Bone Marrow Protective Effect of Trilaciclib in Postoperative CCRT for LA-HNSCC

This study tests whether trilaciclib — a drug that temporarily protects bone marrow — can reduce the blood cell damage (myelosuppression) caused by chemotherapy and radiation in patients with locally advanced head and neck squamous cell cancer after surgery. **You may be eligible if...** - You have confirmed squamous cell cancer of the head and neck (oral cavity, oropharynx, hypopharynx, or larynx) — not lip or nasopharynx - You have had radical (curative) surgery and are scheduled for post-operative chemotherapy plus radiation - You have specific high-risk features such as positive surgical margins or advanced lymph node spread - You are in good health (ECOG 0–1) with adequate blood counts and organ function **You may NOT be eligible if...** - You are pregnant or plan to become pregnant - Your blood counts or organ function fall outside required ranges - You have certain other conditions that make chemotherapy or radiation unsafe Talk to your doctor to see if this trial is right for you.