Memorial Sloan Kettering Cancer Center
The purpose of this study is to test different doses of abemaciclib to find the best dose in participants while receiving hormone therapy and radiation therapy.
Inclusion Criteria: * Aged ≥18 years at signing of informed consent. * Both male and female patients are allowed * Histologically confirmed metastatic breast cancer (mBC), current stage IV. * Plan for ablative radiotherapy (SBRT) to a bone metastasis. * Documented estrogen receptor (ER) positive and/or progesterone receptor (PgR) positive by immunohistochemistry. The threshold to qualify as ER or PgR positive is ≥1% per ASCO/CAP guidelines. * HER2 negative tumor status confirmed by immunohistochemistry or FISH per ASCO/CAP guidelines. * Any line of prior treatments (hormonal therapy and chemo…
The dose escalation portion of the study, a 3+3 design will be used. Once the MTD of Abemaciclib is reached, the phase Ib expansion portion will enroll up to 10 additional patients also requiring palliation to bone metastases
27Gy in 3 daily fractions or 30Gy in 5 daily fractions completed entirely within 28 days of simulation via stereotactic body radiotherapy (SBRT).