An antithrombin replacement strategy during asparaginase therapy for acute lymphoblastic leukemia is associated with a reduction in thrombotic events

A systematic review and meta-analysis of the effectiveness of primary thromboprophylaxis in acute lymphoblastic leukemia during early-phase therapy including asparaginase or its prolonged form

Asparaginase is essential in the initial management of acute lymphoblastic leukemia (ALL) but frequently leads to venous thromboembolism (VTE). Using anticoagulants for primary VTE prevention has been studied with no consensus. We conducted a systematic literature search in PubMed, Scopus, and Web of science and performed random-effect meta-analysis using Mantel-Haenszel method in RevMan 5.4 to analyze primary pharmacological thromboprophylaxis during asparaginase treatment in early-phase (induction, consolidation, or intensification phase) therapy in patients with ALL with all ages and followed with subgroup analysis by age. Meta-analysis of 13 articles describing the effect of antithrombin supplementation in 1375 patients showed that antithrombin prophylaxis decreases the risk of VTE by 43% (RR, 0.57; 95% CI, 0.38 - 0.83; p=0.004), with mild heterogeneity (I2=35%, p=0.10) and moderate certainty by GRADE. 8 articles included for meta-analysis of low-molecular weight heparin (LMWH) treatment in 612 patients showed that it decreased the risk of VTE by nearly 40% (RR, 0.61; 95% CI, 0.45 - 0.81; p=0.00081), with minimal heterogeneity (I2=14%, p=0.31) but low certainty. Subgroup analysis showed that only prophylaxis with antithrombin supplementation significantly decreased the VTE rate in adult patients with moderate certainty. In pediatric patients, one nonrandomized prospective study showed that LMWH combined with antithrombin has a better thromboprophylaxis effect than antithrombin alone. In the PREVAPIX-ALL trial, prophylaxis with direct factor Xa inhibitor Apixaban did not benefit children younger than 18 years except for cases of obesity. We concluded that thromboprophylaxis with antithrombin is effective in ALL patients older than 18 years during the early phase of therapy, and LMWH combined with antithrombin supplementation might be effective for pediatric patients with ALL. Apixaban is effective in pediatric ALL patients with obesity and needs further study in other high-risk patients.

Pegaspargase in Practice: Minimizing Toxicity, Maximizing Benefit

PURPOSE OF REVIEW

The incorporation of pegaspargase in chemotherapy regimens has significantly improved the prognosis of ALL in adults. However, pegaspargase use poses many challenges due to its unique toxicity profile. Here, we review pegaspargase's most clinically significant toxicities, and provide guidance for their prevention and management in order to avoid unnecessary drug discontinuation and achieve maximum clinical benefit.

RECENT FINDINGS

Clinically significant toxicities of pegaspargase include thrombosis, hypersensitivity and inactivation, hepatotoxicity, pancreatitis, and hypertriglyceridemia. The majority of these toxicities are temporary, nonfatal, and can be managed supportively without permanent pegaspargase discontinuation. Special attention should be paid to inactivation, which can lead to treatment failure, as well as pancreatitis, which necessitates complete cessation of asparaginase therapy. The question of how to best proceed in patients who cannot tolerate pegaspargase remains unanswered, and is an important area of future investigation. Pegaspargase is an essential component of the pediatric-inspired regimens that have improved survival in adult ALL. Although pegaspargase's toxicity profile is unique, it is also highly manageable and should not be a barrier to achieving maximum clinical benefit using this drug.

Venous thromboembolism incidence and risk factors in adults with acute lymphoblastic leukemia treated with and without pegylated E. coli asparaginase-containing regimens

PURPOSE

Asparaginases, key agents in treatment of acute lymphoblastic leukemia (ALL), are associated with venous thromboembolism (VTE). While risks of short-acting asparaginase-related VTE is well-known, we studied VTE incidence and risk factors in adult ALL patients treated with and without long-acting pegylated asparaginase (PegA).

METHODS

Single-center, retrospective analysis of 89 ALL patients treated with (n = 61) or without (n = 28) PegA at Greenebaum Comprehensive Cancer Center. Reviewed patient and disease characteristics, treatment, and VTE incidence.

RESULTS

VTE during treatment occurred in 31 patients (35%), and was associated with PegA (p = 0.001) and Philadelphia chromosome negativity (p = 0.002). Among PegA recipients, VTE was associated with a significantly higher mean body mass index (BMI) of 31.3 kg/m² (p = 0.037), and was more common with pre-T/T cell compared to pre-B/B cell ALL (68.2% vs. 33.3%, p = 0.009). Antithrombin-III (ATIII) levels were measured for 26 patients; 16 (61.5%) were < 50%. Of those, 8 (50%) experienced VTE, while 3 of 10 (30%) patients with ATIII levels ≥ 50% experienced VTE. VTE occurred in 7 of 13 (54%) of patients who received ATIII repletion. There was a trend toward a higher incidence of VTE in the PegA group among patients with non-O compared to O blood type (55.9% vs. 33.3%, p = 0.079) as well as those with a higher hemoglobin at diagnosis (9.3 vs 8.1 g/dL, p = 0.056).

CONCLUSION

This study confirms PegA as a risk factor for VTE in patients with ALL. Risk factors among those receiving PegA include higher BMI and pre-T/T cell ALL. ATIII repletion was not shown to be protective against VTE. There was a higher incidence of VTE in patients who received PegA with non-O compared to O blood type, but the precise correlation is uncertain.

Advances in Supportive Care for Acute Lymphoblastic Leukemia

PURPOSE OF REVIEW

Tremendous advances have been made in the treatment armamentarium for acute lymphoblastic leukemia in recent years, which have substantially improved outcomes for these patients. At the same time, unique toxicities have emerged, and without early intervention, are life-threatening. This article will review the novel therapies in acute leukemias and highlight the clinically relevant supportive care advances.

RECENT FINDINGS

The American Society for Transplantation and Cellular Therapy (ASTCT) has put forth the most recent recommendations in managing the cytokine release syndrome and neurotoxicity after chimeric antigen receptor T cells (CAR-T) and blinatumomab. The hepatic injury incurred by inotuzumab, and the vascular toxicity of tyrosine kinase inhibitors, other relatively novel agents, require subspecialist intervention and multidisciplinary care. Asparaginase, a long-established and key element of pediatric regimens, has made a comeback in the young adult leukemia population. Updated guidelines have been outlined for management of asparaginase thrombotic complications. Lastly, although there have been few changes in the applications of growth factor, antimicrobial prophylaxis, and management of neuropathy, these encompass exceedingly important aspects of care. While the rapidly changing treatment paradigms for acute lymphoblastic leukemia have transformed leukemia-specific outcomes, treatment emergent toxicities have forced much necessary attention to better definitions of these toxicities and on improving supportive care guidelines in acute lymphoblastic leukemia.

Impact of exogenous antithrombin on low molecular weight heparin anti-Xa activity assays in a pediatric and young adult leukemia and lymphoma cohort with variable antithrombin levels

BACKGROUND

Low molecular weight heparin (LMWH) remains the most commonly prescribed pediatric anticoagulant. There is debate whether LMWH anti-Xa assays with or without exogenous antithrombin (AT) best reflect anticoagulation effect, and how much discrepancy exists between assay types.

OBJECTIVES

We assessed the effect of variable AT activity on LMWH anti-Xa levels in plasma samples from anticoagulated pediatric and young adult acute lymphoblastic leukemia and lymphoma (ALL/L) patients, using two instruments and their commercial kits with and without exogenous AT (ie, four platforms).

METHODS

We analyzed LMWH anti-Xa levels on 60 plasma samples with known AT activity from 12 enoxaparin-treated ALL/L patients, using four commercial kits from Siemens and Stago containing AT or not, on Siemens BCS and Stago STA R Max, respectively.

RESULTS

Of 236/240 samples with interpretable results, mean AT activity was 80% (46-138%). Correlation was acceptable for published kit ranges of LMWH anti-Xa levels when comparing kits containing AT (r = 0.82, P < .0001), or not (r = 0.93, P < .0001), and within a manufacturer (Berichrom to Innovance, r = 0.92, P < .0001; Stachrom to STA-Liquid Anti-Xa r = 0.98, P < .0001). LMWH anti-Xa levels were lower in platforms without added AT (P < .0001). For Stago kits, this effect increased when AT < 70% (P = .001, n = 19, mean 56%). Assay variability, measured as mean percent difference, was less pronounced with Stago kits (14.7%, n = 49) than Siemens (41.9%, n = 50).

CONCLUSIONS

Although LMWH levels from anti-Xa assays with added AT trend higher than in those without, correlation was fairly good between platforms in pediatric ALL/L plasmas, even when AT activity was <70%.

Prophylaxis of thromboembolism during therapy with asparaginase in adults with acute lymphoblastic leukaemia

BACKGROUND

The risk of venous thromboembolism is increased in adults and enhanced by asparaginase-based chemotherapy, and venous thromboembolism introduces a secondary risk of treatment delay and premature discontinuation of key anti-leukaemic agents, potentially compromising survival. Yet, the trade-off between benefits and harms of primary thromboprophylaxis in adults with acute lymphoblastic leukaemia (ALL) treated according to asparaginase-based regimens is uncertain.  OBJECTIVES: The primary objectives were to assess the benefits and harms of primary thromboprophylaxis for first-time symptomatic venous thromboembolism in adults with ALL receiving asparaginase-based therapy compared with placebo or no thromboprophylaxis. The secondary objectives were to compare the benefits and harms of different groups of primary systemic thromboprophylaxis by stratifying the main results per type of drug (heparins, vitamin K antagonists, synthetic pentasaccharides, parenteral direct thrombin inhibitors, direct oral anticoagulants, and blood-derived products for antithrombin substitution).

SEARCH METHODS

We conducted a comprehensive literature search on 02 June 2020, with no language restrictions, including (1) electronic searches of Pubmed/MEDLINE; Embase/Ovid; Scopus/Elsevier; Web of Science Core Collection/Clarivate Analytics; and Cochrane Central Register of Controlled Trials (CENTRAL) and (2) handsearches of (i) reference lists of identified studies and related reviews; (ii) clinical trials registries (ClinicalTrials.gov registry; the International Standard Randomized Controlled Trial Number (ISRCTN) registry; the World Health Organisation's International Clinical Trials Registry Platform (ICTRP); and pharmaceutical manufacturers of asparaginase including Servier, Takeda, Jazz Pharmaceuticals, Ohara Pharmaceuticals, and Kyowa Pharmaceuticals), and (iii) conference proceedings (from the annual meetings of the American Society of Hematology (ASH); the European Haematology Association (EHA); the American Society of Clinical Oncology (ASCO); and the International Society on Thrombosis and Haemostasis (ISTH)). We conducted all searches from 1970 (the time of introduction of asparaginase in ALL treatment). We contacted the authors of relevant studies to identify any unpublished material, missing data, or information regarding ongoing studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs); including quasi-randomised, controlled clinical, cross-over, and cluster-randomised trial designs) comparing any parenteral/oral preemptive anticoagulant or mechanical intervention with placebo or no thromboprophylaxis, or comparing two different pre-emptive anticoagulant interventions in adults aged at least 18 years with ALL treated according to asparaginase-based chemotherapy regimens. For the description of harms, non-randomised observational studies with a control group were eligible for inclusion.  DATA COLLECTION AND ANALYSIS: Using a standardised data collection form, two review authors independently screened and selected studies, extracted data, assessed risk of bias for each outcome using standardised tools (RoB 2.0 tool for RCTs and ROBINS-I tool for non-randomised studies) and the certainty of evidence for each outcome using the GRADE approach. Primary outcomes included first-time symptomatic venous thromboembolism, all-cause mortality, and major bleeding. Secondary outcomes included asymptomatic venous thromboembolism, venous thromboembolism-related mortality, adverse events (i.e. clinically relevant non-major bleeding and heparin-induced thrombocytopenia for trials using heparins), and quality of life. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions. For non-randomised studies, we evaluated all studies (including studies judged to be at critical risk of bias in at least one of the ROBINS-I domains) in a sensitivity analysis exploring confounding.  MAIN RESULTS: We identified 23 non-randomised studies that met the inclusion criteria of this review, of which 10 studies provided no outcome data for adults with ALL. We included the remaining 13 studies in the 'Risk of bias' assessment, in which we identified invalid control group definition in two studies and judged outcomes of nine studies to be at critical risk of bias in at least one of the ROBINS-I domains and outcomes of two studies at serious risk of bias. We did not assess the benefits of thromboprophylaxis, as no RCTs were included. In the main descriptive analysis of harms, we included two retrospective non-randomised studies with outcomes judged to be at serious risk of bias. One study evaluated antithrombin concentrates compared to no antithrombin concentrates. We are uncertain whether antithrombin concentrates have an effect on all-cause mortality (risk ratio (RR) 0.55, 95% confidence interval (CI) 0.26 to 1.19 (intention-to-treat analysis); one study, 40 participants; very low certainty of evidence). We are uncertain whether antithrombin concentrates have an effect on venous thromboembolism-related mortality (RR 0.10, 95% CI 0.01 to 1.94 (intention-to-treat analysis); one study, 40 participants; very low certainty of evidence). We do not know whether antithrombin concentrates have an effect on major bleeding, clinically relevant non-major bleeding, and quality of life in adults with ALL treated with asparaginase-based chemotherapy, as data were insufficient. The remaining study (224 participants) evaluated prophylaxis with low-molecular-weight heparin versus no prophylaxis. However, this study reported insufficient data regarding harms including all-cause mortality, major bleeding, venous thromboembolism-related mortality, clinically relevant non-major bleeding, heparin-induced thrombocytopenia, and quality of life. In the sensitivity analysis of harms, exploring the effect of confounding, we also included nine non-randomised studies with outcomes judged to be at critical risk of bias primarily due to uncontrolled confounding. Three studies (179 participants) evaluated the effect of antithrombin concentrates and six studies (1224 participants) evaluated the effect of prophylaxis with different types of heparins. When analysing all-cause mortality; venous thromboembolism-related mortality; and major bleeding (studies of heparin only) including all studies with extractable outcomes for each comparison (antithrombin and low-molecular-weight heparin), we observed small study sizes; few events; wide CIs crossing the line of no effect; and substantial heterogeneity by visual inspection of the forest plots. Although the observed heterogeneity could arise through the inclusion of a small number of studies with differences in participants; interventions; and outcome assessments, the likelihood that bias due to uncontrolled confounding was the cause of heterogeneity is inevitable. Subgroup analyses were not possible due to insufficient data.  AUTHORS' CONCLUSIONS: We do not know from the currently available evidence, if thromboprophylaxis used for adults with ALL treated according to asparaginase-based regimens is associated with clinically appreciable benefits and acceptable harms. The existing research on this question is solely of non-randomised design, seriously to critically confounded, and underpowered with substantial imprecision. Any estimates of effect based on the existing insufficient evidence is very uncertain and is likely to change with future research.

The prevention and management of asparaginase-related venous thromboembolism in adults: Guidance from the SSC on Hemostasis and Malignancy of the ISTH

Venous thromboembolism is a common complication of asparaginase-based chemotherapy regimens for the treatment of acute lymphoblastic leukemia. Thrombosis associated with asparaginase administration poses a number of specific and often clinically challenging management decisions. This review provides guidance on the prevention and treatment of thrombosis associated with asparaginase in adults including discussions on antithrombin repletion, pharmacologic thromboprophylaxis, cerebral venous thrombosis, and therapeutic anticoagulation.

Pediatric-inspired protocols in adult acute lymphoblastic leukemia: are the results bearing fruit?

Observational findings demonstrating improved survival for younger adults following pediatric, as opposed to adult, acute lymphoblastic leukemia (ALL) regimens have been translated into international, prospective multicenter clinical trials testing the pediatric regimen in young adult ALL. The results of these studies confirm the feasibility of delivering the pediatric regimen in the adult oncology setting and establish the superiority of this approach relative to historical adult cooperative group regimen results. Specific toxicities, including thrombosis, hepatotoxicity, and osteonecrosis, are more prevalent in adults receiving the pediatric regimen relative to young children. Persistent minimal residual disease (MRD) is a strong prognostic indicator in adults receiving the pediatric regimen; sensitive, high-quality MRD evaluation should be performed in all patients receiving these therapies. Incorporation of targeted agents, particularly in the frontline and MRD+ setting, will usher in the next era of the pediatric regimen in adult ALL.

Capped antithrombin III dosing is cost effective in the management of asparaginase-associated thrombosis

Asparaginase therapy induces a transient antithrombin III (ATIII) deficiency, which contributes to the risk of asparaginase-induced thrombosis. At Cincinnati Children's Hospital Medical Center, management of asparaginase-induced thrombosis includes ATIII supplementation during therapeutic anticoagulation with enoxaparin. Due to the expense associated with ATIII, a capped dosing approach for ATIII was evaluated in this population. Peak ATIII levels were obtained following capped doses to evaluate response. In this pilot evaluation, 11 patients received a total of 138 capped doses for a total cost savings of $803 782. This pilot evaluation represents the first reported analysis of capped ATIII dosing in oncology patients.

Optimizing pegylated asparaginase use: An institutional guideline for dosing, monitoring, and management

The incorporation of L-asparaginase and pegylated asparaginase into pediatric-inspired regimens has conferred a survival advantage in treatment of adults with acute lymphoblastic leukemia. Use of asparaginase products requires careful prevention, monitoring, and management of adverse effects including hypersensitivity, hepatotoxicity, pancreatitis, coagulopathy, and thrombosis. Currently, there is limited published literature to offer guidance on management of these toxicities. At the University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, a standard of practice guideline was created to prevent and manage asparaginase-related adverse events. By sharing our long-term experience with asparaginase products and clinical management of asparaginase-induced toxicities, this article aims to improve patient safety and optimize treatment outcomes.

Thrombotic Risk from Chemotherapy and Other Cancer Therapies

Cancer patients have an increased risk of thrombosis. The development of cancer thrombosis is dependent on a number of factors including cancer type, stage, various biologic markers, and the use of central venous catheters. In addition, cancer treatment itself may increase thrombotic risk. Tamoxifen increases the risk of venous thromboembolism (VTE) by two- to sevenfold, while an impact on risk of arterial thrombosis is uncertain. Immunomodulatory imide drugs (IMiDs) such as thalidomide and lenalidomide increase the risk of VTE in patients with multiple myeloma (MM) by about 10-40% when given in combination with glucocorticoids or other chemotherapy agents; the risk of VTE in MM patients treated with IMiD-containing regimens necessitates that such patients receive thromboprophylaxis with aspirin, low-molecular-weight heparin, or warfarin. Among cytotoxic chemotherapy agents, cisplatin, and to a lesser extent fluorouracil, has been described in association with thrombosis. L-asparaginase in treatment of acute lymphoblastic leukemia is significantly associated with increased thrombosis particularly affecting the CNS, which may be due to acquired antithrombin deficiency; at some centers, plasma infusions or antithrombin replacement is used to mitigate this. Bevacizumab, an inhibitor of vascular endothelial growth factor, increases arterial and possibly venous thrombotic risk, although the literature is conflicting about the latter. Supportive care agents in cancer care, such as erythropoiesis-stimulating agents, granulocyte colony stimulating factor, and steroids, also have some impact on thrombosis. This review summarizes the mechanisms by which these and other therapies modulate thrombotic risks and how such risks may be managed.

The use of prophylactic anticoagulation during induction and consolidation chemotherapy in adults with acute lymphoblastic leukemia

Treatment for acute lymphoblastic leukemia (ALL) in adults confers a high risk of venous thromboembolic (VTE) complications. We describe the implementation and results of prophylactic anticoagulation guidelines in adults (18-50 years) treated on a Dana-Farber Cancer Institute ALL pediatric inspired consortium protocol from 2007 to 2013. A high rate of asparaginase related toxicity events, including thrombosis, resulted in a protocol amendment adding guidelines for prophylactic anticoagulation and a modified asparaginase dose and schedule. After excluding patients with Philadelphia positive ALL, a cohort of 36 patients were treated after the protocol amendment with prophylactic anticoagulation and compared to 49 patients who received no prophylactic anticoagulation. Bleeding complications were not significantly different in those treated with prophylactic anticoagulation compared with those enrolled prior to the amendment (p = 0.26). No patients on prophylactic anticoagulation had grade ≥ 3 bleeding. Prior to the amendment, the 2 year cumulative incidence of VTE post-induction was 41% compared to 28% while on prophylactic anticoagulation (p = 0.32). The 2 year cumulative incidence pulmonary embolus pre-amendment was 16% compared with 8% post-amendment (p = 0.34). Prophylactic anticoagulation can be safely administered to adults with ALL without increasing the number or severity of bleeding events and, in addition to modifications in the asparaginase regimen, resulted in a reduction in the cumulative incidence of VTE.

Safety and feasibility of lower antithrombin replacement targets in adult patients with hematological malignancies receiving asparaginase therapy<sup/>

The optimal antithrombin(AT) activity parameters for replacement as thromboprophylaxis following asparaginase remains unclear. This single-center, retrospective study evaluated two sets of AT replacement thresholds and targets in adults receiving asparaginase-containing chemotherapy. AT supplementation adhered to institutional standards, which lowered the AT activity target from 100% to 80% in 6/2014. Ninety-two patients were evaluated. Cumulative thrombosis incidence was 16% at 6 months (95%CI:6.8-24.0, maximum follow-up 315 days) with similar incidence between the 80% and 100% target groups, 14% (2 of the 14) and 13% (10 of the 78), respectively, with a small non-Line-Related DVT incidence (3%). Most thrombotic events occurred during induction chemotherapy and demonstrated no associations with replacement target, cumulative days or cumulative area under AT activity target, number of asparaginase doses, or cumulative asparaginase dose. Median estimated AT replacement expenditure was $34,963USD (IQR $16,260USD to $79,319USD) per patient. Cost-effectiveness and optimization of AT replacement for thromboprophylaxis following asparaginase requires prospective evaluation.

Central Nervous System Complications in Children Receiving Chemotherapy or Hematopoietic Stem Cell Transplantation

Therapy-related neurotoxicity greatly affects possibility of survival and quality of life of pediatric patients treated for cancer. Central nervous system (CNS) involvement is heterogeneous, varying from very mild and transient symptoms to extremely severe and debilitating, or even lethal syndromes. In this review, we will discuss the broad scenario of CNS complications and toxicities occurring during the treatment of pediatric patients receiving both chemotherapies and hematopoietic stem cell transplantation. Different types of complications are reviewed ranging from therapy related to cerebrovascular with a specific focus on neuroradiologic and clinical features.