Type-level market taxonomy differentiates drugs by mechanism into cytotoxic chemotherapy, targeted agents, and immunotherapies. Cytotoxic chemotherapyโplatinums, taxanes, fluoropyrimidinesโstill generates the highest volume sales because it is protocol-mandated backbone therapy, yet its value share is eroding by low double-digit ASP erosion from generics. Targeted therapies, subdivided into HER2 (trastuzumab, margetuximab), VEGF (ramucirumab), and emerging CLDN18.2, collectively contribute the largest absolute revenue growth; their ability to command >US$5 k monthly costs offsets smaller patient fractions. Immunotherapy, led by pembrolizumab and nivolumab, is the fastest-expanding subtype, capturing incremental revenue as MSI-H and PD-L1 CPS โฅ1 labels broaden. Each subtypeโs uptake directly affects revenue concentration and forecasts within the Gastric Carcinomas Drugs market.