Neoadjuvant Study of Palbociclib in Combination With Letrozole and Trastuzumab in Stage II-III ER+ HER2+ Breast Cancer

Palbociclib is an oral drug given at a dose of 125 mg daily on Days 1-21 of each 28-day cycle for a total of 4 cycles.

Letrozole is an oral drug given at a dose of 2.5 mg orally once a day. It will be taken continuously (Days 1-28 of each cycle) until the day of definitive surgery.

"* Or FDA approved biosimilar~* Trastuzumab will be administered on a weekly basis for 16 weeks (on Days 1, 8, 15, and 22 of each 28-day cycle for a total of 4 cycles). The first dose of trastuzumab on Cycle 1 Day 1 will be a loading dose of 4 mg/kg IVPB over 90 minutes. Subsequent doses of trastuzumab will be 2 mg/kg IVPB over 30 minutes. Weekly trastuzumab will continue after the completion of Cycle 4 of palbociclib until surgery."

Goserelin is given subcutaneously at a dose of 3.6 mg on Day 1 of each cycle. Goserelin will be continued (once every 28-days) after the completion of Cycle 4 of palbociclib if required.

Standard of care

Baseline, cycle 1 day 15, and surgery

Baseline and surgery

Baseline, cycle 1 day 15, surgery, and yearly post-surgery for 5 years

Baseline

Baseline