is 50 mg bid, and other dose levels are: 100 mg bid, 150 mg bid. Receives: Drug: CDK4/6 inhibitor±endocrine therapy drug±OFS treatment combined with synchronous radiotherapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
tolerability and safety
This study aims to investigate the tolerability and safety of postoperative adjuvant radiotherapy combined with CDK4/6 inhibitors in the treatment of hormone receptor-positive, HER2-negative high-risk breast cancer patients.
Safety will be expressed by the incidence (%) of grade 3 and above adverse events during the course of treatment.
Tolerability is expressed by the maximum dose (mg) of CDK4/6 inhibitor that the patient can use during the combination therapy.
Measured: From enrollment to 3 months after the end of radiotherapy
Secondary outcomes (1)
To assess the impact of this combination regimen on patient quality of life
The quality of life of patients was assessed using the FACT-B, FACT-ES, and FACIT-F scales at (the day before radiotherapy (T0), week 4 (T1), after radiotherapy (T2), 1 month after radiotherapy (T3), and 3 months after radiotherapy (T4)), respectively.
The score and total score at each time point are calculated separately through three scales: FACT-B: total score ranges from 0 to 144 points. FACT-ES: Total score ranges from 0-180. FACIT-F: Total score ranges from 0-52 points. In the FACT-B, a higher total score represents a better quality of life. In the FACIT-F and FACT-ES, the higher the total score, the less fatigue and endocrine symptoms are.
Measured: Start of radiotherapy to 3 months after radiotherapy
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Mar 2026
- Study start1 Apr 2026 (estimated)
- Primary completion30 Apr 2027 (estimated)
- Study completion30 Jun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Guizhou Provincial People's Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07446686
- Sponsor's protocol ID
- 2025-169
- Status last verified
- Feb 2026
- First submitted
- 22 Nov 2025
- Last updated
- 3 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study on the Safety and Tolerability of Postoperative Radiotherapy Concurrent With CDK4/6 Inhibitors in HR+/HER2- High-Risk Breast Cancer
- ClinicalTrials.gov ID
- NCT07446686
- Acronym / sponsor ID
- 2025-169
- Conditions
- Breast Cancer
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Guizhou Provincial People's HospitalUniversity, hospital or other
- Study start
- 1 Apr 2026 (estimated)
- Primary completion
- 30 Apr 2027 (estimated)
- Study completion
- 30 Jun 2027 (estimated)
- First posted
- 3 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The investigators combined postoperative radiotherapy with CDK4/6 inhibitors ± endocrine adjuvant therapy to explore the tolerability and safety of this treatment regimen in HR+/HER2- postoperative high-risk breast cancer patients. During the study, investigators also utilized PRO scales (FACT-B, FACT-ES, FACT-F) to evaluate patients' multidimensional experiences, such as physical function, emotional state, and treatment-related symptoms, thereby obtaining more authentic and reliable data for symptom assessment and patient benefit.
Detailed description
- The screening and evaluation of patients are conducted within 28 days prior to their enrollment, with the investigator screening subjects who meet the inclusion criteria. Prior to initiating any study-specific procedures or assessments, it is mandatory to obtain a signed informed consent form (ICF) from the subjects. Suitable candidates are selected through a series of consultations and examinations, which include inquiries about the patient's personal information, medical history, family history, marital and reproductive history, postoperative pathology, electrocardiogram (ECG), CT scans, complete blood count (CBC), blood biochemistry, and other relevant laboratory tests, to determine whether the subjects are eligible for enrollment in this study.
- The patient is orally administered the CDK4/6 inhibitor determined by the dose escalation model one day before radiotherapy. During radiotherapy, patient visits are conducted weekly (±2 days) to record vital signs, adverse reactions, and related management measures, specifically at the following times: 7 days before the start of radiotherapy, the 10th day of radiotherapy, the 20th day of radiotherapy, and the 30th day of radiotherapy. If the patient's radiotherapy is delayed for any reason, the follow-up time should be postponed according to the actual situation. PRO scale questionnaires (FACT-B, FACT-ES, FACT-F) are assessed one day before radiotherapy, on the 14th day of radiotherapy, and on the 28th day of radiotherapy. Follow-up evaluations and PRO scale questionnaire assessments are conducted 2 weeks and 4 weeks after the completion of the combined treatment regimen. After completing the 4-week follow-up period of the combination therapy, the patient may resume the normal oral dosage of CDK4/6 inhibitor medication.
- Evaluate efficacy and safety through statistical methods to form research conclusions. Conduct data cleaning and preprocessing, safety analysis (incidence and severity of AEs; analysis of the correlation between serious adverse events and treatment), and summarize and report the results.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Radiotherapy with concurrent CDK4/6 inhibitors combined with endocrine therapy | Experimental | Drug: CDK4/6 inhibitor±endocrine therapy drug±OFS treatment combined with synchronous radiotherapyAfter the patient is confirmed to be enrolled, the CDK4/6i dose for the next patient is determined by a dose allocation model (empirical logistic model, obtained using the R dfcrm software package) based on the DLT observed in all previously evaluated patients. The starting dose of CDK4/6i (abexiclib, oral) is 50 mg bid, and other dose levels are: 100 mg bid, 150 mg bid. |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (11 listed)
- Age is 18-75 years old, gender is female
- Postoperative pathological examination confirmed HR+, HER2- invasive breast cancer:
- The time from radical surgery or breast-conserving surgery to randomization shall not exceed 6 months;
- Postoperative pathological examination after radical surgery revealed the presence of lymph nodes in the axilla on the ipsilateral side of the breast lesion.
- Metastasis (lymph node micrometastases, ipsilateral internal mammary lymph nodes and supraclavicular lymph nodes are allowed) metastasis, but the number of metastases to the ipsilateral internal mammary lymph nodes and supraclavicular lymph nodes is not included in the positive calculation of sexual lymph nodes), the specific requirements are as follows:
Key exclusion criteria (8 listed)
- Pathological examination diagnosed as HER2-positive breast cancer (HER2-positive definition: standard immune Histochemistry (IHC) test is 3+ or ISH test is positive).
- Local or regional recurrence of breast malignant tumors.
- The clinical stage of the tumor is stage IV (metastatic) breast cancer.
- Bilateral breast cancer (including contralateral carcinoma in situ).
- History of serious lung diseases such as interstitial pneumonia.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CDK4/6 inhibitor±endocrine therapy drug±OFS treatment combined with synchronous radiotherapyAfter the patient is confirmed to be enrolled, the CDK4/6i dose for the next patient is determined by a dose allocation model (empirical logistic model, obtained using the R dfcrm software package) based on the DLT observed in all previously evaluated patients. The starting dose of CDK4/6i (abexiclib, oral) is 50 mg bid, and other dose levels are: 100 mg bid, 150 mg bid. | Drug | Radiotherapy with concurrent CDK4/6 inhibitors combined with endocrine therapy |
Primary outcome
tolerability and safety
Time frame: From enrollment to 3 months after the end of radiotherapy
This study aims to investigate the tolerability and safety of postoperative adjuvant radiotherapy combined with CDK4/6 inhibitors in the treatment of hormone receptor-positive, HER2-negative high-risk breast cancer patients. Safety will be expressed by the incidence (%) of grade 3 and above adverse events during the course of treatment. Tolerability is expressed by the maximum dose (mg) of CDK4/6 inhibitor that the patient can use during the combination therapy.
1 secondary outcome
To assess the impact of this combination regimen on patient quality of life
Time frame: Start of radiotherapy to 3 months after radiotherapy
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Mar 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing CDK4/6 inhibitor±endocrine therapy drug±OFS treatment combined with synchronous radiotherapy in people with Breast Cancer, run by Guizhou Provincial People's Hospital.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 3 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Yong Li (86-13628566285, liyong7229771@163.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
tolerability and safety (time frame: From enrollment to 3 months after the end of radiotherapy). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Mar 2026.