Efficacy of platinum-based regimens as the first-line therapy in Chinese patients with advanced TNBC and deleterious BRCA1/2 mutations.

Abstract

e12565 Background: Platinum-based therapy remains an effective treatment for triple-negative breast cancer (TNBC), however, the usage is largely limited due to its side effect and rapidly developed drug resistance. High prevalence of BRCA1/2 mutations are reported in TNBC. Here we explored efficacy of platinum-based regimens as the first-line treatment for Chinese patients (pts) with advanced TNBC, and analyzed its association with mutations of germline BRCA1/2 (gBRCA). Methods: We retrospectively analyze 220 patients diagnosed as advanced TNBC who were treated at the Dept. of Breast Oncology, Peking University Cancer Hospital in 2013-2018, and routinely evaluated by RECIST 1.1. Statistical analysis is performed in R 3.5.1. Cox proportional-hazard models are used for survival analysis. Results: 129 pts received non-platinum chemotherapy (NPCT) as the first-line therapy, and 91 pts received platinum-based chemotherapy (PBCT). The clinical benefit rate (CBR) and median PFS were not statistically different between NPCT and PBCT groups The median OS was 30.0 and 22.5 months for PBCT and NPCT group respectively (P = 0.09, HR = 0.70). Among them, 114 pts had BRCA gene tested, of which 14 had deleterious gBRCA mutations, 7 in each group. In PBCT group, the CBR was 85.7% and 35.1% for pts with and without deleterious gBRCA mutations respectively (P = 0.04). The median PFS, OS were 14.9 months and 5.3months (P = 0.001), 26.5 and 15.5 months (P = 0.16) for pts with and without the gBRCA mutations. No significant difference was observed between NPCT pts with and without gBRCA mutations as regards the CBR, PFS and OS. PBCT Pts had significantly more grade 3-4 anaemia (5.5% vs 0%) and thrombocytopenia (8.8% vs 0%) while higher percentage of palmar-plantar erythrodysesthesia (PPE) (12.4% vs 0%) and peripheral neuropathy (8.6% vs 1.1%) were observed in NPCT pts. Conclusions: The efficacy of platinum-based regimens as the first-line treatment of advanced TNBC insignificantly differs from that of non-platinum therapy. However, they are more effective for patients with deleterious gBRCA mutations, suggesting a BRCA1/2 genetic testing may be warranted for such patients.