Treatment and Secondary Prevention of Venous Thromboembolism (VTE) in Adult Participants With Solid and Hematologic Cancers

This study is researching an experimental drug called REGN7508 (called "study drug") and will consist of 2 parts: Part 1 and Part 2. The study is focused on participants with or without cancer who develop blood clots in certain veins (called Deep Vein Thrombosis \[DVT\]) that block blood flow (Part 1) or focused on participants with cancer who develop blood clots in certain veins (DVT) or the lungs (also called Pulmonary Embolism \[PE\]) (Part 2). The aim of the study is to see how safe and effective the study drug is at treating and preventing further blood clots in participants with or without cancer (Part 1) or in participants with cancer (Part 2) compared with another treatment (apixaban). The study is looking at several other research questions, including: * What side effects may happen from taking the study drug * How much study drug is in the blood at different times * Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects)