Posted: Tuesday, June 6, 2023
Treatment with the HER2-directed tyrosine kinase inhibitor tucatinib plus the monoclonal antibody trastuzumab appeared to be safe and active in a cohort of patients with previously treated HER2-positive metastatic biliary tract cancer, according to Yoshiaki Nakamura, MD, PhD, of the National Cancer Center Hospital Japan East, Kashiwa, and colleagues. These findings from the phase II SGNTUC-019 basket trial, which were presented during the 2023 American Society for Clinical Oncology (ASCO) Annual Meeting (Abstract 4007), appear to support this combination as a future chemotherapy-free treatment option for this population with historically poor outcomes. Tucatinib has been approved in the United States in the treatment of HER2-positive metastatic breast and colorectal cancers.
A total of 30 patients who experienced disease progression after receiving at least one line of systemic therapy for metastatic disease were administered tucatinib (300 mg orally twice a day) plus trastuzumab (8 mg/kg intravenously followed by 6 mg/kg every 3 weeks) in a 21-day cycle. Follow-up data were provided for a median of 8.3 months.
The confirmed objective response rate was 46.7%; this included 1 patient with a complete response and 13 patients with a partial response. The median durations of response and progression-free survival were 6.0 and 5.5 months, respectively. The disease control rate was 76.7%. At data cutoff, 43.3% of patients had died. The 12-month overall survival rate was 53.8%.
Pyrexia (43.3%) and diarrhea (40.0%) were the most frequently reported treatment-emergent adverse events. Treatment-emergent adverse events of grade 3 or higher were observed in 60.0% of patients; however, of this population, 20.0% and 6.7% experienced events related to tucatinib and trastuzumab, respectively. A total of 6.7% of patients discontinued treatment with tucatinib because of treatment-emergent adverse events, cholangitis, and liver disorder. No deaths related to treatment-emergent adverse events were reported.
Disclosure: For full disclosure information for the study authors, visit coi.asco.org.