Treatment with tucatinib and trastuzumab has demonstrated antitumor activity in previously treated, HER2-positive metastatic biliary tract cancer, according to research presented at the ASCO Annual Meeting 2023.

The combination produced a response in 46.7% of patients, and the 12-month overall survival rate was 53.6%.

These results were seen in the phase 2 SGNTUC-019 basket trial ( Identifier: NCT04579380). The trial included 30 patients with previously treated, HER2-positive metastatic biliary tract cancer.

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The patients had a median age of 68.5 (33-79) years, 50% were men, 76.7% were Asian, and 60.0% had stage IV disease. They had received a median of 2 prior lines of systemic therapy (range, 1-4).

The patients were treated with tucatinib at 300 mg orally twice a day and trastuzumab at 8 mg/kg intravenously on day 1 of cycle 1, followed by 6 mg/kg every 3 weeks.

At a median follow-up of 10.8 months, 10.0% of patients were still on treatment. The most common reason for treatment discontinuation was progressive disease (83.3%).

The confirmed objective response rate was 46.7%, which including 1 complete response and 13 partial responses. The median duration of response was 6.0 months. The disease control rate was 76.7%, and 70.0% of patients had a reduction in tumor size.

The median progression-free survival was 5.5 months, and the median overall survival was 15.5 months. The 12-month overall survival rate was 53.6%.

Grade 3 or higher treatment-emergent adverse events (TEAEs) occurred in 60.0% of patients. The most common grade 3 or higher TEAEs were nausea, decreased appetite, and cholangitis, each occurring in 10.0% of patients. There were no deaths due to TEAEs.

Disclosures: This research was supported by Seagen Inc. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Nakamura Y, Mizuno N, Sunakawa Y, et al. Tucatinib and trastuzumab for previously treated HER2-positive metastatic biliary tract cancer (SGNTUC-019): A phase 2 basket study. ASCO 2023. June 2-6, 2023. Abstract 4007.