ALBERT

Description: INTRODUCTION:Acute promyelocytic leukemia (APL) is the most curable acute leukemia in adults. Advancements in therapeutics such as the use of tretinoin (ATRA) and arsenic trioxide (ATO) have led to an overall survival of over 90% in 5 years. Early mortality, however, remains a major component of overall mortality in this disease and prompt recognition and initiation of adequate treatment has always been considered the most effective strategy to prevent it. Recent reports, though, have failed to show the benefit of prompt ATRA ministration in early mortality, once APL is suspected. These reports come mainly from high-income countries with swift and widespread access to health care services that are capable of recognizing, diagnosing and treating APL in a timely manner. We hypothesized, therefore, that in a lower income country, in a limited resources setting, prompt ATRA administration would improve early mortality in the setting of APL. METHODS: This is a retrospective, single-center study. We included all patients with APL diagnosis, confirmed by molecular or cytogenetics analysis treated in our institution, from January 1999 to May 2018. Until 2006, patients were treated with a modified AIDA regimen (ATRA plus mitoxantrone). After 2006, patients were treated with the International Consortium on Acute Promyelocytic Leukemia - ICAPL protocol (ATRA plus daunorubicin). This was a combined effort of the American Society of Hematology and of healthcare institutions from Latin American countries to improve outcomes in APL through improvements in therapeutics, education of healthcare professionals and expanded access to molecular diagnosis. We retrieved and reviewed patients' records for the time interval from disease presentation until the first hospital admission, and from hospital admission to the first dose of ATRA. We also looked for diagnostic variables that could be related with 30-day survival. RESULTS:Between January 1999 and May 2018, 83 APL patients were evaluated. Table 1 summarizes patients' characteristics. Medical records were available for 81/83 patients; 4 of them did not receive ATRA and died less than 7 days after their presentation. At diagnosis, median age was 37 years, 51.9% of patients were female, 26% were high-risk, 77.8% had bleeding symptoms, 72.8% had abnormal coagulation tests, and 12.3% had an elevated serum creatinine. Seventy-five percent were treated under the IC-APL protocol. Median time from disease presentation to the first hospital admission was 14.3 days (1-64 days) and median time to administration of ATRA after hospital admission was 18.2 hours (0.47-95.47 hours). Time to ATRA administration was significantly higher in patients who died in the first 30 days after diagnosis (median 27.46 vs.15.52 hours p=0.037) and who were treated with the modified AIDA (median 25.04 hours for the modified AIDA vs. 15.2 hours for the IC-APL protocol, p=0.037). Early administration of ATRA (less than 24 hours after the first hospital admission) was associated with a higher 30-day survival (89.4% vs. 63.3%, p=0.007; 75.3% for the whole cohort - Figures 1A and B). This benefit was seen mainly in patients with low or intermediate Sanz's risk score (Figures 1C and D). Serum creatinine, leukocytes count, and Sanz's risk were also predictive of 30-day survival in the whole cohort. There was no correlation between time from disease presentation to first hospital admission with 30-day survival. CONCLUSIONS: Our data support the role of early ATRA administration in the reduction of 30-day mortality in patients with recently diagnosed APL. This contrasts with previous findings from high-income countries that did not support such a benefit. We should highlight that in these cohorts the median time for ATRA administration was longer, which could explain the conflicting results. Furthermore, patients in high-income countries access health services early in their disease course, which could hamper any benefit from early ATRA administration. The correlation of early ATRA administration with the institution of IC-APL protocol underscores the importance of initiatives that promote the education of healthcare professionals and access to diagnostic tests of complex hematological diseases in low-income settings. Disclosures Pagnano: Abbvie: Consultancy; EMS: Other: Financial support for participation in congress; Novartis: Consultancy; Shire: Other: Lecture.

Description: Abstract 4850 Introduction: The WHO 2008 classification of acute myeloid leukemia (AML) is based on morphology, cytogenetics and molecular features. Among them, mutations and internal tandem duplications of FLT3 in AML with a normal karyotype have been associated to a poor prognosis. Mutated NPM1 in the absence of FLT3-ITD is associated to a favorable. On the other hand, variables of nuclear chromatin texture have been described as independent risk factors in several malignancies (ALL, melanoma and multiple myeloma). Aim: To compare the influence on overall survival of the chromatin fractal dimension and molecular features in adult patients with AML. Patients and Methods: We analyzed 106 consecutive cases diagnosed at our Institution between 2007 and 2009. Diagnosis was made by bone marrow (BM) cytology and karyotype, and cases were classified by WHO criteria. Genomic DNA was extracted by phenol-chloroform. Genotyping was made with the MegaBACE 1000 equipment and analyzed in the Fragment Profiler v1.2. For detection of the FLT3-TKD mutation, genomic DNA was amplified by PCR followed by restriction analysis. Blasts from the diagnostic BM cytology were digitalized, segmented and nuclear morphometric variables were examined. Their influence on overall survival was analyzed in the Cox model. Results: Median age: 52 years; peripheral blood (PB) leukocytes: 24.0×109/l (0.7-281.3). In the univariate analysis were significant: PB leukocyte count (p=0.005), low-risk karyotype (p=0.002), FLT3 ITD+ (p=0.002), FLT3+NPM1- (p=0.029) and “goodness of fit” (R245) of the chromatin fractal dimension (Minkowski) (p=0.03). Age, fractal dimension and methylation status of p15, p16, p57, p73, ER and MDR1 were not significant. In the multivariate analyses including age, PB leukocytes, R245 and mutations, high leukocyte counts (p=0.03) and low R245 (p=0.01) were independent unfavorable and FLT3-NPM1- (p=0.04) and FLT3-NPM1+ (p=0.02) were favorable prognostic variables. Conclusions: The blast chromatin texture measured by R245 was an independent prognostic factor together with known risk variables in AML. Supported by: FAPESP and CNPq Disclosures: No relevant conflicts of interest to declare.

Description: Second-generation tyrosine kinase inhibitors (2G-TKI), nilotinib or dasatinib used after imatinib failure can induce complete cytogenetic response (CCR) in 50% of chronic myeloid leukemia (CML) patients. BCR-ABL transcript levels reduction in the initial months of treatment has been associated improved outcome. Aims to evaluate the predictive value of early molecular responses, at 3 and 6 months after treatment with 2G-TKI in CML patients with imatinib failure or intolerance; to correlate these responses with CCR, overall survival (OS), progression-free survival (PFS) and event free survival (EFS). Methods Between September 2007 and August 2012, 71 consecutive patients with CML resistant or intolerant to imatinib were treated with dasatinib (n= 50) or nilotinib (n=21). BCR-ABL transcripts were measured in peripheral blood using real-time quantitative PCR (RQ-PCR) at 3 months intervals. Results were expressed as BCR-ABL/ABL ratio, with conversion to the international scale (IS). Major molecular response (MMR) was defined as a transcript level ≤ 0.1% (IS). Cytogenetic analysis was performed at baseline, 3, 6, 12 and 18 months after starting therapy with 2G-TKI. BCR-ABL mutation analysis by direct sequencing was investigated in resistant patients. Probabilities of OS, PFS and EFS were calculated using Kaplan-Meier method. An event was defined as the loss of CHR, CCR, progression to advanced phases, death or 2G-TKI discontinuation. The CCR probabilities according to molecular responses were calculated by c2 method and cumulative incidence, considering as competitive event death or progression. Results 71 patients were analyzed, median age of 47 years (15-81); Disease status before 2G-TKI was: 50 (71%) CP; 13 (18%) AP and 8 (11%) BC. Responses: 59/71 (83%) obtained CHR; 38/55 (69%) CCR and 37/60 (62%) MMR. At 3 months of therapy, 81.5% (44/54) had a BCR-ABL ratio ≤10% and at 6 months 66% (33/50) had ≤ 1%. At 3 months, CCR was obtained 65% (19/29) pts with ≤10% RQ-PCR and 16% (1/6) with 〉10% RQ-PCR (p= 0.06). At 6 months, CCR was 100% (12/12) in pts with RQ-PCR ≤ 1% and 14% (1/7) in those with 〉1% (p〈 0.0001). The probability to achieve RQ-PCR 〈 10% at 3 month was 43% (95% CI 32-54%). During treatment 3 (4%) progressed to AP and 5 (7%) to BC. The 5-year probability of OS was 78% (95% CI: 68-88%) albeit by disease status was 86% in CP, 92% in AP and 12% in BC (p〈 0.0001). OS was inferior in pts with RQ-PCR 〉 10% at 3 months (60 vs 84%, p= 0.03) and 〉1% at 6 months (68 vs100%, p= 0.006). PFS was 68% in 5-year, and was lower in BC pts (p〈 0.0001) and pts with RQ-PCR 〉1% at 6 months (p= 0.004). EFS was 53% and lower in BC pts (p〈 0.0001), in pts with RQ-PCR 〉 10% at 3 months (p= 0.005) and 〉 1% at 6 months (p〈 0.0001). RQ-PCR at 3 and 6 months were also predictive of a worse survival when patients in CP were analyzed separately. 2G-TKI was discontinued in 44% (31/71) due to: resistance (n=18), intolerance (n=5), death (n= 3), HSCT (n=3) and loss of follow-up (n=2). Eleven BCR-ABL mutations were detected in 36 pts; 3 previously 2G-TKI (L387M-1, E255K-1, M351T-1) and 9 after therapy (T315I-5, M244V-2, E255V-1, Y253H-1). OS by mutation was 45% with any mutation and 88% with no mutation (p= 0.05). Conclusion BCR-ABL transcript levels at 3 and 6 months can identify patients with worse prognosis and less chance to obtain CCR with 2G-TKI after imatinib treatment. Disclosures: No relevant conflicts of interest to declare.

Description: Chronic myeloid leukemia (CML) patients with imatinib failure are usually treated with second generation tyrosine kinase inhibitors (TKI). In case of dasatinib or nilotinib intolerance or resistance patients with HLA matched donor are submitted to allogeneic hematopoietic stem cell transplantation (HSCT) or switch treatment to a different TKI. Aims to evaluate complete hematological response (CHR), cytogenetic and molecular responses, overall, progression free and event free survival (OS, FPS and EFS) in CML patients in third line therapy that previously used 2 TKI. BCR-ABL mutations was also evaluated in this population Patients and methods between July 2008 and August 2012 26 CML patients were evaluated: 10 patients (pts) treated with dasatinib (38,5%) and 16 with nilotinib (61,5%) in third line therapy. OS, PFS and EFS were calculated with Kaplan-Meier method and Log-Rank was used for comparison, from the date of the third TKI start. The events for PFS were progression to accelerated phase (AP) or blast crisis (BC) and death. For EFS, were considered loss of CHR, loss of complete cytogenetic response (CCR), TKI discontinuation for failure or intolerance, progression or death. Patients were censored in HSCT date or TKI discontinuation for cytogenetic and molecular responses evaluation, but not for OS. Mutational analysis was done with Sanger sequencing. Results 13 male (50%) and 13 female patients with median age 54 years (22-75) and median follow-up of 32 months were analyzed (1-59). Previous response to imatinib: only one patient has achieved CCR. Status before third TKI start: 19 (73%) less than partial cytogenetic response (PCyR); 2 (7,7%) PCyR; 4 (15,5%) CCR;and 1 (3,8%) clonal evolution. 8/18 (42%) patients presented the following mutations: F317L (2), E255V (1), Y253H (1), M351T (1), M244V (1) e F359V (2). The median time of the third TKI treatment was 171 days (15-1140). Responses to third line TKI: CHR 17/19 (89%) in CP; 3/3 AF; 0/4 BC; CCR: 3/19 in CP (2 pts at 3 months and one in the 12º month); 1/3 AP; 0/4 BC; MMR: 4/19 in CP; 1/3 AP; 0/4 in BC. Nine lost CHR (45%) (8 in CP and one in AP). At 3 months, 1/21 pts (4.5%) achieved MMR; 2/13 (15%) at 6 months, while at 12 months 1/11 (9%) had MMR. At 3 months 11/21 had a BCR-ABL/ABL(IS) 〉10% and at 6 months 10/13 〉1%. Three patients progressed to advanced phases (11,5%) ; 6 (23%) died (4 due to LMC, 1 acute myocardial infarction and 1 from graft vs host disease after HSCT; one lost follow-up. Third line treatment was discontinued in 12 (46%) pts: 6 for resistance, 2 death; 2 intolerance and resistance; 1 intolerance and one loss of follow-up. OS, PFS and EFS were 69%, 68% e 30% respectively(figure 1). OS was inferior in AP and BC in comparison with CP (0% vs 50% vs 90% - p〈 0,0001)(figure 2). In summary responses may be obtained with dasatinib or nilotinib after 2 TKI failure, but they are not durable in advanced phases. Besides the results, that is an alternative for disease stabilization until the identification of a suitable donor or for patients with no performance status for HSCT. Disclosures: No relevant conflicts of interest to declare.

Description: Several studies demonstrated the prognostic significance of an early molecular response in chronic myeloid leukemia (CML) patients (pts) treated with imatinib in first line or other tyrosine kinase inhibitors. Aims: The aim of this study was to evaluate the impact of early molecular responses, at 3 and 6 months after treatment with imatinib in CML pts and correlate these responses with CCR, MMR, overall survival (OS) and event free survival (EFS). Patients and Methods Between February 2006 and June 2012, 95  adult pts with newly diagnosed CML in chronic phase (CP) received imatinib 400mg/daily. CP was defined using WHO 2008 criteria. All pts received a short course of hydroxiurea until imatinib was available. Cytogenetic analysis was performed at diagnosis, 3, 6, 12 and 18 months after starting therapy and then every 12-24 months thereafter. BCR-ABL transcripts were measured in peripheral blood at 3-month intervals using quantitative RT-PCR (RQ-PCR). Results were expressed as BCR-ABL/ABL ratio, with conversion to the international scale (IS). Major molecular response (MMR) was defined as a transcript level ≤ 0.1% (IS). Statistical analysis: OS was measured from imatinib start until date of death or last visit. An event was defined as death from any cause. EFS was measured from imatinib start until the first event (loss of complete hematological response (CHR); complete cytogenetic response (CCR), progression to advanced phase, death or imatinib discontinuation) or last visit. OS and EFS rates were calculated using Kaplan-Meier method and log-rank test to compare its curves. The MMR probabilities according to molecular responses at 3 and 6 months were calculated by c2 method and cumulative incidence, considering as competitive event death or progression, before the event. Results 95 pts were analyzed, 57 (60%) male, with a median age of 47 years (17-79); Sokal score: high, intermediate and low was 30, 38.6 and 31.4% respectively; EUTOS scores was 81.5% low and 18.5% high. The median time from diagnosis until imatinib therapy was 1 month (0-5) and the follow-up was 39 month (3-89). Responses: 88% achieved CHR; 50% CCR and 53% MMR. One patient progressed to advanced phase during follow-up, while on imatinib treatment. 21 (22%) pts discontinued imatinib due to intolerance (47.6%); resistance (42.9%), death (4.8%) and Allo-HSCT (4.8%). At 3 months from the start of therapy, 30/64 (46.8%) achieved CCR, 15/64 (23.4%) partial cytogenetic response and 20/64 (31.2%) less than partial; by RQ-PCR, 72.3% (68/94) achieved at 3 months BCR-ABL transcripts ≤10% and 27.7% (26/94) 〉 10%. At 6 months 55.2% (48/87) had BCR-ABL transcripts ≤ 1% and 44.8% (39/87) 〉1%. The OS was 97% (95%CI: 95-99%) and EFS 63% (95%CI: 52-75%).There was no significant difference in OS and EFS in pts with RQ-PCR 〉 10% vs ≤ 10% at 3 months (figure 1), but pts with BCR-ABL transcripts 〉 10 and 〉1-10% at 6 months had an inferior EFS in comparison with pts with  BCR-ABL transcripts ≤ 1%  (41%,50%,89% respectively - p= 0.005), (figure 2). The CI showed that CCR pts at 3 months reached MMR earlier at 24 month (54% vs 18%, p=0.03), as well as CCR pts at 6 months, albeit no significance statistically (52% vs 37%, p= 0.16). For RQ-PCR at 3 months, pts with BCR-ABL transcripts 0-1% had a probability of 88% to achieve MMR, 1-10% had 52% and 〉10% 42%, p〈 0.0001 (figure 3). In conclusion, our results show that early molecular responses are predictive of achieving MMR and BCR-ABL transcripts

Description: Besides the known factors such as the presence of oncogenes, the macro-environment (pollution, infections) or organic microenvironment (dysregulation of the immune system) can be the triggering factor of the process of leukemogenesis. It is known that the amount of rainfall can affect the distribution (dilution) of pollutants in the air and water reserves. There is no description of the climate influence in the incidence of Acute Promyelocytic Leukemia (APL), which has its own clinical laboratory characteristics, and is defined by the presence of the PML-RARA rearrangement. The aim of this study was to investigate the impact of seasonality in the incidence of Promyelocytic Leukemia in Brazil, and its characteristics. Patients and methods we analyzed the clinical laboratory data and origin of participant cases of the International Consortium on Acute Promyelocytic Leukemia (IC-APL), a group multicenter treatment of APL with standardized diagnosis and treatment. We included all patients diagnosed with APL of Brazilian centers between 2006 and 2011. We excluded patients without demographics. Patients were divided into macro-climate (Northeast, South and Southeast). Northeast: 49 cases of Pernambuco, Southeast: 16 cases of Minas Gerais, São Paulo 88 cases; South: 27 cases of Rio Grande do Sul and 19 cases of Paraná. Meteorological data were extracted from the database Meteorological Research and Education (BDMEP) of the National Institute of Meteorology (INMET), and grouped by quarter. We studied the mean maximum temperature, mean minimum temperature and rainfall. The relationship between the number of cases and meteorological data were analyzed by the Spearman test. Results We included 149 patients with APL. In the South, there were 46 patients, 50% female and 50% male, mean age: 37 years, 16 cases occurred on the first quarter (January-March), 12 on the second quarter (April-June), 8 cases on third quarter (July-September) and 10 on the fourth quarter (October to December). In the Northeast, there were 49 cases, 25 female and 24 male, mean age 34 years with 11 cases on the first and second quarters, 12 cases on the third quarter and 15 cases on the fourth quarter. Southeast: 54 cases with 29 female cases and 25 male cases, mean age 25 years, with 12 cases on the first and second quarter, 11 cases on the third quarter and 19 cases on the fourth quarter. In the South, there was no statistically significant correlation between the weather and the number of registered cases of APL. In the Northeast, there was a negative correlation between the number of cases of APL and rainfall (r = -0.57, p = 0.004) and a trend with the maximum temperature (r = 0.34, p = .07). In the southeast, there was positive correlation between rainfall (r = 0.42, p = 0.02) but not with temperature. In the northeast, the smallest amount of rainfall is associated with higher temperatures (r = -0.49, p

Description: Rationale for Study Primary Myelofibrosis (PMF) mainly affects individuals in their sixth decade of life or older. It is the most difficult myeloproliferative neoplasm to be defined, as the phenotype mimics a variety of hematological and non-hematological diseases. No symptom or sign is specific for PMF. Many patients are asymptomatic at presentation and the disease is usually detected by the discovery of a splenomegaly or abnormal blood counts during a routine examination. The only treatment with curative potential for PMF is allogeneic stem cell transplantation. This should be reserved only for high-risk patients, after careful consideration, taking into account the option for participation in clinical trials of new drugs. It is therefore extremely important the early identification of poor prognosis patients, to offer the best therapy. In Brazil, we do not have sufficient data to assess a patient's journey between the first symptoms and diagnosis of PMF. Moreover, the real incidence/ prevalence of this disease is unknown and a sub-diagnosis rate is speculated in our country. Objectives Understand and identify the journey of patients with PMF (clinical characteristics, diagnosis process and therapeutics interventions) and the problems between the first symptoms and initiation of treatment. Methods Given the observational nature of the study and the lack of a specific hypothesis to be tested, the statistical analysis is descriptive. This partial analysis includes descriptive results of contents of the database. Categorical data are presented as frequencies and percentages. For continuous data, mean, standard deviation, median, minimum, and maximum values are presented. Results 103 patient disposition (2008-2012); all of them met WHO criteria 2008: median age: 69; 58% male and 13.6% had died. Based on medical history, professional or environmental exposure was related in 4%, but this information was lack in 25% of the medical charts. In almost 42% of the medical records, the family history was not available. Two patients had a positive family history (brother of one and sister from another one with the same disease). Most frequent reason (63,1%) for medical evaluation seeking was symptoms and fatigue happened in 67% of them. Time from symptoms onset date until the confirmed diagnosis took a median of 9.7 months. General physician was the most frequent specialist to do the first evaluation of the patient until confirmed or suspected diagnosis. Bone marrow aspiration and bone marrow biopsy were performed in all patients; mutation status for JAK V617F in 82.5%, PCR for BCR-ABL in 71.8% and bone marrow cytogenetics in 64.1%. According to IPSS (78 patients), 8.5 % were low risk, 63.4% intermediate-1 63.4%, intermediate-2 28.1% and none high risk. Anemia was the most frequent laboratorial finding (67%) and most of the patients were treated with hydroxiurea (75.7%). Conclusions Although most of the patients have apparently the diagnosis of PMF, it took almost 10 months to be done. An expressive number of medical reports do not show a complete history, while 20-30% of them don’t have all the laboratory tools for a precise diagnosis. It is important to know Brazilian needs to improve diagnostic and provide a better treatment, since we are facing new drugs for PMF. Disclosures: No relevant conflicts of interest to declare.

Description: Minimal Residual Disease (MRD) monitoring is recognized as a clinically useful tool for the management of Acute Promyelocytic Leukemia (APL) and has been performed by reverse transcriptase Polymerase Chain Reaction (RT-PCR) and Real-Time Quantitative Polymerase Chain Reaction (RQ-PCR). The vast majority of the published studies were conducted in developed countries within well established clinical trials, but the feasibility of MRD monitoring in developing countries is controversial. Here we describe the experience of Brazilian centers that participated in the International Consortium on Acute Promyelocytic Leukemia (IC-APL). In the present study, the participating centers were located at distances up to 2.500 km of central national laboratory and delivery sample time is less than two days. The aim of this study was to determine the feasibility and compare the effectiveness of RQ-PCR and RT-PCR in the MRD research in the context of IC-APL. We analyzed 398 bone marrow (BM) samples from 74 Brazilians patients with de novo APL; mean follow-up of 18 months. Samples were collected at diagnosis (n=74), at post-induction (n=48) after the third consolidation (n=41), and at maintenance (n=235). Standardized assays developed by Europe Against Cancer (EAC) program were used. Clinical characteristics were similar among the full cohort (patients from Brazil [n=122], Mexico [n=30], Chile [n=23], Uruguay [n=8]). Thirty-nine (52%) patients were classified as intermediate risk. PML breakpoint was bcr1 (n=45), bcr2 (n=1), and bcr3 (n=27). The median NCN of transcripts at diagnosis was 0.5151 (n=41) and 0.4690 (n=27) for the bcr1 and bcr3 subtypes, respectively. At the end of induction, there was a reduction of about 3 logs (0.0004 for bcr1 and 0.0005 for bcr3). In this stage, six discrepant cases were observed, all positive by RQ-PCR. There were no relapsed cases. 66/74 (89%) patients completed induction phase and achieved complete remission, and 8/74 (10%) died of hemorrhagic causes. The rate of molecular remission in our study was 37.5% (18/48) by RQ-PCR and 50% (24/48) by RT-PCR. Considering samples obtained at the end of consolidation phase, one discrepant result was detected as negative by RT; however it was not confirmed by RQ-PCR. Both cases did not relapse. The analysis for RQ-PCR was performed in 64% (41/64) of samples. Two patients have died of infectious diseases during the consolidation phase. All patients achieved molecular remission based on the results of RT-PCR. One patient was positive by RQ-PCR (NCN: 0.00006), but all subsequent samples were negative for both techniques, and the patient is alive, in remission. The median NCN of all samples after the third consolidation phase was 0.00001 PML-RARA/104 copies of ABL copies, regardless of the breakpoint. Within 53 patients who have completed the third cycle of consolidation, only 48 started the maintenance. 235 samples were evaluated during maintenance; 87.6% (206/235) were negative by RQ-PCR technique and 94.4% (222/235) by RT-PCR. The median NCN of all samples in the maintenance was 0.00001 PML-RARA/104 copies of ABL copies. The RQ-PCR technique proved to be predictive of relapse in three out of four cases of molecular relapse. All three cases showed positive results for RT-PCR during the early stages of the maintenance cycle and were confirmed by a second sample taken within 15 days. These results are confirmed in literature, observing that most patients who had negative PCR after consolidation relapsed after few months. In one case of molecular relapse, the RQ-PCR analysis provided much earlier warning of recurring disease, testing positive 5 and 6 months, respectively, before documentation of molecular relapse by conventional RT-PCR assay. In two cases, the negative result was performed by RT-PCR post induction, and was not confirmed by RQ-PCR, which remained positive on subsequent samples, and was confirmed once by RT-PCR after long time. According to transcripts numbers at maintenance, there was a decrease of approximately 5 logs when compared to samples after third consolidation. RQ-PCR technique was more sensitive than RT-PCR, providing earlier warning of relapse, thereby allowing greater opportunity for successful delivery of pre-emptive therapy. In sum, the implementation of the IC-APL allowed the improvement of laboratory standards in parallel to advances in clinical management. Disclosures No relevant conflicts of interest to declare.

Description: Introduction The majority of chronic myeloid leukemia (CML) patients (pts) in chronic phase (CP), present satisfactory response to imatinib treatment. However, 25-30% of these pts exhibit suboptimal response or treatment failure. The probability of achieving optimal response may be related with several factors. The human organic cation transporter 1 (hOCT1, SLC22A1), an influx transporter, is responsible for the uptake of imatinib into chronic myeloid leukemia (CML) cells The aim of this study was to analyze hOCT-1 levels at diagnosis of CML patients and correlate with cytogenetics and molecular responses. Methods hOCT-1 expression was evaluated in 58 newly diagnosed CML pts. Pts were treated with imatinib 400-600mg in first line. Samples were collected from peripheral blood at diagnosis and RNA was obtained from total leucocytes. For cDNA synthesis, 3 ug of RNA was used. hOCT-1 expression was evaluated by real-time PCR with TaqMan probe SLC22A1 (Applied Biosystems) and endogenous GAPDH control. The results were analyzed using 2-ΔΔCT. Cytogenetic analysis was performed at diagnosis, 3, 6, 12 and 18 months after starting therapy and then every 12-24 months thereafter if CCR was achieved. BCR-ABL transcripts were measured in peripheral blood at 3-month intervals using quantitative RT-PCR (RQ-PCR). Results were expressed as BCR-ABL/ABL ratio, with conversion to the international scale (IS). Major molecular response (MMR) was defined as a transcript level ≤ 0.1%. Results 58 CML pts, 60% male, median age of 46 years (19-87) were evaluated, 71% in chronic phase (CP), 21% in accelerated phase (AP) and 5% in blast crisis (BC). The mean and median of hOCT-1 transcript levels in the total group was 2.03 and 0.961 respectively (0.008–19.039) and CP pts was 1.86 and 1.00 (0.008-10.34).The median duration of imatinib treatment was 27 months (1-109) and 96.6% achieved complete hematological response, 79.3% complete cytogenetic response and 69% major or complete molecular response. The regression analysis showed correlation between higher transcript levels of hOCT-1 and BCR-ABL transcripts