margetuximab plus chemotherapy (n=266) vs. trastuzumab plus chemotherapy (n=270)
randomized controlled trial
margetuximab plus chemotherapy (capecitabine or eribulin or gemcitabine or vinorelbine)
margetuximab : 15mg/kg IV over 120min on day 1 of each 21-day cycle. / capecitabine : 1000mg/m² PO 2/day for 14days followed by 7days off or eribulin : 1.4mg/m² IV on days 1 and 8 of each cycle or gemcitabine : 1000mg/m² IV on days 1 and 8 of each cycle or vinorelbine 25 to 30mg/m² IV on days 1 and 8 of each cycle.
trastuzumab plus chemotherapy (capecitabine or eribulin or gemcitabine or vinorelbine)
trastuzumab : 6mg/kg over 30-90min on day 1 of each 21-day cycle after a loading dose of 8mg/kg (over 90min). / capecitabine : 1000mg/m² PO 2/day for 14days followed by 7days off or eribulin : 1.4mg/m² IV on days 1 and 8 of each cycle or gemcitabine : 1000mg/m² IV on days 1 and 8 of each cycle or vinorelbine 25 to 30mg/m² IV on days 1 and 8 of each cycle.
Margetuximab premedication was recommended, if not already given with chemotherapy: standard doses of acetaminophen or ibuprofen, diphenhydramine, ranitidine, and dexamethasone, or equivalents.
la/mBC - HER2 positive - 2nd Line (L2)
Prior brain metastases were allowed if treated and stable.
open label
166 centers in 17 coutries
P3 / PFS by CBA at 0.05, if significant, 0.05 to OS : 2 interim analyses for OS : 1 at the time of PFS analysis (alpha=0.0004), 2 when 70% of OS event (alpha=0.0146), and final OS (alpha = 0.0454), then if significant assessment of PFS (investigator review) and ORR.