Real life data of KEYNOTE 522: The Cleveland Clinic experience.

Abstract

e12612 Background: Triple-negative breast cancer (TNBC) constitutes approximately 15% of all breast cancers and predominantly affects younger women with a disproportionate impact on Black and Hispanic ethnicities. Historically, neoadjuvant therapy centered around chemotherapy alone. However, the KEYNOTE 522 trial has demonstrated improved outcomes with the incorporation of the PD-1 inhibitor Pembrolizumab alongside neoadjuvant chemotherapy. Methods: A retrospective cohort analysis of 106 patients treated with the KEYNOTE 522 regimen within Cleveland Clinic from January 2020 to July 2023. The objective is to evaluate the real-life experience, particularly concerning treatment tolerance and pathologic complete response rates (PCR). Results: Among the 106 female patients, 6.6% completed full neoadjuvant therapy without reporting adverse events (AE), achieving a 71.42% PCR rate. Complications were reported in various subgroups: 54.72% associated with paclitaxel and carboplatin, with discontinuation rates of 60.34%, reduction rates of 33.02%, and full continuation rates of 6.9%. The most prevalent AE included cytopenia (46.55%) and febrile neutropenia, along with other infections (27.59%). For patients discontinuing paclitaxel and carboplatin, the PCR was 68.57%, while with dose reductions, it was 68.75%. Complications related to doxorubicin and cyclophosphamide were reported in 16.04% of patients, with 47.06% either discontinuing or reducing dose, and 5.88% continuing full therapy. Febrile neutropenia, along with other infections (64.71%) and cytopenia (23.53%) were the prominent AE. The PCR for patients discontinuing or reduced doxorubicin and cyclophosphamide was 62.50%. Pembrolizumab-related complications were reported in 16.98% of patients, with a 50% discontinuation rate. The most common AE was dermatologic toxicities (27.78%). The PCR for patients discontinuing pembrolizumab was 83.33% versus 62.5% for those continuing full therapy. Conclusions: This retrospective analysis highlights infections and cytopenias as the primary adverse reactions. Notably, the dose reduction or discontinuation of agents did result in a deterioration of PCR rate compared to patients completing full therapy. Remarkably, PCR was improved for the pembrolizumab discontinuation group, perhaps suggesting a correlation between autoimmune toxicities and improved response. Additional prospective study with larger sample size is needed to understand whether all patients benefit from completing the Keynote 522 regimen. [Table: see text]