INTRODUCTIONIn Brazil, patients with chronic myeloid leukemia (CML) in the chronic phase were not given first-line imatinib treatment until 2008. Therefore, there was a long period of time between diagnosis and the initiation of imatinib therapy for many patients. This study aims to compare the major molecular remission (MMR) rates of early versus late imatinib therapy in chronic phase CML patients.METHODSBetween May 2002 and November 2007, 44 patients with chronic phase CML were treated with second-line imatinib therapy at the Hematology Unit of the Ophir Loyola Hospital (Belém, Pará, Brazil). BCR-ABL transcript levels were measured at approximately six-month intervals using quantitative polymerase chain reaction.RESULTSThe early treatment group presented a 60% probability of achieving MMR, while the probability for those patients who received late treatment was 40%. The probability of either not achieving MMR within one year of the initiation of imatinib therapy or losing MMR was higher in patients who received late treatment (79%), compared with patients who received early treatment (21%, odds ratio=5.75, P=0.012). The probability of maintaining MMR at 30 months of treatment was 80% in the early treatment group and 44% in the late treatment group (P=0.0005).CONCLUSIONSFor CML patients in the chronic phase who were treated with second-line imatinib therapy, the probability of achieving and maintaining MMR was higher in patients who received early treatment compared with those patients for whom the time interval between diagnosis and initiation of imatinib therapy was longer than one year.

Sickle cell disease (SCD) is one of the most common inherited diseases in the world and the patients present notorious clinical heterogeneity. It is known that patients with SCD present activation of the blood coagulation and fibrinolytic systems, especially during vaso-occlusive crises, but also during the steady state of the disease. We determined if the presence of the factor V gene G1691A mutation (factor V Leiden), the prothrombin gene G20210A variant, and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism may be risk factors for vascular complications in individuals with SCD. We studied 53 patients with SCD (60% being women), 29 with SS (sickle cell anemia; 28 years, range: 13-52 years) and 24 with SC (sicklehemoglobin C disease; 38.5 years, range: 17-72 years) hemoglobinopathy. Factor V Leiden, MTHFR C677T polymorphism, and prothrombin G20210A variant were identified by PCR followed by further digestion of the PCR product with specific endonucleases. The following vascular complications were recorded: stroke, retinopathy, acute thoracic syndrome, and X-ray-documented avascular necrosis. Only one patient was heterozygous for factor V Leiden (1.8%) and there was no prothrombin G20210A variant. MTHFR 677TT polymorphism was detected in 1 patient (1.8%) and the heterozygous form 677TC was observed in 18 patients (34%, 9 with SS and 9 with SC disease), a prevalence similar to that reported by others. No association was detected between the presence of the MTHFR 677T allele and other genetic modulation factors, such as α-thalassemia, ß-globin gene haplotype and fetal hemoglobin. The presence of the MTHFR 677T allele was associated with the occurrence of vascular complications in SCD, although this association was not significant when each complication was considered separately. In conclusion, MTHFR C677T polymorphism might be a risk factor for vascular complications in SCD.

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4424 Background. Chronic Myeloid Leukemia represents the first human cancer in which a molecular therapy produces an effective clinical response (Holtz Blood 99:3792-800, 2002). The imatinib mesylate (IM) (Novartis Pharmaceuticals™) is a drug, that was designated to inhibit selectively certain tyrosine kinase proteins involved in the process of oncogenesis (Guilhot, The Oncologist, 9:271-81, 2004). In 2005, Michor (Nature 435:1267-70), through mathematical model, concluded that imatinib efficiently reduces the differentiated leukemic cells population, but it has not the same effect on the cell population that drives this disease, the CD34+ leukemic stem cells, which can be kept alive during the treatment. The search for the main causes of imatinib resistance has been intensified in recent years, with a special focus on the possible role of drug transporters (Apperley, Lancet Oncol 8:1018–29, 2007; Baker and Reddy, Mount Sinai J Med, 77:573–86, 2010). These proteins are the main determinants of the intracellular drug concentration, and how they actively regulating the traffic of small molecules through the cell membrane (Melo, Blood 108:1116-7, 2006). Thus, a cell can be resistant to a drug, because the optimum amount of the drug does not stay inside it to a significant effect to be achieved (Kim, Toxicology 182:291-7, 2002). Purpose. Identify differentially expressed genes in CD34+ and CD66b+ cells as candidates for IM transport. Methods. Samples of bone marrow (BM) and peripheral blood (PB) were obtained from five patients with CML treated with imatinib in better then optimal response according to European LeukemiaNet criteria (Baccarani, Blood 108:1809-20, 2006). Cells Isolation and RNA extraction. CD34+ cells were isolated from BM of five patients with CML. Likewise, mature CD66b+ PB cells were isolated from the same patients. SOLiD sequencing and sequence analysis. cDNA was sequenced according to the manufacturer's protocols for the SOLiD Total RNA-Seq kit for whole transcriptome. Data Analysis. To characterize the class genes, we analyzed the Gene Ontology (GO) annotation (Ashburner, Nature Genetics 25:25-9, 2000), and the software Cufflinks (Trapnell, Nature Biotechnology 28:511–15, 2010) were used to identify the differential expression of genes in both samples, in patients (BM × PB) and in control (BM × PB). The difference in gene expression between compared samples, were calculated based on P < 0.05 significance, were called differentially expressed genes those who submit P ≤ 0.05. Results. In pool sample of patients, it was possible to identify the genes SLC22A1 (OCT1) – in both, BM and PB pool samples, without any significant change (p ≤ 0,05) - and SLCO1A2 (OATP1A2) – only in PB sample. Thus its presence could not be identified in any of the control samples, which may reinforce the fact that these channels are actually responsible for the influx of imatinib in cells from patients undergoing treatment (Crossman, Blood:1133-4, 2005; Hu, Clin Cancer Res 14:3141–8, 2008). The presence of ABC gene family (ABCB1; ABCG2; ABCC1), described in the literature as being responsible for imatinib efflux (Jordanides, Blood 108: 1370–3, 2006; Brendel, Leukemia 21:1267–75, 2007) were found only in BM cells of patients. The presence of other two genes responsible for the drug efflux was also found exclusively in BM pool sample of patients, SLC47A1 and SLC47A2. These genes known as Human multidrug and toxin extrusion (MATE1 and MATE2) have also being identified as one important efflux mechanism of various drugs (Yonezawa and Inui, British J Pharmacol, 164:1817–25, 2011; Minematsu and Giacomini, Mol Cancer Ther, 10:531–9, 2011). Conclusion. The presence of more drug influx channels - the SLC family (OCT1 and OATP1A2) in mature cell - and absence of drug efflux channels - family ABC (ABCB1, ABCG2, ABCC1) and MATE genes (SLC47A1 and SLC47A2) - and the reverse in stem cells (CD34+) of patients with CML analyzed in this study may be the answer of why the insensitivity of CD34+ cells to treatment with IM and consequent failure to eliminate minimal residual disease. These genes can be candidates to therapeutic targets in CML. Disclosures: Lemos: Novartis of Brazil: Research Funding.

Introdução: Mesmo com a expansão de unidades e leitos de transplantes de células tronco hematopoiéticas (TCTH) e laboratórios de HLA, em todo o Brasil, ainda estamos muito aquém da demanda existente. Objetivo: Entender o fluxo e caracterizar os pacientes do estado do Pará registrados no REREME, à espera de um TCTH, no período de janeiro de 2010 a dezembro de 2015. Material e Métodos: Estudo descritivo, retrospectivo, sobre o fluxo, gênero, idade e doença de base (onco-hematológica) de pacientes acima de 18 anos, cadastrados no REREME pelo estado do Pará, à espera, ou que já realizaram TCTH, a partir dos dados obtidos do REREME, da CNCDO/SESPA e Gerência de Imunogenética (GERIM) da Fundação HEMOPA. Resultados: Foi observado que 30,1% dos pacientes estavam cadastrados no REREME (82/272); 69,8% (190/272) realizaram pesquisa para HLA, mas não foram registrados no REREME; 54,9% (45/82) apresentavam leucemia linfóide aguda ou mielóide aguda ou linfoma não-Hodgkin; 45,12% (37/82) tinham entre 18-30 anos; 48,78% (40/82) apresentavam sorologia para citomegalovirus positivo; 52,43% (43/82) eram homens; e 2,43% (2/82) dos pacientes cadastrados realizaram TCTH fora do estado do Pará. Conclusão: Os dados obtidos mostram que, apenas com os sistemas de controle do Ministério da Saúde e REREME, não é possível o planejamento seguro de políticas públicas que embasem a necessidade de TCTH para pacientes do estado do Pará.