bosutinib + exemestane

Bosutinib + exemestane is an investigational combination therapy consisting of bosutinib, a small molecule oral tyrosine kinase inhibitor targeting Src and Abl kinases, and exemestane, a steroidal aromatase inhibitor. This combination was studied as a second-line treatment for postmenopausal women with hormone receptor-positive (HR+), HER2-negative locally advanced or metastatic breast cancer who had progressed on prior nonsteroidal aromatase inhibitors. Bosutinib inhibits signaling pathways involved in tumor cell proliferation and survival by blocking Src/Abl kinases, while exemestane reduces estrogen production by irreversibly inhibiting the aromatase enzyme, thereby decreasing estrogen-driven tumor growth. The combination aimed to enhance antitumor efficacy through dual inhibition of growth signaling and hormonal pathways. Clinical trials found that the risk-benefit profile at tested doses led to early study termination due to limited efficacy and notable toxicity[1][3][7].