Abstract P6-15-09: Final results of weekly (w) neoadjuvant carboplatin (Cp) added to paclitaxel (P) followed by epirubicin (E) and cyclophosphamide (C) in triple negative breast cancer (TNBC) patients (pts): A BSMO breast cancer task force phase II study

Abstract

Abstract Introduction: Overall prognosis of early TNBC remains inferior to that of other breast cancer subtypes. Neoadjuvant platinum added to taxanes-anthracycline regimen has been reported to potentially improve pathologic complete response (pCR) and survival in TNBC pts. Aim: To report the final results of the efficacy and toxicity of the addition of weekly Cp to P and dose dense (dd) EC on the pCR rate in an open-label phase II study in stage II/III TNBC pts. Patients and methods: In the BSMO study sixty three pts received dd P (80mg/m2/wk) concurrent with Cp (AUC=2) for 12 weeks, added to bi-weekly E (90mg/m2) and C (600mg/m2) for 4 cycles, followed by surgery and radiotherapy. The primary endpoint was pCR in the breast and axilla. Additionally actual drug dosing and toxicities were registered. A correlative assessment of germline mutations in HRD genes is ongoing. Pts were monitored for clinical response by magnetic resonance and mammography, and also for relapse free survival and time to treatment failure. The study sample size has been calculated according to the optimal Simon's two-stage design method. The target sample size was 63 patients with 80% power to detect a pCR rate of > or=47% (α= 0.05). Results: Sixty three eligible pts with operable, non-inflammatory stage II/III TNBC were included. Most pts were between 40 and 59 yrs old and had clinical stage II disease. Forty percent were clinically node + and 68% were G3. Seventy three percent received breast conserving surgery. Sixty percent (38 out of 63 pts) achieved a pCR breast/axilla. Sixteen percent (10pts) missed three or more doses of wP, whereas at least 1 EC cycle was skipped in 19% (12pts). Sixty five percent had G3/4 neutropenia. Investigator reported febrile neutropenia occurred in 18 pts (28.5%) of which more than eighty percent during the EC part despite primary prophylaxis. Thrombocytopenia G3/4 was noticed in 10 pts (16%). Only four pts (6%) developed grade 3 peripheral neuropathy. Conclusion: The addition of weekly carboplatinum to neoadjuvant paclitaxel and ddEC is feasible and a pCR rate in the breast and axilla as high as 60% compares nicely with the results achieved with the similar 3 weekly carboplatinum arm of the CALBG 40603 trial. Febrile neutropenia rate was higher than the 3-weekly carboplatin arm in CALGB40603 trial, but occurred mainly during the EC part, while other toxicities are comparable. Future research could focus on this combination in the reverse sequence (first ECdd), which may lead to a better global haematological profile. Citation Format: Fontaine C, Cappoen N, Renard V, Van Den Bulck H, Vuylsteke P, Glorieux P, Dopchie C, Decoster L, De Grève J, Awada A, Wildiers H. Final results of weekly (w) neoadjuvant carboplatin (Cp) added to paclitaxel (P) followed by epirubicin (E) and cyclophosphamide (C) in triple negative breast cancer (TNBC) patients (pts): A BSMO breast cancer task force phase II study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-15-09.