Patients were enrolled in two separate cohorts that accrued sequentially : in cohort 1 , patients were enrolled on the basis of their oestrogen receptor-positive and HER2-negative biomarker status alone , whereas in cohort 2 they were also required to have cancers with amplification of cyclin D1 ( CCND1 ) , loss of p16 ( INK4A or CDKN2A ) , or both .