Marek Kielbinski

Cladribine, But Not Fludarabine, Added to Daunorubicin and Cytarabine During Induction Prolongs Survival of Patients With Acute Myeloid Leukemia: A Multicenter, Randomized Phase III Study

PURPOSE The goal of this study was to evaluate whether the addition of a purine analog, cladribine or fludarabine, to the standard induction regimen affects the outcome of adult patients with acute myeloid leukemia (AML). PATIENTS AND METHODS A cohort of 652 untreated AML patients with median age 47 years (range, 17 to 60 years) were randomly assigned to receive one of three induction regimens: DA (daunorubicin plus cytarabine), DAC (DA plus cladribine), or DAF (DA plus fludarabine). Postremission treatment was the same for all arms. RESULTS Complete remission rate in the DAC arm was higher compared with the DA arm (67.5% v 56%; P = .01) as a consequence of reduced incidence of resistant disease (21% v 34%; P = .004). There was no significant difference in early outcome between the DAF and DA arms. The probability of overall survival was improved for the DAC arm (45% ± 4% at 3 years) compared with the DA arm (33% ± 4%; P = .02), and leukemia-free survival was comparable. Long-term outcome did not differ significantly for the comparison of the DAF and DA arms. A survival advantage of the DAC arm over the DA arm was observed among patients age 50 years or older (P = .005), those with initial leukocyte count above 50 × 10(9)/L (P = .03), and those with unfavorable karyotype (P = .03). DAF revealed a significant advantage over DA in patients with adverse karyotype (P = .02). CONCLUSION The addition of cladribine to the standard induction regimen is associated with increased rate of complete remission and improved survival of adult patients with AML.

Status of minimal residual disease after induction predicts outcome in both standard and high-risk Ph-negative adult acute lymphoblastic leukaemia. The Polish Adult Leukemia Group ALL 4-2002 MRD Study

The treatment of adults with Philadelphia‐negative acute lymphoblastic leukaemia (ALL) depends on the presence of risk factors including age, white blood cell count, immunophenotype and time to complete remission. In recent years, status of minimal residual disease (MRD) has been postulated as an additional risk criterion. This study prospectively evaluated the significance of MRD. Patients were treated with a uniform Polish Adult Leukemia Group (PALG) 4‐2002 protocol. MRD status was assessed after induction and consolidation by multiparametric flow cytometry. Out of 132 patients included (age, 17–60 years), 116 patients were suitable for analysis. MRD level ≥0·1% of bone marrow cells after induction was found to be a strong and independent predictor for relapse in the whole study population (P < 0·0001), as well as in the standard risk (SR, P = 0·0003) and high‐risk (P = 0·008) groups. The impact of MRD after consolidation on outcome was not significant. The combination of MRD status with conventional risk stratification system identified a subgroup of patients allocated to the SR group with MRD <0·1% after induction who had a very low risk of relapse of 9% at 3 years as opposed to 71% in the remaining subjects (P = 0·001). We conclude that MRD evaluation after induction should be considered with conventional risk criteria for treatment decisions in adult ALL.

Cladribine combined with high doses of arabinoside cytosine, mitoxantrone, and G-CSF (CLAG-M) is a highly effective salvage regimen in patients with refractory and relapsed acute myeloid leukemia of the poor risk: a final report of the Polish Adult Leukemia Group.

Objectives: Patients with primary refractory AML and with early relapses have unfavorable prognoses and require innovative therapeutic approaches. Purine analogs fludarabine (FA) and cladribine (2‐CdA) increase cytotoxic effect of Ara‐C in leukemic blasts and inhibit DNA repair mechanisms; therefore its association with Ara‐C and mitoxantrone (MIT) results in a synergistic effect. In the current report, we present the final results of multi‐center phase II study evaluating the efficacy and toxicity of CLAG‐M salvage regimen in poor risk refractory/relapsed AML patients.

Activation of intracellular signaling pathways is necessary for an increase in VDR expression and its nuclear translocation

1,25‐Dihydroxyvitamin D3 (1,25D) regulates gene transcription through the nuclear vitamin D receptor (VDR) and initiates rapid cellular responses via an unknown mechanism. Here we report that 1,25D induces a rapid increase in synthesis of VDR protein and its transport to the nucleus. These results are similarly obtained in myeloid leukemia cell lines, and in blast cells from blood of patients diagnosed with acute myeloid leukemia, subtypes M2 and M4. Our results suggest that stability of unliganded VDR is LY294002‐ and PD98059‐dependent, and that ligation of VDR leads to its increased translation and nuclear translocation. The receptor localized in the cell nucleus is not exported back to the cytosol by exportin 1. We also show that the cytosolic portion of VDR in leukemia cells is localized in the vicinity of the plasma membrane, close to the F‐actin cytoskeleton.

Side-chain modified vitamin D analogs induce rapid accumulation of VDR in the cell nuclei proportionately to their differentiation-inducing potential

1,25-Dihydroxyvitamin D(3) (1,25D) regulates gene transcription through a nuclear vitamin D receptor (VDR) which acts as a ligand-regulated transcription factor. Some structural vitamin D analogs (VDAs) are selective in their biological actions, because they retain cell-differentiating potential, while their calcemic activity is reduced. In this article we have shown that in untreated HL60 cells the expression level of VDR is low, in spite of constant presence of VDR mRNA. Furthermore we have shown that one of the most rapid effects of either 1,25D or VDAs is nuclear accumulation of VDR, which is proportional to the differentiation-inducing potential of given analog. We observed this effect not only in HL60 cells, but also in blast cells isolated from patients with acute myeloid leukemias. After longer incubation time of the cells with various VDAs, the expression levels of VDR have become unrelated to the final differentiation effect.

Structure–function analysis of vitamin D2 analogs as potential inducers of leukemia differentiation and inhibitors of prostate cancer proliferation

We characterized a structure-function relationships of four analogs of vitamin D(2) with extended and branched side-chains. We tested their ability to induce differentiation of human acute myeloid leukemia (AML) cells both in vitro and ex vivo. Our experiments on five human cell lines revealed substantial differences among tested analogs. Analogs with side-chains extended by one (PRI-1906) or two carbon units (PRI-1907) displayed similar or elevated cell-differentiating activity in comparison to 1,25-dihydroxyvitamin D(3) (1,25D), whereas further extending side-chain resulted in substantially lower biological activity (PRI-1908 and PRI-1909). Similar pattern of cell-differentiating activities to that observed in human cell lines has also been shown in blast cells isolated from patients diagnosed with AML. The ability of the analogs to activate expression of CYP24A1 gene has been studied in HL60 cell line. The analog PRI-1906 activated expression of CYP24A1 similarly to 1,25D, while PRI-1907 weaker than 1,25D. In addition, the analogs PRI-1906 and PRI-1907 were able to moderately inhibit proliferation and significantly activate expression of CYP24A1 mRNA in prostate cancer cells PC-3. Finally, we examined the molecular actions triggered by these analogs and found that their biological activity was related to their ability to induce expression and nuclear translocation of VDR and C/EBPβ.

Variations in Suppressor Molecule CTLA-4 Gene Are Related to Susceptibility to Multiple Myeloma in a Polish Population

Various phenotype and functional T-cell abnormalities are observed in multiple myeloma (MM) patients. The aim of this study was to investigate the association between polymorphisms in the gene encoding cytotoxic T-lymphocyte antigen-4 (CTLA-4), a negative regulator of the T-lymphocyte immune response and susceptibility to multiple myeloma in a Polish population. Two hundred MM patients and 380 healthy subjects were genotyped for the following polymorphisms: CTLA-4c.49A>G, CTLA-4g.319C>T, CTLA-4g.*642AT(8_33), CT60 (CTLA-4g.*6230G>A), Jo31 (CTLA-4g.*10223G>T). Our study is the largest and most comprehensive evaluation to date of the association between genetic polymorphisms in the CTLA-4 molecule and multiple myeloma. It was found that CTLA-4c.49A>G[G], CT60[G], and Jo31[G] alleles were more frequently observed in MM patients than in controls (0.50 vs. 0.44, p = 0.03, 0.65 vs. 0.58, p = 0.04, and 0.63 vs. 0.57, p = 0.03, respectively). Moreover, the haplotype CTLA-4c.49A>G[G], CTLA-4g.319C>T[C], CTLA-4g.*642AT(8_33) [8], CT60[G], Jo31[G] including all susceptibility alleles increases the risk of MM about fourfold (OR: 3.79, 95%CI: 2.08–6.89, p = 0.00001). These findings indicate that genetic variations in the CTLA-4 gene play role in susceptibility to multiple myeloma and warrant further investigation through replication studies.

The early reduction of leukemic blasts in bone marrow on day 6 of induction treatment is predictive for complete remission rate and survival in adult acute myeloid leukemia; The results of multicenter, prospective Polish adult leukemia group study

The aim of this study was to prospectively evaluate the impact of early bone marrow response on complete remission (CR) rate and long-term outcome in adults with acute myeloid leukemia. Bone marrow cytology was assessed on day 6 of induction treatment in 164 patients, revealing the presence of ≥5% blasts in 61 cases. In this subgroup the CR rate was significantly lower compared to the remaining patients (P < 0.00001) resulting in decrease of the overall survival (P = 0.002). Persistence of ≥5% blasts in bone marrow on day 6 of induction is an easily available surrogate marker to be used for treatment decisions.

31P MRS analysis of the phospholipid composition of the peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) of patients with acute leukemia (AL).

The aim of this study was to evaluate the phospholipid concentration in acute leukemia (AL) blast cells from peripheral blood (PBMC) and bone marrow (BMMC). In vitro31P Nuclear Magnetic Resonance Spectroscopy (31P MRS) was used. The integral intensities of the resonant peaks and the phospholipid concentrations in PBMC and BMMC were analyzed. Differences in the phospholipid concentrations in cells from myeloblastic or lymphoblastic lines were also evaluated. This investigation was carried out on phospholipid extracts from PBMC and BMMC from 15 healthy volunteers and 77 patients with AL (samples taken at the moment of diagnosis). A significant decrease in sphingomyelin (SM) and phosphtidylserine (PS) was observed in the PBMC of patients with AL relative to the results for the healthy volunteers. For ALL, we found a significant decrease in the concentration of phosphatidylcholine plasmalogen (CPLAS), SM, PI+PE (phosphatidylinositol + phosphatidylethanolamine) and PS in comparison with the results for healthy volunteers and patients with AML. Experiments with BMMC cells revealed a significant decrease in the concentration of CPLAS, SM, PI+PE, and PS in ALL relative to AML. Additionally, a significant decrease in phosphatidylcholine (PC) concentration was observed in ALL compared to AML. If the phospholipid extracts were taken simultaneously from the same patient, there were no significant differences in the integral intensities and phospholipid concentrations between PBMC and BMMC.

ICOS gene polymorphisms in B-cell chronic lymphocytic leukemia in the Polish population.

There is strong evidence that altered immunological function entails an increased risk of B-cell chronic lymphocytic leukemia (B-CLL). The main mechanism of an anti-tumor response depends on T-cell activation. Unlike the constitutively expressed CD28, inducible costimulatory molecule (ICOS) is expressed on the T-cell surface after activation. ICOS enhances all the basic T-cell responses to a foreign antigen, namely proliferation, secretion of lymphokines, the upregulation of molecules that mediate cell-cell interaction, and effective help for antibody secretion by B cells. ICOS is essential for both efficient interaction between T and B cells and normal antibody responses to T cell-dependent antigens. It does not upregulate the production of interleukin-2, but superinduces the synthesis of interleukin-10. Our previous results indicated the ICOS gene has a role as a susceptibility locus to B-CLL. Therefore an extended study was undertaken to evaluate the association between four ICOS polymorphisms (which were recently described as functional ones) and susceptibility to B-CLL in the Polish population. A case-control study of 296 individuals, including 146 B-CLL patients, was conducted on four polymorphisms in the ICOS gene. Genotyping of the polymorphisms ICOS ISV1+173T>C (rs10932029), ICOSc.1624C>T (rs10932037), ICOSc.2373G>C (rs4675379), and ICOSc.602A>C (rs10183087) was carried out using allelic discrimination methods with the TaqMan SNP Genotyping Assay. There were no statistically significant differences in the allele, genotype, or haplotype distributions between B-CLL patients and healthy controls for any of the investigated polymorphic markers in the ICOS gene. However, we noted that patients carrying genotype ICOS ISV1+173T>C [TT], ICOSc.602A>C [AA], ICOSc.1624C>T [CC], and ICOSc.2373G>C [GG] have a decreased frequency of progression to a higher Rai stage during 60-month follow-up (21.35% vs. 40.8%, p = 0.013) compared to other individuals. This indicates that the investigated polymorphisms do not modulate the risk of B-CLL in the Polish population, but are associated with disease dynamics, in particular with the time to Rai stage progression.