Survival of patients with chronic myelogenous leukaemia relapsing after bone marrow transplantation: comparison with patients receiving conventional chemotherapy

Abstract

Summary. Treatment with busulphan and/or hydroxyurea rarely produces remission in patients with chronic myelogenous leukaemia (CML) in chronic phase. HLA-identical sibling transplants almost always produce remission, and only about 20% of patients relapse post-transplant. The increased anti-leukaemic efficacy of transplants results from intensive pretransplant treatment and immune-mediated anti-leukaemia effects. We studied 433 patients surviving 5 2 years after diagnosis of CML to determine if patients who have relapsed after a transplant in chronic phase have longer survival from diagnosis than comparable subjects receiving chemotherapy. The chemotherapy cohort included 344 adults < 50 years of age treated on consecutive trials of the Italian Cooperative Study Group on CML between 1973 and 1986. The transplant cohort included 89 patients reported to the International Bone Marrow Transplant Registry who relapsed after an HLA-identical sibling bone marrow transplant carried out between 1978 and 1992.Survivals in the two groups were compared using Cox proportional hazards regression to adjust for prognostic variables. Median survival was 65 months in the chemotherapy cohort and 86 months in the transplant cohort. The 7-year probability (95% confidence interval) of survival was 34% (28-39%) in the chemotherapy cohort and 57% (43-70%) in the transplant cohort (P¼0 . 003). There was no difference in survival of patients relapsing after T-cell depleted and non-T-cell-depleted transplants. We conclude that patients who relapse after an HLA-identical sibling bone marrow transplant for CML in chronic phase have longer survival from diagnosis than comparable patients receiving chemotherapy. This effect is most likely to be the result of intensive chemotherapy and/or radiation given for pretransplant conditioning.Keywords: CML, bone marrow transplant, chemotherapy, busulphan, hydroxyurea.Intensive chemotherapy with or without radiation followed by an HLA-identical sibling transplant is a very effective antileukaemia therapy for chronic myelogenous leukaemia (CML) in chronic phase Clift et al,

Factors associated with survival in patients with progressive disease following autologous transplant for lymphoma

“…This issue has also been explored in chronic myelogenous leukemia. 19 Although every effort was made to obtain complete data including disease status of the patients, our study may have been limited by insufficient power to detect a difference in postrelapse survival between HD and NHL patients. Nonetheless, we have shown that relapsed patients may survive more than a few months after transplant and many can respond and even obtain remission with posttransplant therapy.…”

Relapse after allogeneic BMT for chronic myeloid leukemia (CML) may be sustained by a small number of leukemic ‘stem cells’: a hypothesis

“…Should this be the case, it may also facilitate a high response rate to DLI 3,4,6,7 and explain the slow pace of the disease after relapse following BMT. 14,15 Nonetheless, this hypothesis is not in contrast and does not rule out other possible explanations for the efficacy of DLI in CML.…”