MONARCH-2 was a phase III study that involved the enrollment of 669 patients with HR-positive, HER2-negative breast cancer who had progressed during adjuvant or neoadjuvant endocrine therapy; the patients were randomized to receive abemaciclib plus fuvestrant or placebo plus fulvestrant: median progression-free survival was longer in abmeciclib arm (16.4 months), when compared to the placebo arm (9.3 months) [362]. The gene discussed is ERBB2; the disease is breast cancer.