The role of HLA-matched unrelated transplantation in adult patients with Ph chromosome-negative ALL in first remission. A decision analysis.

The efficacy of unrelated transplantation for patients with ALL who lack an HLA-matched sibling remains unclear. We performed a decision analysis to determine the efficacy of myeloablative transplantation from a genetically HLA-A, -B, -DRB1 allele-matched unrelated donor for patients with Ph chromosome-negative ALL aged 21-54 years. The transition probabilities were estimated from the Japan Adult Leukemia Study Group studies (ALL93; n=80, ALL97; n=82), and the Japan Marrow Donor Program database (transplantation in first CR (CR1): n=177). The primary outcome measure was the 10-year survival probability with or without quality of life (QOL) adjustment. Subgroup analyses were performed according to risk stratification based on the WBC count and cytogenetics, and according to age stratification. In all patients, unrelated transplantation in CR1 was shown to be superior in analyses both with and without QOL adjustment (40.8 vs 28.4% and 43.9 vs 29.0%, respectively). A similar tendency was observed in all subgroups. The decision model was sensitive to the probability of leukemia-free survival following chemotherapy and the probability of survival after transplantation in standard-risk and higher-aged patients. Unrelated transplantation in CR1 improves the long-term survival probability in patients who lack an HLA-matched sibling. However, recent improvements in treatment strategies may change this result.