Chemotherapy compared with autologous or allogeneic bone marrow transplantation in the management of acute myeloid leukemia in first remission

High dose cytarabine or transplantation for consolidation of younger patients with acute myeloid leukemia

Collaborative study groups have invested considerable effort in the last decade in defining the role of allogeneic and autologous bone marrow transplantation as consolidation treatment for first remission of acute myeloid leukemia in younger patients. These efforts have been able, more precisely, to quantitate the degree to which patients who receive transplantation are a selected group. There has been a trend in recent years to increase the intensity of chemotherapy, which has improved treatment results, and the factors which determine the risk of relapse have become more widely acknowledged. These developments have made the appropriate choice of consolidation treatment less clear. Transplantation significantly reduces the risk of relapse and in some trials has improved the disease-free survival. However, a clear benefit in overall survival has been less clear and more difficult to demonstrate, partly because some patients who fail first-line chemotherapy can be salvaged in second remission. The trials that included high-dose cytarabine (ara-C) in the chemotherapy schedule were the ones in which no survival benefit was seen.

Granulocyte colony-stimulating factor after intensive consolidation chemotherapy in acute myeloid leukemia: results of a randomized trial of the Groupe Ouest-Est Leucémies Aigues Myeloblastiques

PURPOSE

Ten years after the first clinical studies, the clinical impact of myeloid growth factors in acute myeloid leukemia is still unclear. One of the objectives of the Groupe Ouest-Est Leucémies Aigues Myeloblastiques (GOELAM) 2 trial was to evaluate the benefit of granulocyte colony-stimulating factor (GCSF) given only after the two courses of intensive consolidation chemotherapy (ICC) used to maintain complete remission (CR).

PATIENTS AND METHODS

One hundred ninety-four patients who were in CR after induction treatment were randomly assigned to receive G-CSF (100 patients) or no G-CSF (94 patients) after two courses of ICC (ICC 1, high-dose cytarabine plus mitoxantrone; ICC 2, amsacrine plus etoposide). G-CSF (filgrastim) was administered from the day after chemotherapy until granulocyte recovery at a daily dose of 5 microg/kg.

RESULTS

In the G-CSF group, the median duration of neutropenia (< 0.5 x 10(9)/L) was dramatically reduced, both after ICC 1 (12 v 19 days, P <.001) and after ICC 2 (20 v 28 days, P <.001). The median duration of hospitalization was also significantly shorter in the G-CSF group (24 v 27 days after ICC 1, P <.001; 29 v 34 days after ICC 2, P <. 001). The median duration of intravenous antibiotics was significantly reduced after ICC 1 and ICC 2, and the median duration of antifungal therapy was significantly reduced after ICC 1. However, the incidence of microbiologically documented infections, the toxic death rate, the 2-year disease-free survival, and the 2-year overall survival were not affected by G-CSF administration. Moreover, the median interval between ICC1 and ICC2 was reduced by only 2 days, and the number of patients undergoing ICC2 was not increased in the G-CSF arm.

CONCLUSION

G-CSF should be administered routinely after ICC to reduce the duration of neutropenia and hospitalization. However, G-CSF did not seem to significantly increase the feasibility of this two-course program or modify overall outcome.

Effects of imipenem and cilastatin on human T-lymphocytes derived from acute leukemia patients with chemotherapy-induced leucopenia: studies of T-lymphocyte responses in the presence of acute myelogenous leukemia (AML) blast accessory cells

The effects of imipenem and cilastatin on human T-lymphocytes were studied in vitro. As responder T-cells were used T-lymphocyte clones derived from acute leukemia patients with chemotherapy-induced cytopenia, and the accessory cells were highly enriched acute myelogenous leukemia (AML) blasts. The effects of imipenem and cilastatin on phytohemagglutinin (PHA), anti-CD3 and anti-CD3+anti-CD28 stimulated activation were assayed, and in addition drug effects on cytokine-dependent proliferation of activated T-lymphocytes were investigated. Imipenem inhibited IL2-dependent proliferation of activated CD4(+) and CD8(+) T-cell clones, and an inhibition was also detected for IL7-, IL12-, IL15-, IL16- and IL17-dependent clonal proliferation. Imipenem caused a weak inhibition of anti-CD3- and PHA-stimulated T-cell proliferation when using 50 Gy irradiated AML blast accessory cells derived from various patients, whereas no effect was observed for anti-CD3+anti-CD28 stimulated and allostimulated activation. Imipenem decreased the release of IL4 and Interferon-gamma by T-cell clones stimulated with anti-CD3 and PHA in the presence of native (nonirradiated) AML blasts. The imipenem effects were observed at concentrations corresponding to levels reached in vivo, whereas even high concentrations of cilastatin did not alter T-cell responses. The T-lymphocyte inhibition is probably caused by a direct effect of imipenem on the T-cells.

Autologous bone marrow transplantation in acute leukemia

Autologous bone marrow transplantation can induce long-term LFS in 20% to 40% of patients with relapsed acute leukemia and should be considered as salvage therapy for patients who lack an HLA-matched donor and for patients over 45. Adult ALL patients and children with ALL in extramedullary relapse beyond second CR should receive alloBMT if at all possible. The role of ABMT in acute leukemia patients in first CR remains unclear despite randomized trials (Table 2). Because protocol deviations, early relapse, and inappropriately high treatment-related mortality unequally affected the ABMT cohort, and because recent randomized trials have used old purging methodologies, it is not possible to conclude that ABMT is not beneficial. More recent studies show that most patients are able to proceed with the intended ABMT and that modern purging may be associated with a treatment-related mortality rate of less then 5%. Immunomodulation and graft engineering uniquely suited to autologous progenitor cells indicate that ABMT should continue to be studied in the management of acute leukemia.

Improved outcome with T-cell-depleted bone marrow transplantation for acute leukemia

PURPOSE

To eliminate the risk of rejection and lower the risk of relapse after T-cell-depleted bone marrow transplants in acute leukemia patients, we enhanced pretransplant immunosuppression and myeloablation.

PATIENTS AND METHODS

Antithymocyte globulin and thiotepa were added to standard total-body irradiation/cyclophosphamide conditioning. Donor bone marrows were depleted ex vivo of T lymphocytes by soybean agglutination and E-rosetting. This approach was tested in 54 consecutive patients with acute leukemia who received transplants from HLA-identical sibling donors or, in two cases, from family donors mismatched at D-DR. No posttransplant immunosuppressive treatment was given as graft-versus-host disease (GVHD) prophylaxis.

RESULTS

Neither graft rejection nor GVHD occurred. Transplant-related deaths occurred in six (16.6%) of 36 patients in remission and in seven (38.8%) of 18 patients in relapse at the time of transplantation. The probability of relapse was .12 (95% confidence interval [CI], 0 to .19) for patients with acute myeloid leukemia and .28 (95% CI, .05 to .51) for patients with acute lymphoblastic leukemia who received transplants at the first or second remission. At a median follow-up of 6.9 years (minimum follow-up, 4.9 years), event-free survival for patients who received transplants while in remission was .74 (95% CI, .54 to .93) for acute myeloid leukemia patients and .59 (95% CI, .35 to .82) for acute lymphoblastic leukemia patients. All surviving patients have 100% performance status.

CONCLUSION

Adding antithymocyte globulin and thiotepa to the conditioning regimen prevents rejection of extensively T-cell-depleted bone marrow. Even in the complete absence of GVHD, the leukemia relapse rate is not higher than in unmanipulated transplants.