This study is researching 2 different experimental drugs called REGN7508 and REGN9933 (called "study drugs"). The study is focused on people who have a tube placed in a vein to receive treatment (called Peripherally Inserted Central Catheter \[PICC\]). Patients with PICCs have a higher risk of getting blood clots which can block the veins (this is called Venous Thromboembolism \[VTE\]) and lead to serious health problems or be life threatening.
The aim of the study is to see how well REGN7508 and REGN9933 prevent blood clots compared to placebo after PICC placement and to see if these medications cause certain types of bleeding.
The study is looking at several other research questions, including:
* What side effects may happen from taking the study drugs * How much study drug is in the blood at different times * Whether the body makes antibodies against the study drugs (which could make the drugs less effective or could lead to side effects) * If the study drugs affect the ability of the blood to clot normally
Is undergoing PICC placement for Intravenous (IV) administration of clinically indicated medications, including chemotherapy, antibiotics, TPN, and/or other indications as described in the protocol
Has Eastern Cooperative Oncology Group Performance (ECOG) Status ≤3 or equivalent functional status as described in the protocol
Has International Normalization Ratio (INR) and aPTT values no more than 25% above the upper limit as described in the protocol
Weighs at least 40 kg during the screening period
Has a history of prior venous thrombosis in the arm and/or ipsilateral thoracic central veins in which the PICC is to be placed
Has acute leukemia, myelodysplastic syndrome, or primary and secondary myelofibrosis
Has unresected luminal gastrointestinal (GI) (including esophageal) or unresected genitourinary (GU) malignancy
Has current or history of known brain tumors or brain metastases