Disitamab vedotin combined with apatinib in gastric cancer: A case report and review of literature.

Background: In patients with human epidermal growth factor receptor 2 (HER2)-overexpressing gastric cancer (GC), the combination of HER2 targeting and a standard first-line chemotherapy regimen has been demonstrated to significantly improve their prognosis. However, in a proportion of patients, cancer progresses within a short period of time, and there is currently no standard treatment after disease progression.

Case summary: This study presents a case of a 51-year-old male with advanced GC who underwent radical resection (Billroth type II subtotal gastrectomy and gastrojejunostomy) and resection of liver metastases. Immunohistochemical staining revealed a HER2 score of 2+, a dMMR status, and a Ki67 proliferation index of 30% to 40%. The gene test results indicated the presence of ERBB2 amplification and a PD-L1 expression level of less than 5%. Since December 2021, the patient has experienced disease progression during both first-line (two cycles of KN026 combined with KN046) and second-line (five cycles of nivolumab combined with trastuzumab and SOX chemotherapy) treatment regimens. The patient's prognosis following the first and second lines of treatment was unfavorable, with progression occurring in a relatively short time. For third-line therapy, disitamab vedotin (RC48) plus apatinib was used. At the time of this report, the patient had achieved a progression-free survival (PFS) of 25.8 months, which exceeded the median survival time for patients with advanced GC.

Conclusion: Despite the unfavorable prognosis associated with advanced GC, the implementation of personalized treatment approaches may still prove beneficial for select patients. In patients with HER2-positive GC with extensive metastatic involvement, the use of the HER2-targeted combination with apatinib has demonstrated the potential to prolong both PFS and overall survival.