disitamab vedotin + camrelizumab + tegafur + gimeracil + oteracil

The combination of disitamab vedotin (RC48), camrelizumab, and S-1 (tegafur/gimeracil/oteracil) is an investigational chemo-immunotherapy regimen being evaluated for the treatment of HER2-overexpressing locally advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. Disitamab vedotin is a novel antibody-drug conjugate (ADC) targeting HER2 that delivers the microtubule-disrupting cytotoxin monomethyl auristatin E (MMAE) directly to tumor cells. Camrelizumab is a humanized monoclonal antibody that blocks the PD-1 receptor, restoring T-cell-mediated anti-tumor immune responses. S-1 is an oral fluoropyrimidine combination consisting of tegafur (a 5-fluorouracil prodrug), gimeracil (a dihydropyrimidine dehydrogenase inhibitor that prevents 5-FU degradation), and oteracil (which reduces gastrointestinal toxicity by blocking 5-FU phosphorylation in the gut). Together, these agents act synergistically to enhance pathological complete response rates and improve surgical outcomes in the neoadjuvant or perioperative setting.