Basket Study for Oligo-metastatic Breast Cancer

Overview

The study will include patients with HER2-positive breast cancer and 1- 3 distant metastatic lesions, all amenable for curative intervention. Patients will be stratified by prior therapy and ER expression. In the initial baskets patients with be treated with trastuzumab-deruxtecan. Patients are treated with T-DXd 5.4mg/kg on a three weekly (21 day) basis, with the goal of 16 cycles leading to a treatment period of year, including local treatment. The first 8 cycles of T-DXd are administered neo-adjuvant, and 8 cycles adjuvant, after completion of local treatment. The proposed M22BOL trial is based on an important knowledge gap for regarding breast cancer patients with 'oligo-metastatic' disease who are usually not included in clinical trials for patients with metastatic disease since loco-regional treatments (radiation, surgery) with curative intent is not allowed in clinical trials for metastatic breast cancer. Moreover, neo-adjuvant trial protocols for early breast cancer exclude patients with distant metastases that can be treated with curative intent. This basket trial evaluates T-DXd for oligo-metastatic breast cancer with the goal to induce deep responses and subsequently long-lasting disease remissions and potentially cure.

The study will include patients with HER2-positive breast cancer and 1- 3 distant metastatic lesions, all amenable for curative intervention. Patients will be stratified by prior therapy and ER expression. Given the basket-design of this trial other baskets for oligo-metastatic breast cancer can be added, such as but not limited to other breast cancer subtypes or with other promising drugs. Baskets for de novo oligo-metastatic disease I. ER+/HER2+ II. ER-/HER2+ Baskets for oligo-metastatic disease after prior chemo/anti-HER2 therapy for primary disease III. ER+/HER2+ IV. ER-/HER2+