Alexandra Oltová

Detailed analysis of therapy-driven clonal evolution of TP53 mutations in chronic lymphocytic leukemia

In chronic lymphocytic leukemia (CLL), the worst prognosis is associated with TP53 defects with the affected patients being potentially directed to alternative treatment. Therapy administration was shown to drive the selection of new TP53 mutations in CLL. Using ultra-deep next-generation sequencing (NGS), we performed a detailed analysis of TP53 mutations’ clonal evolution. We retrospectively analyzed samples that were assessed as TP53-wild-type (wt) by FASAY from 20 patients with a new TP53 mutation detected in relapse and 40 patients remaining TP53-wt in relapse. Minor TP53-mutated subclones were disclosed in 18/20 patients experiencing later mutation selection, while only one minor-clone mutation was observed in those patients remaining TP53-wt (n=40). We documented that (i) minor TP53 mutations may be present before therapy and may occur in any relapse; (ii) the majority of TP53-mutated minor clones expand to dominant clone under the selective pressure of chemotherapy, while persistence of minor-clone mutations is rare; (iii) multiple minor-clone TP53 mutations are common and may simultaneously expand. In conclusion, patients with minor-clone TP53 mutations carry a high risk of mutation selection by therapy. Deep sequencing can shift TP53 mutation identification to a period before therapy administration, which might be of particular importance for clinical trials.

Prognosis of children with mixed phenotype acute leukemia treated on the basis of consistent immunophenotypic criteria

Background Mixed phenotype acute leukemia (MPAL) represents a diagnostic and therapeutic dilemma. The European Group for the Immunological Classification of Leukemias (EGIL) scoring system unambiguously defines MPAL expressing aberrant lineage markers. Discussions surrounding it have focused on scoring details, and information is limited regarding its biological, clinical and prognostic significance. The recent World Health Organization classification is simpler and could replace the EGIL scoring system after transformation into unambiguous guidelines. Design and Methods Simple immunophenotypic criteria were used to classify all cases of childhood acute leukemia in order to provide therapy directed against acute lymphoblastic leukemia or acute myeloid leukemia. Prognosis, genotype and immunoglobulin/T-cell receptor gene rearrangement status were analyzed. Results The incidences of MPAL were 28/582 and 4/107 for children treated with acute lymphoblastic leukemia and acute myeloid leukemia regimens, respectively. In immunophenotypic principal component analysis, MPAL treated as T-cell acute lymphoblastic leukemia clustered between cases of non-mixed T-cell acute lymphoblastic leukemia and acute myeloid leukemia, while other MPAL cases were included in the respective non-mixed B-cell progenitor acute lymphoblastic leukemia or acute myeloid leukemia clusters. Analogously, immunoglobulin/T-cell receptor gene rearrangements followed the expected pattern in patients treated as having acute myeloid leukemia (non-rearranged, 4/4) or as having B-cell progenitor acute lymphoblastic leukemia (rearranged, 20/20), but were missing in 3/5 analyzed cases of MPAL treated as having T-cell acute lymphobastic leukemia. In patients who received acute lymphoblastic leukemia treatment, the 5-year event-free survival of the MPAL cases was worse than that of the non-mixed cases (53±10% and 76±2% at 5 years, respectively, P=0.0075), with a more pronounced difference among B lineage cases. The small numbers of MPAL cases treated as T-cell acute lymphoblastic leukemia or as acute myeloid leukemia hampered separate statistics. We compared prognosis of all subsets with the prognosis of previously published cohorts. Conclusions Simple immunophenotypic criteria are useful for therapy decisions in MPAL. In B lineage leukemia, MPAL confers poorer prognosis. However, our data do not justify a preferential use of current acute myeloid leukemia-based therapy in MPAL.

Complex karyotype and translocation t(4;14) define patients with high-risk newly diagnosed multiple myeloma: results of CMG2002 trial

Abstract The prognostic impact of chromosomal abnormalities was evaluated by fluorescence in situ hybridization with cytoplasmic immunoglobulin light chain staining (cIg-FISH) and by classical metaphase cytogenetics in a cohort of 207 patients with newly diagnosed multiple myeloma who were treated with high-dose therapy followed by autologous stem cell transplantation in the CMG2002 clinical trial. The incidence of chromosomal abnormalities detected by FISH was as follows: 52.7% for del(13)(q14), 6.5% for del(17)(p13), 18.6% for t(11;14)(q13;q32), 22.8% for t(4;14)(p16;q32) and 45.7% for gain(1)(q21). Metaphase cytogenetic analysis revealed a complex karyotype in 19.1% and hyperdiploidy in 21.7% of patients. The overall response rate was not influenced by the presence of any studied chromosomal abnormality. Patients with a complex karyotype, those with translocation t(4;14) and those with gain of the 1q21 locus had a shorter time to progression (TTP) and overall survival (OS). Other genomic changes such as translocation t(11;14) and del(13q) had less impact on TTP and OS. In multivariate analysis, complex karyotype, translocation t(4;14) and β2-microglobulin level > 2.5 mg/L were independent prognostic factors associated with poor overall survival. Their unfavorable prognostic impact was even more pronounced if they were present in combination. Patients with t(4;14) present together with a complex karyotype had the worst prognosis, with a median OS of only 13.2 months, whereas patients with a normal karyotype or karyotype with ≤ 2 chromosomal changes had the best outcome, with 3-year OS of 85.9%. In conclusion, complex karyotype, gain of 1q21 region and translocation t(4;14) are major prognostic factors associated with reduced survival of patients with newly diagnosed multiple myeloma treated with autologous stem cell transplantation.

Ofatumumab added to dexamethasone in patients with relapsed or refractory chronic lymphocytic leukemia: Results from a phase II study

The treatment of relapsed/refractory chronic lymphocytic leukemia (CLL) remains a challenging clinical issue. An important treatment option is the use of high‐dose corticosteroids. The purpose of this clinical trial was to determine the efficacy and toxicity of an ofatumumab–dexamethasone (O‐Dex) combination in relapsed or refractory CLL. The trial was an open‐label, multicenter, nonrandomized, Phase II study. The O‐Dex regimen consisted of intravenous ofatumumab (Cycle 1: 300 mg on day 1, 2,000 mg on days 8, 15, and 22; Cycles 2–6: 1,000 mg on days 1, 8, 15, and 22) and oral dexamethasone (40 mg on days 1–4 and 15–18; Cycles 1–6). The O‐Dex regimen was given until best response, or a maximum of six cycles. Thirty‐three patients (pts) were recruited. Twenty‐four (73%) pts completed at least three cycles of therapy. The remaining nine pts were prematurely discontinued owing to Grade 3/4 infections (seven pts), disease progression (one pt), or uncontrollable diabetes mellitus (one pt). Overall response rates/complete remissions (ORR/CR) were achieved in 22/5 pts (67/15%). The median progression‐free survival (PFS) was 10 months. In pts with p53 defects (n = 8), ORR/CR were achieved in 5/2 pts (63/25%) with a median PFS of 10.5 months. The median overall survival (OS) was 34 months. The Grades 3–5 infectious toxicity in 33% of pts represented the most frequent side effect during the treatment period. In conclusion, the O‐Dex regimen shows a relatively high ORR and CR with promising findings for PFS and OS. The study was registered at www.clinicaltrials.gov (NCT01310101). Am. J. Hematol. 90:417–421, 2015.

Imatinib as the first-line treatment of patients with chronic myeloid leukemia diagnosed in the chronic phase: Can we compare real life data to the results from clinical trials?†

Imatinib (IM) dramatically improved the prognosis of chronic myeloid leukemia (CML), particularly with newly diagnosed patients in a chronic phase (CP) [1]. The most robust source of data about IM efficacy in this setting is the IRIS trial. However, every day clinical practice data are still scarce. We analyzed IM efficacy and safety in the first-line therapy of 152 consecutive adult CP-CML patients from a defined region. The estimated 4-year cumulative incidences of complete hematologic, complete cytogenetic, major, and complete molecular responses were 95.3%, 80.6%, 65.4%, and 39.2%, respectively. The 4-year probability of overall and progression-free survival (PFS) defined as with the IRIS [2] was 91.5% and 78.1%, respectively. We thus confirmed very good IM efficacy also in patients not participating in clinical trials. However, the estimated 4-year event-free survival (EFS), which also counted failure events according to valid recommendations [3] or IM discontinuation due to intolerance, was only 60.7%. The 4-year probability of an alternative treatment-free survival, our newly defined parameter, which better reflects the proportion of patients remaining on IM despite an event, was 67.6%. Therefore, more appropriate selection and unification of survival analyses end-points is desirable to describe and compare IM real efficacy.

Clonal evolution in chronic lymphocytic leukemia detected by fluorescence in situ hybridization and conventional cytogenetics after stimulation with CpG oligonucleotides and interleukin-2: A prospective analysis

Chronic lymphocytic leukemia (CLL) patients may acquire new chromosome abnormalities during the course of their disease. Clonal evolution (CE) has been detected by conventional chromosome banding (CBA), several groups also confirmed CE with fluorescence in situ hybridization (FISH). At present, there are minimal prospective data on CE frequency determined using a combination of both methods. Therefore, the aim of our study was to prospectively assess CE frequency using a combination of FISH and CBA after stimulation with CpG oligonucleotides and interleukin-2. Between 2008 and 2012, we enrolled 140 patients with previously untreated CLL in a prospective trial evaluating CE using FISH and CBA after stimulation. Patients provided baseline and regular follow-up peripheral blood samples for testing. There was a median of 3 cytogenetic examinations (using both methods) per patient. CE was detected in 15.7% (22/140) of patients using FISH, in 28.6% (40/140) using CBA, and in 34.3% (48/140) of patients by combining both methods. Poor-prognosis CE (new deletion 17p, new deletion 11q or new complex karyotype) was detected in 15% (21/140) of patients and was significantly associated with previous CLL treatment (p=0.013). CBA provides more complex information about cytogenetic abnormalities in CLL patients than FISH and confirms that many patients can acquire new abnormalities during the course of their disease in a relatively short time period.

Chk1 inhibition significantly potentiates activity of nucleoside analogs in TP53-mutated B-lymphoid cells

Treatment options for TP53-mutated lymphoid tumors are very limited. In experimental models, TP53-mutated lymphomas were sensitive to direct inhibition of checkpoint kinase 1 (Chk1), a pivotal regulator of replication. We initially tested the potential of the highly specific Chk1 inhibitor SCH900776 to synergize with nucleoside analogs (NAs) fludarabine, cytarabine and gemcitabine in cell lines derived from B-cell malignancies. In p53-proficient NALM-6 cells, SCH900776 added to NAs enhanced signaling towards Chk1 (pSer317/pSer345), effectively blocked Chk1 activation (Ser296 autophosphorylation), increased replication stress (p53 and γ-H2AX accumulation) and temporarily potentiated apoptosis. In p53-defective MEC-1 cell line representing adverse chronic lymphocytic leukemia (CLL), Chk1 inhibition together with NAs led to enhanced and sustained replication stress and significantly potentiated apoptosis. Altogether, among 17 tested cell lines SCH900776 sensitized four of them to all three NAs. Focusing further on MEC-1 and co-treatment of SCH900776 with fludarabine, we disclosed chromosome pulverization in cells undergoing aberrant mitoses. SCH900776 also increased the effect of fludarabine in a proportion of primary CLL samples treated with pro-proliferative stimuli, including those with TP53 disruption. Finally, we observed a fludarabine potentiation by SCH900776 in a T-cell leukemia 1 (TCL1)-driven mouse model of CLL. Collectively, we have substantiated the significant potential of Chk1 inhibition in B-lymphoid cells.

Treatment of chronic myeloid leukemia with autologous transplantation using peripheral blood stem cells or bone marrow cultured in IL-2 followed by IL-2, GM-CSF, and IFN-alpha administration.

Interleukin-2 (IL-2) is able to generate nonspecific cytotoxic effectors from hematopoietic precursors. We evaluated the feasibility and efficacy of chronic myeloid leukemia (CML) treatment with autologous hematopoietic stem cell transplantation (HSCT) using grafts cultured in IL-2 followed by immunotherapy with IL-2, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon (IFN)-α. Eight patients with CML were enrolled: five in an accelerated phase and three in a chronic phase. They received peripheral blood stem cells (PBSC) or bone marrow (BM) cultured in a medium containing IL-2 for 24 h. A median of 1.29 × 106 CD34+ cells/kg were infused after conditioning with busulfan (12–16 mg/kg) in PBSC recipients. BM was infused without prior myeloablative therapy. The engraftment occurred with a median of 15 d. Engraftment failure developed in one patient. The transplantation was followed by a 1-mo regimen of IL-2 (0.5 × 106 IU/m2 daily) and GM-CSF, and 6 mo of IFN-α. One complete and one transient minor cytogenetic remission were observed. At 24 mo after transplantation, two patients had died of progressive disease and one of infection. Five patients had stable disease in the chronic phase. Autologous transplantation using IL-2-activated graft is feasible and the subsequent IL-2, GM-CSF, and IFN-α administration has acceptable toxicity. However, no benefits in comparison with conventional autologous transplantation for CML were identified in our study.

Failure of molecular diagnostics in chronic myeloid leukemia: an aberrant form of e13a2 BCR–ABL transcript causing false-negative results by standard polymerase chain reaction

In 95% of patients suffering from chronic myeloid leukemia (CML), and in 25% of patients suffering from acute lymphoblastic leukemia (ALL), the leukemic cells are characterized by the presence of the Philadelphia chromosome (Phþ), which results from the reciprocal translocation t(9;22)(q34;q11). The resultant BCR–ABL fusion gene encodes oncogenic proteins that vary in size, depending on the breakpoint within the BCR gene. A majority of patients with Phþ CML (*90%) have the most common type of breakpoint, denoted as M-bcr (major), resulting in e13a2 and/or e14a2 fusion transcripts. A minor portion of cases with Phþ CML (*10%) are associated with two other types of breakpoint, termed m-bcr (minor) and m-bcr (micro), involving e1a2 and e19a2 junctions, respectively [1,2]. For the abovementioned fusions (M-bcr, m-bcr, m-bcr), powerful molecular diagnostic tools based on reverse-transcriptase polymerase chain reaction (RT-PCR) have been purposefully used in routine practice. Considering the fact that the majority of patients with Phþ CML and ALL harbor the typical BCR–ABL fusion transcript, many modern molecular diagnostic techniques for the qualitative detection of BCR–ABL fusions are based on a multiplex RT-PCR method reported by Cross et al. in the early 1990s [3]. These authors described a rapid and simple PCR method capable of identifying the common BCR–ABL breakpoints, a technique that was also expected to distinguish all the theoretical in-frame mRNAs, including e19a2, e13a3, and e1a3 transcripts. Unfortunately, to date, atypical types of BCR–ABL fusion genes have also been reported. Involvement of the BCR gene breakpoints outside the cluster regions [4–7], insertion of small sequences [8,9], or genomic breakpoints within individual exons [10,11] represent a risk of misinterpretation during routine investigation at diagnosis. To reduce the possibility of misinterpretation, an improved RT-PCR assay for the simultaneous detection of common (M-bcr, m-bcr, m-bcr) and also rare BCR–ABL fusion transcripts has been recently reported [12]. It is well known that the common strategy for follow-up of patients with Phþ CML on a molecular level is based on characterization of the BCR–ABL fusion transcript at the time of diagnosis (by RT-PCR) and its subsequent quantitative assessment (by real-time quantitative RT-PCR). Therefore, it is evident that exact fusion determination plays a crucial role in the long-term monitoring of minimal residual disease (MRD) in these patients. Here we report on a ‘illustrative’ case where the molecular diagnostics covering mainly common BCR–ABL fusions failed. Moreover, within this case report, we highlight the importance of precise qualitative BCR–ABL fusion detection before quantitative monitoring.

The BCR–ABL1 T315I mutation and additional genomic aberrations are dominant genetic lesions associated with disease progression in patients with chronic myelogenous leukemia resistant to tyrosine kinase inhibitor therapy

The BCR-ABL1 T315I mutation and additional genomic aberrations are dominant genetic lesions associated with disease progression in patients with chronic myelogenous leukemia resistant to tyrosine kinase inhibitor therapy. The BCR-ABL1 T315I mutation and additional genomic aberrations are dominant genetic lesions associated with disease progression in patients with chronic myelogenous leukemia resistant to tyrosine kinase inhibitor therapy. The BCR-ABL1 T315I mutation and additional genomic aberrations are dominant genetic lesions associated with disease progression in patients with chronic myelogenous leukemia resistant to tyrosine kinase inhibitor therapy.