IBCSG 36-07/BIG 2-06 (ALTTO)

A randomized, multi-center, open-label, phase III study of adjuvant lapatinib, trastuzumab, their sequence and their combination in patients with HER2/ErbB2 positive primary breast cancer Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization Study - ALTTO

Design 1

Initiation of targeted therapy after completing all (neo) adjuvant chemotherapy

Patients will receive either trastuzumab 8 mg/kg IV loading dose followed by 6mg/kg IV every 3 weeks for 1 year (52 weeks), oral lapatinib 1500 mg daily for 1 year (52 weeks), weekly trastuzumab for 12 weeks (4 mg/kg IV loading dose followed by 2 mg/kg IV weekly) followed by a 6-week treatment-free interval followed by oral lapatinib 1500 mg daily for 34 weeks (total: 52 weeks of treatment) or oral lapatinib 1000 mg daily in combination with trastuzumab 8 mg/kg IV loading dose followed by 6mg/kg IV every 3 weeks for 1 year (52 weeks).

Design 2

In patients scheduled to receive taxanes after anthracyclines and together with the targeted agents, paclitaxel will be administered concomitantly with the targeted therapy and according to a weekly schedule (80mg/m2 IV for 12 weeks). When dosed concomitantly with paclitaxel, the weekly schedule of trastuzumab will be used (4 mg/kg IV loading dose followed by 2 mg/kg IV weekly). After completion of paclitaxel, trastuzumab will revert to the three-weekly schedule (6 mg/kg without loading dose) and radiotherapy will be started, if indicated. Docetaxel may become an option pending the results of ongoing safety studies in combination with lapatinib.