Weekly carboplatin plus neoadjuvant anthracycline-taxane-based regimen in early triple-negative breast cancer: a prospective phase II trial by the Breast Cancer Task Force of the Belgian Society of Medical Oncology (BSMO)

Abstract

Aim: To evaluate the pCR rate and toxicity of the addition of weekly carboplatin (Cp) to paclitaxel (wP) and dose-dense (dd) epirubicin/cyclophosphamide (EC) in an open-label phase II study in TNBC patients.

Methods: Patients were included if they had stage II and III TNBC and received wP (80 mg/m²/week) concurrent with weekly Cp (AUC = 2) for 12 weeks, followed by bi-weekly epirubicin (90 mg/m²) and cyclophosphamide (600 mg/m²) plus granulocyte colony-stimulating factor (G-CSF) for four cycles, followed by surgery. The primary endpoint was the rate of pCR [(ypT0/isypN0)]. Secondary endpoints included safety and drug delivery.

Results: Sixty-three eligible patients were included. Median age was 51 years (range 29-74); 88.9% had stage II disease, 46% were clinically node positive, and 77.8% had grade 3 tumors. Fifty-four percent achieved a pCR. Twelve percent missed two or more doses of wP, whereas at least two cycles of EC were missed in 9.5%. The rate of tolerance without delays or dose reductions is very low (16%). Sixty-two percent had G3/4 neutropenia. Febrile neutropenia occurred in 18 patients of which more than eighty percent occurred during EC despite primary prophylaxis with G-CSF. Thrombocytopenia grade 3/4 was noticed in 11 pts. Three patients developed grade 3 peripheral neuropathy.

Conclusion: The addition of weekly carboplatin to neoadjuvant paclitaxel and dd EC leads to a pCR rate comparable to prior studies (54%). However, hematological toxicity and febrile neutropenia rate was unexpectedly high. Future investigations could focus on reversing the sequence, which may lead to better hematological tolerability.

Keywords: Neoadjuvant chemotherapy; Phase 2 trial; Triple-negative early breast cancer; Weekly carboplatin and paclitaxel.