Stereotactic Radiotherapy for Oligoprogressive ER+/HER- Metastatic Breast Cancer, a Prospective Phase 2 Study (Oligopro-Breast)

NCT06925984 | Recruiting

• 1 other identifier: CE4005
• Study Type: interventional
• Target: 48
• Locations: 1 country
• Sites: 5

Brief Summary

The Oligopro-Breast trial is a Phase II study targeting women with ER+/HER2- metastatic breast cancer who have been on endocrine therapy and/or CDK4/6 inhibitors for at least 6 months, and show progressive disease at 1-3 extracranial metastases, which are treatable locally. The trial aims to investigate if treating these resistant metastases with SBRT (or other local treatments if SBRT is not possible) can extend the use of the current systemic therapy. Patients will continue their existing systemic treatment while receiving SBRT on all progressive lesions. If new oligoprogression occurs, SBRT will be performed again. A new systemic treatment line will start if there is polyprogression (more than 3 lesions at once), progression of more than 6 lesions over 12 months, intracranial progression, or lesions that cannot be treated locally. The scientific question is whether local treatment of resistant metastases can prolong the effectiveness of ongoing systemic therapy, which is particularly beneficial if the treatment is well-tolerated. The primary objective is to measure the proportion of patients surviving without changing their systemic treatment line at 6 months after SBRT. This trial is significant for patients as it explores a method to potentially extend the duration of effective and well-tolerated treatments, offering hope for better management of metastatic breast cancer.

Conditions

OligoProgressive Metastatic Disease

Keywords

Oligoprogression; metastatic breast cancer; CDK4/6 inhibitors; SBRT; SABR; radiotherapy

Outcome Measures

Primary Outcomes (1)

• NExt Systemic Treatment-Free Survival (NEST-FS)

  At 6 months

Secondary Outcomes (9)

• Time to next line of systemic therapy (NEST)

  3 years

• Progression-free survival (PFS)

  3 years

• Modified Progression-free survival (mPFS)

  3 years

• Chemotherapy-free survival

  3 years

• Progression-free survival after start of the subsequent line of systemic treatment (PFS2)

  3 year

Other Outcomes (1)

• Correlation between (1) ctDNA burden at baseline and (2) ctDNA burden 10-12 weeks after SBRT versus the modified progression-free-survival (mPFS). NEST-FS in function of ESR1 status.

  3 years

Study Arms (1)

SBRT on the oligoprogressive metastases. Continuation of same systemic therapy.

EXPERIMENTAL

Radiation: SBRT

Interventions

SBRT RADIATION

SBRT of all oligoprogressive metastases (or other local therapy if SBRT not advisable), followed by continuation of the same systemic therapy.

SBRT on the oligoprogressive metastases. Continuation of same systemic therapy.

Eligibility Criteria

• Age: 18 Years+
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• ECOG performance status 0-2.
• Histologically confirmed ER+/HER2- MBC.
• History of polymetastatic disease. Patients with genuine oligometastatic disease and 1-3 oligoprogressive lesions are only allowed if ablative therapy of all metastases is deemed impossible.
• Under 1st to 2nd systemic treatment line with hormonotherapy and/or CDK4/6 inhibitors for at least 6 months before progression.
• Progressive disease at 1-3 extracranial sites.
• Ability to treat all progressive lesions locally according to the treating radiation oncologist.

You may not qualify if:

• Second malignancy if it is not in complete remission.
• Previous local treatment for oligoprogression under the current systemic treatment line
• Current progression in a lesion that has been treated with SBRT before and is not amendable for surgery or radiofrequency ablation (RFA).
• Inability to continue the same ST line after local therapy (for example because of toxicity or patient refusal).
• Pregnancy.
• Inability to sign the informed consent.

Sponsors & Collaborators

• Jules Bordet Institute: lead

Study Sites (5)

Jules Bordet Institute

Brussels, Belgium

RECRUITING

UZ Gent

Ghent, Belgium

RECRUITING

AZ Groeninge

Kortrijk, Belgium

RECRUITING

AZ Sint-Maarten

Mechelen, Belgium

RECRUITING

CHU UCL Namur - Site Saint Elisabeth

Namur, Belgium

RECRUITING

MeSH Terms

Conditions

Breast Neoplasms

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Central Study Contacts

Robbe Van den Begin, MD PhD

CONTACT

+32 2 541 38 28; robbe.vandenbegin@hubruxelles.be

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 26, 2025
• First Posted: April 13, 2025
• Study Start: October 30, 2025
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): May 1, 2030
• Last Updated: February 2, 2026

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share

Locations

BE (5)