Dual-targeting strategy using trastuzumab and lapatinib in a patient with HER2 gene amplification in recurrent metachronous metastatic gallbladder carcinoma.

Gallbladder carcinoma (GBC) is a rare and highly aggressive tumor. Early diagnosis is challenging, which results in a poor prognosis using systemic therapy. Recent studies have identified a subset of GBC patients with HER2 gene (ERBB2) amplification that could benefit from HER2-targeted therapy. Here, we report one patient with recurrent metachronous GBC with metastasis, who received the combination of trastuzumab and lapatinib. This approach achieved a partial response for both the brain and the lung metastases. This study demonstrated that HER2 inhibition is a promising therapeutic strategy for GBC with HER2 amplification and, combined with lapatinib, it can effectively target brain metastasis.