Chronic myelogenous leukemia, version 1.2015.

Chronic myelogenous leukemia (CML) is usually diagnosed in the chronic phase. Untreated chronic phase CML will eventually progress to advanced phase (accelerated or blast phase) CML. Tyrosine kinase inhibitors (TKIs) have been shown to induce favorable response rates in patients with accelerated and blast phase CML. The addition of TKIs to chemotherapy has also been associated with improved outcomes in patients with blast phase CML. Allogeneic hematopoietic stem cell transplant remains a potentially curative option for patients with advanced phase CML, although treatment with a course of TKIs will be beneficial as a bridge to transplant. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnosis and management of patients with advanced phase CML.

Initial treatment for patients with CML.

For adult patients who present with chronic myeloid leukemia (CML) in chronic phase it is now generally agreed that initial treatment should start with the tyrosine kinase inhibitor (TKI) imatinib at 400 mg daily. Five years after starting imatinib about 60% of these patients will be in complete cytogenetic response (CCyR), still taking imatinib; an appreciable proportion of these will have achieved a major molecular response, defined as a 3-log reduction in the level of BCR-ABL1 transcripts in their blood. The patients in CCyR seem to have a very low risk of relapse to chronic phase or of progression to advanced phase. Other patients may be resistant to imatinib or may experience significant side effects that require change of therapy. The best method of monitoring responding patients is to enumerate Philadelphia chromosome-positive marrow metaphases at 3-month intervals until CCyR and to perform RQ-PCR for BCR-ABL1 transcripts at 3-month intervals after starting imatinib. The recommendations for defining "failure" and "sub-optimal response" proposed by the European LeukemiaNet in 2006 have proved to be a major contribution to assessing responses in individual patients and are now being updated. Patients who fail imatinib may respond to second-generation TKIs, but allogeneic stem cell transplantation still plays an important role for eligible patients who fare badly with TKIs. Patients who present in advanced phases of CML should be treated initially with TKI alone or with TKI in conjunction with cytotoxic drugs, but their overall prognosis is likely to be much inferior to that of those presenting in early chronic phase.

A comparison of donor lymphocyte infusions or imatinib mesylate for patients with chronic myelogenous leukemia who have relapsed after allogeneic stem cell transplantation.

Imatinib mesylate is highly effective in relapsed chronic myelogenous leukemia (CML) after allogeneic hematopoetic stem cell transplantation (HSCT). However, it is unknown whether imatinib produces durable molecular remissions. The outcome of CML patients transplanted at our center who had received only imatinib for relapse after HSCT was compared with that of patients treated with donor lymphocyte infusions (DLI). Imatinib therapy resulted in a higher incidence of relapse and inferior leukemia-free survival (p=0.006 and p=0.016, respectively). These data suggest that imatinib alone probably does not cure relapse after HSCT.

T cell and NK cell mediated graft-versus-leukaemia reactivity following donor buffy coat transfusion to treat relapse after marrow transplantation for chronic myeloid leukaemia.

Two patients with chronic myeloid leukaemia in cytogenetic relapse following T lymphocyte-depleted BMT were treated with transfusions of donor buffy coat leucocytes. In both patients the marrow reverted to a completely normal karyotype and was negative for the BCR-ABL fusion gene transcript by polymerase chain reaction analysis. Before buffy coat transfusion the cytotoxic T lymphocyte precursor frequency against pre-BMT patient leukaemia cells (Lk-CTLP) was lower than that against pre-BMT patient PHA-transformed lymphocytes (Ly-CTLP) in both cases. At 2 weeks (case 1) and 8 weeks (case 2) after transfusion this ratio inverted so that Lk-CTLP predominated. Natural killer (NK) function fell initially and then recovered to exceed pre-transfusion values prior to normalization of the bone marrow karyotype. These changes in cytotoxic T lymphocytes and NK cells following donor buffy coat transfusions for patients with relapsed chronic myeloid leukaemia after marrow transplantation support the concept of a graft-versus-leukaemia effect mediated by both MHC restricted and non-restricted pathways.

Molecular remission occurring after donor leukocyte infusions for the treatment of relapsed chronic myelogenous leukemia after allogeneic bone marrow transplantation.

Donor leukocyte infusions were administered to a patient who had relapsed with chronic myelogenous leukemia after having failed two successive HLA-matched allogeneic bone marrow transplants. Serial cytogenetic, restriction fragment length polymorphism, and polymerase chain reaction studies of the patient's marrow and blood after receiving donor leukocyte infusions revealed disappearance of the leukemic clone and the establishment of complete donor chimerism. An antileukemic response in this patient occurred initially in the absence of clinically evident graft-versus-host disease (GVHD), but complete eradication of the leukemic clone did not occur until after the onset of GVHD. The patient is now 48 weeks post infusion and remains in complete remission. This case demonstrates that leukocyte infusions are an effective form of adoptive immunotherapy which can result in a sustained molecular remission.

Prolonged remission of accelerated phase Philadelphia chromosome negative chronic myeloid leukemia following autologous recovery of normal hematopoietic elements after busulfan/cyclophosphamide and allogeneic marrow transplantation.

We describe here a patient with accelerated phase Philadelphia chromosome (Ph1) negative chronic myelogenous leukemia without BCR gene rearrangement, who received an allogeneic bone marrow transplant following a conditioning regimen consisting of busulfan (BU) and cyclophosphamide (CY). Hematopoiesis was restored following splenectomy performed 1 month post-transplant. There were no distinguishing cytogenetic differences between donor and host. Five years post-transplant the patient relapsed with the original disease. Restriction fragment length polymorphism (RFLP) studies performed at that time exhibited host specific DNA markers suggesting recurrent leukemia of host origin. RFLP analysis of the cells cryopreserved immediately post-transplant also revealed all cells to be of host origin. This patient experienced 5 years of remission with autologous hematopoietic recovery from an aggressive myeloproliferative disorder after high dose BU and CY without engraftment of donor hematopoietic cells.

Bone marrow transplantation for chronic myeloid leukaemia.

Only a minority of all patients with CML can today be treated by allogeneic bone marrow transplantation (BMT) but the probability of cure for such patients is high. The complications of BMT are similar to those that occur following transplant for other diseases, notably GVHD, pneumonitis and infections. Of special interest is the demonstration that a graft-versus-leukaemia effect plays a role in the cure of CML. Studies using the polymerase chain reaction to detect minimal residual disease (BCR/ABL transcripts) may prove useful in predicting relapse and optimizing conditioning schedules. It is now important to test whether BMT can be equally successful in older patients (over 50 years) and in those lacking HLA-identical sibling donors. For other patients autografting may offer the possibility of achieving complete cytogenetic remission and perhaps prolonging life.

Interferon alpha treatment of accelerated-phase chronic myeloid leukemia in relapse after bone marrow transplantation: a case with complete cytogenetic and molecular remission.

We describe here a patient with Philadelphia-positive chronic myeloid leukemia who had a hematologic and cytogenetic relapse after bone marrow transplantation. A diagnosis of accelerated phase was made when an additional malignant clone was detected. This clone was probably derived from the primitive Philadelphia clone, with duplication and rearrangement of the Philadelphia chromosome. The patient was treated with interferon alpha 2a and experienced a complete cytogenetic and molecular remission, with full reconstitution of the donor marrow.

Fatal B-cell lymphoproliferative syndrome in allogeneic marrow graft recipients. A clinical, immunobiological and pathological study.

We have studied four cases of fatal B-cell lymphoproliferative syndrome (LPS) developing among 333 patients (incidence 1.2%) treated with allogeneic bone marrow transplantation (BMT). All four patients had received a T-cell depleted graft. Onset of the first clinical symptoms (palpable lymph node enlargement in three and IgA-lambda paraproteinemia in two patients) occurred between 41 and 188 days post-BMT (median 76 days). The course of the LPS was rapidly progressive in all cases, leading to death in 2-5 weeks. The peripheral blood showed progressive pancytopenia with disproportionally high numbers of activated NK cells, apparently compensating for the T-cell deficiency. Post-mortem histological studies disclosed polymorphic B-cell proliferations, most pronounced in the lymph nodes, spleen, liver, lungs and kidneys. Lymphohemopoietic cells were of donor origin in three patients. In the fourth patient, graft failure suggested a host origin for the proliferating cells. Immunophenotyping and gene rearrangement analysis revealed polyclonal proliferation in one patient, monoclonal proliferation in another patient, and an oligoclonal pattern in the other two patients. The clinical behavior of the LPS was independent of clonality. Immunohistologically, the proliferating cells showed characteristics of relatively mature B-cells in three cases, and pre-B-cell features in one case. Epstein Barr virus (EBV) serology indicated seroconversion (primary infection) in one child, and chronic active EBV infection in both adults. EBV DNA as well as EBV nuclear antigen (EBNA) were detected in infiltrated tissues of all four patients. The labeling pattern on in situ hybridization suggested a replicative EBV infection comparable to that in lymphoblastoid cell lines. We conclude that EBV-associated LPS developing as a result of post-transplant immunodeficiency is a distinct clinicopathologic entity, differing from non-Hodgkin's lymphoma (including Burkitt's lymphoma) and infectious mononucleosis of the immunocompetent host.

HLA-identical marrow transplantation during accelerated-phase chronic myelogenous leukemia: analysis of survival and remission duration.

Results of HLA-identical allogeneic marrow transplantation were analyzed for 66 patients with accelerated-phase chronic myelogenous leukemia (CML). Multivariate proportional hazards regression models were used to determine disease-related and transplant-related factors associated with posttransplant mortality and relapse. The projected 5-year survival rate was estimated at 18% by the product-limit method. The major causes of death were interstitial pneumonia, infection, and relapse. Splenomegaly at initial diagnosis and longer time interval from diagnosis to transplant were associated with decreased overall survival and event-free survival. Sixteen patients have relapsed between 17 and 1,569 days (median, 486) posttransplant. The use of T-cell-depleted marrow and older age of the donor or recipient were associated with an increased probability of leukemic relapse. Ten of the 16 relapses occurred among the 15 patients who received T-cell-depleted marrow. The actuarial relapse risk 2.5 years posttransplant was 100% in patients administered T-cell-depleted marrow as compared with 25% in patients administered unmodified marrow. The data in this report emphasize the increased risks and relatively poor results that occur when marrow transplantation is deferred until after signs of acceleration appear. When compared with results for patients who received transplants during chronic phase, the poor results seen here in patients administered unmodified marrow stem primarily from increased transplant-related mortality rather than increased relapse risk. The strikingly increased relapse rate associated with the use of T-cell depletion would discourage its use for graft-v-host disease prevention in patients who receive transplants for CML.