OBJECTIVES: Pembrolizumab in combination with chemotherapy obtained an European marketing authorization on October 19, 2021 for the treatment of patients with locally recurrent unresectable or metastatic triple-negative breast cancer (TNBC), whose tumors express PD-L1 with CPS ≥ 10 and who have not received prior chemotherapy for metastatic disease. An Early Access Program (EAP) was granted on November 3^rd 2021 by French HTA body (HAS) based on the seriousness of the disease, the urge to treat, the lack of other appropriate treatment and the presumed innovative nature of pembrolizumab in this indication.

METHODS: We conducted a prospective non-interventional study from November 5^th 2021 to January 13^th 2023.

RESULTS: During this period, 627 patients from 211 French centers were included in the EAP. Pembrolizumab was prescribed for 98,6% of patients at 200 mg every 3 weeks. The majority were female (99,4%), postmenopausal (75,6%) and the median (IQR) age was 59 (48-70) years. The gBRCA 1-2 gene mutation was explored for 46,6% patients, the mutation has been identified in 5.7% among them. Patients with metastatic cancer (recurrent or de novo) accounted for 89.6%, main sites of metastases were lymph node (57.9%) and lung (34,6%). Main chemotherapy regimen prescribed in combination with pembrolizumab were paclitaxel (53.4%) or carboplatin + gemcitabine (45.4%). In this analysis, almost 15 months after the start of the EAP, 156 (24,8%) patients had permanently discontinued the treatment.

CONCLUSIONS: In the EAP, pembrolizumab was prescribed in accordance with the protocol of KEYNOTE-355 in combination with paclitaxel or carboplatin + gemcitabine and initiated mostly at 200 mg. Furthermore, patient characteristics were comparable to the overall population and to the French subgroup in the KEYNOTE-355 trial. The EAP is ongoing and updated data will be presented after final database cut-off date within the next few months.