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Quizartinib improved outcome compared to chemotherapy in the QuANTUM-R study (median overall survival (OS): 6.2 months for quizartinib vs. 4.7 in the chemotherapy group; hazard ratio 0.76, p = 0.02...

Clofarabine, a second-generation purine analog displaying potent inhibition of DNA synthesis and favorable pharmacologic profile, is approved for the treatment of acute lymphoblastic leukemia (ALL) after failure of at least two previous regimens in patients up to 21 years of age at diagnosis. Good neurologic tolerance, synergy with alkylating agents, management guidelines defined through pediatric ALL and adult acute myeloid leukemia, have also prompted its administration in more than 100 adults with Philadelphia chromosome-positive and negative B lineage and T lineage ALL, as single agent (40 mg/m(2)/ day for 5 days), or in combination. In a Group for Research on Adult Acute Lympho- blastic Leukemia (GRAALL) retrospective study of two regimens (clofarabine ± cyclophosphamide + / - etoposide (ENDEVOL) ± mitoxantrone ± asparaginase ± dexamethasone (VANDEVOL)), remission was achieved in 50% of 55 relapsed/refractory patients, and 17-35% could proceed to allogeneic stem cell. Clofarabine warrants further exploration in advanced ALL treatment and bridge-to-transplant.

Post-remission options were compared in a population of 262 relapsing and refractory acute myeloid leukemia patients achieving complete remission (CR) after the same re-induction according to etoposide - mitoxantrone - cytarabine (EMA) trials. The selection of post-remission therapy depended on trial recommendations, age, performance status, and availability of an HLA-identical sibling. One hundred and thirty patients received chemotherapy consolidation courses, 50 received autologous stem cell transplantation (SCT), and 43 underwent allogeneic bone marrow transplantation (BMT), while 39 did not receive any additional therapy. The preliminary analysis identified 3 favorable prognostic factors correlated with event-free survival (EFS): M3 subtype, previous CR duration > 1 year, and transplantation. Three year EFS was 68 vs. 23% with autologous SCT and allogeneic BMT in M3 patients and, respectively, 41 vs. 20% in non-M3 patients. Three year probabilities of treatment-related mortality were 11 and 47%, respectively. A statistical model was conceived with adjustment on prognostic factors and post-remission option. In the multivariate analysis, autologous SCT appeared significantly better than allogeneic BMT (P < 0.01) or chemotherapy (P = 0.001), while allogeneic BMT was not statistically different than chemotherapy. This indicates a high treatment-related toxicity with allogeneic BMT in patients re-induced by highly intensive chemotherapy, and therefore a tendency for a better outcome with autologous SCT as post-remission treatment in those patients.

Allogeneic transplantation is a well recognized treatment strategy of leukemia. However, its use in advanced leukemia patients is a subject of some debate especially when donors are not HLA-identical siblings because of the toxicity and cost of the procedure. We reviewed retrospectively the outcome of patients (pts) who received allogeneic transplantation for advanced acute leukemia in our center between 09/86 and 11/97. Thirty-six pts (study group) who lacked a matched sibling donor received partially matched related donor (n=14: PMRD group) or matched unrelated donor transplantation (n=22: MUD group). Fifteen pts had AML and 21 ALL. Seventeen pts (47%) were in CR1, 13 pts (36%) had refractory disease and six pts (17.7%) were in untreated relapse. The outcome was compared to that of 56 patients (AML: 45.5 %, ALL: 55.5 %, CR1: 49.9 %, refractory disease: 37.5 %, untreated relapse 19.6 %) who received allogeneic transplantation from a matched sibling donor (control group). Various conditioning regimens and GVHD prophylaxis were used. The actuarial incidence of grade II to IV acute GVHD was significantly higher in the study group (57%) than in the control group (34%) (p=0.047). The actuarial risk of relapse at three years was 21% +/- 22% in the study group versus 65% +/- 16% in the control group (p= 0.04). The actuarial probability of transplant-related mortality at 3 years is 64 +/- 16% for the study group and 25 +/- 11% for the control group (p=0.001). The leading cause of death in the study group was infection (30%) followed by acute GVHD and relapse. Relapse was the major cause of death in the control group (54%), followed by infection, interstitial pneumonia, veno-occlusive disease and GVHD. The OS and probability of leukemia-free survival at 3 years were 28 % +/- 15% (95% CI) and 27% +/- 15% (95% CI) in the study group. The overall survival and probability of LFS at 3 years were respectively 28 +/- 12% (95% CI) and 23 +/- 12% (95% CI) in the control group (p = 0.08 and p=0.11 respectively). In multivariate analysis, transplant-related mortality was higher in the study group (p=0.04) and lower if both donor and recipient were seronegative for CMV (p=0.007). OS was significantly higher for seronegative couples (p=0.0001), and when CR was achieved before BMT (p=0.0022). These results suggest that all efforts in this field should be directed on lowering the transplant related mortality for non geno-identical transplants and the relapse rate in geno-identical transplants.

Chronic myeloid leukemia (CML) is a hematopoietic stem cell disorder characterized by a specific hybrid gene BCR-ABL (formed as a result of t(9;22)). This leads to two possible mRNA usually present in leukemic cells, either B2A2 or B3A2. Targeting these mRNA by antisense oligonucleotides (AS) might offer the opportunity to decrease leukemic growth. We have tested the ability of AS to inhibit the in vitro proliferation of CD34 positive (CD34+) blood cells from 16 patients with newly diagnosed CML. CD34+ cells were isolated by an immunomagnetic technique and incubated for 16 to 18 hours with an 18 mer AS (0.25 mM). Sense oligonucleotides served as controls. The effects of AS were evaluated by clonogenic test (production of CFU-GM). Moreover, colonies were picked out and studied by RT-PCR to analyse the presence of BCR-ABL transcript. For nine patients with B3A2 transcript, the median inhibition of CFU-GM formation at day 14 was 64.0 +/- 11.2% (68.0 +/- 11.4% at day 21) and for the seven patients with a B2A2 transcript: 59.0 +/- 11.4% (72.5 +/- 12.0% at day 21). AS showed no effect on CD34+ cells from three normal volunteer donor cells. However, for every patient studied, colonies picked out remained BCR-ABL positive with the RT-PCR technique.