The dose escalation will follow the traditional 3+3 design. Cohorts of 3-6 subjects will be enrolled sequentially at escalating doses of 1, 2.5, 5 and 10 mg/kg weekly. Dosing schedule for cohorts 2 and above may change after interim PK analysis after Cohort 1 Cycle 1 to bi-weekly or other regimen based on elimination profile of KN035 to avoid excessive drug accumulation. Dose escalation will continue until identification of MTD, up to a maximum dose of 10 mg/kg. MTD is defined as the highest dose studied at which no more than 1 of 6 subjects has experienced a dose-limiting toxicity (DLT) in Cycle 1.