Updated results from BEGONIA Phase Ib/II trial presented at ESMO

Updated results from the BEGONIA Phase Ib/II trial for the cohort of patients treated with datopotamab deruxtecan plus Imfinzi showed that the combination demonstrated durable tumour responses and no new safety signals in patients with previously untreated advanced or metastatic triple-negative breast cancer with six months additional follow-up from the previous data cut-off. These data will be presented in a mini oral session at the European Society for Medical Oncology 2023 Congress in Madrid, Spain. Datopotamab deruxtecan is a specifically engineered TROP2-directed DXd antibody drug conjugate being jointly developed by AstraZeneca and Daiichi Sankyo. Approximately 300,000 people worldwide are diagnosed annually with TNBC, the most aggressive breast cancer subtype. Less than half of patients with metastatic TNBC respond to current 1st-line treatment options which can include chemotherapy alone or in combination with an immunotherapy. Among patients with tumours that do respond to initial treatment, disease progression is common and rapid, often occurring within two years. Results showed that datopotamab deruxtecan plus Imfinzi, an anti-PD-L1 therapy, demonstrated a confirmed objective response rate of 79% including six complete responses and 43 partial responses. Responses were observed regardless of PD-L1 expression level. Median progression-free survival was 13.8 months and median duration of response was 15.5 months with 11.7 months of follow-up. The safety profile of datopotamab deruxtecan in combination with Imfinzi was consistent with the known safety profiles of both agents. Grade 3 or higher treatment-emergent adverse events occurred in 57% of patients. There were three interstitial lung disease events adjudicated as drug-related by an independent committee including two Grade 2 events and one Grade 1 event. In Arm 7 of the BEGONIA trial, the majority of patients had tumours with low PD-L1 expression. Seven patients had tumours with high PD-L1 expression. As of the 2 February 2023 data cut-off, 29 patients remained on study treatment.