Comparison of 100-day mortality rates associated with i.v. busulfan and cyclophosphamide vs other preparative regimens in allogeneic bone marrow transplantation for chronic myelogenous leukemia: Bayesian sensitivity analyses of confounded treatment and center effects.

We evaluated the 100-day mortality rates associated with busulfan-based myeloablative conditioning regimens based on data from 1812 chronic myelogenous leukemia patients who underwent allogeneic blood or marrow transplantation (allotx). In all, 47 patients received intravenous (i.v.) busulfan and cyclophosphamide (i.v.BuCy2) with allotx at MD Anderson Cancer Center (MDACC) during 1995-1999. The remaining 1765 patients, whose data were supplied by the International Bone Marrow Transplant Registry (IBMTR), received alternative preparative regimens, primarily Cy-total body irradiation ( approximately 45%) or oral BuCy ( approximately 35%) during 1997-1998. As patients were not randomized between conditioning regimens, the i.v.BuCy2-versus-alternative treatment effect is confounded with a possible center effect due to nontreatment differences associated with factors differing between MDACC and the IBMTR centers. Additional complications are that the i.v.BuCy2-MDACC patients all survived 100 days, and three prognostic subgroups were included. Bayesian sensitivity analyses were performed to assess treatment effect on the probability of 100-day mortality, over a range of possible MDACC-versus-IBMTR center effects. For these patients, the posterior probability that i.v.BuCy2 was superior to alternative conditioning regimens ranges from 0.54 to 0.99, depending on prognosis and the magnitude of the assumed center effect.

RCT Entities:   Population Interventions Outcomes