This is a proof-of-concept phase II trial to assess the safety (as primary endpoint) and clinical efficacy of neoadjuvant therapy with Elacestrant and PULSAR.
The study will enroll 21 postmenopausal patients with early HR+ HER2- node positive BC, clinically staged II-III. Patients will receive Elacestrant 345 mg orally once daily for 24 weeks and PULSAR on the MRI-based breast gross tumor volume (GTVt), consisting of 10 Gy "pulse" every 4 weeks for a maximum of 5 or less in case of radiologic complete response.
Surgery will be planned 24 weeks after Elacestrant initiation and at least 2 weeks from the last pulse and will be performed as per recommended clinical practice. Patients will then receive adjuvant systemic therapy as per standard of care and postoperative RT to the locoregional lymph nodes in case of nodal residual disease, if indicated.
Histologically proven HR-positive, HER2-negative BC
Clinical disease stage II-III
Post-menopausal female patients or male patients
Eligible for neoadjuvant treatment and subsequent surgery
1. Patients with stage IV disease 2. Patients with a history of any disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding that, based on the Investigator's judgement, provides a reasonable suspicion of a disease or condition that contraindicates the use of RT and/or Elacestrant or that might affect the interpretation of the trial results or render the patient at high risk for treatment complications.
Immune colitis
Inflammatory bowel disease
History of severe vomiting or diarrhea not having resolved to Grade 1 at Baseline