GB221 + capecitabine

GB221 + capecitabine is a combination regimen composed of **GB221**, a humanized monoclonal antibody targeting the extracellular domain of human **ERBB2 (also known as HER2/neu receptor)**, and **capecitabine**, an orally administered prodrug of fluorouracil (5-FU) that inhibits cancer cell proliferation. Capecitabine is FDA-approved for use in colorectal, breast, and gastric cancers, working through inhibition of DNA and RNA synthesis after conversion to 5-FU, with the primary mechanism in gastrointestinal cancers being RNA synthesis inhibition. GB221 is in clinical development as an anti-HER2 agent for HER2-positive cancers and functions by direct binding and inhibition of HER2 signaling. The combination aims to enhance antitumor efficacy in HER2-positive tumors, leveraging the targeted action of GB221 with the cytotoxic effects of capecitabine. GB221 was developed by Shanghai Biomabs Pharmaceutical and is under clinical evaluation, commonly investigated in combination with capecitabine for metastatic breast cancer and other HER2-positive solid tumors[8][3][7].