Wednesday, December 06, 2023 Permanent trial closure of the MA38 trial: Randomized Phase II Study Comparing Two Different Schedules of Palbociclib plus Second Line Endocrine Therapy in Women with Estrogen Receptor Positive, HER2 Negative Advanced/Metastatic Breast Cancer. The purpose of this study was to determine if the combination of endocrine therapy and Palbociclib at a daily dose of 100 mg will result in a better response to therapy with fewer dose interruptions than the proposed dosing regimen of 125 mg daily for 21 days out of a 28 day cycle in combination with endocrine therapy. For more information please visit the CCTG MA38 members trial page.