Clinical networking results in continuous improvement of the outcome of patients with acute promyelocytic leukemia.

ABSTRACT: The introduction of all-trans retinoic acid combined with anthracyclines has significantly improved the outcomes for patients diagnosed with acute promyelocytic leukemia (APL), and this strategy remains the standard of care in countries in which arsenic trioxide is not affordable. However, data from national registries and real-world databases indicate that low- and middle-income countries (LMIC) still face disappointing results, mainly because of high induction mortality and suboptimal management of complications. The American Society of Hematology established the International Consortium on Acute Leukemias (ICAL) to address this challenge through international clinical networking. Here, we present the findings from the International Consortium on Acute Promyelocytic Leukemia study involving 806 patients with APL recruited from 2005 to 2020 in Brazil, Chile, Paraguay, Peru, and Uruguay. The induction mortality rate has notably decreased to 14.6% compared with the pre-ICAL rate of 32%. Multivariable logistic regression analysis revealed as factors associated with induction death: age of ≥40 years, Eastern Cooperative Oncology Group performance status score of 3, high-risk status based on the Programa Español de Tratamiento en Hematologia/Gruppo Italiano Malattie EMatologiche dell'Adulto classification, albumin level of ≤3.5 g/dL, bcr3 PML/RARA isoform, the interval between presenting symptoms to diagnosis exceeding 48 hours, and the occurrence of central nervous system and pulmonary bleeding. With a median follow-up of 53 months, the estimated 4-year overall survival rate is 81%, the 4-year disease-free survival rate is 80%, and the 4-year cumulative incidence of relapse rate is 15%. These results parallel those observed in studies conducted in high-income countries, highlighting the long-term effectiveness of developing clinical networks to improve clinical care and infrastructure in LMIC.

Cytoreductive chemotherapy in induction therapy plays a key role in the prognosis of patients with low-risk acute promyelocytic leukaemia.

In order to explore the risk factors of relapse and potential optimized therapeutic regimen of low-risk acute promyelocytic leukaemia (APL), here we retrospectively analysed 282 patients who were diagnosed between February 2014 and September 2021. The median follow-up was 59 (9-102) months. The 5-year overall survival and cumulative relapse incidence were 97.9% and 5.9%, respectively. In terms of different cytoreductive therapies, 86 patients were administered with hydroxycarbamide (30.5%), 113 with anthracyclines or cytarabine (40.1%), 31 with etoposide (11.0%) and 52 with no cytoreductive therapy (18.4%) during the induction therapy. The hydroxycarbamide treatment group did not decrease the relapse rate compared to the no cytoreduction group (11.4% vs. 5.9%, p = 0.289). Compared with the hydroxycarbamide group, the anthracyclines/cytarabine treatment group showed improved 5-year RFS (88.145% vs. 98.113%, p = 0.008). Multivariate Cox regression analysis revealed that myeloblasts in bone marrow at diagnosis, and PML-RARA transcript level of 6.5% or more after induction therapy were associated with a subsequent risk of relapse. The only factor positively reducing the relapse rate was anthracyclines/cytarabine cytoreductive treatment. In conclusion, cytoreductive chemotherapy in induction therapy plays a potential key role in the prognosis of low-risk APL.

A complete oral regimen for induction therapy of patients with high-risk APL: An oral etoposide instead of intravenous infusion for cytoreductive chemotherapy.

There is an urgent need for an oral, efficient and safe regimen for high-risk APL under the pandemic of COVID-19. We retrospectively analysed 60 high-risk APL patients. For induction therapy (IT), in addition to all-trans retinoic acid (ATRA) and oral arsenic (RIF), 22 patients received oral etoposide (VP16) as cytotoxic chemotherapy (CC), and 38 patients received intravenous CC as historical control group. The median dose of oral VP16 was 1000 mg [interquartile rage (IQR), 650-1250]. One patient died during IT in the control group, 59 evaluable patients (100%) achieved complete haematological remission (CHR) after IT and complete molecular remission (CMR) after consolidation therapy. The median time to CHR and CMR was 36 days (33.8-44) versus 35 days (32-42; p = 0.75) and 3 months (0.8-3.5) versus 3.3 months (2.4-3.7; p = 0.58) in the oral VP16 group and in the control group. Two (9.1%) and 3 (7.9%) patients experienced molecular relapse in different group respectively. The 2-year estimated overall survival and event-free survival were 100% versus 94.7% (p = 0.37) and 90.9% versus 89.5% (p = 0.97) respectively. A completely oral, efficient and safe induction regimen including oral VP16 as cytoreductive chemotherapy combined with ATRA and RIF is more convenient to administer for patients with high-risk APL.

Biochemical risk factors and outcomes of acute promyelocytic leukemia patients with thrombotic events: a matched pair analysis.

Acute promyelocytic leukemia (APL) stands out as a distinctive form of acute leukemia, exhibiting a higher occurrence of thrombotic events when contrasted with other leukemia subtypes. Since thrombosis is a relatively rare but unfavorable condition with poor prognostic implications, it is crucial to determine the risk factors for thrombotic events in APL(thrombosis in large venous or arterial from onset to differentiation therapy in 30d). We performed a retrospective study involving 950 APL patients between January 2000 and October 2022, from which 123 were excluded by younger than 16 years of age, 95 were excluded by incomplete data, and 6 were excluded by thrombosis related to CVC or PICC. A total of 23 APL patients with thrombosis for inclusion in our analysis were performed a 1:5 ratio matching based on sex (perfect match) and age (within 5 years) to patients without thrombosis. These patients were continuously monitored in the outpatient department over a period of 5 years. We meticulously examined clinical and laboratory data to pinpoint the risk factors related to thrombotic events in APL. Our primary clinical endpoints were all-cause mortality and achieving complete remission, while secondary clinical outcomes included APL relapse. Thrombotic events were observed in 2.4% (23/950) of APL patients. Compared to patients without thrombosis, patients with thrombosis had higher lactate dehydrogenase (LDH) [313 (223, 486) vs. 233 (188, 367) U/L, p = 0.020], higher indirect bilirubin [11.2 (7.4, 18.6) vs.8.3 (6.0, 10.7) umol/L, p = 0.004], higher creatinine [72 (62, 85) vs. 63 (54, 74) umol/L, p = 0.026], higher CD2 expression (65.2 vs. 15.2%, p < 0.001), higher CD15 expression (60.9 vs. 24.3%, p = 0.001), and PML/RARαisoforms (p < 0.001). Multivariate-logistic-regression analysis revealed several factors that were markedly related to thrombosis, including LDH (OR≈1.003, CIs≈1.000-1.006, p = 0.021), indirect bilirubin (OR≈1.084, CIs≈1.000-1.188, p = 0.043), CD2 expression positive (OR≈16.629, CIs≈4.001-62.832, p < 0.001), and CD15 expression positive (OR≈7.747, CIs≈2.005-29.941, p = 0.003). The S-type (OR≈0.012, CIs≈0.000-0.310, p = 0.008) and L-type (OR≈0.033, CIs≈0.002-0.609, p = 0.022) PML/RARα isoforms were negatively associated with thrombosis. Kaplan-Meier curves indicated that the survival rates were remarkably varied between APL patients with and without thrombosis (HR:21.34, p < 0.001). LDH and indirect bilirubin are variables significantly associated with thrombosis in APL, S-type and L-type PML/RARαisoforms exhibit a negative association with thrombotic events. The thrombotic events of APL can predict the subsequent survival of thrombosis. The findings of our study have the potential to facilitate early detection of thrombosis and enhance the prognosis for individuals with APL who develop thrombosis. Further validation of our findings will be essential through future prospective or multicenter studies.

Characteristics and complications of acute promyelocytic leukemia in children: an analysis of a national database.

Acute promyelocytic leukemia (APL) is an uncommon subtype of acute myelogenous leukemia (AML) that was previously one of the most fatal forms of acute leukemia. With advances in diagnosis and treatment, APL has become one of the most curable myeloid leukemias. The major reason for treatment failure in APL is early death after initiation of treatment. We performed a retrospective cross-sectional analysis of the Healthcare Cost and Utilization Project 2016 and 2019 Kids' Inpatient Database, with the diagnosis of APL or AML not in remission as defined by ICD-10-CM codes. We compared complications and outcomes associated with APL and AML (exclusive of APL) in hospitalized children in the U.S. and described yearly national incidence. The national incidence of APL was 2.2 cases per million children per year. Children with APL were more likely to have cardiopulmonary complications (OR 1.79; CI 1.20-2.67; p = 0.004), coagulation abnormalities or DIC (OR 7.75; CI 5.81-10.34; p < 0.001), pulmonary hemorrhage (OR 2.18; CI 1.49-3.17; p < 0.001), and intracranial hemorrhage (OR 10.82; CI 5.90-19.85; p < 0.001) and less likely to have infectious complications (OR 0.48; CI 0.34-0.67; p < 0.001) compared to children with AML. In-hospital mortality rates were similar in children with APL and AML (4.2% vs 2.6%; OR 1.62; CI 0.86-3.06; p = 0.13), while the median length of stay for children who died from APL was shorter compared to AML (2 (IQR: 1-7) versus 25 (IQR: 5-66) days; p < 0.05). Hemorrhagic complications occur more often, and infectious complications occur less often in hospitalized children with APL compared to AML.

Epidemiology and early mortality patterns of acute promyelocytic leukemia in the United States.

There is a lack of contemporary population-based data on the epidemiology of acute promyelocytic leukemia (APL) in the United States. In this study, we aim to elucidate the demographics and early mortality patterns of APL hospitalizations utilizing the National Inpatient Sample database from 2016-2019. APL's annual age-adjusted incidence rate was 0.28/100,000, and the incidence increased with age, with the peak incidence in the 75-79 age group at 0.62/100,000. Whites constituted the majority of admissions at 67.7%, followed by Hispanics at 15.3%, the youngest racial group with a median age of 40 years. The median length of stay was 31 days for patients age < 60 years and 25 days for age ≥ 60 years (p < 0.001). After adjusting for confounders, the mean length of stay was 7 days higher in teaching hospitals compared to non-teaching hospitals (p 0.001). Overall mortality was 12.1% (22.2% for age ≥ 60 and 6.4% for < 60 years {p < 0.001}), and 56.5% of deaths happened before 7 days, with the median time to death being 6 days. The proportion of early deaths (< 7 days) in non-teaching hospitals was higher than late deaths (≥ 7 days) (19.2% vs. 5%; p 0.03), and admission to a teaching hospital was associated with lower mortality (adjusted odds ratio 0.27; p 0.01). Therefore, optimal treatment strategies need to be explored to mitigate this significant early mortality, especially in non-teaching hospitals.

Increased survival disparities among children and adolescents & young adults with acute myeloid leukemia: A Dutch population-based study.

For many cancers, adolescents and young adults (AYAs) have a poorer prognosis than pediatric patients. Our study evaluates survival outcomes of children (0-17 years) and AYAs (18-39 years) diagnosed with acute myeloid leukemia (AML) in the Netherlands between 1990 and 2015 (N = 2058) utilizing the population-based Netherlands Cancer Registry, which includes information on therapy and site of primary treatment. Five- and 10-year relative (disease-specific) survival were estimated for all patients, children and AYAs. Multivariable analyses were performed using generalized linear models (excess mortality) and logistic regression (early mortality). AYAs with AML had a substantially lower 5- and 10-year relative survival than children (5-year: 43% vs 58%; 10-year: 37% vs 51%). The gap in 5-year relative survival was largest (nearly 20 percent-points) in 2010 to 2015, despite survival improvements over time across all ages. The multivariable-adjusted excess risk of dying was 60% higher in AYAs (95% CI: 37%-86%). Early mortality (death within 30 days of diagnosis) declined over time, and did not differ between children and AYAs. In conclusion, AYAs diagnosed with AML in the Netherlands had a worse prognosis than pediatric patients. The survival gap seemed most pronounced in recent years, suggesting that improvements in care resulting in better outcome for children have not led to equal benefits for AYAs.

Acute myeloid leukemia: Treatment and research outlook for 2021 and the MD Anderson approach.

The unraveling of the pathophysiology of acute myeloid leukemia (AML) has resulted in rapid translation of the information into clinical practice. After more than 40 years of slow progress in AML research, the US Food and Drug Administration has approved nine agents for different AML treatment indications since 2017. In this review, we detail the progress that has been made in the research and treatment of AML, citing key publications related to AML research and therapy in the English literature since 2000. The notable subsets of AML include acute promyelocytic leukemia (APL), core-binding factor AML (CBF-AML), AML in younger patients fit for intensive chemotherapy, and AML in older/unfit patients (usually at the age cutoff of 60-70 years). We also consider within each subset whether the AML is primary or secondary (therapy-related, evolving from untreated or treated myelodysplastic syndrome or myeloproliferative neoplasm). In APL, therapy with all-trans retinoic acid and arsenic trioxide results in estimated 10-year survival rates of ≥80%. Treatment of CBF-AML with fludarabine, high-dose cytarabine, and gemtuzumab ozogamicin (GO) results in estimated 10-year survival rates of ≥75%. In younger/fit patients, the "3+7" regimen (3 days of daunorubicin + 7 days of cytarabine) produces less favorable results (estimated 5-year survival rates of 35%; worse in real-world experience); regimens that incorporate high-dose cytarabine, adenosine nucleoside analogs, and GO are producing better results. Adding venetoclax, FLT3, and IDH inhibitors into these regimens has resulted in encouraging preliminary data. In older/unfit patients, low-intensity therapy with hypomethylating agents (HMAs) and venetoclax is now the new standard of care. Better low-intensity regimens incorporating cladribine, low-dose cytarabine, and other targeted therapies (FLT3 and IDH inhibitors) are emerging. Maintenance therapy now has a definite role in the treatment of AML, and oral HMAs with potential treatment benefits are also available. In conclusion, AML therapy is evolving rapidly and treatment results are improving in all AML subsets as novel agents and strategies are incorporated into traditional AML chemotherapy. LAY SUMMARY: Ongoing research in acute myeloid leukemia (AML) is progressing rapidly. Since 2017, the US Food and Drug Administration has approved 10 drugs for different AML indications. This review updates the research and treatment pathways for AML.

Ethnic and border differences on blood cancer presentation and outcomes: A Texas population-based study.

BACKGROUND: The Texas/Chihuahua (US/Mexico) border is a medically underserved region with many reported barriers for health care access. Although Hispanic ethnicity is associated with health disparities for many different diseases, the population-based estimates of incidence and survival for patients with blood cancer along the border are unknown. The authors hypothesized that Hispanic ethnicity and border proximity is associated with poor blood cancer outcomes. METHODS: Data from the Texas Cancer Registry (1995-2016) were used to investigate the primary exposures of patient ethnicity (Hispanic vs non-Hispanic) and geographic location (border vs non-border). Other confounders and covariates included sex, age, year of diagnosis, rurality, insurance status, poverty indicators, and comorbidities. The Mantel-Haenszel method and Cox regression analyses were used to determine adjusted effects of ethnicity and border proximity on the relative risk (RR) and survival of patients with different blood cancer types. RESULTS: Hispanic patients were diagnosed at a younger age than non-Hispanic patients and presented with increased comorbidities. Whereas non-Hispanics had a higher incidence of developing blood cancer compared with Hispanics overall, Hispanics demonstrated a higher incidence of acute lymphoblastic leukemia (RR, 1.92; 95% CI, 1.79-2.08; P < .001) with worse outcomes. Hispanics from the Texas/Chihuahua border demonstrated a higher incidence of chronic myeloid leukemia (RR, 1.28; 95% CI, 1.07-1.51; P = .02) and acute myeloid leukemia (RR, 1.17; 95% CI, 1.04-1.33; P = .0009) compared with Hispanics living elsewhere in Texas. CONCLUSIONS: Hispanic ethnicity and border proximity were associated with a poor presentation and an adverse prognosis despite the younger age of diagnosis. Future studies should explore differences in disease biology and treatment strategies that could drive these regional disparities.

Risk factors for early in-hospital death in patients who developed coagulopathy during induction therapy for acute promyelocytic leukemia: a nationwide analysis in Japan.

To prevent early death, management of coagulopathy is important in patients with untreated acute promyelocytic leukemia (APL). This study aimed to clarify factors associated with in-hospital death in patients with coagulopathy during induction therapy for APL. We retrospectively identified patients with newly diagnosed APL who received induction therapy including all-trans retinoic acid (ATRA) and developed coagulopathy, using a nationwide inpatient database in Japan. Of 1115 eligible patients, 175 (15%) died at a median of 13 days (interquartile range, 7-30) after admission. In the multivariable analysis, compared with younger patients (aged < 40 years), the occurrence of in-hospital death was significantly more common among older patients (aged ≥ 40 and < 60 years: odds ratio = 2.58 [95% confidence interval: 1.29-5.19]; aged ≥ 60 and < 80 years: 7.66 [3.89-15.10]; aged ≥ 80 years: 16.83 [7.41-38.21]). Delayed initiation of ATRA and no conventional chemotherapy were significantly associated with in-hospital death (1.79 [1.16-2.76] and 2.40 [1.47-3.92], respectively). A total of 699 patients (63%) received anticoagulant therapies, but none of these was significantly associated with lower mortality. Although the present study was constrained by a lack of laboratory findings because of database limitations, the results showed that untreated patients with APL, especially the elderly, had a poor prognosis. Immediate administration of ATRA may reduce in-hospital mortality.

The economic research of arsenic trioxide for the treatment of newly diagnosed acute promyelocytic leukemia in China.

BACKGROUND: The objective of this study was to conduct the first systematic evaluation of the long-term economic impact of arsenic trioxide (ATO) plus all-trans retinoic acid (ATRA) for the treatment of patients with newly diagnosed acute promyelocytic leukemia (APL) from the perspective of the Chinese health care system. METHODS: On the basis of clinical data from a randomized phase 3 trial, a time-dependent Markov model with 4 health states (complete remission, relapse or treatment failure, post-treatment failure, and death) was used to evaluate the incremental costs per quality-adjusted life-year (QALY) gained from the ATO plus ATRA regimen compared with the ATRA plus chemotherapy (CT) regimen over a 30-year period. All costs were adjusted to 2018 levels based on the Chinese Consumer Price Index. Both costs and health outcomes were discounted by 3% annually. One-way sensitivity analysis and probability sensitivity analysis were performed. RESULTS: Compared with the ATRA plus CT strategy, the ATO plus ATRA strategy was associated with 1.38 additional QALYs gained and $392.05 (estimated in 2018 US dollars) in incremental costs per patient over 30 years. Consequently, the incremental cost-effectiveness ratio was $284.02 per QALY gained, which was far below the Chinese willingness-to-pay threshold of $29,306 per QALY gained. Sensitivity analyses demonstrated the robustness of these results. CONCLUSIONS: From the perspective of the Chinese health care system, the ATO plus ATRA strategy is cost-effective for patients with newly diagnosed APL compared with the ATRA plus CT strategy. Therefore, the authors strongly suggest that China's health authorities choose the former strategy for these patients, whether for the elderly or for young people.

Safety and efficacy of arsenic trioxide and all-trans retinoic acid therapy in acute promyelocytic leukemia patients with a high risk for early death.

In this study, we investigated the safety and efficacy of arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) in patients with acute promyelocytic leukemia (APL). The patients had been classified as unfit to receive anthracycline-based chemotherapy due to high-risk factors for early death. Twenty-five patients with APL receiving ATO/ATRA between 2007 and 2018 were divided into 3 groups as follows: elderly patients (age ≥ 70 years) with poor performance status (32%); patients with severe active infections at diagnosis (56%); and patients with multiple significant comorbidities (24%) who were unfit for conventional chemotherapy, regardless of age. Induction therapy comprised 0.15 mg/kg/day ATO combined with 45 mg/m2/day ATRA until patients attained complete remission (CR). Notably, only one patient (4.0%) died of septic shock 2 days after the ATO treatment had been initiated. The remaining 24 patients attained CR despite their serious and desperate conditions at diagnosis. In total, 44%, 28%, and 32% of the patients experienced neutropenia (grade 3 or 4), thrombocytopenia, and hepatopathy, respectively. Twenty-three of the 24 patients in CR proceeded to consolidation therapy and attained complete molecular remission with favorable overall survival (90.7%). This study demonstrates the safety and efficacy profile of ATO/ATRA first-line therapy for patients with APL and high-risk features for early death.

Predictors of early death, serious hemorrhage, and differentiation syndrome in Japanese patients with acute promyelocytic leukemia.

Significant advancements have been achieved with regard to the outcomes of acute promyelocytic leukemia (APL) patients through the introduction of all-trans retinoic acid; however, early hemorrhagic death and differentiation syndrome remain the major causes of remission induction failure in patients with APL. To investigate early death, serious hemorrhage, and differentiation syndrome during remission induction therapy in terms of incidence, risk factors, influence on outcomes, and prophylactic effects of several new anticoagulants, the results of 344 patients enrolled in the Acute Promyelocytic Leukemia 204 study conducted by the Japan Adult Leukemia Study Group were analyzed. Early death was observed in 16 patients (4.7%), of whom 14 had serious hemorrhage and 2 had differentiation syndrome. Serious hemorrhage and differentiation syndrome of grade 2 or higher were observed in 21 and 54 patients, respectively. Patients who achieved complete remission had a 7-year disease-free survival of 84.8% if they did not experience serious hemorrhage and 40.0% if they experienced serious hemorrhage during remission induction therapy (P = 0.001). Risk factor analyses showed that higher white blood cell count was associated with early death, higher white blood cell count and lower platelet count with serious hemorrhage, and leukocytosis during induction therapy and higher body surface area with differentiation syndrome. In conclusion, these results indicate that patients with such high-risk features may benefit from more intensive supportive care. The hemorrhagic risk was not relieved by the introduction of new anticoagulants. Further studies are required to establish the predictive impact of body surface area on differentiation syndrome. This trial is registered with UMIN-CTR as C000000154 on September 13, 2005.

Characteristics and outcome of adult patients with acute promyelocytic leukemia and increased body mass index treated with the PETHEMA Protocols.

OBJECTIVE: The obesity/overweight may have an influence on APL outcomes. METHODS: This is the biggest multicentre analysis on 1320 APL patients treated with AIDA-induction and risk-adapted consolidation between 1996 and 2012. Patients body mass index (BMI) was classified as underweight (<18.5 kg/m2 ), normal (18.5-25 kg/m2 ), overweight (25-29.9 kg/m2 ), and obese (≥30 kg/m2 ) according to the World Health Organization (WHO) criteria. RESULTS AND CONCLUSIONS: Relationship between male gender, older age, and other known laboratory abnormalities in overweight/obese patients was significant. The induction mortality rate was significantly higher in APL with BMI ≥25 vs BMI <25 (10% vs 6%; P = .04). APL patients with BMI ≥25 had a trend to lower OS (74% vs 80%; P = .06). However, in the multivariate analysis, BMI did not retain the independent predictive value (P = .46). There was no higher incidence of differentiation syndrome with BMI ≥25, but there was a trend in obese. There was no difference in relapse rate according to the BMI. In summary, overweight/obesity does not represent an independent risk factor for APL outcomes. The influence of obesity in APL patients treated with chemotherapy-free regimens remains to be established.

Hematopoietic stem cell transplantation for pediatric acute promyelocytic leukemia in Japan.

BACKGROUND: The number of hematopoietic stem cell transplantation (HSCT) procedures performed for pediatric acute promyelocytic leukemia (APL) has decreased in the all-trans retinoic acid (ATRA) era. Although HSCT is still widely adopted as part of salvage therapy for relapsed patients, there is no general consensus about the optimal transplant type (autologous [auto-HSCT] or allogeneic HSCT [allo-HSCT]). PROCEDURES: We retrospectively reviewed the clinical data of 95 childhood APL patients who underwent their first HSCT between 1990 and 2014. Of the 95 patients, 40 (42%), 41 (43%), and 3 (3%) underwent HSCT procedures after achieving their first complete remission (CR1), CR2, and CR3, respectively, and 11 (12%) underwent HSCT while in a non-CR state. RESULTS: The non-CR group exhibited significantly worse five-year overall survival (5yOS) and disease-free survival (5yDFS) (5yOS: 46%; 5yDFS: 46%) than the CR1 (5yOS: 80%; 5yDFS: 78%) and CR2 + CR3 groups (5yOS: 81%; 5yDFS: 76%) (P = 0.013 and P < 0.01, respectively). Of the patients treated in CR2, no significant differences in 5yOS or the five-year cumulative incidence of relapse (5yRI) were detected between the auto-HSCT and allo-HSCT groups (5yOS: 85%, vs 78%, P = 0.648; 5yRI: 9%, vs 11%, P = 0.828). Among the patients who underwent allo-HSCT in CR2, those with matched sibling donors displayed a significantly higher 5yRI (33%) than those with other types of donors (0%, P = 0.015). CONCLUSIONS: Even after relapsing, childhood APL can be cured with HSCT if CR is achieved. These findings demonstrate that achieving CR followed by HSCT is the preferred strategy for treating children with relapsed or refractory APL.

Early Mortality in Children and Adolescents with Acute Promyelocytic Leukemia: Experience of the Boldrini Children's Center.

INTRODUCTION: Acute promyelocytic leukemia (APL) is currently considered a highly curable disease. However, an early death (ED) remains one of the main causes of APL treatment failure. PATIENTS AND METHODS: In this retrospective study, we aimed to analyze the clinical characteristics of 91 children and adolescents with APL, who were consecutively registered at the (name of institution removed) Children's Center from January 1, 1998 to December 31, 2017. Data were assessed for age, sex, ethnicity, body mass index percentile, initial white blood cell count, peripheral blood blast count, and platelet count, hemoglobin value, partial thromboplastin time, prothrombin time, fibrinogen level, serum creatinine level, APL morphology subtype (classic vs. hypogranular variant M3v), and FLT3 gene mutations. RESULTS: ED occurred in 12 of 91 (13.1%) patients and was mainly related to cerebral thromboembolism. Overall 66% of deaths occurred in the second week after diagnosis. ED was associated with white blood cell ≥10×10 cells/L (odds ratio of 8.44; 95% confidence interval [CI]=1.48-48.26; P=0.0016), initial promyelocytes ≥20×10/L (odds ratio of 9.29; 95% CI=2.45-35.8; P=0.001), morphologic subtype M3v (odds ratio of 3.63; 95% CI=1.04-12.64; P=0.043), and creatinine serum levels >0.7 mg/dL (odds ratio of 6.78; 95% CI=1.83-25.13; P=0.004). In multivariate analyses, ED was associated with initial peripheral promyelocytes ≥20×10 blasts/L and creatinine serum levels >0.7 mg/dL. CONCLUSIONS: EDs were mainly caused by thrombohemorrhagic events and occurred within the second week after diagnosis. High peripheral promyelocytes and creatinine levels were predictors of ED in APL.

Oral arsenic trioxide incorporation into frontline treatment with all-trans retinoic acid and chemotherapy in newly diagnosed acute promyelocytic leukemia: A 5-year prospective study.

BACKGROUND: Strategies using oral arsenic trioxide (As2 O3 ) are efficacious in relapsed acute promyelocytic leukemia (APL), but they have not been examined in newly diagnosed cases. METHODS: Sixty-two consecutive patients (24 men and 38 women) with a median age of 52 years (range, 22-85 years), 36% of whom had high-risk features, underwent induction with all-trans retinoic acid at 45 mg/m2 /d, oral As2 O3 at 10 mg/d, and ascorbic acid at 1 g/d (the all-trans retinoic acid-arsenic trioxide-ascorbic acid [AAA] regimen) for 6 weeks (with patients younger than 70 years additionally receiving daunorubicin at 50 mg/m2 /d × 3); they then underwent consolidation with 2 monthly cycles of daunorubicin (50 mg/m2 /d × 2) and cytarabine (100 mg/m2 /d × 5) and received AAA maintenance (2 weeks every 8 weeks) for 2 years. A contemporaneous cohort of 37 newly diagnosed patients (15 men and 22 women) with a median age of 51 years (range, 23-78 years), not consenting to oral As2 O3 induction but receiving similar induction, consolidation, and AAA maintenance, served as a comparator group; 46% of these patients had high-risk features. RESULTS: The oral As2 O3 induction cohort showed a complete remission (CR) rate of 100%. After a median of 37 months (range, 13-82 months), there were no relapses, so conventional risks (age, leukocyte and platelet counts, and Fms-like tyrosine kinase 3 [FLT3] mutations) were not relevant. The leukemia-free survival (LFS) and overall survival (OS) rates were 100% at 3 years and 94.1% at 5 years. The non-As2 O3 induction cohort showed a CR rate of 100%. After a median of 52 months (range, 14-77 months), there were 3 relapses (8%). Comparable patients in the oral As2 O3 induction and non-As2 O3 induction cohorts showed similar OS, but LFS was significantly superior in the oral As2 O3 induction cohort. CONCLUSIONS: The incorporation of oral As2 O3 into induction for newly diagnosed APL was safe and decreased relapses.

Factors affecting thrombohemorrhagic early death in patients with acute promyelocytic leukemia treated with arsenic trioxide alone.

Acute promyelocytic leukemia (APL) is often accompanied by a potentially devastating coagulopathy. Predictors of thrombohemorrhagic early death (TH-ED)/early bleeding death are not well characterized. In this retrospective study, eleven baseline clinical variables that can be assessed easily and promptly were chosen for evaluation in a cohort of 364 patients with APL who were administered arsenic trioxide (ATO) alone as remission induction therapy. TH-ED was defined as death from bleeding or thrombosis within 30 days after hospital admission. Cox proportional hazards regression model was used for both the univariate and multivariate analyses. Totally, 53 patients died from severe bleeding (51 cases) or thrombosis (2 cases), and at 30 days the cumulative incidences of TH-ED were 14.6%. Six independent risk factors for TH-ED were identified, including relapse, male, white blood cell (WBC) count above 10 × 109/L, fibrinogen level below 1 g/L, D-dimer level above 4 mg/L and increased creatinine level. Increased creatinine level was the most powerful risk factor, followed by WBC count > 10 × 109/L. This study identified risk factors for TH-ED in a large cohort of patients with APL, which enriched clinical information on identifying patients at high risk of TH-ED.

The Role of Abnormal Hemostasis and Fibrinolysis in Morbidity and Mortality of Acute Promyelocytic Leukemia.

Despite the improved therapeutic advances in the management of acute promyelocytic leukemia (APL), a significant early mortality during induction, also referred to as early death (ED), remains an obstacle for further improvement in outcome. Hemorrhagic complications are the most common cause of morbidity and mortality. Perturbed hemostatic dysfunction is present as the result of abnormalities in both the coagulation and the fibrinolytic systems. The activation of coagulation is distinct from the classical disseminated intravascular coagulation. Multiple abnormalities in the fibrinolytic system have recently been identified. The most significant change is increased production of tissue plasminogen activator (tPA) and its receptor annexin A2 by the APL promyelocytes. Among the hemorrhagic complications, intracranial hemorrhage predominates. The pathogenesis of this catastrophic event is elucidated by new evidence of adverse effect of tissue plasminogen activator (tPA) on the brain, including both the plasmin-dependent and plasmin-independent pathways. In order to address the hemorrhagic complications, a thorough understanding of the hemostatic dysfunction is essential. In this article, our current concept of the abnormal hemostasis in APL is reviewed. The failure to reduce the early death rate, despite the introduction of effective therapy, will also be discussed.

Long-term outcome of acute promyelocytic leukemia treated with all-trans-retinoic acid, arsenic trioxide, and gemtuzumab.

The combination of all-trans-retinoic acid (ATRA) plus arsenic trioxide (ATO) has been shown to be superior to ATRA plus chemotherapy in the treatment of standard-risk patients with newly diagnosed acute promyelocytic leukemia (APL). A recent study demonstrated the efficacy of this regimen with added gemtuzumab ozogamicin (GO) in high-risk patients. We examined the long-term outcome of patients with newly diagnosed APL treated at our institution on 3 consecutive prospective clinical trials, using the combination of ATRA and ATO, with or without GO. For induction, all patients received ATRA (45 mg/m2 daily) and ATO (0.15 mg/kg daily) with a dose of GO (9 mg/m2 on day 1) added to high-risk patients (white blood cell count, >10 × 109/L), as well as low-risk patients who experienced leukocytosis during induction. Once in complete remission, patients received 4 cycles of ATRA plus ATO consolidation. One hundred eighty-seven patients, including 54 with high-risk and 133 with low-risk disease, have been treated. The complete remission rate was 96% (52 of 54 in high-risk and 127 of 133 in low-risk patients). Induction mortality was 4%, with only 7 relapses. Among low-risk patients, 60 patients (45%) required either GO or idarubicin for leukocytosis. Median duration of follow-up was 47.6 months. The 5-year event-free, disease-free, and overall survival rates are 85%, 96%, and 88%, respectively. Late hematological relapses beyond 1 year occurred in 3 patients. Fourteen deaths occurred beyond 1 year; 12 were related to other causes. This study confirms the durability of responses with this regimen.