Abstract: Currently, effective therapies for advanced gastric cancer with systemic metastasis are lacking. Pharmacological research has been slowly progressing over the past decades. Here, we report the case of a 56-year-old female with human epidermal growth factor receptor 2 (HER2) expression (IHC 2+/FISH-) in gastric cancer with systemic metastasis. The first-line therapeutic regime consisted of systemic administration of camrelizumab, local arterial infusion of oxaliplatin and arterial embolization, oral apatinib, and PS scheme (oral tegafur-gimeracil-oteracil (S-1) and paclitaxel (PTX), which was administered both intraperitoneally and systemically). After the treatment, a 3-month progression-free survival (PFS) was observed. Due to the occurrence of CTCAE grade 4 adverse reactions, the patient could not tolerate chemotherapy. In the second line of treatment, we replaced the PS scheme with disitamab vedotin and continued the use of carrilizumab and apatinib. After four cycles, efficacy evaluation showed that it was stable disease (SD), only CTCAE 1/2 grade adverse reactions occurred, and endoscopy examination showed local tumor control with a reduction in the ulcer lesion. At the time of submission of the current manuscript, a 6-month PFS was achieved and the treatment was continued. Due to the safety and efficacy of disitamab vedotin observed in our case, we propose that disitamab vedotin could be a promising drug for the treatment of advanced gastric cancer patients with HER2 expression.
Keywords: gastric cancer, human epidermal growth factor receptor 2, disitamab vedotin