Real-World Validation of the Transplant Conditioning Intensity (TCI) Score in Allogeneic Hematopoietic Cell Transplantation: A Spanish Multicenter Study on behalf of GETH-TC.

The Transplant Conditioning Intensity (TCI) score is a novel tool aiming to stratify conditioning intensity more effectively than the existing nomenclature. TCI is predictive of early nonrelapse mortality (NRM), 2-year NRM and relapse incidence (RI). We retrospectively analyzed 455 acute myeloid leukemia patients who underwent hematopoietic cell transplantation reported to Grupo Español de Trasplante Hematopoyetico y Terapia Celular (GETH). Patients were classified as low (TCI 1 to 2, 44 %, n = 200), intermediate (TCI 2.5 to 3.5, 36%, n = 162) or high (TCI 4 to 6, 20%, n = 93). All low‑score cases were reduced‑intensity conditioning, whereas every high‑score TCI was myeloablative. Among intermediate TCI, 97% (n = 158) received a myeloablative therapy. Patients were in first complete remission in 83% (n = 366) cases. Multivariate analysis revealed an increased NRM for high versus low TCI (hazard ratio [HR] 2.95; P = .01) and a reduced RI for intermediate versus low TCI (HR 0.62; P = .042). Adverse cytogenetics independently increased both NRM (HR 2.71, P = .03) and RI (HR 2.26, P = .006). Age > 65 gt; 65 years was associated with higher NRM (HR 2.72, P = .04). In a real-world setting, the TCI score effectively differentiates patients by post-transplant outcomes, highlighting high TCI as a key predictor of increased NRM.