This trial is to assess the safety and tolerability of Sym004, administered weekly or
biweekly as monotherapy in Japanese subjects with advanced solid tumors.This study consisted
of two parts, a dose-escalation part ("Part-A") and a dose-expansion part ("Part-B"). In
Part-A, Sym004 will be administered weekly or biweekly as monotherapy in Japanese subjects
with advanced solid tumors. In Part-B, Sym004 will be administered weekly as monotherapy to
Japanese subjects with advanced esophageal squamous cell carcinoma (ESCC) as dose-expansion.
A subject will receive Sym004 administration weekly at a dose that will determined to be the
MTD or a dose that will lower than the MTD and determined to be appropriate with
recommendation by Safety monitoring committee (SMC). The dose going to used in Part-B will be
determined after safety confirmation of weekly regimens in Part-A of this trial.