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The treatment of refractory acute myeloid leukemia (AML) patients presents considerable challenges. They are often critically ill. The critical conditions of these patients are mainly associated with severe infectious complications resulting in sepsis as well as with the extramedullary lesions with organ dysfunctions. So far, the obtained data demonstrated the successful use of gemtuzumab ozogamicin, the mechanism of which is likely to be based not only on depletion of CD33-positive tumor cells but also on its immunomodulatory effect. The present article focuses on the fast-effect mechanisms of gemtuzumab ozogamicin and deals with clinical experience of successful use of this drug combined with hypomethylating agents in patients with refractory AML whose condition is critical by the time therapy begins. The use of this drug combination results in fast stabilization of health status, recovery of internal organs, and apyrexia with the decreasing systemic inflammatory response within the first days of therapy. All this together with significantly lower blast count in blood and in bone marrow can bring critically ill patients to recovery.

Aim. To assess the efficacy of FLAG/FLAG-Ida regimen and to identify factors that influence remission, duration of disease-free survival (DFS) and overall survival (OS) of patients with relapsed/refractory acute myeloid leukemia (AML). Materials & Methods. The trial included 54 patients (28 men and 26 women), median age was 37 years (range 18–70 years). 27 (50 %) out of 54 patients had refractory AML and 27 (50 %) patients had relapsed AML. FLAG and FLAG-Ida regimens were administered as induction therapy. 37 (68.5 %) patients received bone marrow transplantation. Molecular genetic and cytogenetic examinations were performed prior to therapy and on the 28th day after the start of treatment. WT1 gene expression was evaluated on the 14th–16th day of treatment. Results. Complete remission (CR) was achieved in 42 (77.8 %) out of 54 patients. Refractoriness to therapy was observed in 9 (16.7 %) out of 54 patients, mortality was 5.5 % (3/54). Remission rate was higher in patients with relapsed AML compared with refractory AML: 85.2 % (23/27) and 70.4 % (19/27), respectively. On the 14th–16th day of treatment patients with blast cell count ≥ 10 % in bone marrow (BM) showed significantly lower CR rate (60 %) compared with the group of patients with < 10 % blast cells in BM (89.6 %; p = 0.024) and shorter DFS (median 7.6 vs. 17.6 months, respectively; p = 0.03). Median DFS in patients with WT1 expression reduction to < 1 log on the 14th–16th day was 5 vs. 18 months in patients without WT1 expression reduction (p = 0.01). DFS varied in groups of patients with blast cell count < 10 % in BM on the 14th–16th day of treatment based on the level of WT1 expression reduction (p = 0.04). MRD-negative patients (57.1 %) showed significantly longer DFS and OS compared with MRD-positive patients (median DFS was 17.6 vs. 5.2 months, respectively, p = 0.02; median OS was 19 vs. 6.9 months, p = 0.0002). Median DFS and OS were different only in ELN low- and high-risk groups (median not reached vs. 5.2 months, respectively, p = 0.039; median not reached vs. 10.2 months, p = 0.039). Conclusion. FLAG and FLAG-Ida are effective and safe regimens in the treatment of relapsed/refractory AML. Achieving remission depends on neither the risk group nor the time of relapse occurrence. The blast cell count in BM on the 14th–16th day of FLAG/FLAG-Ida treatment is a prognostic factor determining achievement and duration of remission. WT1 expression level in the early post-induction period is a sensitive DFS marker. MRD status and molecular genetic risk (ELN) group affiliation are essential prognostic factors determining DFS and OS.

Background. In patients with chronic lymphocytic leukemia (CLL) the eradication of minimal residual disease (MRD) is a prognostic factor of overall survival (OS) and progressionfree survival (PFS). IGHV mutational status has also independent prognostic value. Aim. To analyse the impact of mutational status and MRD eradication in CLL patients after first-line standard BR (ben-damustine + rituximab) immunochemotherapy. Materials & Methods. The prospective study included patients with immunophenotypically confirmed CLL who had not previously received anticancer therapy. All patients were treated by BR combination from 2012 to 2015. MRD level was determined in 109 patients after completing the 3rd and the 6th treatment courses. IGHV mutational status data were available for 98 patients. IGHV mutational status was evaluated in accordance with ERIC recommendations. MRD was assessed by standardized method of 4-color flow cytometry. Results. MRD negativity was achieved in 37 (34 %) out of 109 patients. MRD eradication correlated with the best PFS (p = 0.04). IGHV mutational status had a statistically significant impact on PFS (p = 0.02). In patients with MRD-nega-tive response and IGHV mutation no unfavorable events occurred during the period of monitoring. Conversely, PFS rates in MRD-negative patients having no IGHV mutation and in MRD-positive patients with mutation were significantly worse. MRD eradication resulted in statistically significant improvement of PFS rates after completing 3 treatment courses, compared with the cases with MRD persistence regardless of residual malignant clone level (p = 0.01). Conclusion. BR therapy as first-line treatment statistically improved PFS in patients who achieved MRD-negative remission after completing the 3rd treatment course. PFS was significantly higher in MRD-negative patients with IGHV mutation after 6 treatment courses. MRD negativity resulting from 6 BR therapies in patients having no / GHV mutation was not accompanied by PFS improvement. It follows that by itself MRD negativity cannot be considered to be a universal prognostic factor.

Background & Aims. Flow cytometry is successfully used for diagnosis of malignant lymphoproliferative disorders. However, there are atypical cases that are difficult to interpret; thus, new markers relevant for the differential diagnosis are to be searched for. The aim is to analyze CD200 expression in patients with B-cell lymphoproliferative disorders. Materials & Methods. 187 patients with chronic lymphocytic leukemia (CLL), 14 patients with mantle cell lymphoma (MCL), 9 patients with marginal zone lymphoma (MZL), and 5 patients with hairy cell leukemia (HCL) were enrolled in the study. Neoplasm was not confirmed in 12 subjects. The patients underwent the following tests: CBC, immunophenotyping of peripheral blood or bone marrow lymphocytes, and a cytogenetic test. In some cases, an additional immunohistochemical test of bone marrow trepanobiopsy or lymph node biopsy samples was required. Results. In all cases of CLL and HCL, the CD200 expression was positive; mean fluorescence intensity was higher in these cases as compared to other groups. Negative expression of CD200 prevailed in MCL patients; however, at the same time 2 cases of intermediate and positive expression were reported, both showing moderate fluorescence intensity values. CD200 expression was heterogeneous in MZL patients. Conclusion. The CD200 negative expression excludes typical HCL and CLL. Additional cytogenetic and immunnohistoсhemical tests should be performed in such cases to verify the diagnosis, first of all, MCL or MZL.

Background. Acute myeloblastic leukemia (AML) with NPM7 mutation amounts to 30 % of all AML and is characterized by good prognosis with the exception of cases with FLT3-/TD mutation. Despite the good prognosis, the likelihood of relapses in patients with NPM7 mutation may significantly differ. Thus, the estimation of the minimal residual disease (MRD) after chemotherapy and during follow-up is becoming increasingly important. This approach will make it possible to predict the sensitivity of a tumoral clone to chemotherapy. Aim. To evaluate the prognostic value of highly specific marker (NPM7 mutation) and non-specific marker (WT1 overexpression) of MRD, as well as to identify the correlation between the levels of NPM7 and WT7 at different stages of therapy and in the follow-up period. Materials & Methods. The research included 14 patients with AML. All patients had the NPM7 mutation and WT7 overexpression: 50 % of patients had additional molecular markers (BAALC overexpression, FLT3-/TD, DNMT3A, and MLL mutations). Real-time PCR was used for long-term monitoring of WT7 expression levels and NPM7 mutation. Results. The median decrease of NPM7 levels after the induction therapy was 3 log. All patients had relapses, NPM7 mutation, and lower rates of OS/RFS, which significantly correlated with prognostically negative molecular markers. There were no statistically significant differences in RFS in groups with the decrease of WT7 expression level < 2 log and ≥ 2 log on day 28 of treatment. At the same time, the decrease of WT7 expression by > 2 log was associated with significant differences in early relapses, which correlated with the decrease of NPM7 levels (> and < than 3 log) is revealed. RFS rates were higher in patients with WT7 expression level of < 100 per 104 copies ABL on day 28 and WT7 of < 250 per 104 copies ABL on day 14 of treatment. WT7 expression was significantly lower on days 14 and 28 in patients with NPM7 decrease of > 3 log on day 28. The decrease in WT7 expression of < 100 per 104 copies ABL on day 28 was more common in patients with isolated NPM1 mutation, compared to patients with additional negative molecular markers. Conclusion. The decrease in NPM1 levels after the induction therapy may serve as reliable prognostic marker of RFS and OS rates. New correlation between the degree of NPM1 reduction and the presence of additional molecular markers was established. Highly specific (NPM1 mutation) was shown to be more specific compared to non-specific markers ( WT1 overexpression). The research showed the predictive value of a lower limit level of WT1 on day 28 of treatment (100 per 104 copies ABL), and for the first time, the importance of the early assessment WT1 expression reduction on day 14 of induction therapy.

Background. The current approach to treatment of acute myeloblastic leukemia (AML) includes the achievement of maximum tumor reduction and, therefore, eradication of a leukemic clone. The goal of the therapy is to achieve undetectable levels of the target gene, except an isolated molecular rearrangement of RUNX1-RUNX1T1. Aim. To estimate the dynamics of the RUNX1-RUNX1T1 level and relevant clinical manifestations during the monitoring of various stages of the program therapy and after its completion. Methods. The article presents a description of 10 cases of AML with isolated RUNX1-RUNX1T1 expression (n = 4) and the expression in combination with different molecular and cytogenetic abnormalities (n = 6). In addition, a long-term monitoring of the gene expression by quantitative determination of RUNX1-RUNX1T1 using a real-time PCR was presented. Results. The incidence of relapses in a group with a decreased RUNX1-RUNX1T1 expression level of >2 log is 75 % as compared to patients with a less significant reduction of the transcript level (with the relapse incidence equal to 0 %) (p = 0.05). The increase of the RUNX1-RUNX1T1 level against the background of bone marrow remission by more than 1 log coincided with a bone marrow relapse within 5-18 weeks. In addition, long-term persistence of a certain transcript level after the completion of a program therapy without relapse is possible. Conclusion. The study analyzed possible molecular background of different clinical outcomes of long-term persistence of the RUNX1-RUNX1T1 transcript that might lead to an individualized approach to AML patients.