Efficacy of escalated imatinib combined with cytarabine in newly diagnosed patients with chronic myeloid leukemia.

BACKGROUND: In order to improve the molecular response rate and prevent resistance to treatment, combination therapy with different dosages of imatinib and cytarabine was studied in newly diagnosed patients with chronic myeloid leukemia in the HOVON-51 study. DESIGN AND METHODS: Having reported feasibility previously, we hereby report the efficacy of escalated imatinib (200 mg, 400 mg, 600 mg or 800 mg) in combination with two cycles of intravenous cytarabine (200 mg/m(2) or 1000 mg/m(2) days 1 to 7) in 162 patients with chronic myeloid leukemia. RESULTS: With a median follow-up of 55 months, the 5-year cumulative incidences of complete cytogenetic response, major molecular response, and complete molecular response were 89%, 71%, and 53%, respectively. A higher Sokal risk score was inversely associated with complete cytogenetic response (hazard ratio of 0.63; 95% confidence interval, 0.50-0.79, P<0.001). A higher dose of imatinib and a higher dose of cytarabine were associated with increased complete molecular response with hazard ratios of 1.60 (95% confidence interval, 0.96-2.68, P=0.07) and 1.66 (95% confidence interval, 1.02-2.72, P=0.04), respectively. Progression-free survival and overall survival rates at 5 years were 92% and 96%, respectively. Achieving a major molecular response at 1 year was associated with complete absence of progression and a probability of achieving a complete molecular response of 89%. CONCLUSIONS: The addition of intravenous cytarabine to imatinib as upfront therapy for patients with chronic myeloid leukemia is associated with a high rate of complete molecular responses (Clinicaltrials.Gov Identifier: NCT00028847).

KIR2DS5 is associated with leukemia free survival after HLA identical stem cell transplantation in chronic myeloid leukemia patients.

BACKGROUND: Alloreactive NK cells play a role in tumor eradication after allogeneic HLA mismatched stem cell transplantation (SCT). The effect of NK alloreactivity in HLA identical SCT is still under debate and in particular in transplantation for chronic myeloid leukemia (CML) the data are very limited and with conflicting outcome. The aim of our study was to evaluate the effect of KIR genes and KIR ligands on leukemia free survival (LFS) and relapse rate in a well-defined, homogeneous group of CML patients phase upon HLA identical sibling SCT. METHODOLOGY: We retrospectively analyzed the effect of KIRs and KIR ligands (C1 and C2) on LFS and relapse in 70 CML patients in 1st chronic phase, who had received an HLA identical sibling graft. For KIR typing we used a single PCR based KIR typing protocol that also included primers allowing for the identification of the KIR binding site on HLA-Cw (AA 77 and 80). PRINCIPAL FINDINGS: The data show clear differences in transplant outcome between patients having both ligands (C1 and C2) as compared to patients having only one ligand (C1 or C2). In the latter group, the stimulatory KIR2DS5 gene was associated with improved leukemia free survival (p=0.007; hazard ratio 4.3; 95% confidence interval 1.3-6.7) and lower relapse rates (p=0.028; HR 4.3, 95% CI 1.1-9.1). In contrast, in patients carrying both ligands, KIR2DS5 was associated with reduced LFS (p=0.0056; HR 0.3; 95% CI 0.1-0.7) and higher relapse rate (p=0.02; HR 0.35, 95% CI 0.1-0.8). CONCLUSIONS: Our data indicate a role for an NK mediated anti-CML response after HLA identical sibling SCT that is influenced by KIR ligands and, more importantly, by stimulatory KIRs present in the donor.

Dose-finding study of imatinib in combination with intravenous cytarabine: feasibility in newly diagnosed patients with chronic myeloid leukemia.

The HOVON cooperative study group performed a feasibility study of escalated imatinib and intravenous cytarabine in 165 patients with early chronic-phase chronic myeloid leukemia (CML). Patients received 2 cycles of intravenous cytarabine (200 mg/m(2) or 1000 mg/m(2) days 1-7) in conjunction with imatinib (200 mg, 400 mg, 600 mg, or 800 mg), according to predefined, successive dose levels. All dose levels proved feasible. Seven dose-limiting toxicities (DLTs) were observed in 302 cycles of chemotherapy, which were caused by streptococcal bacteremia in 5 cases. Intermediate-dose cytarabine (1000 mg/m(2)) prolonged time to neutrophil recovery and platelet recovery compared with a standard dose (200 mg/m(2)). High-dose imatinib (600 mg or 800 mg) extended the time to platelet recovery compared with a standard dose (400 mg). More infectious complications common toxicity criteria (CTC) grade 3 or 4 were observed after intermediate-dose cytarabine compared with a standard-dose of cytarabine. Early response data after combination therapy included a complete cytogenetic response in 48% and a major molecular response in 30% of patients, which increased to 46% major molecular responses at 1 year, including 13% complete molecular responses. We conclude that combination therapy of escalating dosages of imatinib and cytarabine is feasible. This study was registered at www.kankerbestrijding.nl as no. CKTO-2001-03.

Differences between the different conditioning regimens for allogeneic stem cell transplantation.

PURPOSE OF REVIEW: The aim of this article is to compare the differences in efficacy and toxicity between the various conditioning regimens for allogeneic stem cell transplantation. RECENT FINDINGS: Several studies, all retrospective, that compare the impact of various different conditioning regimens amongst each other are presented. Reduced intensity conditioning apparently lowered transplant-related mortality in patients with minimal residual disease who were at high risk for treatment-related mortality. In contrast, patients with active disease could only be salvaged when a myeloablative conditioning regimen was used. By consequence, it was concluded that patients without contraindications for a myeloablative conditioning regimen should not receive reduced regimens outside a prospective randomized trial. SUMMARY: Despite high expectations, non-myeloablative conditioning regimens and regimens that have been reduced in intensity did not prove to be superior in survival when the outcomes were compared with those obtained with conventional myeloablative conditioning. Randomized prospective studies are needed to explore the appropriate niche for the various different regimens.

The origin of epithelial neoplasms after allogeneic stem cell transplantation.

We analyzed five women, who have developed epithelial neoplasms after sex-mismatched stem cell transplants. Using in situ hybridization for sex chromosome-specific DNA probes and immunohistochemistry we identified the origin of the tumor cells. We conclude that none of the non-hematologic malignancies was of donor origin.

Cellular adoptive immunotherapy after allogeneic stem cell transplantation.

PURPOSE OF REVIEW: This review presents the role of donor lymphocyte infusion, natural killer cells, and dendritic cells in cellular immunotherapy after allogeneic stem cell transplantation. RECENT FINDINGS: It becomes increasingly possible to infuse more specialized subsets of lymphocyte cells after transplantation. The infusion of natural killer cells, especially in non human leukocyte antigen-identical transplantation, may become an important tool in enhancing the graft-versus-tumor effect. Vaccination of patients after stem cell transplantation with autologous-derived dendritic cells merits further investigation. SUMMARY: Stem cell transplantation has evolved to a specialized form of immunotherapy.

Allogeneic stem cell transplantation for patients with acute myeloid leukemia or myelodysplastic syndrome who have chromosome 5 and/or 7 abnormalities.

BACKGROUND AND OBJECTIVES: Chromosome 5 and/or 7 abnormalities are cytogenetic findings indicative of a poor prognosis in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). The only potential cure for such patients is allogeneic stem cell transplantation (SCT). As data on allogeneic SCT in this context are limited we did a retrospective study of allogeneic SCT in patients with AML or MDS who had chromosome 5 and/or 7 abnormalities. DESIGN AND METHODS: This was a retrospective study of 65 patients (16 children, 49 adults) with AML (n=33) or MDS (n=32) who had chromosome 5 and/or 7 abnormalities and who underwent allogeneic SCT in six Dutch Centers between 1983 and 2001. Data on all these patients are recorded in the Netherlands Stem Cell Transplant Registry (Typhon). RESULTS: The 3-year overall survival rate among all patients was 25%. Patients below the age of 40 years had significantly fewer relapses (40%) and better survival (38%) than those above the age of 40 (86% and 8%, respectively). Relapses were less frequent in recipients of unrelated grafts than in those whose grafts were from HLA-identical siblings (30% versus 69%). The development of acute graft-versus-host disease (GVHD) grades II-IV was independently associated with significantly higher transplant-related mortality (TRM). Patients with either chromosome 5 or chromosome 7 abnormalities had a significantly better survival than patients with both chromosome 5 and 7 abnormalities. These patients with poor-risk chromosome 5 and/or 7 abnormalities were compared with a group of patients with a secondary AML/MDS and normal cytogenetics and were found to have significantly more relapses and significantly worse survival but a similar TRM. INTERPRETATION AND CONCLUSIONS: We conclude that patients with AML or MDS with chromosome 5 and/or 7 abnormalities do rather poorly after allogeneic SCT, mainly because of the very high relapse rate. Nevertheless, this is the only approach that can cure some of these patients.

The impact of intensive antileukaemic treatment strategies on prognosis of myelodysplastic syndrome patients aged less than 61 years according to International Prognostic Scoring System risk groups.

The present study applied the International Prognostic Scoring System (IPSS) to 306 consecutive myelodysplastic syndrome (MDS) patients diagnosed between August 1977 and September 2000 at the University Medical Centre Nijmegen. The aim was to investigate whether the IPSS could be used as a prognostic tool in MDS patients aged less than 61 years who were treated with acute myeloid leukaemia (AML)-like chemotherapy with or without transplantation, and whether the scoring system discriminated between the subgroups of patients who benefit from intensive treatment strategies. The patients were retrospectively assigned to the IPSS risk categories and compared with the IPSS workshop patients. Eighty-three of 159 patients aged < 61 years, classified as intermediate 1, intermediate 2 and high risk according to the IPSS, received intensive treatment consisting of chemotherapy only (n = 30), chemotherapy followed by either autologous stem cell transplantation (n = 7) or allogeneic stem cell transplantation (n = 46). After intensive treatment, the median survival was 2.6 years for the intermediate 1 risk group (n = 33), 3.4 years for the intermediate 2 risk group (n = 27) and 0.9 years for the high-risk group (n = 23). We conclude that the IPSS is an improved scoring system for patients receiving supportive care. Nevertheless, the scoring system does not seem to be the best method for predicting outcome after intensive antileukaemic treatment. In particular, intermediate 2 risk patients may benefit from intensive treatment.