Timed sequential chemotherapy with concomitant Granulocyte Colony-Stimulating Factor for high-risk acute myelogenous leukemia: a single arm clinical trial

BACKGROUND: The timed-sequential chemotherapy regimen consisting of etoposide, mitoxantrone and cytarabine (EMA) is an effective therapy for relapsed or refractory acute myelogenous leukemia (AML). We postulated that granulocyte colony-stimulating factor (G-CSF) might enhance the cytotoxicity of EMA by increasing the proportion of leukemic blasts in S-phase. We added G-CSF to EMA (EMA-G) for therapy of advanced high-risk AML patients. METHODS: High-risk AML was defined as refractory, relapsed or secondary to either an antecedent hematologic disorder or exposure to cytotoxic agents. The patients were treated with one course of EMA-G consisting of mitoxantrone and cytarabine on days 1–3, and etoposide and cytarabine on days 8–10. G-CSF was started on day 4 and continued until absolute neutrophil count recovered. RESULTS: Thirty patients were enrolled. The median age was 51 years (range, 25–75). Seventeen (61%) patients had unfavorable cytogenetic karyotypes. Twenty (69%) patients had secondary AML. Ten (34%) had relapsed disease. Four (14%) had refractory AML. Three (10%) patients died from febrile neutropenia and sepsis. Major non-hematologic toxicity included hyperbilirubimenia, renal insufficiency, mucositis, diarrhea, nausea and vomiting, skin rash. A complete remission was achieved in 13 (46%) patients. Median overall survival was 9 months (range, 0.5–66). Median relapse-free survival (RFS) for those who had a CR was 3 months (range, 0.5–63) with RFS censored at the time of allogeneic bone marrow transplantation or peripheral stem cell transplantation for 6 of the patients. CONCLUSIONS: EMA-G is a safe and efficacious option for induction chemotherapy in advanced, high-risk AML patients. The activity of EMA may be increased if applied in patients with less advanced disease

Hemochromatois-Associated Gene Mutations in Patients with Myelodysplastic Syndromes with Refractory Anemia and Ringed Sideroblasts

Abstract Complex interaction between a multitude of genetic variants may be responsible for differential susceptibility to specific diseases, and be responsible for phenotypic variability and heterogeneity of clinical presentations. Such a variability in clinical features confounded for many years investigations into the pathogenesis of myelodysplastic syndromes (MDS). We made a curious observation of increased ferritin levels in some newly diagnosed patients with MDS RARS (refractory anemia with ringed sideroblasts) in whom transfusional iron-overload was unlikely due to very low transfusion burden. Hence, we hypothesized that RARS patients may harbor hemochromatosis-related mutations, which could contribute to the pathophysiology of this particular subset of MDS. We studied a cohort of 109 MDS patients; 42 with RARS, and 67 with other forms of MDS (18 RA, 12 RAEB, 7 RAEB-T, 1 CMML, and 29 MDS/MPD overlap). All patients were genotyped using restriction fragment length polymorphism (RFLP) method, designed to detect presence of C282Y and H63D mutations of the HFE gene. We found significantly higher frequency of heterozygozity for the C282Y mutation in 21% of RARS patients (vs 9% in control population, n=2016, p= 0.017) while H63D genotype was not increased. The possible pathogenic role of this finding in RARS was supported by the normal distribution of mutant HFE alleles in patients with other forms of MDS (5% vs. 9%, p =0.35). Interestingly, 3/7 patients with RA not fulfilling the RARS criteria, but having increased numbers of ringed sideroblasts (<15%) also showed heterozygozity for either C282Y or H63D allele. To correlate the presence of C282Y allele with clinical features of RARS patients, we have performed a subset analysis. Within this group we have included patients with a rather nebulous and rare form of MDS, provisionally subclassified by WHO as RARS with thrombocytosis (RARSt); 7 of these patients (n=10) were found to have either C282Y or H63D allele resulting in a frequency of 30% and 40% of C282Y or H63D allele, respectively. The combined prevalence of either of these alleles in the control population is 33% (vs. 70% in RARSt, p=.01). Previously, we have demonstrated that RARSt patients are characterized by a high prevalence of the V617F JAK2 mutation (Szpurka et al, Blood 2006) suggestive of the pathophysiologic derivation of this syndrome from MPD rather than MDS. Consequently, we have tested the frequency of HFE gene variants associated with hemochromatosis in patients with MPD and Jak2 mutations. Of note is that patients with RARS harbored more C282Y alleles than those with other forms of MDS or MPD with Jak2 mutation (except for those with RARSt; (21% vs 5% and 3%, p =0.036 and .012, respectively). We conclude that hemochromatosis associated mutations may contribute to the pathogenesis of RARS. In patients with MPD and Jak2 mutation, concomitant presence of hemachromatosis-predisposing HFE variants may result in the unusual presentation associated with ringed sideroblasts

Hemochromatosis-associated gene mutations in patients with myelodysplastic syndromes with refractory anemia with ringed sideroblasts

We observed increased ferritin levels in newly diagnosed MDS-RARS patients without transfusional iron-overload. Hence, we hypothesized RARS patients may harbor hemochromatosis-related mutations, which could contribute to the pathophysiology of this myelodysplastic syndromes (MDS) subset. We studied a cohort of 140 MDS patients: 42 with RARS, 10 with increased ringed sideroblasts, and 96 with other forms of MDS (43 RA, 27 RAEB, 17 RAEB-T, 8 MDS/MPD, 1 CMML). Patients were genotyped using restriction fragment length polymorphism, designed to detect C282Y and H63D mutations of the HFE gene. We found significantly higher frequency of heterozygosity for C282Y mutation in RARS patients compared with a large control population of matched race individuals (21 vs. 9.8% in controls, P = 0.03); H63D genotype was not significantly increased. Frequency of HFE variation in other MDS subtypes failed to differ significantly from controls. Within this group, we included patients with a rare form of MDS, provisionally subclassified by WHO as RARS with thrombocytosis (RARSt). 10/14 RARSt patients were carriers of either C282Y or H63D allele significantly increased compared with the combined prevalence in a healthy population (71 vs. 33%, P < 0.01). We found expected distribution of mutant HFE alleles in patients with other forms of MDS (9.1 vs. 9.8%, P = 0.82). Increased prevalence of HFE gene mutations is not a generalized feature of MDS, but some subgroups of MDS, especially those characterized by excessive accumulation of ringed sideroblasts, exhibit C282Y mutations at a higher frequency than in other forms of MDS and healthy controls

SNP Array Karyotyping Improves Detection Rate of Clonal Chromosomal Abnormalities in Refractory Anemia with Ringed Sideroblasts

Abstract Among WHO low-risk categories of MDS, refractory anemia with ringed sideroblasts (RARS) can be more accurately diagnosed by characteristic pathomorphology. Clonal hematopoiesis and chromosomal abnormalities exemplify a close pathogenetic relationship to other forms of MDS. RARS shows considerable clinical variability even for patients (pts) with identical cytogenetic defects. Due to the low resolution of metaphase cytogenetics (MC) and its dependence on cell growth in vitro, this test is often non-informative in MDS. High-density SNP arrays (SNP-A) allow for a precise identification of unbalanced genomic lesions and copy-neutral loss of heterozygozity. We hypothesize that cryptic chromosomal (chr) aberrations exist in most, if not all, pts with RARS. Their detection may help to improve prognostication, distinguish distinct phenotypes and point towards unifying pathogenic defects. Initially, we analyzed the results of MC in pts with MDS and MDS/MPD (N=455) and in a sub-cohort of RARS, RCMD-RS, RARSt and other MDS subtypes with >15% RS. When we compared pts with/without RS, chr defects were found at comparable frequencies (∼50%). The most commonly occurring defects associated with RS, compared to other forms of MDS, included those of chr 5 (9% vs. 16%, 7 (8% vs. 12%) and 20 (3% vs. 8%). DNA was available for 36 pts with RS and was subjected to 250K SNP-A karyotyping. Pathologic lesions were defined upon exclusion of normal copy number polymorphisms identified in 81 controls (O’Keefe at al ASH 2007), as well as the Database of Genomic Variants (http://projects.tcag.ca/variation). By MC, a defective karyotype was present in 16/36 pts (44%). Deletions involving chr 5, 7 and complex MC were found in 3, 5, and 2pts, respectively. However, when SNP-A was applied as a karyotyping tool (copy number and LOH analysis), all aberrations found by MC were confirmed, but also new lesions were detected so that an abnormal karyotype was established in 62% of pts. Several previously cryptic/recurrent lesions included losses of a portion of chr. 2 (N=2; 2p16.2, 2p16.3), and deletions (N=4; 7p11.1–14.1, 7p21.3, 7q11.23–21.11, 7q21.12-qter) as well as gains (N=1; 7q33) on chr 7. We have also detected segmental uniparental disomy (UPD) in chr 1 (N=2; 1p21.3–22.2, 1p). This type of lesion cannot be detected using MC and provides an additional mechanism leading to LOH. When both bone marrow and blood of 5 RARS patient were tested using SNP-A, blood analysis had 100% accuracy rate as compared to marrow; all defects seen in the marrow were also found in blood. We conclude that chromosomal defects are present in a majority of RARS patients and arrays with higher resolution will identify defects in most, if not all of the patients. Our study also demonstrates testing of peripheral blood by SNP-A can complement marrow MC, especially in cases in which marrow is not available. Detection of clonal marker aberrations in blood of RARS patients suggests that mostly clonal dysplastic progenitor cells contribute to blood production rather than residual “normal” progenitors

Presence of JAK2 Mutations in MDS/MPD-u WHO Classified Patients and Not Other Forms of MDS Suggests Their Derivation from Classical Myeloproliferative Syndrome

Abstract The WHO classification of myeloid neoplasms recognizes a category of myeloid disorders that overlaps traditional myelodysplastic syndromes (MDS) and myeloproliferative disorders (MPD) as the entity MDS/MPD disease. This disease category includes CMML, JMML, atypical CML and MDS/MPD unclassifiable (MDS/MPD-u). The provisional entity termed RARS associated with marked thrombocytosis (RARS-t) is currently best classified as MDS/MPD-u until further information is available regarding its pathogenesis. Recently a JAK2 mutation V617F (G→T) was identified as a pathogenetic lesion in typical myeloproliferative disorders (Kralovics et al, NEJM, 2005). Subsequent studies of the JAK2 mutation concentrated on more proliferative forms of MDS or MDS/MPD such as CMML and CNL (Steensma et al, Blood, 2005). These studies demonstrated that homo- and heterozygous JAK2 mutants are present in a rather small proportion of these patients. Based on similar clinical features, we theorized that JAK2 mutants might be also found in patients with MDS/MPD-u. We have collected a cohort of these patients (N=202) and analyzed them for the presence of JAK2 mutation using a molecular allele-specific PCR assay. Positive cases were confirmed by sequencing with a sensitivity of about 20% of mutated cells. A group of patients with PV, MF and ET served as positive controls (N=66). In agreement with previous reports, the detection rate of JAK2 mutants for PV, MF and ET was 92%, 55% and 55%, respectively. Our experimental group included 104 patients with MDS or MDS/MPD (53 RA/RS, 14 RAEB, 22 RAEB-t/sAML, and 15 CMML). Most significantly, the RA/RS group contained 13 patients with WHO-defined MDS/MPD overlap and 3 with RARS-t (among these patients, 3 were JAK2 mutants; all of them were heterozygous - 18.8%). Within 16 patients with CMML1 or 2 we found only 2 heterozygous for JAK2 mutation (12.5%). The remaining cohort of 73 patients in MDS categories revealed only 1 patient to be heterozygous for JAK2 mutation (RARS, 1.4%). As expected MDS/MPD patients with JAK2 mutation showed various degrees of BM fibrosis, splenomegaly and less pronounced cytopenias. Except for one patient, JAK2 mutants had normal cytogenetics. All had normal MCV and ANC. In 4/5 increased megakaryocytes with/or without atypia was seen. One CMML patient with abnormal cytogenetics showed an unusual translocation t(8;9)(q22;p24). JAK2 is located at 9p24 so it is possible that the JAK2 gene was involved in the translocation generating a novel fusion protein in addition to an activating JAK2 mutant. Our results showed that JAK2 mutations are rarely found in typical cases of MDS or CMML. However, further analysis of JAK2 mutational status in patients with MDS/MPD-u is warranted. The reported detection rate may suggest that the pathogenesis of these entities is more akin to myeloproliferative than myelodysplastic syndromes

SNP Array Analysis in Refractory Anemia with Ringed Sideroblast Allows for Detection of a High Frequency of Previously Cryptic Chromosomal Defects with Possible Clinical Significance

Abstract Among WHO low-risk categories of MDS, refractory anemia with ringed sideroblasts (RARS) can be more precisely identified based on typical findings in the iron stain preparations of marrow aspirates. Clonal hematopoiesis and chromosomal (chr) abnormalities are features that reveal a clear pathogenetic relationship to MDS. However, despite characteristic morphology, chr defects in RARS are heterogeneous, RARS shows considerable variability in the clinical course even for patients with identical cytogenetic defects. We analyzed the results of metaphase cytogenetics (MC) in a cohort of patients classified as RARS, RCMD-RS, or more advanced forms of MDS associated with ringed sideroblasts. Similar proportions of defects (around 50%) were found in RARS patients (n=68) as in all other remaining MDS forms studied (n=288). The most commonly occurring defects associated with ringed sideroblasts, compared to other forms of MDS, included those of chr 5 (14% vs 31%), 7 (11% vs 14%) and 8 (17% vs 20%), respectively. However, due to the low resolution of MC and its dependence on cell growth in vitro, this test is often negative or non-informative in MDS. High-density SNP arrays (SNP-A) allow for a precise identification of unbalanced genomic lesions. We hypothesize that cryptic chr aberrations do exist in most, if not all, patients with RARS. Their detection may help to improve prognostication, distinguish distinct subgroups of patients and point towards unifying pathogenic defects. Consequently, we have applied 250K SNP-A to analyze the marrow (n=14) or blood (n=15) in RARS. Pathologic lesions were defined based on a study of 36 normal marrow specimens (O’Keefe at al ASH 2006). By traditional MC, a defective karyotype was present in 18 of 29 patients (34%). Monosomy 7/7q- was found in 5 patients; deletions involving chr 5 and 11 in 2 cases; and 5 patients showed a complex karyotypes. However, when SNP-A was applied as a karyotyping tool (copy number and LOH analysis), we were able to detect lesions in 65% of patients (vs 34% by cytogenetics, p<.01). All but 2 aberrations found by MC were confirmed. New, previously cryptic lesions were identified, including losses of a portion of chr 8 (n=4) and deletions (n=2) as well as gains (n=2) within chr 17q. We have also detected segmental uniparental disomy (UPD) in 2 patients. This type of lesion cannot be detected using MC and provides an additional mechanism that can lead to LOH. When comparing MC to SNP-A, 1 lesion was found in 7/29 patients vs 12/29; 2 lesions in 0/29 vs 5/29; and ≥3 lesions in 3/29 vs 2/29 patients, respectively. Most remarkably, we have identified shared lesions, including an invariant deletion involving 4q31-21 (n=3, with 2/3 diagnosed as RARSt), loss of 8q24.23 (n=2); and a UPD involving 1p21.3-22.2 (n=2). These lesions contain important genes, including IL-15 and GAB1 (4p) or DR1 and TGFBR3 (1p). Our results indicate that if more precise techniques are applied, chr abnormalities can be detected in a higher proportion of patients with RARS. Analysis of clinical outcomes associated with defects identified by A-SNP is currently ongoing in our laboratory