The primary purpose of this study is to determine the recommended dose (RD) of OTX015/MK-8628 for further phase II studies, in participants with acute leukemias (acute myeloid leukemia [AML; de novo and secondary to a myelodysplastic syndrome] or acute lymphoblastic leukemia [ALL]) or hematologic malignancies (diffuse large B cell lymphoma [DLBCL] or multiple myeloma [MM]).