Real-World Outcome and Prognostic Factors in MDS Patients Treated with Azacitidine-A Retrospective Analysis

Azacitidine (AZA) is recognized as a vital drug used in the therapy of myelodysplastic syndromes (MDS) due to its beneficial effect on survival and quality of life. Nevertheless, many patients fail to respond to AZA treatment, as prognostic factors still are not identified. The present retrospective analysis included 79 patients with MDS treated with AZA as first-line therapy in a real-life setting. The percentage of patients with good, intermediate, and poor cytogenetics was 46.8%, 11.4%, and 34.2%, respectively. The overall response rate (complete remission [CR], partial remission [PR], and hematological improvement [HI]) was 24%. The CR, PR, and HI rates were 13.9%, 2.5%, and 7.6%, respectively. Stable disease (SD) was documented in 40.5% of patients. The median overall survival (OS) and progression-free survival (PFS) were 17.6 and 14.96 months, respectively. Patients with ORR and SD had a significantly longer median OS (23.8 vs. 5.7 months, p = 0.0005) and PFS (19.8 vs. 3.5 months, p < 0.001) compared to patients who did not respond to AZA. In univariate analysis, only an unfavorable cytogenetic group was a prognostic factor of a lower response rate (p = 0.03). In a multivariate model, older age (p = 0.047), higher IPSS (International Prognostic Scoring System) risk (p = 0.014), and higher IPSS-R cytogenetic risk (p = 0.004) were independent factors of shorter OS. Independent prognostic factors for shorter PFS were age (p = 0.001), IPSS risk (p = 0.02), IPSS cytogenetic risk (p = 0.002), and serum ferritin level (p = 0.008). The safety profile of AZA was predictable and consistent with previous studies. In conclusion, our study confirms the efficacy and safety of AZA in a real-world population and identifies potential biomarkers for response and survival.

Richter transformation - retrospective treatment outcomes analysis in Polish Adult Leukemia Study Group

Richter transformation (RT) is defined as developing an aggressive lymphoma in 2-10% of patients suffering from chronic lymphocytic leukemia (CLL). So far, no complex analysis of RT demographics and treatment outcomes has been performed in Poland. Thus, the retrospective analysis of 124 patients with RT from Polish hematology centers was designed. Ninety-nine patients with diffuse large B-cell lymphoma (DLBCL-RT) were identified. The median overall survival (OS) for DLBCL-RT was 17.3 months, while for Hodgkin lymphoma (HL-RT)-21.3 months. In multivariate analysis, the independent factors of worse OS for DLBCL-RT were: prior CLL therapy, ECOG stage ≥2, and elevated serum LDH activity. Patients who proceeded to hematopoietic stem cell transplantation (HSCT) achieved better results. The median OS in allogeneic HSCT recipients was not reached, while in autologous HSCT median OS was 51.3 months. In conclusion, our study represents the largest dataset of patients diagnosed with RT in Poland and confirms its dismal prognosis.

Characteristics of patients with newly diagnosed hematological malignancies referred for echocardiography

Objective

The importance of cardio-hemato-oncology programs is increasing. The main aim of the study was to identify all coexisting cardiovascular disorders in patients with new hematological malignancies referred for echocardiography during baseline evaluation before anticancer therapy.

Material and methods

The study was based on 900 echocardiographic examinations performed within 12 months at the Institute of Hematology and Transfusion Medicine in Poland: 669 tests (74.3%) were dedicated to hemato-oncology patients at the different stages of cancer therapy, however almost a third of the tests (277, 30.8%) were part of a baseline evaluation before starting first line anticancer therapy due to newly diagnosed hematological malignancies.

Results

The group of 277 patients with new hematological malignancies (138 women, 49.82%) with a median age of 66 years (interquartile range: 53-72 years) was included in the main analyses. The three most frequent new histopathological diagnoses were: non-Hodgkin lymphoma (63 cases; 22.74%), acute myeloid leukaemia (47 cases; 16.97%), and multiple myeloma (45 cases; 16.25%). The three most common clinical cardiology disorders were arterial hypertension (in 133 patients, 48.01%), arrhythmias (48 patients, 17.33%), and heart failure (39 patients, 14.08%). Among 48 patients with arrhythmias there were 22 cases with atrial fibrillation. The most frequently detected echocardiographic abnormality was Left Atrial Volume Index >34 ml/m2 which was present in 108 of 277 patients (38.99%) and associated with a significantly greater chance of concomitant diagnosis of arrhythmias (OR=1.98; p=0.048) especially atrial fibrillation (OR=3.39; p=0.025). The second most common echocardiographic finding was diastolic dysfunction 2nd or 3rd degree revealed in 43 patients (15.52%) and associated with a greater chance of simultaneous diagnosis of heart failure (OR=8.32; p<0.0001) or arrhythmias (OR=4.44; p<0.0001) including atrial fibrillation (OR=5.40; p=0.0003).

Conclusions

In patients with newly diagnosed hematological malignancies left ventricular diastolic dysfunction is a common abnormality in echocardiography and may determine diagnoses of heart failure or arrhythmias.

Prognostic Impact of Copy Number Alterations' Profile and AID/RAG Signatures in Acute Lymphoblastic Leukemia (ALL) with BCR::ABL and without Recurrent Genetic Aberrations (NEG ALL) Treated with Intensive Chemotherapy

Adult acute lymphoblastic leukemia (ALL) is associated with poor outcomes. ALL is initiated by primary aberrations, but secondary genetic lesions are necessary for overt ALL. In this study, we reassessed the value of primary and secondary aberrations in intensively treated ALL patients in relation to mutator enzyme expression. RT-PCR, genomic PCR, and sequencing were applied to evaluate primary aberrations, while qPCR was used to measure the expression of RAG and AID mutator enzymes in 166 adult ALL patients. Secondary copy number alterations (CNA) were studied in 94 cases by MLPA assay. Primary aberrations alone stratified 30% of the patients (27% high-risk, 3% low-risk cases). The remaining 70% intermediate-risk patients included BCR::ABL1pos subgroup and ALL lacking identified genetic markers (NEG ALL). We identified three CNA profiles: high-risk bad-CNA (CNAhigh/IKZF1pos), low-risk good-CNA (all other CNAs), and intermediate-risk CNAneg. Furthermore, based on RAG/AID expression, we report possible mechanisms underlying the CNA profiles associated with poor outcome: AID stratified outcome in CNAneg, which accompanied most likely a particular profile of single nucleotide variations, while RAG in CNApos increased the odds for CNAhigh/IKZF1pos development. Finally, we integrated primary genetic aberrations with CNA to propose a revised risk stratification code, which allowed us to stratify 75% of BCR::ABL1pos and NEG patients.

Clinical efficacy and tolerability of venetoclax plus rituximab in patients with relapsed or refractory chronic lymphocytic leukemia-a real-world analysis of the Polish Adult Leukemia Study Group

The results of the MURANO trial showed encouraging progression-free survival (PFS) and overall survival (OS) in relapsed/refractory chronic lymphocytic leukemia (RR-CLL) patients treated with venetoclax-rituximab (VEN-R). A retrospective analysis was performed to evaluate the efficacy and safety of VEN-R within the Polish Adult Leukemia Study Group (PALG) centers. The study group included 117 patients with RR-CLL (with early relapse after immunochemotherapy or bearing TP53 aberrations) treated with VEN-R in 2019-2023 outside clinical trials. Patients were treated with a median of 2 (range 1-9) previous lines of therapy. Twenty-two participants were previously treated with BTKi (18.8% out of 117). The median follow-up was 20.3 months (range 0.27-39.1). The overall response rate (ORR) was 95.3% in the group of patients in whom a response to treatment was assessed and 86.3% for all patients. Twenty patients (17.1% out of 117) achieved a complete response (CR), 81 (69.2%) achieved a partial response (PR), and in 5 patients (4.3%), disease progression was noted (assessed as the best response during treatment). The median PFS in the whole cohort was 36.97 (95% CI 24.5, not reached) months, and the median OS was not reached (95% CI 27.03, not reached). Thirty-six patients died during the follow-up, 10 (8.5%; 27.8% of deaths) due to COVID-19 infection. All grade neutropenia (n = 87/117, 74.4%; grade 3 or higher n = 67/117, 57.3%) was the most common treatment adverse event. Forty-five patients (38.5%) remained on treatment, and twenty-two (18.8%) completed 24 months of therapy, while it was discontinued in fifty cases (42.7%). In this real-world setting of early access in very high-risk RR-CLL patients, the VEN-R regimen was associated with shorter median PFS compared with the results of the MURANO trial. This outcome, however, could be attributed to patients' exposure to SARS-CoV-2 infection and the aggressive course of the disease as very high-risk patients, after multiple lines of prior therapies, were included in the Polish Ministry of Health reimbursement program.

Bing-Neel Syndrome, a Rare Presentation of Waldenström Macroglobulinemia—A Multicenter Report by the Polish Lymphoma Research Group

Bing-Neel syndrome (BNS) is a rare presentation of Waldenström macroglobulinemia (WM). BNS is a consequence of the central nervous system (CNS) involvement by lymphoplasmacytic lymphoma (LPL) and, rarely, the peripheral nervous system. The data on BNS are extremely scarce. Therefore, we performed a multicenter retrospective analysis of BNS patients diagnosed and treated in centers aligned with the Polish Lymphoma Research Group. The analysis covers the years 2014–2021. Eleven patients were included, 55% females and the median age at BNS diagnosis was 61 years. The median time from WM to BNS was 3.5 years; 27% of patients did have a diagnosis of WM and BNS made simultaneously or within 30 days from each other. Isolated parenchymal involvement was the least frequent (20%). Patients were treated with different regimens, mostly able to cross the blood-brain barrier, including 18% treated with ibrutinib first line. The cumulative objective response to treatment was 73%. With the median follow-up of 20 months (95% CI, 2–32), the 36-month estimates were: overall survival (OS) 47%, progression-free survival (PFS) 33%, and cumulative incidence of BNS-associated death 41%. The performance status according to ECOG was significant for PFS (HR = 7.79) and the hemoglobin concentration below 11 g/dL was correlated with PFS. To conclude, BNS is a very rare manifestation of WM. It is associated with a poor outcome with most patients succumbing to BNS.

Tracking Clonal Evolution of Multiple Myeloma Using Targeted Next-Generation DNA Sequencing

Clonal evolution drives treatment failure in multiple myeloma (MM). Here, we used a custom 372-gene panel to track genetic changes occurring during MM progression at different stages of the disease. A tumor-only targeted next-generation DNA sequencing was performed on 69 samples sequentially collected from 30 MM patients. The MAPK/ERK pathway was mostly affected with KRAS mutated in 47% of patients. Acquisition and loss of mutations were observed in 63% and 37% of patients, respectively. Four different patterns of mutation evolution were found: branching-, mutation acquisition-, mutation loss- and a stable mutational pathway. Better response to anti-myeloma therapy was more frequently observed in patients who followed the mutation loss-compared to the mutation acquisition pathway. More than two-thirds of patients had druggable genes mutated (including cases of heavily pre-treated disease). Only 7% of patients had a stable copy number variants profile. Consequently, a redistribution in stages according to R-ISS between the first and paired samples (R-ISS″) was seen. The higher the R-ISS″, the higher the risk of MM progression and death. We provided new insights into the genetics of MM evolution, especially in heavily pre-treated patients. Additionally, we confirmed that redefining R-ISS at MM relapse is of high clinical value.

Eculizumab treatment in pregnant women with paroxysmal nocturnal hemoglobinuria: A Polish experience

BACKGROUND

Eculizumab is an antibody targeting the C5 complement protein. Clinical trials suggest that eculizumab significantly reduces transfusion requirements and prevents disease complications in patients with paroxysmal nocturnal hemoglobinuria (PNH).

OBJECTIVES

To analyze the outcome of pregnancies among Polish women with PNH treated with eculizumab as a part of the Polish National Health Fund program.

MATERIAL AND METHODS

We report the outcomes of 3 pregnancies among women treated with eculizumab between 2017 and 2020. For 1 of these woman, it was the 1st pregnancy, while the remaining 2 patients had previously had 1 previous successful pregnancy each.

RESULTS

All 3 mothers survived pregnancy, and all children were born alive. One of the patients had a vaginal delivery. Another required cesarean delivery at the 34th week due to a decreasing platelet count. In 1 case, premature rupture of the fetal membranes occurred at week 36, followed by artificial labor induction. All children were born without any inborn defects. The 2 prematurely born babies required a prolonged hospital stay.

CONCLUSION

Treatment with eculizumab seems to reduce the risk to a mother and a child associated with PNH. However, more data are necessary to confirm this notion.

Efficacy of high-dose corticosteroid-based treatment for chronic lymphocytic leukemia patients with p53 abnormalities in the era of B-cell receptor inhibitors

PURPOSE

High-dose methylprednisolone (HDMP) with or without anti-CD20 antibody treatment in the pre B-cell receptor inhibitor (BCRi) era was used as potential salvage therapy for relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (r/r CLL/SLL) patients bearing the 17p deletion.

PATIENTS AND METHODS

Outcomes were compared in retrospect between r/r patients treated with HDMP (n = 20), ibrutinib (n = 39) and idelalisib with rituximab (n = 14).

RESULTS

Higher overall response rates were found in those patients undergoing BCRi therapy compared to HDMP (79.2% vs. 0%; p < 0.0001), along with longer median progression-free survival (not reached vs. 24.1 months; p < 0.01). Nevertheless, there were no differences in the overall survival (HDMP 35.87 months vs. not reached; p = 0.58).

CONCLUSION

HDMP treatment was significantly inferior in terms of response rate and progression-free survival in r/r CLL/SLL patients with the 17p deletion, and may only be used whenever novel compounds are unavailable.

Hematological malignancies in Polish population: what are the predictors of outcome in patients admitted to Intensive Care Unit?

INTRODUCTION

Patients with hematological malignancies (HM) require intensive chemotherapy with curative intent, especially in case of AML that results in more frequent admissions to Intensive Care Units (ICU). Due to our knowledge, this study is the first multicenter retrospective analysis in Polish population.

METHODS

A total of 200 patients with HM hospitalized in 4 Polish hematological centers. Data concerning clinical indices and outcomes during admission and ICU stay were collected retrospectively.

RESULTS

The most common hematological malignancy was acute leukemia (55%). The main cause of ICU admission was respiratory failure (88.5%), often accompanied by sepsis (58.5%) and acute renal failure (51.5%). In patients with hematological malignancies, the following factors were associated with ICU mortality: prolonged ICU stay (odd ratio [OR] = 6.98, 95% confidence interval [CI]: 1.38-35.33, χ² = 5.61, p = 0.02), the presence of acute respiratory failure (odd ratio [OR] = 5.35, 95% confidence interval [CI]: 1.01-28.46, χ² = 3.93, p = 0.04), and the need for renal replacement therapy (odd ratio [OR] = 8.75, 95% confidence interval [CI]: 1.23-62.11, χ² = 4.78, p = 0.03). There were following associations with in-hospital mortality in patients with hematological malignancies: prolonged ICU stay (odd ratio [OR] = 10.12, 95% confidence interval [CI]: 1.85-55.37, χ² = 7.21, p = 0.008), the presence of acute respiratory failure (odd ratio [OR] =5.24, 95% confidence interval [CI]: 1.36-20.16, χ² = 5.87, p = 0.02), the need for catecholamine support (odd ratio [OR] =3.43, 95% confidence interval [CI]: 1.06-11.05, χ² = 4.32, p = 0.04), and renal replacement therapy (odd ratio [OR] =5.55, 95% confidence interval [CI]: 1.14-26.92, χ² = 4.59, p = 0.03).

CONCLUSIONS

We have demonstrated that ICU and in-hospital mortalities among patients with hematological malignancies are still poor, but easier access to the intensive care unit and close cooperation between hematologists and intensivists may improve outcomes. We have found that acute failure of key organs (acute respiratory failure, end-stage renal failure requires renal replacement therapy) and length of ICU stay (but probably no comorbidities and illness severity) may have impact on mortality (both ICU and in-hospital).

Hepatitis B virus screening in patients with non-Hodgkin lymphoma in clinical practice in Poland - a report of the Polish Lymphoma Research Group

INTRODUCTION

The risk of HBV reactivation is important in lymphoma patients receiving immunosuppressive chemotherapy containing steroids or anti-CD20 antibodies. We aimed to establish the prevalence of HBV Ag and anti-HBc serologic positive results in patients with non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL) in Poland before anti-CD20 therapy initiation; to assess the frequency of insufficient HBV screening; and to assess the association between inadequate HBV screening and diagnosis according to the WHO classification and age or gender.

MATERIAL AND METHODS

We retrospectively collected data from 805 patients with non-Hodgkin lymphoma and chronic lymphocytic leukemia treated in 2016-2018.

RESULTS

We found a positive result of HBsAg in 13 (1.16%), and a negative result in 633 (78.64%) patients. The test was not done in 159 (19.75%) patients. In the HBsAg negative subgroup of 633 patients, we found that the anti-HBc was positive in 52 (8.22%), negative in 303 (47.87%) and not done in 278 patients. In 136 out of 805 (16.9%) patients diagnostics tests were not performed before therapy initiation. We found that age is significantly associated (p = 0.0002) with the lack of HBV infection screening, and in CLL this risk is significantly (p = 0.024) higher (by 49%) compared with other WHO diagnosis subgroups.

CONCLUSIONS

In Polish lymphoma patients the incidence of positive HBsAg and/or anti-HBc results is consistent with the prevalence in the United States or Australia. The adherence to appropriate HBV screening guidelines in Polish centers is not sufficient. We should intensify educational strategies in the global oncohematologic medical community.

Decreased Activity of Blood Acid Sphingomyelinase in the Course of Multiple Myeloma

Acid sphingomyelinase (aSMase) is involved in the generation of metabolites that function as part of the sphingolipid signaling pathway. It catalyzes the breakdown of sphingomyelin into ceramide, a bioactive lipid that, among other roles, is involved in regulation of apoptosis. Dry drop blood test (DBS) and colorimetric 2-step enzymatic assay were used to assess the activity of human blood aSMase, beta-galactosidase, and beta-glucosidase, these enzymes are lysosomal hydrolases that catalyze the degradation of related sphingolipids, of sphingolipid signaling molecules. Blood was collected from a group of healthy volunteers and patients that were diagnosed with multiple myeloma (MM) in various stages of the disease. Additionally, activity of those enzymes in patients diagnosed with other hematological cancers was also assessed. We found that aSMase activity in the blood of patients with MM (at the time of diagnosis) was 305.43 pmol/spot*20 h, and this value was significantly lower (p < 0.030) compared to the healthy group 441.88 pmol/spot*20 h. Our collected data suggest a possible role of aSMase in pathogenesis of MM development.

Comparable Efficacy of Idelalisib Plus Rituximab and Ibrutinib in Relapsed/refractory Chronic Lymphocytic Leukemia: A Retrospective Case Matched Study of the Polish Adult Leukemia Group (PALG)

BACKGROUND/AIM

There is limited amount of data available on the comparative efficacy of ibrutinib and idelalisib, the B-cell receptor inhibitors (BCRi) newly approved for relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (r/r CLL/SLL) treatment. The aim of our study was to analyze and compare the outcomes of real-world r/r CLL/SLL patients treated with these two BCRi in outside clinical trials.

PATIENTS AND METHODS

A comparative case matched 1:2 analysis was performed on idelalisib combined with rituximab and ibrutinib efficacy in 102 patients with r/r CLL/SLL from two observational studies of the Polish Adult Leukemia Group (PALG).

RESULTS

Both therapies produced similar overall response rates (idelalisib plus rituximab 76.4% and ibrutinib 72.1%). Median progression-free survival (PFS) and overall survival (OS) in both groups were not reached. Furthermore, no significant difference was observed between both BCRi regimens in regard to PFS (HR=0.75, 95% CI=0.30-1.86, p=0.55) and OS (HR=0.65, 95%CI=0.26-1.68, p=0.39).

CONCLUSION

In summary, the results of this retrospective analysis suggest that idelalisib combined with rituximab and ibrutinib therapies have comparable activity in r/r CLL/SLL in daily clinical practice.

Microenvironment-induced PIM kinases promote CXCR4-triggered mTOR pathway required for chronic lymphocytic leukaemia cell migration

Lymph node microenvironment provides chronic lymphocytic leukaemia (CLL) cells with signals promoting their survival and granting resistance to chemotherapeutics. CLL cells overexpress PIM kinases, which regulate apoptosis, cell cycle and migration. We demonstrate that BCR crosslinking, CD40 stimulation, and coculture with stromal cells increases PIMs expression in CLL cells, indicating microenvironment‐dependent PIMs regulation. PIM1 and PIM2 expression at diagnosis was higher in patients with advanced disease (Binet C vs. Binet A/B) and in those, who progressed after first‐line treatment. In primary CLL cells, inhibition of PIM kinases with a pan‐PIM inhibitor, SEL24‐B489, decreased PIM‐specific substrate phosphorylation and induced dose‐dependent apoptosis in leukaemic, but not in normal B cells. Cytotoxicity of SEL24‐B489 was similar in TP53‐mutant and TP53 wild‐type cells. Finally, inhibition of PIM kinases decreased CXCR4‐mediated cell chemotaxis in two related mechanisms‐by decreasing CXCR4 phosphorylation and surface expression, and by limiting CXCR4‐triggered mTOR pathway activity. Importantly, PIM and mTOR inhibitors similarly impaired migration, indicating that CXCL12‐triggered mTOR is required for CLL cell chemotaxis. Given the microenvironment‐modulated PIM expression, their pro‐survival function and a role of PIMs in CXCR4‐induced migration, inhibition of these kinases might override microenvironmental protection and be an attractive therapeutic strategy in this disease.

Real‑life experience with bortezomib‑based regimens in elderly patients with newly diagnosed multiple myeloma and comorbidities: a Polish retrospective multicenter study

INTRODUCTION    Bortezomib was the first proteasome inhibitor approved for the therapy of multiple myeloma (MM). Currently, VMP (bortezomib, melphalan, prednisone) is one of the standard regimens recommended as the first‑line therapy for patients with MM ineligible for high‑dose chemotherapy (HDT) with autologous stem‑cell transplantation (auto‑SCT). OBJECTIVES    Participants of clinical trials are highly selected populations; therefore, the aim of this study was to present observations from real practice that might provide important information for practitioners. PATIENTS AND METHODS    We retrospectively analyzed the data on the efficacy and safety of bortezomib‑based regimens in 154 patients with newly diagnosed MM ineligible for HDT with auto‑SCT (median age, 73 years; range, 39-89 years) with particular attention to the effect of age, performance status, and concomitant diseases. RESULTS    Patients aged 75 years or older constituted 53.2% of the study cohort. Performance status was impaired in 34.4% of the patients, according to the Eastern Cooperative Oncology Group scale. Comorbidities were reported in 83.8% of the patients (mainly arterial hypertension and atherosclerotic vascular disease). A total of 798 courses of bortezomib‑based regimens (mainly VMP, 86%) were administered. The overall response rate was 81.7%, including 12.7% for complete response and 29.6% for very good partial response. The median progression‑free survival (PFS) and event‑free survival were 17.3 and 7.1 months, respectively. The impaired performance status and age of 75 or older were negative predictors of PFS. The most common severe adverse events were neuropathy (19.4%), infections (19.2%), and neutropenia (14.9%). CONCLUSIONS    Bortezomib‑based regimens are effective and well tolerated in the first‑line therapy of elderly patients with MM and comorbidities, with advanced disease, and light chain MM. A more detailed assessment of patients' frailty is needed to increase the efficacy of treatment.

Abstract 4087: Development of a potent, dual pan-PIM/FLT3 inhibitor for the treatment of heme malignancies

Despite huge effort spent on understanding the pathogenesis of acute myeloid leukemia (AML), current standards of care are still based on the same chemotherapy agents as two decades ago - combinational treatment of cytarabine with an anthracycline. Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is one of the most common genetic lesions in AML. Although FLT3 inhibitors initially exhibit clinical activity, resistance to treatment inevitably occurs within months. PIM kinases are thought to be major drivers of the resistance phenotype and their inhibition in relapsed samples restores cell sensitivity to FLT3 inhibitors. Thus, simultaneous PIM and FLT3 inhibition represents a promising strategy in AML therapy. Selvita has developed a potent and selective first-in-class, dual PIM/FLT3 kinase inhibitor, the SEL24-B489 compound, and profiled its activity for in vitro and in vivo AML models showing significantly broader anti-tumor activity of SEL24-B489 than selective FLT3-ITD or PIM inhibitors. We compared SEL24-B489 head-to-head with a selective PIM inhibitor (AZD1208) and a selective FLT3-ITD inhibitor (AC220) in a panel of AML cell lines with FLT3-ITD or unmutated kinase (FLT3-WT) as well as peripheral AML cells and CD34+ bone marrow blasts. SEL24-B489 exhibited a significantly broader activity, irrespective of FLT3 status, than either of the selective inhibitors. Since PIM kinases have emerged as important mediators of FLT3-inhibitor resistance, we hypothesized that the dual specificity of SEL24-B489 might overcome the phenotype of resistance. We utilized previously developed MOLM-14 cells transduced with either FLT3-WT or FLT3 alleles containing TKD point mutations to show that neither of the these mutations decreased the cellular sensitivity to SEL24-B489. Higher cellular activity and biomarker response of SEL24-B489 than competitive inhibitors was shown by inhibition of specific biomarkers such as S6 and STAT5 phosphorylation at nanomolar concentrations in both FLT3-ITD positive and FLT3-WT cell lines in vitro. We have also demonstrated SEL24-B489 superior potency of SEL24-B489 in xenograft models in vivo. Consistent with the experiments in vitro showing marked synergy between SEL24-B489 and AraC, a combination of these agents resulted in almost completely blocked tumor growth in vivo. Most importantly, SEL24-B489 has been selected as a clinical candidate and is currently in phase I clinical trials.

Citation Format: Wojciech Czardybon, Renata Windak, Aniela Gołas, Michał Gałęzowski, Aleksandra Sabiniarz, Izabela Dolata, Magdalena Salwińska, Paweł Guzik, Magdalena Zawadzka, Ewelina Gabor-Worwa, Bożena Winnik, Małgorzata Żurawska, Ewa Kolasińska, Ewelina Wincza, Marta Bugaj, Monika Danielewicz, Grzegorz Dubin, Ewa Jabłońska, Maciej Szydłowski, Tomasz Sewastianik, Bartosz Puła, Anna Szumera-Ciećkiewicz, Monika Prochorec-Sobieszek, Elżbieta Mądro, Ewa Lech-Marańda, Krzysztof Warzocha, Jerome Tamburini, Przemysław Juszczyński, Krzysztof Brzózka. Development of a potent, dual pan-PIM/FLT3 inhibitor for the treatment of heme malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4087. doi:10.1158/1538-7445.AM2017-4087

Treatment adherence in chronic myeloid leukaemia patients receiving tyrosine kinase inhibitors

Failure to comply with treatment recommendations is very common in patients, but still poorly recognised by doctors. The current practice of using oral therapy on a large scale has been increasingly adopted for cancer patients. Chronic myeloid leukaemia (CML) is just such an example, where the introduction of taking new oral medications, the tyrosine kinase BCR-ABL inhibitors (TKI), has now revolutionised the treatment. The aim of our study was to assess treatment adherence in a group of Polish CML patients (a survey was conducted on 140 patient aged ≥18 years) treated with oral TKI (imatinib, dasatinib and nilotinib) taking into account the following variables: gender, age, education, place of residence, family circumstances and duration of therapy. In addition, we evaluated whether there is a relationship between how patients perceive their level of adherence to treatment recommendations with how subjectively the required dosage regimen was followed. Half the patients admitted to skipping at least one drug dose during the entire course of treatment and 39% did so within their last treatment month. Patients were also found to overestimate their own adherence assessment; around 60% of those missing at least 1 drug dose within the last treatment month believed they 'always' followed recommendations. The study demonstrated that adherence deteriorates over time. Furthermore, patients aged >65 years and patients suffering at least one comorbid disease had better adherence (p < 0.011). There were no differences in adherence among patients treated with imatinib, dasatinib and nilotinib (p = 0.249).

MEK Inhibition Sensitizes Precursor B-Cell Acute Lymphoblastic Leukemia (B-ALL) Cells to Dexamethasone through Modulation of mTOR Activity and Stimulation of Autophagy

Resistance to glucocorticosteroids (GCs) is a major adverse prognostic factor in B-ALL, but the molecular mechanisms leading to GC resistance are not completely understood. Herein, we sought to elucidate the molecular background of GC resistance in B-ALL and characterize the therapeutic potential of targeted intervention in these mechanisms. Using exploratory bioinformatic approaches, we found that resistant cells exhibited significantly higher expression of MEK/ERK (MAPK) pathway components. We found that GC-resistant ALL cell lines had markedly higher baseline activity of MEK and small-molecule MEK1/2 inhibitor selumetinib increased GCs-induced cell death. MEK inhibitor similarly increased in vitro dexamethasone activity in primary ALL blasts from 19 of 22 tested patients. To further confirm these observations, we overexpressed a constitutively active MEK mutant in GC-sensitive cells and found that forced MEK activity induced resistance to dexamethasone. Since recent studies highlight the role GC-induced autophagy upstream of apoptotic cell death, we assessed LC3 processing, MDC staining and GFP-LC3 relocalization in cells incubated with either DEX, SEL or combination of drugs. Unlike either drug alone, only their combination markedly increased these markers of autophagy. These changes were associated with decreased mTOR activity and blocked 4E-BP1 phosphorylation. In cells with silenced beclin-1 (BCN1), required for autophagosome formation, the synergy of DEX and SEL was markedly reduced. Taken together, we show that MEK inhibitor selumetinib enhances dexamethasone toxicity in GC-resistant B-ALL cells. The underlying mechanism of this interaction involves inhibition of mTOR signaling pathway and modulation of autophagy markers, likely reflecting induction of this process and required for cell death. Thus, our data demonstrate that modulation of MEK/ERK pathway is an attractive therapeutic strategy overcoming GC resistance in B-ALL patients.

Efficacy and safety of lenalidomide treatment in multiple myeloma (MM) patients--Report of the Polish Myeloma Group

The aim of the multi-centre retrospective study was to evaluate the efficacy and safety of lenalidomide (LEN) therapy in patients with resistant or relapsed multiple myeloma (MM) as well as in patients with stable disease (LEN used due to neurological complications). The primary endpoint of this study was an overall response rate (ORR). The secondary endpoints were as follows: time to progression (TTP), overall survival (OS) and the safety of drug use. Data were collected in 19 centres of the Polish Multiple Myeloma Study Group. The study group consisted of 306 subjects: 153 females and 153 males. In 115 patients (38.8%, group A), a resistant myeloma was diagnosed; in 135 (44.1%, group B) a relapse, and in 56 (18.3%, group C) a stable disease were stated. In 92.8% of patients, LEN+DEX combination was used; in remaining group, LEN monotherapy or a combination therapy LEN+bortezomib or LEN+bendamustine and other were used. In the entire study group, ORR was 75.5% (including 12.4% patients achieving complete remission [CR] or stringent CR [sCR]). Median time to progression (TTP) was 20 months. Median overall survival (OS) was 33.3 months. The regression model for "treatment response" was on the borderline of statistical significance (p=0.07), however the number of LEN treatment cycles ≥ 6 (R(2)=17.2%), baseline LDH level (R(2)=1.1%) and no ASCT use (R(2)=1.7%) where the factors most affecting treatment response achievement. The regression model for dependant variable--"overall survival"--was statistically significant (p=0.0000004). Factors with the most impact on OS were as follows: number of LEN cycles treatment ≥ 6 (R(2)=16.7%), treatment response achievement (R(2)=6.9%), β-2-microglobulin (β-2-M) level (R(2)=4.8%), renal function (R(2)=3.0%) and lack of 3/4 grade adverse events (R(2)=1.4%).

SUMMARY

LEN is an effective and safe therapeutic option, even in intensively treated resistant and relapsed MM patients, as well as in patients with stable disease and previous treatment-induced neurological complications. In particular, the number of LEN treatment cycles ≥ 6 was the factor which affected treatment response achievement the most, together with an important impact on OS.

Abstract 5394: First-in-class dual PIM/FLT3 kinase inhibitor SEL24-B489 for the treatment of hematological malignancies

Despite huge effort spent on understanding acute myeloid leukemia (AML), current standards of care are still based on the same chemotherapy agents as two decades ago - typically based on cytarabine chemotherapy with an anthracycline. Although patients aged &lt;60 years may achieve remission to induction therapy, most patients will relapse. One of primary reasons for that is high heterogeneity of the disease. Recently one of the most extensively investigated approaches to the treatment of AML, are targeted therapies, especially inhibition of certain kinases. Probably mostly investigated up to date are inhibitors of FLT3 with most advanced clinical compound - AC220 (Quizartinib). FLT3 inhibitors are very effective in killing cancer lines with a major drawback of the therapy being fast development of resistance.

PIM kinases are expressed in various cancers including AML but also other liquid tumors as well as in some solid tumors. Inhibition of PIM kinases which are downstream in the FLT3 signaling cascade have already shown influence on cancer cell survival. In addition there are great hopes related to the fact that PIM kinases were shown to contribute in resistance to FLT3 inhibitors. This leads to the conclusion that combined inhibition of PIM and FLT3 may be a rational strategy.

Selvita has developed series of inhibitors combining activity against PIM and FLT3 kinases. Selected clinical candidate SEL24-B489 - has shown excellent anticancer efficacy. It is active against broad panel of AML cell lines and primary blasts, but also against other hematological cancers: DLBCL, CLL, HL - both in vitro on cell lines, patient samples and in vivo. Head to head comparison of SEL24-B489 with PIM (AZD1208) and FLT3 (AC220) inhibitors currently in clinical development will be presented. Comparison shows strong activity of SEL24-B489 against broader panel of cell lines in vitro and in vivo (in xenograft models) than AZD1208 or AC220. SEL24-B489 is currently in preclinical development and details of toxicology profile will also be discussed.

Citation Format: Krzysztof Brzózka, Wojciech Czardybon, Aniela Gołas, Renata Windak, Michał Gałęzowski, Ewelina Gabor-Worwa, Bożena Winnik, Agnieszka Przybyłowicz, Maciej Szydłowski, Emilia Białopiotrowicz, Tomasz Sewastianik, Elżbieta Mądro, Ewa Lech-Marańda, Krzysztof Warzocha, Przemysław Juszczyński. First-in-class dual PIM/FLT3 kinase inhibitor SEL24-B489 for the treatment of hematological malignancies. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5394. doi:10.1158/1538-7445.AM2015-5394

High incidence of intact or fragmented immunoglobulin in urine of patients with multiple myeloma

In this prospective study we determined the incidence of intact/fragmented immunoglobulin and Bence Jones protein in urine immunofixation using Sebia reagents and HydrasysTM 2 apparatus and compared the results to concentrations of serum free light chains (FLC) assessed using Siemens BNTM II nephelometer and the immunoassay Freelite (Binding Site) in 289 patients with multiple myeloma at diagnosis. It was found that in one third of IgG, IgA and IgD myeloma patients, intact/fragmented immunoglobulin can be detected in urine and is connected with impaired renal function and reduced survival. Urine immunofixation detects monoclonal protein (FLC and intact/fragmented immunoglobulin) in 66-79% of IgG and IgA myeloma patients while serum FLC immunoassay detect it in 82-94% of IgG and IgA myeloma patients. However, the latter method is inadequate for detection of intact/fragmented immunoglobulin in urine. Serum FLC immunoassay and urine immunofixation are complementary methods in diagnosing and monitoring monoclonal protein in patients with myeloma.

[Necrotizing gastritis in a patient in severe neutropenia]

One extremely rare complication of chemotherapy for hematologic malignancies that is burdened with a high mortality rate (50%-80%) is necrotizing gastritis and gastric gangrene as result of poor clinical outcome of neutropenic gastritis (NG). We present a unique case of a neutropenic patient with necrotizing full thickness gastritis due to bacterial and fungal infection. Up to date only few such cases have been reported in world literature. A 28-year-old patient was subjected to dose-escalated BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone), (chemotherapy regimen) for Hodgkin lymphoma. In neutropenic patient abdominal pain, bleeding from the alimentary tract was observed. Hemorrhagic gastritis was recognized at endoscopy and CT demonstrated marked gastric wall thickness. Following NG diagnosis intensive treatment was initiated. On day 2 the patient's condition deteriorated (septic shock, multiple organ failure). Repeat endoscopy revealed gastric necrosis and laparotomy was performed. As consequence of cardiac arrest and cardiopulmonary resuscitation the surgical procedure was limited to total gastrectomy, feeding jejustomy and esophageal drainage through nasoesophageal catherization. Roux-loop esophagojejunostomy was performed on day 22 and supplemented 4 days later by endoscopic placement of covered self-expandable stent due to anastomosis leak. The procedure proved successful and oral feeding was well-tolerated. The patient was discharged in 32 days following recognition of gastric necrosis. Chemotherapy complications in neutropenic patients are life-threatening conditions. Immediate pharmacological treatment usually leads to improvement. Surgical management usually the resection of necrotic zones is restricted to cases of poor prognosis or deterioration of patient's condition and complications.

Abstract 1749: Preclinical characterization of SEL24-B489, a dual PIM/FLT3 inhibitor for the treatment of hematological malignancies

PIM kinases represent an emerging therapeutic target in multiple hematological malignancies, as exemplified by currently ongoing phase I clinical trials by Astra Zeneca (AZD1208) and Novartis (LGH447) in acute myeloid leukemia and multiple myeloma. Selvita has developed a potent and selective dual PIM/FLT3 mutant kinase inhibitor - SEL24-B489 showing high inhibitory activity on all three PIM kinase isoforms and FLT3 kinase mutants. We have previously reported that PIM kinases are important downstream effectors of FLT3 signaling and play a crucial role in cell survival and inhibition of apoptosis upon expression. Due to heterogeneous nature of AML, dual inhibition of FLT3 mutant kinase and PIM kinases led to improved efficacy of our compound in comparison to selective inhibitors of either PIM of FLT3 kinases.

Herewith, we would like to report further progress of characterizing the B489 inhibitor beyond AML. We assessed PIM kinase expression levels in a panel of lymphoid malignancies and found that PIM1 and PIM2 exhibit high expression levels in a fraction of mantle cell lymphoma (MCL), diffuse large-B-cell lymphoma (DLBCL), follicular lymphoma (FL), Hodgkin's lymphoma (HL), chronic lymphocytic leukemia (CLL) and mucosa associated lymphoid tissue-type (MALT) lymphoma cell lines and primary tumors . High levels of PIM kinases were associated with certain established adverse prognostic factors and clinical outcome of the patients and correlated with aggressiveness of the disease in some of these tumors. Inhibition of PIM kinases with tool inhibitors was shown to influence cellular proliferation and, translational inhibition of 4EBP1 as reported in the literature. In addition, SEL24-B489 inhibited NFκB activity and decreased CXCR4 expression. Comparison of SEL24-B489 to competitive PIM inhibitors revealed higher cellular activity and biomarker response, as shown by inhibition of phospho-S6 phosphorylation in sub-microM concentrations. The presented data will further validate SEL24-B489 as a successful example of rational drug design and present a promising therapeutic approach in multiple hematological malignancies, both stand alone and in combination with standard of care and targeted therapies in clinical development.

Citation Format: Wojciech Czardybon, Renata Windak, Izabela Dolata, Magdalena Salwińska, Maciej Szydlowski, Tomasz Sewastianik, Emilia Białopiotrowicz, Elżbieta Mądro, Ewa Lech-Marańda, Bożena K. Budziszewska, Katarzyna Borg, Przemysław Juszczynski, Krzysztof D. Brzózka. Preclinical characterization of SEL24-B489, a dual PIM/FLT3 inhibitor for the treatment of hematological malignancies. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1749. doi:10.1158/1538-7445.AM2014-1749

Hodgkin's lymphoma mimicking tuberculosis in cervical lymph nodes

The authors present a case description of an 81-year-old male with general symptoms (fever, night sweats, weight loss) and cervical/supraclavicular lymphadenopathy. The revised lymph node histopathological examination revealed nodular sclerosis classical Hodgkin's lymphoma associated with abundant tuberculosis-mimicking granulomatous reaction. The diagnosis may be difficult due to similarities in clinical course, laboratory tests and imaging. The morphology of Hodgkin-Reed-Sternberg cells and the immunohistochemical profile are the most helpful in differential diagnosis. In cases where granulomas coexist with negative acid-fast staining, pathologists should always recommend evaluation of further and broader diagnostic procedures to exclude Mycobacterium tuberculosis infection.

Novel purine nucleoside analogues for hematological malignancies

Recently, the search for more effective and safer antineoplastic agents has led to synthesis and introduction into preclinical and clinical studies of a few new purine nucleoside analogues (PNA). Three of them: clofarabine (CAFdA), nelarabine, and forodesine (immucillin H, BCX-1777), despite belonging to the same group of drugs such as PNA, have shown some differences concerning their active forms, metabolic properties and mechanism of action. However, all these drugs have demonstrated promising activity in patients with relapsed and refractory acute lymphoblastic leukemia (ALL). CAFdA was approved for the therapy of relapsed or refractory ALL in the third line of treatment. It has proved promising in pediatric patients as well as in some patients who are able to proceed to allogenic hematopietic stem cell transplantation (HSCT). Moreover, the drug exhibits an efficacy in acute myeloid leukemia (AML), blast crisis of chronic myelogenous leukemia (CML-BP) and myelodysplastic syndrome (MDS). Nelarabine is recommended for T-ALL and T-cell lymphoblastic lymphoma (T-LBL) with the overall response rates ranging from 11 to 60%. However, the use of the drug is limited by potentially severe neurotoxicity. Forodesine is a purine nucleoside phosphorylase (PNP) inhibitor and it has shown activity in relapsed and refractory T- and B-cells leukemias as well as in cutaneous T-cell lymphoma (CTCL). Recently patented, a few of inventions in the field of pharmaceutical preparation of new PNA have also been published. Great hopes are currently set on the use of these drugs in the treatment of lymphoid and myeloid malignancies in adult and in pediatric patients, however ongoing studies will help to define their role in the standard therapy.

Prophylaxis and therapy of central nervous system involvement in adult acute lymphoblastic leukemia: recommendations of the Polish Adult Leukemia Group

The central nervous system (CNS) is one of the most frequent extramedullary locations of adult acute lymphoblastic leukemia (ALL), affecting approximately 5% of patients at diagnosis. T-lineage ALL, high initial leukocyte counts and mediastinal involvement are the predisposing factors. In case of relapse, if no prophylaxis was administered, the rate of CNS involvement reaches 30-50%. As the prognosis of patients with isolated or mixed CNS relapse is particularly poor, adequate prophylaxis seems critical. The treatment comprises intrathecal cytostatics, cranial and spinal cord irradiation, as well as systemic chemotherapy including agents penetrating to the CNS. This strategy allows a reduction in CNS relapses to less than 5% of cases. Compliance to the prophylactic protocols should be one of the principles in the treatment of adult ALL.

Immunogenicity of influenza vaccination in patients with non-Hodgkin lymphoma

PURPOSE

The purpose of this study was to assess humoral response to influenza vaccine in patients (pts) with non-Hodgkin lymphoma (NHL) as compared to healthy subjects (ctrl).

PATIENTS AND METHODS

In two epidemic seasons, 2003/2004 and 2004/2005, 163 pts and 92 ctrl were vaccinated. Antibody titers to hemagglutinin (HA) and neuraminidase (NA) were measured in serum samples collected before vaccination, and 1 and 6 months apart. Changes in antibody titers were assessed by comparing geometric mean titers (GMT), mean fold increases (MFI), and seroprotection and seroresponse rates to baseline values.

RESULTS

Pts vaccinated in 2003/2004 had, after 1 month, increase in GMT by a factor of 8.64-26.60 for antihemagglutinin antibodies (HI) and 6.93-12.66 for antineuraminidase antibodies (NI), as compared to factor of 9.12-24.41 for HI and 4.83-10.31 for NI in ctrl. At 1 month after vaccination, seroprotection and seroresponse rates were similar in both groups, ranging from 68.42 to 84.21% and 71.93 to 94.74% in NHL, and 66.67-82.22% and 62.22-86.67% in ctrl, respectively. Pts vaccinated in 2004/2005 had increase in the GMT by a factor of 38.76-41.49 for HI and 26.59-30.31 for NI, as compared to factor of 81.19-104.32 for HI and 52.16-54.52 for NI in ctrl. Seroprotection and seroresponse rates were lower in the former group, ranging from 62.11 to 65.26% and 74.47 to 77.66%, respectively. In both seasons, pts achieved titres of antibodies greater than the protective threshold, irrespective of the previous chemotherapy administration.

CONCLUSIONS

The results indicate that influenza vaccination induces sufficient immune response in pts with NHL, irrespective of previous chemotherapy.

Cytotoxic activity of the selected pyridinium salts against murine leukemia L1210

The objective of this work was to evaluate the relationship between chemical reactivity of 3-substituted pyridinium salts and their cytotoxic properties against murine leukemia L1210. Chemical reactivity of pyridinium salts towards NADH oxidation following one-step hydride transfer depends strongly on their redox properties. The investigated reaction may reflect the ability of the salts to deplete NADH level in cells and to affect their metabolic functions. On the other hand, the cytotoxic activity against murine leukemia cells, expressed as ED50 values, varied strongly depending upon the compound used. The investigated salts showed also a diverse antileukemic effect in in vivo experiments as measured by the increase in the survival time of L1210 leukemia-bearing mice. These biological effects were correlated with equilibrium constants found for the reaction of pyridinium salts with NADH.

A multicenter, open, noncomparative, phase II study of the combination of cladribine (2-chlorodeoxyadenosine), cytarabine, granulocyte colony-stimulating factor and mitoxantrone as induction therapy in refractory acute myeloid leukemia: a report of the Polish Adult Leukemia Group

Purine nucleoside analogues, cladribine (2-chlorodeoxyadenosine, 2-CdA) and fludarabine (FAMP) are active agents in acute myeloid leukemias (AMLs). Synergistic interaction between FAMP or 2-CdA with cytarabine (cytosine arabinoside, Ara-C) has been demonstrated in preclinical and clinical studies. The current multicenter phase II study was initiated to evaluate the efficacy and toxicity of induction treatment consisting of 2-CdA (5 mg/m2), Ara-C (2 g/m2), mitoxantrone (MIT, 10 mg/m2) and granulocyte colony-stimulating factor (G-CSF) (CLAG-M) in refractory AML. In case of partial remission, a second CLAG-M was administered. Patients in complete remission (CR) received consolidation courses based on high-dose Ara-C and MIT with or without 2-CdA. Forty-three patients from five centers were registered: 25 primary resistant and 18 relapsed. CR was achieved in 21 (49%) patients, 20 (47%) were refractory and 2 (5%) died early. Hematologic toxicity was the most prominent toxicity of this regimen. The overall survival (OS; 1 year) for the 42 patients as a whole and the 20 patients in CR were 43% and 73%, respectively. Disease-free survival (1 year) was 68.6%. None of the analyzed prognostic factors influenced the CR and OS probability significantly. We conclude that CLAG-M regimen has significant antileukemia activity in refractory AML, which seems to be better than the activity of many other regimens. The toxicity of the treatment is acceptable.

A multicenter, open, non-comparative, phase II study of the combination of cladribine (2-chlorodeoxyadenosine), cytarabine, and G-CSF as induction therapy in refractory acute myeloid leukemia - a report of the Polish Adult Leukemia Group (PALG)

OBJECTIVES

To evaluate the efficacy and toxicity of cladribine (2-chlorodeoxyadenosine, 2-CdA), cytarabine (Ara-C), and granulocyte-colony stimulating factor (G-CSF) (CLAG) regimen in refractory acute myeloid leukemia (AML) in the multicenter phase II study.

METHODS

The induction chemotherapy consisted of 2-CdA 5 mg/m2, Ara-C2 g/m2, and G-CSF. In the case of partial remission (PR), a second CLAG was administered. Patients in complete remission (CR) received two consolidation courses based on HD Ara-C, mitoxantrone or idarubicine, with or without 2-CdA.

RESULTS

Fifty-eight patients from 11 centers were registered; 50 primary resistant and eight early relapsed (CR1 < 6 months). CR was achieved in 29 (50%) patients, 19 (33%) were refractory, and 10 (17%) died early. Forty of 50 primary resistant patients received daunorubicin (DNR) and Ara-C as the first-line induction therapy (DA-7), 10 received additional 2-CdA (DAC-7). The CR rates after CLAG were 58% and 10%, respectively in each group (P = 0.015). Five of six patients with myelodysplastic syndrome (MDS)/AML achieved CR. Hematologic toxicity was the most prominent toxicity of this regimen. The overall survival (OS, 1 yr) for the 58 patients as a whole, and the 29 patients in CR were 42% and 65%, respectively. Disease-free survival (DFS, 1 yr) was 29%. Only first-line induction treatment with DA-7 significantly influenced the probability of CR after CLAG. None of the analyzed factors significantly influenced DFS and OS.

CONCLUSION

CLAG regimen has significant anti-leukemic activity and an acceptable toxicity in refractory AML. The addition of 2-CdA to the first-line induction treatment may worsen the results of salvage with CLAG. The high CR rate in patients with MDS preceding AML deserves further observation.

Circulating VEGF and its soluble receptors sVEGFR-1 and sVEGFR-2 in patients with acute leukemia

Angiogenesis plays an important role in the pathogenesis of acute leukemia, and vascular endothelial growth factor (VEGF) is a crucial, positive regulator of this process. The biological activity of VEGF is mediated by two different receptor tyrosine kinases: VEGFR-2 and VEGFR-1. The soluble form of VEGFR-1 is likely to be a negative regulator of VEGF availability, but the physiological role of sVEGFR-2 is still unclear. The plasma levels of sVEGFR-1 and sVEGFR-2 in patients with acute leukemia have not been investigated. We measured the plasma concentrations of VEGF and its two soluble receptors in 39 AML and 15 ALL patients as well as in the control group, using the ELISA assay. We also correlated the plasma levels of these proteins with disease status and known prognostic factors. The sVEGFR-1 level was significantly higher in patients with AML and ALL than in the healthy subjects (p < 0.002 and p < 0.03 respectively). The sVEGFR-2 level was significantly higher in AML patients compared with the control group (p < 0.03). The VEGF levels in AML and ALL patients and in healthy subjects did not differ significantly. The sVEGFR-1 level was higher in AML patients with > 50% of blasts in the bone marrow (BM), WBC > 20 G/L and elevated LDH level, than in the group with BM blasts < 50% (p < 0.01), WBC < 20 G/L (p < 0.02) and a normal LDH level (p < 0.05). Positive correlations between sVEGFR-1 level and WBC (p < 0.02),% of BM blasts (p < 0.05), the absolute blast count in peripheral blood (ABC) (p < 0.009) and LDH (p < 0.000001) were found. The sVEGFR-1/VEGF ratio (R1) was calculated, and a positive correlation between R1 and ABC in AML (p < 0.03) was determined. A higher (above median) sVEGFR-1/VEGF ratio correlated with a lower CR rate and a shorter survival (p < 0.03 and p = 0.0007 respectively). In conclusion, the plasma concentration of sVEGFR-1 is higher in leukemia patients than in healthy subjects and correlates with tumour burden and poor prognosis. The sVEGFR-1/VEGF ratio may be of greater prognostic value than VEGF alone. Further investigation is recommended to better determine their function.

Cladribine in combination with mitoxantrone and cyclophosphamide(CMC) in the treatment of heavily pre-treated patients with advanced indolent lymphoid malignancies

The aim of our study was to determine the effectiveness and toxicity of combined chemotherapy consisting of cladribine (2-chloro-deoxyadenosine, 2-CdA), mitoxantrone and cyclophosphamide (CMC regimen) in the treatment of refractory or relapsed indolent lymphoproliferative disorders. The treatment course consisted of 2-CdA given at a dose of 0.12 mg/kg/24 h in a 2-h intravenous infusion for 5 (CMC5) or 3 (CMC3) consecutive days, mitoxantrone 10 mg/m2 on day 1 and cyclophosphamide 650 mg/m2/iv on day 1. Thirty-three patients (19 with B-CLL and 14 with LG-NHL) entered the study and all of them were eligible. Twenty patients (60.6%) were recurrent after prior therapy and 13 (39.4%) had refractory disease. All patients received 5 or more cycles of chemotherapy before CMC treatment. Twenty-one patients were treated with CMC5 regimen and 12 with CMC3 regimen. The overall response rate, including CR and PR, was 48.6% (95% CI 32-66). There were no differences in the frequency of responses between the CMC3 and CMC5 treated groups (p>0.05). One patient with B-CLL and three patients with lymphocytic lymphoma achieved CR (12.1%). Among 12 patients (36.4%) who achieved PR there were 6 CLL patients, and 6 lymphoma patients. The major toxicity was myelosuppression. Severe neutropenia was seen in 11/33 (33.3%) patients, more frequently in patients who received CMC5 than in the patients who received CMC3, both in the CLL (50.0% and 28.5%, respectively) and in the LG-NHL group (22.2% and 0%, respectively). The rate of thrombocytopenia was similar in both groups. Infections and fever of unknown origin complicated the treatment with CMC5 more often than with CMC3: five episodes were seen in 3 patients treated with CMC3 when compared to 15 episodes in 12 patients treated with CMC5. In conclusion, the CMC programme is an active combined regimen in heavily pre-treated CLL and LG-NHL patients. However, its toxicity is significant and we suggest a shortening of 2-CdA infusion from 5 to 3 d in further studies. Whether a combination of 2-CdA with cyclophosphamide and mitoxantrone would result in improved outcome as compared to 2-CdA alone, is being investigated in a prospective, randomised trial.

Influence of gemcitabine (2',2'-difluoro-deoxycytidine) and 2-chlorodeoxyadenosine on growth of normal and leukemic cells in vitro

The aim of the study was to investigate the influence of gemcitabine (2',2'-difluorodeoxycytidine, dFdC) used alone and in combination with 2-chlorodeoxyadenosine (2-CdA) on the colony growth of normal granulocyte-macrophage progenitor cells (CFU-GM) from 15 hematologically healthy donors as well as on CFU-GM from 15 chronic myelogenous leukemia (CML) patients in semisolid cultures in vitro. dFdC and 2-CdA were used either separately or in the following combinations of concentrations: (1) 0.25 nM of dFdC and 2.5 nM of 2-CdA; (2) 0.5 nM of dFdC and 5 nM of 2-CdA; (3) 1 nM of dFdC and 10 nM of 2-CdA; (4) 2 nM of dFdC and 20 nM of 2-CdA. We observed that both dFdC and 2-CdA used separately inhibited the growth of colonies formed by normal and CML CFU-GM cells in a dose-dependent manner. Moreover, the combined therapy with dFdC and 2-CdA caused statistically significant inhibition of the colony growth in both normal and CML CFU-GM cultures. In addition, the inhibition of CML CFU-GM colony formation was greater and statistically significant in the case of the combined therapy using higher concentrations of these drugs as compared with inhibition of the growth of normal CFU-GM colonies. These observations were the basis for the evaluation of the interaction type between dFdC and 2-CdA. We have shown that dFdC used in a combination with 2-CdA acts in an additive way on normal and CML CFU-GM cells.

Combination regimen of cladribine (2-chlorodeoxyadenosine), cytarabine and G-CSF (CLAG) as induction therapy for patients with relapsed or refractory acute myeloid leukemia

The aim of the study was efficacy and toxicity evaluation of combination of 2-Chlorodeoxyadenosine (2-CdA) with cytarabine (Ara-C) and G-CSF (CLAG regimen) as reinduction therapy in patients with refractory or relapsed acute myeloid leukemia (AML). The protocol stipulated an infusion of 5 mg/m2 of 2-CdA over 2 hours daily for 5 consecutive days. A 4-hour infusion of Ara-C (2 g/m2) was started 2 hours after each infusion of 2-CdA. G-CSF at a dose 300 microg s.c was given 24 hours before the first dose of 2-CdA for 6 days. In case of WBC>20x10(9)/l G-CSF was started simultaneously with 2-CdA. In the case of complete response (CR) consolidation treatment with 2-CdA containing regimens was started. In case of partial response a second identical course of CLAG was given. Response criteria were established according to those developed by the NCI Sponsored Workshop. Among 20 patients accrued all but 2 received at least one course of CLAG induction therapy in the planned doses. 10/20 (50%) (95% CI 27-73%) patients achieved a CR with a median duration of 22.5 weeks (range 3.5-53 weeks). Two (10%) patients had a PR and 8 were non-responders. One patient underwent peripheral blood stem cell transplantation. Overall 4 patients are in continuous CR with a median duration of 16.2 weeks (range 3.5-36.5). Among non-responders two patients did not receive the full dose of treatment because of complications during the cycle, both of them died; 3 died early after complete induction therapy before recovery of the bone marrow and 3 were resistant to CLAG. All 20 patients but one experienced granulocytopenia <0.2x10(9)/l and thrombocytopenia <20x10(9)/l. Median time to reach PMN>0.5x10(9) G/l was 18.7 days and platelets>50x10(9)/l was 27.2 days. In conclusion, the CLAG regimen had significant antileukemic activity and acceptable toxicity as reinduction treatment in refractory or relapsed AML patients.