Trial NCT06377202 is an observational long‑term safety follow‑up for patients previously treated with SynKIR‑110. Intervention: SynKIR‑110, an autologous, gene‑modified CAR T‑cell therapy made via lentiviral transduction. The CAR uses a KIR‑based (killer immunoglobulin‑like receptor) architecture directed against mesothelin. Mechanism of action: engineered T cells bind mesothelin on tumor cells through the KIR‑CAR, activating T‑cell effector functions and cytotoxic killing, study monitoring assesses persistence of lentiviral vector sequences and replication‑competent lentivirus. Targets: mesothelin (MSLN) on solid tumors, immune effector pathway is T‑cell activation via KIR‑CAR signaling. Note: The study was withdrawn to be replaced by a new multicenter LTFU basket study covering all SynKIR CAR T products.