Neoadjuvant carboplatin in triple-negative breast cancer: results from NACATRINE, a randomized phase II clinical trial.

BACKGROUND: Neoadjuvant chemotherapy (NACT) is the mainstay of treatment of stages II and III triple-negative breast cancer (TNBC). This study aims to evaluate if the addition of carboplatin to NACT is associated with an increase in the pathological complete response (pCR) rates in TNBC. METHODS: We conducted an open-label phase II randomized clinical trial in a single center in Brazil. Patients with stage II and III TNBC were randomized to receive standard NACT with or without carboplatin. All the patients received doxorubicin (60 mg/m2) plus cyclophosphamide (600 mg/m2) both intravenously (i.v.) q21 days for four cycles. Patients were then randomized for additional treatment with weekly (wk) paclitaxel (80 mg/m2 i.v., for 12 cycles) plus wk carboplatin AUC 1.5 (experimental arm) or without wk carboplatin (control arm). Randomization was stratified according to gBRCA status, age, and AJCC 8th edition clinical stage (II vs. III). The primary endpoint was the pathologic complete response (pCR) rate. Secondary endpoints included recurrence-free survival and overall survival. RESULTS: Between 2017 and 2021, 146 patients were randomized, 73 on each arm. The median age was 45 years. Most patients (66.4%) had locally advanced stage III disease, 67.1% had T3/T4 tumors, and 56.2% had clinically positive axillary lymph nodes. Germline BRCA status was available for all patients, and 19.9% had pathogenic BRCA1/2 variants. The pCR rate (ypT0ypN0) was numerically increased by 13.7%, being 43.8% (31 of 73 patients) in the experimental and 30.1% (22 of 73 patients) in the control arm, not meeting the prespecified goal of increasing the pCR in 15% (p-value = 0.08). Survival outcomes are immature. CONCLUSION: The addition of carboplatin to standard NACT in stages II and III TNBC was associated with a non-statistically significant numerical increase in the pCR rate. Follow-up for survival outcomes and translational research initiatives are ongoing.

PF-05280014 (a trastuzumab biosimilar) plus paclitaxel compared with reference trastuzumab plus paclitaxel for HER2-positive metastatic breast cancer: a randomised, double-blind study.

BACKGROUND: This randomised, double-blind study compared PF-05280014 (a trastuzumab biosimilar) with reference trastuzumab (Herceptin®) sourced from the European Union (trastuzumab-EU), when each was given with paclitaxel as first-line treatment for HER2-positive metastatic breast cancer. METHODS: Between 4 April 2014 and 22 January 2016, 707 participants were randomised 1:1 to receive intravenous PF-05280014 plus paclitaxel (PF-05280014 group; n = 352) or trastuzumab-EU plus paclitaxel (trastuzumab-EU group; n = 355). PF-05280014 or trastuzumab-EU was administered weekly (first dose 4 mg/kg, subsequent doses 2 mg/kg), with the option to change to a 3-weekly regimen (6 mg/kg) from Week 33. Treatment with PF-05280014 or trastuzumab-EU could continue until disease progression. Paclitaxel (starting dose 80 mg/m2) was administered on Days 1, 8 and 15 of 28-day cycles for at least six cycles or until maximal benefit of response. The primary endpoint was objective response rate (ORR), evaluating responses achieved by Week 25 and confirmed by Week 33, based on blinded central radiology review. RESULTS: The risk ratio for ORR was 0.940 (95% CI: 0.842-1.049). The 95% CI fell within the pre-specified equivalence margin of 0.80-1.25. ORR was 62.5% (95% CI: 57.2-67.6%) in the PF-05280014 group and 66.5% (95% CI: 61.3-71.4%) in the trastuzumab-EU group. As of data cut-off on 11 January 2017 (using data up to 378 days post-randomisation), there were no notable differences between groups in progression-free survival (median: 12.16 months in the PF-05280014 group vs. 12.06 months in the trastuzumab-EU group; 1-year rate: 54% vs. 51%) or overall survival (median: not reached in either group; 1-year rate: 89.31% vs. 87.36%). Safety outcomes and immunogenicity were similar between the treatment groups. CONCLUSION: When given as first-line treatment for HER2-positive metastatic breast cancer, PF-05280014 plus paclitaxel demonstrated equivalence to trastuzumab-EU plus paclitaxel in terms of ORR. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01989676.