DLT was evaluated according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.03 and was defined as any of the following events: 1. Grade 4 neutropenia for more than 7 days under maximum supportive therapy; 2. Febrile neutropenia; 3. Platelet counts decreased of Grade 3 requiring platelet transfusion or blood platelet decreased of Grade 4; 4. If Course 2 was not initiated within 14 days due to AE related to the protocol treatment; 5. Grade 3 or higher non-hematologic toxicity that was considered clinically significant, except the following cases, Grade 3 gastrointestinal symptoms that could be controlled with supportive therapy (eg, appropriate use of antiemetics, antidiarrheals), and Grade 3 or higher electrolyte abnormalities that were not deemed clinically significant.

PFS rate at 6 months was defined as the crude rate of surviving participants who survived or were not determined as progressive at 6 months from the day of enrollment. Although the subjects who had no imaging data on progression at 6 months after enrollment or the subjects who had lost to follow-up were included in the denominator, these subjects were not handled as progression-free. Progression included both progression disease (PD) based on diagnostic imaging assessed according to response evaluation criteria in solid tumors (RECIST) ver 1.1 and primary disease progression that cannot be confirmed by diagnostic imaging (clinical progression). PD: at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that is the smallest on study).