Increasing dose intensity of anthracycline antibiotics improves outcome in patients with acute myelogenous leukemia

To understand the effect of dose concentration in the overall survival of AML, we conducted a study on the efficacy and toxicity of a drug combination where the dose of daunorubicin was intensified. For this analysis, the outcome of patients entered into two consecutive prospective trials was compared. Inclusion criteria in both arms were identical and consisted of primary AML in adults. Treatment protocol for Cape Town Regimen 4 (CTR-IV) comprised of cytarabine infusion (100 mg/m(2)) and etoposide (100 mg/m(2)), injection daily for 7 days in combination with daunorubicin (45 mg/m(2)) on days 1, 2, and 3. Patients achieving remission were given two further courses of the same chemotherapy and received allogeneic or autologous transplantation. CTR-V was a similar treatment program, except that daunorubicin was escalated on days 1, 2, and 3 to 75 mg/m(2) during induction and to 60 mg/m(2) during a single consolidation. Patients were also offered stem cell transplantation. Between 1990 and 1997, 78 patients (median age 33; range 13-67 years) fulfilled entry criteria and received CTR-IV. From 1998 onwards, 35 patients (median age 36; range 15-66 years) were prospectively enlisted into the CTR-V trial. The patient population in CTR-V had fewer Caucasian individuals (P = 0.02) and had significantly lower presentation hemoglobin (P = 0.0002). Following initiation of induction chemotherapy, 40 patients failed to respond. Among these, 10 patients demised before day 28. Another 30 (25/69 CTR-IV and 5/32 in CTR-V groups; P = 0.01) had leukemia that was resistant to chemotherapy, and all died. Remission was achieved in 59% of patients treated with CTR-IV and 77% of those receiving CTR-V (P = 0.03). CR occurred with a single course in 64% versus 88% (P = 0.02), respectively. There were no differences in the toxicity profile between these two combinations. Disease recurred in 50% and 28% (P = 0.07) of patients. For the 113 individuals, median follow up is 254 (range 19-4,451) and 304 (12-1,702; P = 0.03) days. Survival is 23% and 40%, respectively, favoring patients treated with CTR-V (log rank; P = 0.03). Cox regression analysis showed that treatment group (P < 0.001), FAB type, hemoglobin level, and platelet count were independent factors for response to chemotherapy. Older age and not undergoing myeloablative therapy were the only adverse factors for survival. We conclude that increase in the treatment dose of daunorubicin in patients with AML led to a higher remission rate, particularly with a single course of chemotherapy and had an equivalent toxicity profile. This therapeutic modification is also likely to result in substantial reduction in patient stay in hospital and in the overall expenditure.

CD52 antibodies for prevention of graft-versus-host disease and graft rejection following transplantation of allogeneic peripheral blood stem cells

Graft-versus-host disease (GVHD) is a major cause of mortality and morbidity after allogeneic bone marrow transplantation, but can be avoided by removing T lymphocytes from the donor bone marrow. However, T cell depletion increases the risk of graft rejection. In this study, two strategies are used to overcome rejection: (1) use of high doses of stem cells obtained from peripheral blood (PBSC), (2) admixture with a CD52 monoclonal antibody in order to deplete both donor and residual recipient lymphocytes. Two antibodies are compared: CAMPATH-1G (rat IgG2b) and its humanized equivalent CAMPATH-1H (human IgG1). A total of 187 consecutive patients at six centers received PBSC transplants from HLA-matched siblings between 1997 and 1999. A wide spectrum of diseases, both malignant and non-malignant, was included. The recovery of CD34+ cells after antibody treatment was close to 100%. The risk of acute GVHD (grade 2 to 4) was 11% in the CAMPATH-1G group and 4% in the CAMPATH-1H group (P = NS). The risk of chronic GVHD (any grade) was 11% in the CAMPATH-1G group and 24% in the CAMPATH-1H group (P = 0.03) but the risk of extensive chronic GVHD was only 2%. The overall risk of graft failure/rejection was 2%, not significantly different between the two antibodies. Antibody treatment was equally effective at concentrations between 10 microg/ml and 120 microg/ml and it made no significant difference to the outcome whether the patients received post-transplant immunosuppression or not (87% did not). Transplant-related mortality in this heterogenous group of patients (including high-risk and advanced disease) was 22% at 12 months. It is proposed that treatment of peripheral blood stem cells with CAMPATH-1H is a simple and effective method for depleting T cells which may be applicable to both autologous and allogeneic transplants from related or unrelated donors. Special advantages of this approach are the simultaneous depletion of donor B cells (which reduces the risk of EBV-associated lymphoproliferative disease) and the concomitant infusion of CAMPATH-1H to deplete residual recipient T cells and thus prevent graft rejection.

Immune reconstitution after allogeneic bone marrow transplantation depleted of T cells

BACKGROUND

Immune reconstitution following transplantation in individuals who had received T-cell-depleted marrow from HLA identical siblings was serially documented and correlated with the clinical recovery.

METHODS

Patients were preconditioned with radiation containing programs. GvHD prophylaxis was by T-cell depletion with CAMPATH 1G (ex vivo; median dose 20 mg). After transplantation lymphoid development was studied by flow cytometry and serum Ig concentrations were determined. Charts were reviewed to determine the effects of the immune reconstitution on the clinical performance.

RESULTS

The mean donor mononuclear cell number infused was 0.89x10(8)/kg. Within 6 months all the patients recovered their blood parameters and only one required therapy for GvHD. However, despite normal blood counts, 15 suffered life-threatening opportunistic infections, developing at a median of 24 weeks post grafting, but occurring even after 11 months. At 8 weeks from marrow infusion when leukocyte values had normalized in 15/20, compared to normal, immunophenotyping of blood cells from BMT revealed a significantly reduced mean lymphocyte count (1.06, SD 0.83x10(9)/l; P = 0.01), cells expressing CD3 (0.7x10(9)/l, SD 0.68; P = 0.05), CD4 (0.13x10(9)/l, SD 0.21; P = 0.0001) and CD19 (0.04x10(9)/l, SD 0.05; P = 0.001). Populations expressing CD8 and CD56 remained within normal range throughout the study. Normalization of cell numbers displaying CD2, CD3 and CD19 was delayed until 52, 52 and 24 weeks respectively, while CD4 counts persisted subnormal even at 72 weeks. Serum IgA levels were significantly decreased for the entire study period.

CONCLUSIONS

T-cell depletion with CAMPATH 1G while effectively preventing GvHD, also causes clinically significant and prolonged immunosuppression with apparently important clinical implications.