Background and aims: Anemia is a common feature in patients presenting for major elective surgery, and it is considered an independent risk factor associated with adverse outcomes. Although several studies suggest that preoperative anemia is associated with poor outcomes after elective orthopedic surgery, data are still scarce in middle-and low-income countries where this problem may be even greater. The objective of this study was to evaluate the impact of preoperative anemia in clinical outcomes in patients submitted to hip and knee arthroplasty in a single tertiary hospital.

4425 Adherence to imatinib therapy has proven to be a major determinant of treatment results, but the degree of impact and the determinants of nonadherence are still contradictory. There is no information regarding adherence to imatinib therapy in the Brazilian public health system. The aims of this study were to identify the characteristics related to treatment interruptions and nonadherence and to examine how these interruptions affect treatment responses and survival. Materials and Methods We conducted a retrospective study in a cohort of patients (pts) with CP-CML enrolled in 14 Hematology centers in South Brazil. All pts received imatinib 400mg as first or second-line therapy. Early-imatinib treatment was considered when imatinib started before 12 months (mo) from diagnosis. Patient evaluation and response criteria followed the ELN recommendations. The ACE-27 (Adult Comorbidity Evaluation-27) is a 27 item comorbidity index for patients with cancer and assign weights from 1 to 3 based on the dysfunction grade of each condition (mild, moderate and severe, respectively). An ACE-27 score was applied to each patient. Imatinib suspensions were considered if superior to 20 days at any point during therapy. Two levels of analysis were performed: all kinds of interruptions (nonadherence and toxicity) and only nonadherence ones. Information for nonadherence was taken from medical and pharmacy registers (pt self-report, missing scheduled appointments and pill counts). Results We analyzed data from 185 pts with CP-CML diagnosed since 1990. The median age at diagnosis was 48 yr (4 – 85) and 55% were male. The median time from diagnosis to imatinib was 7 mo (0 – 178) and 71% pts were early-imatinib treated. Prior therapy with interferon was used in 70% pts. The median of follow-up was 47 mo. Treatment interruption was observed in 63/185 patients (34%) and was related to toxicities in 35/63 pts (55%) and to nonadherence in 28/63 pts (45%). The adherence rate was 85%. In a multivariate analysis, only late-onset imatinib treatment (Odds Ratio [OR]=36,05; p<0,001) and severe comorbidity (OR=27,05; p=0,03) were associated with higher risk of interrupting imatinib for any reason. The only variable associated with nonadherence was late-onset imatinib treatment (OR=14,76; p<0,001). Although not statistical significant, male and comorbidity showed a tendency to be linked with nonadherence (Table 1). Nonadherent pts, compared with adherent ones, had lower complete cytogenetic response (CCyR) rates at 12 mo (39% and 65%; p=0,004, respectively; Figure 1) and lower major molecular response (MMR) rates at 18 mo (9,5% and 35%; p=0,002, respectively; Figure 2). Finally, treatment interruption had a relevant negative impact on EFS in 4 yr. In the group that had treatment interruption, EFS was 52%, compared with 78,5% in the group without interruptions (p=0,002; Figure 3). Analysis performed only on nonadherence treatment interruption groups showed no significant difference (53% and 71%; p=0,15, respectively). Conclusions In this cohort, a substantial proportion of pts failed to take imatinib properly, decreasing the chances of disease control. The late onset of imatinib therapy correlates with lower adherence, so front-line imatinib therapy should be started as soon as possible. Special attention should be given to pts with severe comorbidities, as they are more prone to suffer side effects or to lack adherence. Finally, pts who interrupted treatment had lower CCyR, MMR and EFS. Clinical and patient characteristics related to nonadherence Disclosures: No relevant conflicts of interest to declare.

Introduction Convalescent Plasma therapy is one of the therapeutic strategies that has been used for patients with the Covid-19 disease. Implementing a program with national extension to supply hospitals with this blood component is a great challenge mainly in a middle-income economy. Objectives Our objective was to develop and implement a Covid-19 Convalescent Plasma Program which met established quality standards and was adapted to a reality of limited resources. Methods A multicentric convalescent plasma collection program was developed and implemented, based on four main sequential procedures: selective donor recruitment, pre-donation antibody screening (Anti-SARS-CoV-2- Chemiluminescence IgG Abbott), convalescent plasma collection by apheresis or whole-blood processing and distribution to the hospitals according to local demand. Results From the 572 candidates submitted to the pre-donation antibody screening, only 270 (47%) were considered eligible for plasma donation according to the established criteria. Higher levels of total antibody were associated with the donor age being above 45 years old ( p = 0.002), hospital admission ( p = 0.018), and a shorter interval between the diagnosis of the SARS-CoV-2 infection and plasma donation ( p < 0.001). There was no association between the ABO and Rh blood groups and their antibody levels. Of the 468 donations made, 61% were from the collection of whole-blood and 39%, from apheresis. The Covid-19 Convalescent Plasma units obtained were distributed to 21 different cities throughout the country by air or ground transportation. Conclusion The implementation of a Covid-19 Convalescent Plasma program in a continental country with relatively scarce resources is feasible with alternative strategies to promote lower cost procedures, while complying with local regulations and meeting quality standards.

4423 Background Treatment of chronic myeloid leukemia with imatinib leads to disease remission in a majority of patient, but in some patients (pts) controlling the disease remains a challenge. One of the proposed prognostic factors for identifying this subset of pts is the treatment response in the first months of therapy. Objectives We conducted a study to evaluate the importance of the early complete cytogenetic response (CCyR) and the factors associated with its achievement. Methods This is a retrospective study in a cohort of pts with chronic-phase chronic myeloid leukemia (CP-CML) enrolled in 14 Hematology centers in South Brazil. All pts received imatinib 400mg as first or second-line therapy. Early-imatinib treatment was considered when imatinib started before 12 months (mo) from diagnosis. Patient evaluation and response criteria followed the ELN recommendations. The ACE-27 (Adult Comorbidity Evaluation-27) is a 27 item comorbidity index for patients with cancer and assign weights from 1 to 3 based on the dysfunction grade of each condition (mild, moderate and severe, respectively). An ACE-27 score was applied to each patient. Imatinib suspensions were considered if superior to 20 days at any point during therapy. EFS was measured from the start of imatinib to the date of any of the following events while on therapy: death from any cause, loss of complete hematologic response, loss of complete cytogenetic response, discontinuation of therapy for toxicity or lack of efficacy, or progression to accelerated phase or blastic phase. Results We analyzed data from 450 pts with CP-CML diagnosed since 1990. The median age at diagnosis was 48 yr (4 – 85) and 55% were male. The median time from diagnosis to imatinib was 7 mo (0 – 178) and 71% pts were early-imatinib treated. Prior therapy with interferon was used in 60% pts. The median of follow-up was 47 mo. With 6 months of imatinib therapy, 198 pts (44%) achieved CCyR. In this group, the four year cumulative incidence of events was 33 (17%) and the EFS was 75,5%. 252 (56%) were not in CCyR at 6 months of therapy. In this group, a greater proportion of cumulative of events was observed: 86 (34%), and the EFS was 62,3%. This difference was significant (P=0,03; Figure 1). In this group of pts, 63% achieved CCyR after 6 months any time during follow up and the median time for CCyR in these pts was 17 months. The chance of achieving major molecular response (MMR) during follow up was 79% for the pts with CCyR at 6 months compared to 53% for the group with no CCyR at 6 months (P<0,001). Some factors were associated with reduced chance of CCyR at 6 months. In a multivariate analysis, the pts with late-onset imatinib treatment (more than 12 mo from diagnosis) had a CCyR rate of 31%, in contrast, the pts who started imatinib before 12 mo had a rate of 50% (P=0,02). The pts with good adherence to treatment had greater CCyR rate than those with poor adherence (interruption greater than 20 days), 51,4% and 35%, respectively (P=0,04). Comorbidity measured by ACE-27 score also influenced the CCyR rates at 6 months: 54% of score 0 (no comorbidity) patients achieved CCyR, compared to 30% of pts with score 1 (mild comorbidity), 33% of pts with score 2 (moderate) and 47% of pts with score 3 (severe) (P=0,009). The greater CCyR rate in the severe comorbidity group probably lacks significance due to the reduced number of pts in this group (22). Conclusions A great proportion of pts achieve CCyR after 6 months of imatinib therapy, nevertheless, the pts who achieve CCyR by 6 months of therapy have greater proportion of major molecular response and event-free survival. Imatinib therapy should be started as soon as possible and additional efforts must be taken to avoid nonadherence. Finally, special attention should be given to pts with comorbidities as their results tend to be worse. Disclosures: No relevant conflicts of interest to declare.

Background Monitoring response to TKI therapy is one of the key management strategies of chronic myeloid leukemia (CML). Early molecular response to first-line TKI therapy is emerging as an effective prognostic factor indicator of long-term durable response and survival. Objectives We conducted a study to evaluate the importance of the early molecular response (EMR) at 3, 6 and 12 months (mo), and 3-year event free survival (EFS). Methods This is a retrospective study in a cohort of pts with chronic myeloid leukemia chronic phase (CP) enrolled in 14 Hematology centers in South Brazil. All pts received imatinib 400mg as first or second-line therapy. Patient evaluation and response criteria followed the ELN recommendations. EFS was measured from the start of imatinib to the date of any of the following events while on therapy: death from any cause, loss of complete hematologic response, loss of complete cytogenetic response, discontinuation of therapy for toxicity or lack of efficacy, or progression to accelerated phase or blastic phase. Results We analyzed data from 517 pts with CML-CP diagnosed since 1990. After a median observation time of 46 months, 5-year overall survival (OS) was 86% and 5-year event-free-survival was 53%. At 3 mo, EFS was 72,5% for 46 pts with BCR-ABLIS ≤10% compared to 58% for 14 pts with BCR-ABLIS >10% (p<0,07). Similarly, when EMR was analysed at 6 mo, the EFS was 81% for 75 pts with BCR-ABLIS ≤1%, while 31% of EFS was achieved for 38 pts with BCR-ABLIS >1% (p<0,001). At 12 mo, the 3-year EFS was 86% for 65 pts with with BCR-ABLIS ≤0,1% compared to 54% for pts with BCR-ABLIS>0,1% (p<0,001). Conclusions A significant proportion of pts achieve ERM after 3,6 and 12 mo of imatinib therapy with better 3-year EFS. ERM may could identify those pts more likely to have a favorable outcome. Disclosures No relevant conflicts of interest to declare.

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Sustained deep molecular response (MR4.5) after imatinib treatment defines a subgroup of patients with chronic myeloid leukemia (CML) with better outcome and that probably would be able to stop treatment in the future, according to results of clinical TKI discontinuation trials. Most of these trials showed that patients with a long-term imatinib treatment and low Sokal risk have a higher probability of maintain a deep molecular remission after stopping treatment. OBJECTIVES The main objective is to review the molecular responses, overall survival and event free survival of CP CML patients that have been treated with imatinib in 14 hematology centers in South Brazil. Using our data basis we also would like to see how many of them present long-term imatinib treatment, sustained deep molecular remission and correlate these findings with the Sokal risk groups. These data would allow us to predict patient profile that could be able to discontinue the treatment in the future in a prospective clinical trial. PATIENTS AND METHODS This is a retrospective study in a cohort of pts with chronic myeloid leukemia chronic phase (CP) that have been treated in 14 hematology centers in South Brazil. All pts received imatinib 400mg as first or second-line therapy. Patient evaluation and response criteria followed the ELN recommendations. MR(4.5) was defined as ≥ 4.5 log reduction of BCR-ABL on the international scale (IS) and determined by reverse transcriptase polymerase chain reaction. All tests were performed at a central standardized according to ELN. Event-free-survival (EFS) was measured from the start of imatinib to the date of any of the following events while on therapy: death from any cause, loss of complete hematologic response, loss of complete cytogenetic response, discontinuation of therapy for toxicity or lack of efficacy, or progression to accelerated phase or blastic phase. Overall survival (OS) was measured from the start of imatinib until death of any cause or to the date patient was last known to be alive. RESULTS Data from 474 patients was analyzed. After a median observation time of 46 months, 5-year overall survival (OS) was 86%, 5-year event-free-survival was 53%. Of the 474 patients, 258 had adequate PCR evaluations during treatment. 118 of 258 (45,7%) patients achieved MR(4.5) and 69 of 258 (27%) had sustained response for at least two years after a minimum time of treatment of 3 years. The cumulative incidence of MR(4.5) after 9 years was 76% (median, 3 years). In the group that achieved MR(4.5), there was only 1 (0,8%) death and 1 (1,1%) progression compared to 8 deaths (5,7%) and 8 progressions (7,5%) in the group without MR(4.5); these differences were significant with p=0,03 and 0,02 respectively. In the subgroup of 69 patients that had had been treated with imatinib for 3 year or more and sustained deep response (RM4,5) for at least two years, 21 pts had low Sokal risk, 7 pts intermediate Sokal risk and only 4 pts a high Sokal risk. Unfortunately, in 37 pts the Sokal risk could not be accessed due to missing information. CONCLUSION In our series MR(4.5) is reached in the majority of patients with long-term imatinib treatment. MR(4.5) is a predictor of outcome with only one disease progression and one death due to CML in this group of patients. Unfortunatly PCR are not available for all patients in our clinical practice, but this situation are improving. Regarding the 69 patients with TKI discontinuation trial criteria, we find out that 21 patients fulfill such criteria. In the future, according to the results of current stop trials it could be possible include this selected group of CP CML patients in a prospective clinical trial. Disclosures No relevant conflicts of interest to declare.

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