VELOCITY-HNSCC Substudy-01: A Phase 2 Study of Novel Combination Therapies in Participants With Previously Untreated Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma Regardless of PD-L1 Expression Status

This is a Phase 2 study to learn about the safety and effectiveness of the study medications zimberelimab and domvanalimab when given with the chemotherapy medications paclitaxel and carboplatin in participants with head and neck cancer that has returned after treatment or spread to another part of the body. Zimberelimab and domvanalimab are medications called inhibitors, which are designed to work by targeting specific parts of your immune cells to help the immune system to better attack and destroy the cancer cells.The study is split into two cohorts:Cohort 1 participants will be randomised (chosen by chance—like flipping a coin) into either treatment Group A or Group B to receive:• Group A: zimberelimab, domvanalimab, paclitaxel, and carboplatin.• Group B: zimberelimab, paclitaxel, and carboplatin.Cohort 2 is a biomarker cohort that may open at the discretion of the sponsor. Participants will receive domvanalimab + zimberelimab + paclitaxel + carboplatin.Participant involvement will include:• Screening Period- will determine if the participant meets the requirements to take part in the study. Will be a maximum of 28 days.• Treatment- Study treatments will be administered via an intravenous (IV) infusion in 3-week (21 days) cycles. This means that it is given slowly through a needle, which will be inserted in a vein.• Follow-up- After stopping study medications the participant will have an End of Dosing Visit within 7 days after last dose of study medications, then Safety Follow Up Visits will happen 30, 60, and 100 days after last dose of study medications. Participants will enter a long-term follow-up and shall be contacted every 12 weeks.Approximately 120 participants (100 in Cohort 1 and 20 in Cohort 2) will take part in this study. The study will be run atabout 70 clinics/hospitals located globally.Gilead Sciences is the sponsor for this study responsible for starting, overseeing, and/or paying for a clinical researchstudy.