RecruitingDrug trialA Phase Ⅰ/Ⅱa Study of HMPL-A251 in Participants With Advanced or Metastatic HER2-expressing Solid TumorsThis is a first-in-human (FIH), phase Ⅰ/Ⅱa, open-label, multicenter clinical study of HMPL-A251 monotherapy in adult participants with unresectable, advanced or metastatic HER2-expressing solid tumors.