Administration of the antibody-targeted chemotherapy agent Mylotarg to patients with CD33-positive AML in first relapse induces complete remissions with what appears to be a favorable safety profile.

The Dutch-Belgian Hemato-Oncology Cooperative Group and the Swiss Group for Clinical Cancer Research (HOVON-SAKK) collaborative study group evaluated outcome of patients (pts) with acute myeloid leukemia (AML) in first remission (CR1) entered in 3 consecutive studies according to a donor versus no-donor comparison. Between 1987 and 2004, 2287 pts were entered in these studies of whom 1032 pts (45%) without FAB M3 or t(15;17) were in CR1 after 2 cycles of chemotherapy, received consolidation treatment, and were younger than 55 years of age and therefore eligible for allogeneic hematopoietic stem cell transplantation (allo-SCT). An HLA-identical sibling donor was available for 326 pts (32%), whereas 599 pts (58%) lacked such a donor, and information was not available in 107 pts. Compliance with allo-SCT was 82% (268 of 326). Cumulative incidences of relapse were, respectively, 32% versus 59% for pts with versus those without a donor (P < .001). Despite more treatmentrelated mortality (TRM) in the donor group (21% versus 4%, P < .001), disease-free survival (DFS) appeared significantly better in the donor group (48% ؎ 3% versus 37% ؎ 2% in the no-donor group, P < .001). Following risk-group analysis, DFS was significantly better for pts with a donor and an intermediate-(P ‫؍‬ .01) or poor-risk profile (P ‫؍‬ .003) and also better in pts younger than 40 years of age (P < .001). We evaluated our results and those of the previous MRC, BGMT, and EORTC studies in a meta-analysis, which revealed a significant benefit of 12% in overall survival (OS) by donor availability for all patients with AML in CR1 without a favorable cytogenetic profile. (Blood.

BACKGROUNDIn this study, the authors analyzed the efficacy and safety of gemtuzumab ozogamicin (GO) (Mylotarg®), an antibody‐targeted chemotherapy for CD33‐positive acute myeloid leukemia (AML).METHODSPatients with CD33‐positive AML in first recurrence were entered in 3 open‐label, single‐arm, Phase II studies. Patients received monotherapy with GO 9 mg/m2 as a 2‐hour intravenous infusion in 2 doses separated by 2 weeks. Patients were evaluated for remission, survival, and treatment‐emergent adverse events.RESULTSTwo hundred seventy‐seven patients (median age, 61 yrs) were treated with GO, and 71 patients (26%) achieved remission, which was defined as ≤ 5% blasts in the bone marrow without leukemic blasts in the peripheral blood, neutrophil recovery to ≥ 1500/μL, hemoglobin ≥ 9 g/dL, and independence from red blood cell and platelet transfusions. Complete remission (CR) with platelet recovery (≥ 100,000/μL) or without full platelet recovery (< 100,000/μL) (CRp) was observed in 35 patients (13%) and 36 patients (13%), respectively. The median recurrence‐free survival was 6.4 months for patients who achieved CR and 4.5 months for patients who achieved CRp. Although expected incidences of Grade 3 or 4 neutropenia (98%) and thrombocytopenia (99%) were observed, the incidence of Grade 3 or 4 sepsis (17%) and pneumonia (8%) was relatively low. Grade 3 or 4 hyperbilirubinemia and hepatic aspartate aminotransferase and alanine aminotransferase elevations were reported in 29%, 18%, and 9% of patients, respectively; 0.9% of patients who did not undergo prior or subsequent hematopoietic stem cell transplantation developed hepatic venoocclusive disease after GO treatment.CONCLUSIONSWhen it was administered to patients with CD33‐positive AML in first recurrence, single‐agent GO induced a 26% remission rate with a generally acceptable safety profile. Cancer 2005. © 2005 American Cancer Society.

Induction therapy with cytarabine at the lower dose already produced maximal antileukemic effects for all response end points, suggesting a plateau in the dose-response relationship above this dose level. High-dose cytarabine results in excessive toxic effects without therapeutic benefit. (Netherlands Trial Register number, NTR230.).

We identified a tumor-associated cytotoxic T lymphocyte (CTL) epitope derived from the widely expressed human MDM2 oncoprotein and were able to bypass self-tolerance to this tumor antigen in HLA-A*0201 (A2.1) transgenic mice and by generating A2.1-negative, allo-A2.1-restricted human T lymphocytes. A broad range of malignant, as opposed to nontransformed cells, were killed by high-avidity transgenic mouse and allogeneic human CTLs specific for the A2.1-presented MDM2 epitope. Whereas the self-A2.1-restricted human T cell repertoire gave rise only to low-avidity CTLs unable to recognize the natural MDM2 peptide, human A2.1+ T lymphocytes were turned into efficient MDM2-specific CTLs upon expression of wild-type and partially humanized high-affinity T cell antigen receptor (TCR) genes derived from the transgenic mice. These results demonstrate that TCR gene transfer can be used to circumvent self-tolerance of autologous T lymphocytes to universal tumor antigens and thus provide the basis for a TCR gene transfer-based broad-spectrum immunotherapy of malignant disease.