Venous Thromboembolism (VTE) Prophylaxis With REGN7508 and REGN9933 in Adult and Adolescent Participants With a Peripherally Inserted Central Catheter (PICC)

A Master Protocol for a Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of REGN7508 and REGN9933, Monoclonal Antibodies Against Factor XI, for Prophylaxis of Venous Thromboembolism in Participants With a Peripherally Inserted Central Catheter (PICC) (ROXI-PEAK)

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

Key Inclusion Criteria:

1. 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
2. Has Eastern Cooperative Oncology Group Performance (ECOG) Status ≤3 or equivalent functional status as described in the protocol
3. Has International Normalization Ratio (INR) and aPTT values no more than 25% above the upper limit as described in the protocol
4. Weighs at least 40 kg during the screening period

Key Exclusion Criteria:

1. Has a history of prior venous thrombosis in the arm and/or ipsilateral thoracic central veins in which the PICC is to be placed
2. Has acute leukemia, myelodysplastic syndrome, or primary and secondary myelofibrosis
3. Has unresected luminal gastrointestinal (GI) (including esophageal) or unresected genitourinary (GU) malignancy
4. Has current or history of known brain tumors or brain metastases
5. Has any major cardiovascular event within approximately the past 30 days prior to study administration
6. Pre-existing central venous catheter or indwelling spinal or epidural catheter during the screening period

Note: Other Protocol Defined Inclusion/ Exclusion Criteria Apply