Stereotactic Ablative Body Radiotherapy (SABR) With Maintenance of Systemic Therapy Versus Physicians' Choice of Systemic Therapy for Oligoprogressive ER-positive, Her-2 Negative Breast Cancer II

Plain English Summary

Stereotactic Ablative Body Radiotherapy (SABR) With Maintenance of Systemic Therapy Versus Physicians' Choice of Systemic Therapy for Oligoprogressive ER-positive, Her-2 Negative Breast Cancer II is a Not Applicable clinical trial sponsored by Peter MacCallum Cancer Centre, Australia studying Breast Cancer, Metastatic, Metastatic Breast Cancer. This trial tests if a focused radiation treatment called SABR can help patients with advanced ER-positive, HER2-negative breast cancer delay needing a different systemic therapy. It is for patients with ER-positive, HER2-negative advanced breast cancer that has spread to other parts of the body but has only a few areas of progression. Participation involves being randomly assigned to either receive SABR on progressing areas while continuing current systemic therapy, or to receive a physician's choice of new systemic therapy. Alternatives include standard treatment approaches where a change in systemic therapy is made upon disease progression. The trial aims to enroll 74 participants.

Official Summary

The goal of this clinical trial is to assess Stereotactic Ablative Radiotherapy (SABR) as a method to delay a change in systemic therapy in patients with oligoprogressive ER-positive, HER2-negative advanced breast cancer. The main question it aims to answer is to assess whether the addition of SABR to continuation of first line endocrine therapy and CDK 4/6 inhibitor (Arm A) to patients with oligoprogressive ER-positive, HER2-negative advanced breast cancer could have longer time to strategy failure (TSF) in comparison to physician choice of systemic treatment (Arm B) in patients who had progressed first line. The treatment strategy in Arm A is to maintain patients on current endocrine therapy and CDK 4/6 inhibitor, controlling localised progressing sites of disease with SABR. Treatment strategy in Arm B is to maintain disease control with physician's choice of systemic therapy alone.

Who Can Participate

Here is what you need to know about eligibility for this trial. Patients must be 18 or older and have ER-positive, HER2-negative advanced breast cancer that has spread. They must have been responding to their current endocrine therapy and CDK 4/6 inhibitor for at least six months and have a limited number of progressing sites (1-5). Patients with uncontrolled brain metastases, certain bone issues, or more than one type of metastatic disease clone are not eligible. Women who are pregnant or breastfeeding cannot participate. This trial is studying Breast Cancer, Metastatic, Metastatic Breast Cancer, so participants generally need a confirmed diagnosis.

What They're Measuring

The primary outcome measures how long patients can continue their current treatment strategy before their cancer progresses or they pass away, indicating how well SABR helps to manage the disease. The specific primary outcome measures are: Primary Outcome Measure (Time from randomisation to progression of disease resulting in a failure of treatment strategy or death by any cause assessed until withdrawal of consent, death, or 3 years after the last patient has been randomised, whichever is earlier.). These endpoints are how researchers determine whether the treatment is effective and will form the basis of any future regulatory submissions.

About This Phase

This study does not have a traditional clinical phase designation. It may be an observational study that follows patients without intervening in their care, an expanded access or compassionate use program, or other non-interventional research. These studies contribute valuable data about disease progression, treatment patterns, and patient outcomes.

Why This Trial Matters

This trial addresses a critical need to extend the effectiveness of current treatments for advanced breast cancer, potentially allowing patients to avoid switching to new therapies sooner. This research targets Breast Cancer, Metastatic, Metastatic Breast Cancer, where improved treatment options are needed.

Investor Insight

This trial targets a significant unmet need in advanced breast cancer, a large market, with a novel approach that could offer a competitive advantage if successful, potentially improving treatment par

Is This Trial Right for Me?

Ask your doctor if your cancer has progressed in only a few areas and if you meet the specific criteria for this trial. Understand that you will be randomly assigned to one of two treatment groups, and participation involves regular check-ups and imaging. Be prepared for potential side effects from radiation therapy and discuss any concerns about quality of life questionnaires. The trial is being conducted at multiple sites. Always discuss clinical trial participation with your healthcare provider before making any decisions. This information is for educational purposes only and is not medical advice.

AI-generated analysis for educational purposes only. This is not medical advice. Discuss clinical trial participation with your doctor. Data sourced from ClinicalTrials.gov.

Study Design

• Study Type: INTERVENTIONAL
• Allocation: RANDOMIZED
• Model: PARALLEL
• Masking: NONE
• Enrollment: 74 participants

Interventions

• RADIATION: Stereotactic Ablative Radiotherapy — Stereotactic Ablative Radiotherapy
• OTHER: Physician's choice of systemic treatment — Physician's choice of systemic therapy does not mandate a change in systemic therapy, however, SABR is not permitted for management in this arm

Primary Outcomes

• Primary Outcome Measure (Time from randomisation to progression of disease resulting in a failure of treatment strategy or death by any cause assessed until withdrawal of consent, death, or 3 years after the last patient has been randomised, whichever is earlier.)

Secondary Outcomes

• Secondary Objective 1 (Time from randomisation to progression of disease resulting in a failure of treatment strategy or death by any cause assessed until withdrawal of consent, death, or 3 years after the last patient has been randomised, whichever is earlier.)
• Secondary Objective 2 (Time from randomisation to progression of disease resulting in a failure of treatment strategy or death by any cause assessed until withdrawal of consent, death, or 3 years after the last patient has been randomised, whichever is earlier.)
• Secondary Objective 3 (Time from randomisation to progression of disease resulting in a failure of treatment strategy or death by any cause assessed until withdrawal of consent, death, or 3 years after the last patient has been randomised, whichever is earlier.)
• Secondary Objective 4 (Time from randomisation to progression of disease resulting in a failure of treatment strategy or death by any cause assessed until withdrawal of consent, death, or 3 years after the last patient has been randomised, whichever is earlier.)
• Secondary Objective 5 (Time from randomisation to progression of disease resulting in a failure of treatment strategy or death by any cause assessed until withdrawal of consent, death, or 3 years after the last patient has been randomised, whichever is earlier.)

Full Eligibility Criteria

INCLUSION CRITERIA

Patients will be eligible for inclusion in this trial if all the following criteria apply:

1. Patient has signed the AVATAR-II Patient Information and Consent Form (PICF)
2. Male or female, ≥ 18 years of age at the time signing consent
3. Patients with histologically proven ER-positive, HER2-negative advanced breast cancer receiving an ET in combination with a CDK 4/6 inhibitor. Biopsy of metastatic disease if technically feasible but not mandatory
4. Patients must have evidence of extracranial metastatic disease, with no evidence of uncontrolled intracranial metastases. (Controlled intracranial metastases are defined as stable disease on repeat CT imaging performed at least one month apart.)
5. Patients must have evidence of radiological response to ET and CDK 4/6 inhibitor for a minimum of six months prior to randomisation (defined as either stable disease or partial response).

   Note: Patient must have ongoing stability/response in at least one lesion at the time of randomisation.
6. Evidence of new or existing OPD, as determined by the Investigator and defined according to RECIST1.1 (33), via CT on a per-lesion basis (between 1-5 metastases, including the primary) as follows:

   * At least a 20% increase in the diameter of a lesion, taking as reference the smallest diameter on a previous CT scan with an absolute increase of at least 5mm
   * Appearance of a new lesion(s) Note: A new lesion can be identified using various imaging modalities, such as PET-CT or WBBS, as long as the lesion is visible on serial CT scans.
7. For patients with liver or lung metastases, maximum of 3 oligoprogressive lesions in single organ
8. All OPD must be amenable to SABR, as per the radiotherapy guidelines in section 11.1 and Appendix 4 and 5
9. ECOG performance status 0-2
10. Life expectancy ≥ 6 months
11. Clinician and patient are willing to continue current line of therapy
12. Patient is able to complete QoL questionnaires, and other assessments required as part of the study

EXCLUSION CRITERIA

Patients will not be eligible for inclusion in this trial if any of the following criteria apply:

1. Is pregnant or lactating at the time of randomisation
2. Evidence of more than one clone of metastatic disease e.g., a patient with both ER-positive and triple negative clones of disease And ER-negative and/or HER2-positive disease would be excluded from the study
3. Evidence of leptomeningeal disease
4. Evidence of malignant cord compression
5. Evidence of lesion within femoral bone requiring surgical fixation
6. Patients with risk of bone fracture are not candidate for SABR (Appendix 4 and 5)
7. Previous chemotherapy for metastatic disease Note: chemotherapy for primary breast cancer is allowed
8. Contraindications to radiotherapy
9. Any condition deeming the patient unsuitable to comply with the study
10. Substantial overlap with previously treated area. Reirradiation is permitted with the condition that the combined plan adheres to the specific dose constraints outlined in this protocol. It is advised to use biological effective dose (BED) calculations to correlate previous doses with the tolerance doses documented in the protocol
11. Evidence of progression in more than 5 lesions
12. Prior SABR delivered for oligoprogressive disease with the intent of delaying a change in systemic therapy.

Frequently Asked Questions

Related Conditions

• Breast Cancer
• Metastatic Breast Cancer
• ER-positive Breast Cancer
• HER2-negative Breast Cancer
• Hormone Receptor-positive Breast Cancer
• Advanced Breast Cancer
• Oligometastatic Breast Cancer
• Endocrine Therapy Resistance
• CDK 4/6 Inhibitor Therapy
• Metastatic Cancer

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