ERBB2 and breast cancer: In a phase II study conducted in a second-line hormone therapy setting in patients with hormone receptor-positive, HER2-negative breast cancer, the use of Ruxolitinib in combination with exemestane resulted in a clinical benefit rate of 24% in the overall population (95% CI 9.4–45.1), with 6/25 patients experiencing stable disease for more than 6 months.