Durable Clinical Response to Pyrotinib After Resistance to Prior Anti-HER2 Therapy for HER2-Positive Advanced Gastric Cancer: A Case Report

Background: Patients with advanced gastric cancer, especially the HER2-positive type, have a poor prognosis; there is a paucity of effective anti-HER2 drug therapies in patients who develop resistance to trastuzumab. Case presentation: We report the case of a 36-year-old male with HER2-positive gastric cancer with lung and liver metastases. The patient responded after treatment with trastuzumab combined with chemotherapy and attained a...