ESR1 and breast cancer: Another phase II trial of GDC-0941 in combination with fulvestrant (NCT01437566), both in HR+ postmenopausal breast cancer patients, was updated with a result of no PFS significance in the combination group (HR = 0.74; 95 % CI 0.51-1.05), otherwise effective in the ER and PR positive subgroup (HR = 0.44; 95 % CI 0.28-0.69).