A Phase 1b, Multicenter, Open-Label Study of Valemetostat Tosylate in Combination With DXd ADCs in Subjects With Solid Tumors

Key Inclusion Criteria All participants must meet all of the following criteria, as well as all criteria from the relevant sub-protocol to be eligible for enrollment: * At least 18 years or the minimum legal adult age (whichever is greater) at the time the ICF is signed. * Has at least 1 measurable lesion based on investigator imaging assessment (computed tomography or magnetic resonance imaging) using RECIST v 1.1 at Screening. * Is willing to provide an adequate tumor sample. * Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1 at Screening. Additional Key Inclusion…