A Study of KM257 in Patients With Advanced HER2-positive or Expressing Solid Tumors.

"Part 1a dose escalation:~There will be 3 increasing dose levels (3mg/kg,6mg/kg,12mg/kg). Patients will be intravenously administrated with one dose of KM257, QW for continuous cycles of 21 consecutive days for each cycle. The dosing interval may be adjusted during the study based on emerging data from this trial.~Part 1b dose expansion:~Part1b:For cohort 1 and cohort2, KM257 will be given at the RP2D identified in Part1a;~For cohort 3 to 7:KM257 will be given combined with one of the following selected drug combination:~Drug: Capecitabine Combination therapy with KM257 - Cohort 3~Drug: Paclitaxel or Docetaxel or Irinotecan Combination therapy with KM257 - Cohort 4~Drug: Gemcitabine+Cisplatin Combination therapy with KM257 - Cohort 5~Drug: Gemcitabine+Cisplatin or Carboplatin Combination therapy with KM257 - Cohort 6~Drug:Carboplatin+Paclitaxel Combination therapy with KM257 - Cohort 7"