A DLT was defined as any of the following toxicities that were considered by the investigator to be related to MK-8628: Hematologic toxicity: Grade 4 hematologic toxicity or febrile neutropenia, Grade 3 neutropenia with infection, Grade 3 thrombocytopenia with bleeding or lasting \>7 days; Non-hematologic toxicity: Grade 3 or 4 non-hematologic toxicity (regardless of duration) unless it was not optimally managed with supportive care, Grade 3 or 4 laboratory abnormality, with or without symptoms, lasting \>48 hours, Intolerable Grade 2 non-hematologic toxicity resulting in study drug discontinuation or delay \>7 days with or without dose reduction, Designated alanine aminotransferase (ALT) or aspartate aminotransferase (AST) liver test abnormalities; Treatment delay \>2 weeks or dose reduction requirement for initiating Cycle 2.