A similar observation has been recorded with abemaciclib (150 mg, twice daily) in combination with a non-steroidal aromatase inhibitor either anastrozole (1 mg/day) or letrozole (2.5 mg/day) in a phase III clinical study (NCT02246621) involving postmenopausal women with HR + and HGR2 − progressive breast cancer [85]. The gene discussed is CYP19A1; the disease is breast cancer.