A randomized, open-label, Phase III trial of pertuzumab retreatment in HER2-positive locally advanced/metastatic breast cancer patients previously treated with pertuzumab, trastuzumab and chemotherapy: the Japan Breast Cancer Research Group-M05 PRECIOUS study.

ABSTRACT

The PRECIOUS study (UMIN000018202) is being conducted as a multicenter, randomized, open-label Phase III study to determine if retreatment with pertuzumab is more effective than conventional treatment in HER2-positive locally advanced (LA)/metastatic breast cancer (MBC) patients previously treated with pertuzumab, trastuzumab and chemotherapy. Patients are randomized 11 into chemotherapy plus trastuzumab with or without pertuzumab groups. The latest regimen before enrollment did not include pertuzumab, and the number of previous chemotherapy regimens for LA/MBC did not exceed three. The primary endpoint is investigator-assessed progression-free survival. Secondary endpoints include independent reviewer-assessed progression-free survival, progression-free survival in patients treated with trastuzumab emtansine as the latest regimen, response rate, response duration, overall survival, safety and health-related quality of life. Target accrual is 370 patients, allowing the observation of 325 events, yielding an 80% power for detection of a hazard ratio of 0.739 with a one-sided 5% level of significance.