CHICAGO — Neoadjuvant docetaxel plus carboplatin and trastuzumab followed by pertuzumab (TCH+P) was associated with improved pathologic complete response rate compared with trastuzumab emtansine (T-DM1) plus pertuzumab in patients with HER2-positive early breast cancer, researchers reported at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting.1

“Combined use of pertuzumab and trastuzumab with docetaxel significantly improved pathologic complete response in the neoadjuvant setting vs trastuzumab plus docetaxel,” said lead investigator Sara A. Hurvitz, MD, medical oncologist at the University of California, Los Angeles. “In patients with HER2-positive metastatic breast cancer, T-DM1 is associated with improved survival in patients who had previously received trastuzumab and a taxane. T-DM1 was noninferior to trastuzumab plus a taxane as a first-line treatment in patients who had not received prior chemotherapy.”

Therefore, researchers sought to evaluate the impact of T-DM1 plus pertuzumab on pathologic complete response compared with TCH+P in patients with early breast cancer in a phase 3 trial.

“The KRISTINE trial presents the first phase 3 data for a neoadjuvant regimen that omits standard chemotherapy for HER2-positive breast cancer,” Dr Hurvitz noted.

For the study, investigators enrolled 444 patients with centrally confirmed HER2-positive, operable, locally advanced, or inflammatory breast cancer from 68 centers in 10 countries. Patients were randomly assigned 1:1 to receive TCH+P or T-DM1 plus pertuzumab for 6 cycles followed by surgery. Patients then continued pertuzumab plus trastuzumab or T-DM1, respectively, for 12 cycles.

Results showed that at a median follow-up of 8.9 months in the chemoimmunotherapy arm and 8.8 months in the double immunotherapy arm, pathologic complete response was reported in 56% and 44%, respectively (P=.0155).

“Neoadjuvant TCH+P achieved a superior pathologic complete response rate compared with T-DM1,” Dr Hurvitz said. “Neoadjuvant TCH+P was also associated with a higher breast-conserving surgery rate (53% vs 42%).”

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In terms of safety, neoadjuvant T-DM1 plus pertuzumab was associated with a lower incidence of grade 3 or worse adverse events (13% vs 64%), serious adverse events (5% vs 29%), and adverse events leading to treatment discontinuation (3% vs 9%).

“Neoadjuvant T-DM1 plus pertuzumab was associated with a longer maintenance of patient-reported health-related quality of life and physical function,” Dr Hurvitz added.

Reference

  1. Hurvitz SA, Martin M, Symmans WF, et al. Pathologic complete response (pCR) rates after neoadjuvant trastuzumab emtansine (T-DM1 [K]) + pertuzumab (P) vs docetaxel + carboplatin + trastuzumab + P (TCHP) treatment in patients with HER2-positive (HER2+) early breast cancer (EBC) (KRISTINE). J Clin Oncol. 2016; 34 (suppl; abstr 500).