Study to Assess the Safety and Tolerability of U3-1565 in Subjects With Advanced Solid Malignant Tumors

This study will be conducted in 2 phases: a dose-escalation phase corresponding to Part 1 and a dose-expansion phase articulated in 2 concomitant parts (i.e., Parts 2a and 2b). All parts of this study are single arm and open label. In all parts, tumor assessments will be performed at screening and every 3 cycles thereafter, while the subject remains on study. U3-1565 clinical activity will be assessed measuring tumor response by physical examination and imaging according to RECIST version 1.1, if applicable.