|The following article features coverage from the 2017 San Antonio Breast Cancer Symposium (SABCS) in San Antonio, Texas. Click here to read more of Oncology Nurse Advisor‘s conference coverage.|
Currently no systemic agents are approved for the treatment of hormone receptor-positive (HR+) breast cancer brain metastases. In a recent phase 2, Simon 2-stage trial, researchers found that the drug, abemaciclib, a selective CDK4/6 inhibitor, was effective in eliciting a partial treatment response in HR+/HER2– patients. These results were presented at the 2017 San Antonio Breast Cancer Symposium (SABCS 2017).
The study included 23 patients with HR+ metastatic breast cancer with at least one measurable brain lesion, divided into 2 cohorts: one of patients with HR+/HER2– disease and the other of patients with HR+/HER2+ disease. Intracranial response rate was evaluated using the Response Assessment in Neuro-Oncology brain metastases response criteria. The researchers observed no response to treatment in the HR+/HER2+ group. However, in the HR+/HER– group, there were 2 confirmed cases of durable partial response.
In stage I of the trial, if at least 2 patients responded to abemaciclib, then 33 additional patients would be enrolled in a stage II of the study. “The current results provide sufficient evidence of antitumor activity on brain metastases in patients with HR+/HER2– metastatic breast cancer to merit further exploration,” noted the researchers, “but not for patients with HR+/HER2+ disease.” Enrollment for stage II is ongoing.
Bachelot T, Kabos P, Yardley D, et al. Abemaciclib for the treatment of brain metastases secondary to hormone receptor positive breast cancer. Poster Presentation at: 2017 San Antonio Breast Cancer Symposium; December 6-9, 2017; San Antonio, TX. Abstract P1-17-03.