JS105 + pyrotinib + capecitabine

JS105 + pyrotinib + capecitabine is a combination regimen under clinical investigation for solid tumors and HER2-positive cancers. **Pyrotinib** is an orally bioavailable, irreversible, pan-ErbB receptor tyrosine kinase inhibitor targeting EGFR (HER1), HER2, and HER4, thereby blocking downstream oncogenic signaling via PI3K/Akt and RAS/RAF/MAPK pathways, and is developed by Jiangsu Hengrui Medicine[1][5]. **Capecitabine** is an oral prodrug that is converted to 5-fluorouracil (5-FU), which inhibits DNA synthesis by blocking thymidylate synthase, resulting in cytotoxicity specific to rapidly proliferating tumor cells. **JS105** is referenced as an investigational agent used in combination with other anti-tumor therapies, including pyrotinib, in the context of solid tumors, but its precise identity, modality, or mechanism is not fully disclosed in available sources—likely it is a novel compound being evaluated for synergy or additive effect in combination therapy[2][8]. The primary indications for this combination are HER2-positive advanced or metastatic breast cancer and other solid tumors, being evaluated for efficacy and safety in ongoing clinical studies.