Erwinia asparaginase achieves therapeutic activity after pegaspargase allergy: a report from the Children's Oncology Group

Intravenous pegylated asparaginase versus intramuscular native Escherichia coli L-asparaginase in newly diagnosed childhood acute lymphoblastic leukaemia (DFCI 05-001): a randomised, open-label phase 3 trial

BACKGROUND

l-asparaginase is a universal component of treatment for childhood acute lymphoblastic leukaemia, and is usually administered intramuscularly. Pegylated Escherichia coli asparaginase (PEG-asparaginase) has a longer half-life and is potentially less immunogenic than the native Escherichia coli (E coli) preparation, and can be more feasibly administered intravenously. The aim of the Dana-Farber Cancer Institute Acute Lymphoblastic Leukaemia Consortium Protocol 05-001 (DFCI 05-001) was to compare the relative toxicity and efficacy of intravenous PEG-asparaginase and intramuscular native E colil-asparaginase in children with newly diagnosed acute lymphoblastic leukaemia.

METHODS

DFCI 05-001 enrolled patients aged 1-18 years with newly diagnosed acute lymphoblastic leukaemia from 11 consortium sites in the USA and Canada. Patients were assigned to an initial risk group on the basis of their baseline characteristics and then underwent 32 days of induction therapy. Those who achieved complete remission after induction therapy were assigned to a final risk group and were eligible to participate in a randomised comparison of intravenous PEG-asparaginase (15 doses of 2500 IU/m(2) every 2 weeks) or intramuscular native E colil-asparaginase (30 doses of 25 000 IU/m(2) weekly), beginning at week 7 after study entry. Randomisation (1:1) was unmasked, and was done by a statistician-generated allocation sequence using a permuted blocks algorithm (block size of 4), stratified by final risk group. The primary endpoint of the randomised comparison was the overall frequency of asparaginase-related toxicities (defined as allergy, pancreatitis, and thrombotic or bleeding complications). Predefined secondary endpoints were disease-free survival, serum asparaginase activity, and quality of life during therapy as assessed by PedsQL surveys. All analyses were done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00400946.

FINDINGS

Between April 22, 2005, and Feb 12, 2010, 551 eligible patients were enrolled. 526 patients achieved complete remission after induction, of whom 463 were randomly assigned to receive intramuscular native E colil-asparaginase (n=231) or intravenous PEG-asparaginase (n=232). The two treatment groups did not differ significantly in the overall frequency of asparaginase-related toxicities (65 [28%] of 232 patients in the intravenous PEG-asparaginase group vs 59 [26%] of 231 patients in the intramuscular native E colil-asparaginase group, p=0·60), or in the individual frequency of allergy (p=0·36), pancreatitis (p=0·55), or thrombotic or bleeding complications (p=0·26). Median follow-up was 6·0 years (IQR 5·0-7·1). 5-year disease-free survival was 90% (95% CI 86-94) for patients assigned to intravenous PEG-asparaginase and 89% (85-93) for those assigned to intramuscular native E colil-asparaginase (p=0·58). The median nadir serum asparaginase activity was significantly higher in patients who received intravenous PEG-asparaginase than in those who received intramuscular native E colil-asparaginase. Significantly more anxiety was reported by both patients and parent-proxy in the intramuscular native E colil-asparaginase group than in the intravenous PEG-asparaginase group. Scores for other domains were similar between the groups. The most common grade 3 or worse adverse events were bacterial or fungal infections (47 [20%] of 232 in the intravenous PEG-asparaginase group vs 51 [22%] of 231 patients in the intramuscular E colil-asparaginase group) and asparaginase-related allergic reactions (14 [6%] vs 6 [3%]).

INTERPRETATION

Intravenous PEG-asparaginase was not more toxic than, was similarly efficacious to, and was associated with decreased anxiety compared with intramuscular native E colil-asparaginase, supporting its use as the front-line asparaginase preparation in children with newly diagnosed acute lymphoblastic leukaemia.

FUNDING

National Cancer Institute and Enzon Pharmaceuticals.

Best Practices in Adolescent and Young Adult Patients with Acute Lymphoblastic Leukemia: A Focus on Asparaginase

The inclusion of asparaginase in chemotherapy regimens to treat acute lymphoblastic leukemia (ALL) has had a positive impact on survival in pediatric patients. Historically, asparaginase has been excluded from most treatment protocols for adolescent and young adult (AYA) patients because of perceived toxicity in this population, and this is believed to have contributed to poorer outcomes in these patients. However, retrospective analyses over the past 12 years have shown that 2-, 5-, and 7-year overall survival of AYA patients is significantly improved with pediatric versus adult protocols. The addition of asparaginase to adult protocols yielded high rates of first remission and improved survival. However, long-term survival remains lower compared with what has been seen in pediatrics. The notion that asparaginase is poorly tolerated by AYA patients has been challenged in multiple studies. In some, but not all, studies, the incidences of hepatic and pancreatic toxicities were higher in AYA patients, whereas the rates of hypersensitivity reactions did not appear to differ with age. There is an increased risk of venous thromboembolic events, and management with anti-coagulation therapy is recommended. Overall, the risk of therapy-related mortality is low. Together, this suggests that high-intensity pediatric protocols offer an effective and tolerable approach to treating ALL in the AYA population.

Clinical application of asparaginase activity levels following treatment with pegaspargase

Asparaginase, an enzyme used to treat acute lymphoblastic leukemia and related forms of nonHodgkin lymphoma, depletes asparagine, which leads to lymphoblast cell death. Unlike most chemotherapeutic agents, asparaginase is a foreign protein that can result in clinical allergy and/or silent hypersensitivity with production of neutralizing antibodies that inactivate asparaginase. In North America, asparaginase activity levels can now be obtained via a commercially available assay, for therapeutic drug monitoring and investigation of potential allergic reactions. Herein, we provide recommendations and a corresponding algorithm for the clinical application of this assay after treatment with pegaspargase to evaluate suspected hypersensitivity reactions and/or silent inactivation.

Asparaginase pharmacokinetics and implications of therapeutic drug monitoring

Asparaginase is widely used in chemotherapeutic regimens for the treatment of acute lymphoblastic leukemia (ALL) and has led to a substantial improvement in cure rates, especially in children. Optimal therapeutic effects depend on a complete and sustained depletion of serum asparagine. However, pronounced interpatient variability, differences in pharmacokinetic properties between asparaginases and the formation of asparaginase antibodies make it difficult to predict the degree of asparagine depletion that will result from a given dose of asparaginase. The pharmacological principles underlying asparaginase therapy in the treatment of ALL are summarized in this article. A better understanding of the many factors that influence asparaginase activity and subsequent asparagine depletion may allow physicians to tailor treatment to the individual, maximizing therapeutic effect and minimizing treatment-related toxicity. Therapeutic drug monitoring provides a means of assessing a patient's current depletion status and can be used to better evaluate the potential benefit of treatment adjustments.

How to manage asparaginase hypersensitivity in acute lymphoblastic leukemia

Outcomes for children with acute lymphoblastic leukemia (ALL) have improved significantly in recent decades, primarily due to dose-intensified, multi-agent chemotherapy regimens, of which asparaginase has played a prominent role. Despite this success, hypersensitivity remains a significant problem, often requiring the termination of asparaginase. Failure to complete the entire asparaginase therapy course due to clinical hypersensitivity, subclinical hypersensitivity (i.e., silent inactivation), or other treatment-related toxicity is associated with poor ALL outcomes. Thus, it is critical to rapidly identify patients who develop clinical/subclinical hypersensitivity and switch these patients to an alternate asparaginase formulation. This article provides an overview of asparaginase hypersensitivity, identification and management of hypersensitivity and subclinical hypersensitivity, and issues related to switching patients to asparaginase Erwinia chrysanthemi following hypersensitivity reaction.

Will novel agents for ALL finally change the natural history?

Pediatric acute lymphoblastic leukemia (ALL) cure rates have markedly improved over the past years to approximately 85%, but remain at 40%-50% in adults. Redefining current adult chemotherapy regimens is likely to improve the natural course of the disease, but new agents are needed. Immunotherapy approaches for pre-B ALL are in the forefront of research on novel agents; in particular, advances are being made in manipulating autologous T cells either by infusion of a bifunctional antibody (eg, blinatumomab) or by ex vivo genetic modification of chimeric antigen receptors (CARs). The natural course of Philadelphia positive ALL has already improved by targeting ABL/BCR1. Other mutated genes are being discovered and novel small molecules that target their products are being studied in clinical trials. Finally, ALL is a heterogeneous disease and novel agents are likely to impact the natural course of smaller populations of biologically defined ALL subtypes.

Rationale for a pediatric-inspired approach in the adolescent and young adult population with acute lymphoblastic leukemia, with a focus on asparaginase treatment

In the last two decades great improvements have been made in the treatment of childhood acute lymphoblastic leukemia, with 5-year overall survival rates currently approaching almost 90%. In comparison, results reported in adolescents and young adults (AYAs) are relatively poor. In adults, results have improved, but are still lagging behind those obtained in children. Possible reasons for this different pattern of results include an increased incidence of unfavorable and a decreased incidence of favorable cytogenetic abnormalities in AYAs compared with children. Furthermore, in AYAs less intensive treatments (especially lower cumulative doses of drugs such as asparaginase, corticosteroids and methotrexate) and longer gaps between courses of chemotherapy are planned compared to those in children. However, although favorable results obtained in AYAs receiving pediatric protocols have been consistently reported in several international collaborative trials, physicians must also be aware of the specific toxicity pattern associated with increased success in AYAs, since an excess of toxicity may compromise overall treatment schedule intensity. Cooperative efforts between pediatric and adult hematologists in designing specific protocols for AYAs are warranted.

Safety profile of asparaginase Erwinia chrysanthemi in a large compassionate-use trial

BACKGROUND

L-Asparaginase is an integral component of standard chemotherapy regimens for the treatment of acute lymphoblastic leukemia (ALL). Clinical hypersensitivity, a common reason for treatment discontinuation, has been reported in 10-30% of patients receiving Escherichia coli-derived asparaginase. After hypersensitivity, E. coli-derived asparaginase should be discontinued and an alternative asparaginase preparation, such as asparaginase Erwinia chrysanthemi, may be initiated. We conducted a compassionate-use study to collect additional safety information on asparaginase Erwinia chrysanthemi and to support FDA approval of the product.

PROCEDURE

Patients with ALL or lymphoblastic lymphoma (LBL; N = 1368) who developed a hypersensitivity reaction (grade ≥2) to an E. coli-derived asparaginase participated in this trial. The recommended asparaginase Erwinia chrysanthemi dose was 25,000 IU/m(2) three days per week (Monday/Wednesday/Friday) for two consecutive weeks for each missed pegylated E. coli-derived asparaginase dose and 25,000 IU/m(2) for each missed nonpegylated asparaginase dose for the completion of their planned asparaginase treatment.

RESULTS

Adverse event reports and/or case report forms were completed for 940 patients. The most common adverse event (AE) was hypersensitivity (13.6%). Eighteen patients (1.9%) died during the study. Most patients (77.6%) completed their planned asparaginase treatment with asparaginase Erwinia chrysanthemi. There was no apparent difference in the incidence of the most commonly reported AEs with asparaginase treatment by age, administration, or disease state.

CONCLUSIONS

This study further established the safety profile of asparaginase Erwinia chrysanthemi in patients with ALL or LBL who had a hypersensitivity reaction to an E. coli-derived asparaginase.

Shedding light on the asparaginase galaxy

In this issue of Blood, Tong et al have reported that therapeutic drug monitoring (TDM) of asparaginase (ASP) activity levels in plasma may be an important tool for the optimization of its therapeutic effects in pediatric acute lymphoblastic leukemia (ALL).

Treatment of children with advanced-stage lymphoblastic lymphoma with pegaspargase

OBJECTIVE

To evaluate the feasibility of Pegaspargase instead of L-asparaginase to treat children with advanced-stage lymphoblastic lymphoma (LBL) on the Berlin-Frankfurt-Munster (BFM)-95 protocol.

METHODS

Fifty-four newly diagnosed patients with stage III or IV LBL and without any treatment were enrolled in this study. Pegaspargase took place of L-asparaginase in BFM-95. The complications and treatment responses of patients treated on the BFM-95 protocol and modified BFM-95 protocol were then evaluated respectively. Findings : For LBL patients treated with BFM-95 protocol or modified BFM-95 protocol, the complete response, event-free survival, overall survival were similar. Stage 4 myelosuppression was the most common complication in both groups. Besides that, among 31 patients receiving modified BFM-95 protocol, coagulation defects were the most common complication. In contrast, anaphylactic reaction was the most common complication in the other 23 patients receiving BFM-95 protocol.

CONCLUSION

Modified BFM-95 protocol is available to children with advanced-stage LBL with an equal outcome and enhances its compliance and decreases the incidence of anaphylactic reaction, compared to BFM-95 protocol. Coagulation defects are the major complication and tolerable in modified one.

A prospective study on drug monitoring of PEGasparaginase and Erwinia asparaginase and asparaginase antibodies in pediatric acute lymphoblastic leukemia

This study prospectively analyzed the efficacy of very prolonged courses of pegylated Escherichia coli asparaginase (PEGasparaginase) and Erwinia asparaginase in pediatric acute lymphoblastic leukemia (ALL) patients. Patients received 15 PEGasparaginase infusions (2500 IU/m(2) every 2 weeks) in intensification after receiving native E coli asparaginase in induction. In case of allergy to or silent inactivation of PEGasparaginase, Erwinia asparaginase (20 000 IU/m(2) 2-3 times weekly) was given. Eighty-nine patients were enrolled in the PEGasparaginase study. Twenty (22%) of the PEGasparaginase-treated patients developed an allergy; 7 (8%) showed silent inactivation. The PEGasparaginase level was 0 in all allergic patients (grade 1-4). Patients without hypersensitivity to PEGasparaginase had serum mean trough levels of 899 U/L. Fifty-nine patients were included in the Erwinia asparaginase study; 2 (3%) developed an allergy and none silent inactivation. Ninety-six percent had at least 1 trough level ≥100 U/L. The serum asparagine level was not always completely depleted with Erwinia asparaginase in contrast to PEGasparaginase. The presence of asparaginase antibodies was related to allergies and silent inactivation, but with low specificity (64%). Use of native E coli asparaginase in induction leads to high hypersensitivity rates to PEGasparaginase in intensification. Therefore, PEGasparaginase should be used upfront in induction, and we suggest that the dose could be lowered. Switching to Erwinia asparaginase leads to effective asparaginase levels in most patients. Therapeutic drug monitoring has been added to our ALL-11 protocol to individualize asparaginase therapy.