Clinical Utility of Pegaspargase in Children, Adolescents and Young Adult Patients with Acute Lymphoblastic Leukemia: A Review

How I treat newly diagnosed acute lymphoblastic leukemia

Treatment algorithms differ for adult patients with Philadelphia-negative (Ph-) and Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL). For Ph- ALL intensive induction-consolidation chemotherapy using "pediatric-inspired" protocols is a standard of care. Allogeneic hematopoietic cell transplantation (allo-HCT) from either an HLA-matched sibling, unrelated or haploidentical donor should be considered for patients with high estimated risk of relapse. Inadequate response at the level of measurable residual disease (MRD) is the strongest adverse prognostic factor. Patients with B-ALL and detectable MRD should be treated with blinatumomab. In the future, the use of blinatumomab and/or inotuzumab ozogamycin in addition to first-line chemotherapy may become a new standard of care reducing the role of allo-HCT. For patients with Ph+ ALL, tyrosine kinase inhibitors (TKI) are the most important components of treatment protocols, while the intensity of chemotherapy may be reduced. Allo-HCT is recommended for all patients treated with imatinib along with low-intensity chemotherapy. Results of phase-II studies using front-line dasatinib or ponatinib in sequence or in combination with blinatumomab are very promising. Such a strategy may allow the avoidance of systemic chemotherapy. The future role of allo-HCT in this context appears uncertain.

Retrospective review of the toxicities and change in dosing patterns for pegaspargase in patients with acute lymphoblastic leukemia/lymphoma and T-cell lymphoma

INTRODUCTION

Pegaspargase (PEG) is a key component of standard regimens for acute lymphoblastic leukemia/lymphoma (ALL) and extranodal natural killer/T-cell lymphoma (NKTCL). Emerging evidence suggests an opportunity to decrease incidence of PEG-associated toxicities with dose capping, but evidence is limited. This study aims to evaluate whether a significant difference in PEG-associated toxicities related to dosing strategy exists and to identify patient-specific or regimen-specific factors for PEG-related toxicity.

METHODS

A retrospective analysis of PEG-associated toxicities was completed in adult patients with ALL or NKTCL who received PEG within Cancer and Leukemia Group B (CALGB) 10403 or modified dexamethasone, methotrexate, ifosfamide, L-asparaginase, etoposide (mSMILE) regimens at the UW Medical Center/Fred Hutchinson Cancer Center. PEG-associated toxicities that occurred through 8 weeks after PEG doses were noted.

RESULTS

Twenty-eight patients received dose-capped PEG, and 29 received noncapped PEG. Fewer all-grade and grade 3/4 toxicities were observed in the dose-capped cohort. Grade 3/4 toxicities observed were hepatotoxicity, hyperglycemia, hypersensitivity, and hypertriglyceridemia. In addition, fewer grade 3/4 pancreatitis and thrombosis events occurred in the dose-capped cohort. Hypertriglyceridemia and hepatotoxicity were associated with the highest cumulative incidence proportions among all toxicities.

CONCLUSION

Dose capping of PEG was associated with a similar or later median onset for most toxicities, a less heterogeneic toxicity profile, and a lower recurrence of most toxicities upon PEG rechallenge compared to the non-dose-capped cohort. Standardizing PEG dose capping in the CALGB 10403 and mSMILE regimens may translate to improved tolerance compared to a historical standard of no dose capping PEG.

l-Asparaginase from Solanum lycopersicum as a Nutraceutical for Acute Lymphoblastic Leukemia

l-Asparaginase (E.C. 3.5.1.1) is an indispensable analeptic anticancer enzyme used as an amalgam with additional cancer medicines for the cure of acute lymphoblastic leukemia (ALL). The presence of lAparaginase in tomato was confirmed byWestern blotting and DNA sequencing. The l-Asparaginase gene from tomato has been deposited in the NCBI database with accession number: OR736141. Crude enzyme was extracted from the fruit pulp of Solanum lycopersicum, and the activity was determined by the Nesslerization method. Further, the crude extract was subjected to purification, and kinetic parameters were studied. The percentage yield was calculated to be 6.457, and the purification fold was 0.086. The enzyme showed maximum activity at optimum pH 7.0, optimum temperature 37 °C, and incubation time of 05 min. The Michaelis constant "Km" and maximum velocity "Vmax" values were determined by the Lineweaver-Burk plot, which showed a low Km value of 0.66 and Vmax of 3.846 IU. Cytotoxic studies were carried out for crude and purified l-asparaginase. Purified l-Asparaginase has exhibited anticancer activity against the ALL model system, K-562 cell line, comparable to that of the anticancer compound vinblastine. Hence, l-Asparaginase from the fruit extract of tomato could be used as a nutraceutical to support cancer treatment in acute lymphoblastic leukemia.

Impact of medical insurance access negotiation on the utilization of innovative anticancer drugs in China: an interrupted time series analysis

BACKGROUND

The high costs of innovative anticancer drugs hinder a number of cancer patients' access to these drugs in China. To address this problem, in 2018, the medical insurance access negotiation (MIAN) policy was implemented, when the prices of 17 innovative anticancer drugs were successfully negotiated and they were therefore included in the reimbursement list. This study aimed to explore the impact of the MIAN policy on the utilization of innovative anticancer drugs.

METHODS

With monthly data on drug expenditures and defined daily doses (DDDs) of each innovative anticancer drug from January 2017 to December 2019, interrupted time series analysis was employed to estimate both the instant (change in the level of outcome) and long-term (change in trends of outcomes) impacts of the MIAN policy on drug utilization in terms of drug expenditures and DDDs. Our sample consists of 12 innovative anticancer drugs.

RESULTS

From January 2017 to December 2019, the monthly drug expenditures and DDDs of 12 innovative anticancer drugs increased by about 573% (from US$8,931,809.30 to US$51,138,331.09) and 1400% (from 47,785 to 668,754), respectively. Overall, the implementation of the MIAN policy led to instant substantial increases of US$8,734,414 in drug expenditures and 158,192.5 in DDDs. Moreover, a sharper upward trend over time was reported, with increases of US$2,889,078 and 38,715.3 in the monthly growth rates of drug expenditures and DDDs, respectively. Regarding individual innovative anticancer drugs, the most prominent instant change and trend change in drug utilization were found for osimertinib, crizotinib, and ibrutinib. In contrast, the utilization of pegaspargase was barely affected by the MIAN policy.

CONCLUSIONS

The MIAN policy has effectively promoted the utilization of innovative anticancer drugs. To ensure the continuity of the effects and eliminate differentiation, supplementary measures should be carried out, such as careful selection of drugs for medical insurance negotiations, a health technology assessment system and a multichannel financing mechanism.

Asparaginase-associated Pancreatitis Complicated by Pancreatic Fluid Collection Treated with Endoscopic Cistogastrostomy in Pediatric Acute Lymphoblastic Leukemia: A Case Report and Systematic Review of the Literature

Asparaginase-associated pancreatitis complicates 2-10% of patients treated for acute lymphoblastic leukemia, causing morbidity and discontinuation of asparaginase administration. Among acute complications, pancreatic fluid collections can be managed conservatively, but intervention is indicated when associated with persistent insulin therapy need and recurrent abdominal pain. Endoscopic treatment has become the standard approach in adult patients, with increasing favorable evidence in children. This work compares the characteristics of a pediatric oncology patient treated at our institution with reported literature experiences, showing feasibility, safety and effectiveness of endoscopic approach.

Asparaginase dosing for obese patients with acute lymphoblastic leukemia and factors that contribute to outcomes

Asparaginase in various forms is a standard part of the treatment of acute lymphoblastic leukemia (ALL) in children and adolescents. However, its use is more selective in adults. One of the key reasons is the toxicity observed from this class of agents. In a series of recent post hoc analyses of large prospective studies, obesity has emerged as a key factor that contributes to the challenges with administering regimens that include asparaginase. In this review, the most salient findings are highlighted from these latest publications, both from the pediatric and adult literature. These data are consolidated into recommendations for clinicians who treat adults with ALL, including proposals for how treatment may be modified to try to account for these complications. Lastly, avenues for future investigation are proposed in an attempt to narrow our knowledge gaps in this field, with the goal of safer and more effective treatment for adults with obesity who develop ALL.

Pegylated-l-asparaginase therapy for feline large cell lymphoma: 82 cases (2017-2020)

OBJECTIVES

The present study aimed to investigate pegylated-l-asparaginase monotherapy for feline large cell lymphoma as a potential alternative to palliative corticosteroids treatment in animals whose owners declined cytotoxic chemotherapy.

METHODS

A retrospective, descriptive case series of cats treated initially with pegylated-l-asparaginase as a sole therapy for feline large cell lymphoma is reported. The treatment protocol consisted of 12 intramuscular injections of pegylated-l-asparaginase with increasing intervals. If cats were unresponsive to pegylated-l-asparaginase monotherapy, a second-line treatment was initiated. Signalment, origin of lymphoma, staging, treatment, possible adverse events and follow-up data were extracted from the medical records. Responses and survival data were analysed.

RESULTS

Eighty-two cats with lymphoma of five different anatomic types were included: alimentary, abdominal extra-alimentary, peripheral nodal, nasal/nasopharyngeal and other (mediastinal, renal [solitary] and miscellaneous combined in one group for analytical purposes). The response rate was 74.1% (95% confidence interval = 63.4-83.5) with 38.3% (95% confidence interval = 27.8-48.8) in complete remission. The median disease-free period and calculated overall survival time were 70 days (12-1702+) and 79 days (1-1715+), respectively. The response rate was significantly correlated with the origin of the lymphoma and the combined group had a significantly lower response rate (P = 0.035). Twenty-four cats were also treated with corticosteroids. There was no significant difference in outcomes between the group treated with or without corticosteroids. Adverse events were present in a small number of cats (14/82). The majority of these adverse events were mild to moderate in 5/14 cats; however, the adverse events were severe enough to cause discontinuation of therapy.

CONCLUSIONS AND RELEVANCE

Based on the response rate and median disease-free period, treatment with pegylated-l-asparaginase is inferior when compared with historical chemotherapy protocols. However, some cats demonstrated an exceptional long disease-free period. Therefore, pegylated-l-asparaginase could be offered as an alternative to corticosteroid therapy alone. Further studies are needed to evaluate the additional benefit over palliative corticosteroid monotherapy.

Can pharmacy students use Wikipedia as a learning resource? Critical assessment of articles on chemotherapeutic drugs

Pharmacy students tend to use Wikipedia as a quick resource of knowledge. This study aimed to evaluate the accuracy of content and readability level of Wikipedia articles on chemotherapeutics, using quality and readability tools. Using the British National Formulary (BNF-2018) and ClinicalTrials.gov, we identified 188 chemotherapeutic drugs. We randomly selected 100 drugs with an Excel randomization program. The English Wikipedia was searched for the selected 100 drugs, and prints of the identified articles were obtained. Readability was calculated with an online instrument (http://www.readabilityformulas.com/). Articles were independently scored by two researchers using the modified DISCERN tool for content assessment. The modified DISCERN scores had a median value of 24 [interquartile range (IQR) = 7.5]. Two articles (2%) had good quality (DISCERN score 36-40), thirty-eight (38%) were moderate (DISCERN 26-35), and sixty (60%) were poor in score (DISCERN ≤25). The articles covered drug indications and most side effects. However, the majority lacked information on the routes of administration, contraindications, pharmacokinetics, and mechanisms of action. We found a correlation between DISCERN scores and number of edits (P value = 0.00033, R² = 0.1238). The number of references varied from 2 to 150 (median= 17, IQR = 17). Several problems were identified in the lists of references and citations. Most articles lacked tables and figures. The readability of the articles was 14.35 ± 3.13, consistent with the readability level of university students. In conclusion, the Wikipedia articles on chemotherapeutic drugs were not written for professional pharmacy students. Although they matched the expected readability level of university students, most were incomplete and lacked essential information.NEW & NOTEWORTHY Pharmacy students use Wikipedia as a quick resource of knowledge. However, Wikipedia articles are not written for professional pharmacy students. The study shows that although Wikipedia articles on chemotherapeutic drugs matched the expected readability level of university students, most needed to be completed and lacked essential information.

PEG-asparaginase treatment regimens for acute lymphoblastic leukaemia in children: a network meta-analysis

BACKGROUND

Asparaginase has played a crucial role in the improvement of survival in children with acute lymphoblastic leukaemia (ALL), which is the commonest cancer among children. Survival rates have steadily increased over decades since the introduction of asparaginase to ALL therapy, and overall survival rates reach 90% with the best contemporary protocols. Currently, polyethylene glycolated native Escherichia coli-derived L-asparaginase (PEG-asparaginase) is the preferred first-line asparaginase preparation. Besides its clinical benefits, PEG-asparaginase is well known for severe toxicities. Agreement on the optimal dose, treatment duration, and frequency of administration has never been reached among clinicians.

OBJECTIVES

Primary objective To assess the effect of the number of PEG-asparaginase doses on survival and relapse in children and adolescents with ALL. Secondary objectives To assess the association between the number of doses of PEG-asparaginase and asparaginase-associated toxicities (e.g. hypersensitivity, thromboembolism, pancreatitis and osteonecrosis). To undertake a network meta-analysis at dose-level in order to generate rankings of the number of doses of PEG-asparaginase used in the treatment for ALL, according to their benefits (survival and relapse) and harms (toxicity).

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, Web of Science databases and three trials registers in November 2021, together with reference checking, citation searching and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different PEG-asparaginase treatment regimens in children and adolescents (< 18 years of age) with first-line ALL treated with multiagent chemotherapy including PEG-asparaginase.

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 a standardised tool (RoB 2.0) and assessed the certainty of evidence for each outcome using the GRADE approach. Primary outcomes included overall survival, event-free survival and leukaemic relapse. Secondary outcomes included asparaginase-associated toxicities (hypersensitivity, thromboembolism, pancreatitis, sinusoidal obstruction syndrome and osteonecrosis as well as overall asparaginase-associated toxicity). We conducted the review and performed the analyses in accordance with the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included three RCTs in the review, and identified an additional four ongoing studies. We judged outcomes of two RCTs to be at low risk of bias in all the Cochrane risk of bias (RoB 2) domains. We rated the remaining study as having some concerns regarding bias. Due to concerns about imprecision, we rated all outcomes as having low- to moderate-certainty evidence.  One study compared intermittent PEG-asparaginase treatment (eight doses of PEG-asparaginase, 1000 IU/m2, intramuscular (IM) administration) versus continuous PEG-asparaginase treatment (15 doses of PEG-asparaginase, 1000 IU/m2, IM) in 625 participants with non-high risk ALL aged 1.0 to 17.9 years. We found that treatment with eight doses probably results in little to no difference in event-free survival compared to treatment with 15 doses (RR 1.01, 95% CI 0.97 to 1.06; moderate-certainty evidence). Compared to treatment with 15 doses, treatment with eight doses may result in either no difference or a slight reduction in hypersensitivity (RR 0.64, 95% CI 0.21 to 1.93; low-certainty evidence), thromboembolism (RR 0.55, 95% CI 0.22 to 1.36; low-certainty evidence) or osteonecrosis (RR 0.68, 95% CI 0.35 to 1.32; low-certainty evidence). Furthermore, we found that treatment with eight doses probably reduces pancreatitis (RR 0.31, 95% CI 0.12 to 0.75; moderate-certainty evidence) and asparaginase-associated toxicity (RR 0.53, 95% CI 0.35 to 0.78; moderate-certainty evidence) compared to treatment with 15 doses. One study compared low-risk standard treatment with additional PEG-asparaginase (six doses, 2500 IU/m2, IM) versus low-risk standard treatment (two doses, 2500 IU/m2, IM) in 1857 participants aged one to nine years old with standard low-risk ALL. We found that, compared to treatment with two doses, treatment with six doses probably results in little to no difference in overall survival (RR 0.99, 95% CI 0.98 to 1.00; moderate-certainty evidence) and event-free survival (RR 1.01, 95% CI 0.99 to 1.04; moderate-certainty evidence), and may result in either no difference or a slight increase in osteonecrosis (RR 1.65, 95% CI 0.91 to 3.00; low-certainty evidence). Furthermore, we found that treatment with six doses probably increases hypersensitivity (RR 12.05, 95% CI 5.27 to 27.58; moderate-certainty evidence), pancreatitis (RR 4.84, 95% CI 2.15 to 10.85; moderate-certainty evidence) and asparaginase-associated toxicity (RR 4.49, 95% CI 3.05 to 6.59; moderate-certainty evidence) compared to treatment with two doses. One trial compared calaspargase (11 doses, 2500 IU/m2, intravenous (IV)) versus PEG-asparaginase (16 doses, 2500 IU/m2, IV) in 239 participants aged one to 21 years with standard- and high-risk ALL and lymphoblastic lymphoma. We found that treatment with 11 doses of calaspargase probably results in little to no difference in event-free survival compared to treatment with 16 doses of PEG-asparaginase (RR 1.06, 95% CI 0.97 to 1.16; moderate-certainty evidence). However, treatment with 11 doses of calaspargase probably reduces leukaemic relapse compared to treatment with 16 doses of PEG-asparaginase (RR 0.32, 95% CI 0.12 to 0.83; moderate-certainty evidence). Furthermore, we found that treatment with 11 doses of calaspargase results in either no difference or a slight reduction in hypersensitivity (RR 1.17, 95% CI 0.64 to 2.13; low-certainty evidence), pancreatitis (RR 0.85, 95% CI 0.47 to 1.52; low-certainty evidence), thromboembolism (RR 0.83, 95% CI 0.48 to 1.42; low-certainty evidence), osteonecrosis (RR 0.63, 95% CI 0.15 to 2.56; low-certainty evidence) and asparaginase-associated toxicity (RR 1.00, 95% CI 0.71 to 1.40; low-certainty evidence) compared to treatment with 16 doses of PEG-asparaginase.

AUTHORS' CONCLUSIONS

We were not able to conduct a network meta-analysis, and could not draw clear conclusions because it was not possible to rank the interventions. Overall, we found that different numbers of doses of PEG-asparaginase probably result in little to no difference in event-free survival across all studies. In two studies, we found that a higher number of PEG-asparaginase doses probably increases pancreatitis and asparaginase-associated toxicities.

The anticancer effect of PASylated calreticulin-targeting L-ASNase in solid tumor bearing mice with immunogenic cell death-inducing chemotherapy

L-Asparaginase (L-ASNase), a bacterial enzyme that degrades asparagine, has been commonly used in combination with several chemical drugs to treat malignant hematopoietic cancers such as acute lymphoblastic leukemia (ALL). In contrast, the enzyme was known to inhibit the growth of solid tumor cells in vitro, but not to be effective in vivo. We previously reported that two novel monobodies (CRT3 and CRT4) bound specifically with calreticulin (CRT) exposed on tumor cells and tissues during immunogenic cell death (ICD). Here, we engineered L-ASNases conjugated with monobodies at the N-termini and PAS200 tags at the C-termini (CRT3LP and CRT4LP). These proteins were expected to possess four monobody and PAS200 tag moieties, which did not disrupt the L-ASNase conformation. These proteins were expressed 3.8-fold more highly in E. coli than those without PASylation. The purified proteins were highly soluble, with much greater apparent molecular weights than expected ones. Their affinity (Kd) against CRT was about 2 nM, 4-fold higher than that of monobodies. Their enzyme activity (∼6.5 IU/nmol) was similar to that of L-ASNase (∼7.2 IU/nmol), and their thermal stability was significantly increased at 55 °C. Their half-life times were > 9 h in mouse sera, about 5-fold longer than that of L-ASNase (∼1.8 h). Moreover, CRT3LP and CRT4LP bound specifically with CRT exposed on tumor cells in vitro, and additively suppressed the tumor growth in CT-26 and MC-38 tumor-bearing mice treated with ICD-inducing drugs (doxorubicin and mitoxantrone) but not with a non-ICD-inducing drug (gemcitabine). All data indicated that PASylated CRT-targeted L-ASNases enhanced the anticancer efficacy of ICD-inducing chemotherapy. Taken together, L-ASNase would be a potential anticancer drug for treating solid tumors.

Recombinant Erwinia asparaginase (JZP458) in acute lymphoblastic leukemia: results from the phase 2/3 AALL1931 study

AALL1931, a phase 2/3 study conducted in collaboration with the Children's Oncology Group, investigated the efficacy and safety of JZP458 (asparaginase erwinia chrysanthemi [recombinant]-rywn), a recombinant Erwinia asparaginase derived from a novel expression platform, in patients with acute lymphoblastic leukemia/lymphoblastic lymphoma who developed hypersensitivity/silent inactivation to Escherichia coli-derived asparaginases. Each dose of a pegylated E coli-derived asparaginase remaining in patients' treatment plan was substituted by 6 doses of intramuscular (IM) JZP458 on Monday/Wednesday/Friday (MWF). Three regimens were evaluated: cohort 1a, 25 mg/m2 MWF; cohort 1b, 37.5 mg/m2 MWF; and cohort 1c, 25/25/50 mg/m2 MWF. Efficacy was evaluated by the proportion of patients maintaining adequate nadir serum asparaginase activity (NSAA ≥0.1 IU/mL) at 72 hours and at 48 hours during the first treatment course. A total of 167 patients were enrolled: cohort 1a (n = 33), cohort 1b (n = 83), and cohort 1c (n = 51). Mean serum asparaginase activity levels (IU/mL) at 72 hours were cohort 1a, 0.16, cohort 1b, 0.33, and cohort 1c, 0.47, and at 48 hours were 0.45, 0.88, and 0.66, respectively. The proportion of patients achieving NSAA ≥0.1 IU/mL at 72 and 48 hours in cohort 1c was 90% (44/49) and 96% (47/49), respectively. Simulated data from a population pharmacokinetic model matched the observed data well. Grade 3/4 treatment-related adverse events occurred in 86 of 167 (51%) patients; those leading to discontinuation included pancreatitis (6%), allergic reactions (5%), increased alanine aminotransferase (1%), and hyperammonemia (1%). Results demonstrate that IM JZP458 at 25/25/50 mg/m2 MWF is efficacious and has a safety profile consistent with other asparaginases. This trial was registered at www.clinicaltrials.gov as #NCT04145531.

Case report: Hyperosmolar hyperglycemic syndrome secondary to PEG-asparaginase-induced hypertriglyceridemia and pancreatitis

Pegylated (PEG)-asparaginase is an established treatment for acute lymphoblastic leukemias that exhibits an antitumor effect by depleting asparagine, an amino acid essential for leukemia cell protein synthesis. Pancreatitis with hypertriglyceridemia is a well-established toxidrome associated with PEG-asparaginase. However, impaired pancreatic synthetic function and hormone release have rarely been reported as a result of PEG-asparaginase pancreatitis. In this report, we present a 22-year-old woman recently diagnosed with T-acute lymphoblastic leukemia (T-ALL), who presented to the hospital with progressive weakness, confusion, blurry vision, hallucinations, and abdominal pain after induction treatment with daunorubicin, vincristine, PEG-asparaginase, and dexamethasone following the AYA protocol. She was found to have hypertriglyceridemia, acute pancreatitis, and hyperosmolar hyperglycemic syndrome. While pancreatitis and hypertriglyceridemia are commonly reported side effects of PEG-asparaginase, HHS related to these conditions has been sparsely reported. Providers should maintain awareness of this association and consider routine serial glucose monitoring of patients receiving PEG-asparaginase.

Allogeneic hematopoietic stem cell transplantation overcome the poor prognosis of patients with IKZF1plus CD20-a very high-risk subtype in B-cell acute lymphoblastic leukemia

Genetic deletions of IKZF1 (IKZF1^del) and IKZF1^del plus other mutations (IKZF1^plus) have been identified in B-cell acute lymphoblastic leukemia (B-ALL) with a poor prognosis. Herein, we investigated the combination of IKZF1^del and CD20 immunotypes in adult patients with B-ALL in the PDT-ALL-2016 cohort. This study cohort consisted of 161 patients with B-ALL with detailed information on IKZF1^del and CD20 expression. The independent cohort included 196 patients from the TARGET dataset. IKZF1^del was detected in 36.0% of patients with 3-year event-free survival (EFS) of 37.1 ± 6.7% and overall survival (OS) of 51.5 ± 7.3%, compared to IKZF1 wild-type (IKZF1^wt) with an EFS 55.3 ± 5.1% (P = 0.011) and OS 74.4 ± 4.5% (P = 0.013), respectively. CD20-positive (CD20⁺) was associated with inferior EFS compared to the CD20-negative (CD20^-) group (P = 0.020). Furthermore, IKZF1^del coupled with CD20+, IKZF1^del/CD20⁺, comprised 12.4% of patients with a 3-year EFS of 25.0 ± 9.7%, compared with IKZF1^wt/CD20^- (P ≤ 0.001) and IKZF1^del/CD20^- (P = 0.047) groups. Multivariable analyses demonstrated the independence of IKZF1^del/CD20⁺, with the highest predicted hazard ratio for EFS and OS. Furthermore, the prognostic panel of IKZF1^del/CD20⁺ was confirmed in the TARGET cohort. Notably, neither the IKZF1^del, CD20⁺, or IKZF1^del/CD20⁺ groups were identified to have poor outcomes in the cohort of allogeneic hematopoietic stem cell transplantation (n = 81).Collectively, our data define IKZF1^del/CD20⁺ as a very high-risk subtype in B-ALL, and allo-HSCT could abrogate the poor outcome of both IKZF1^del and IKZF1^del/CD20⁺ subsets.

Pegylated asparaginase in feline high-grade lymphoma: clinical results of single injection and continued incorporation into a modified COP regimen

OBJECTIVES

The aim of this retrospective study was to determine the response to a single injection of pegylated asparaginase ('pegaspargase') and to assess the tolerability and outcome of prolonged incorporation of pegaspargase into a modified COP (cyclophosphamide, vincristine, prednisolone) regimen in pegaspargase sensitive cats.

METHODS

Fifty-six client-owned cats with confirmed macroscopic high-grade lymphoma at any anatomical site were included. Treatment was commenced with a single pegaspargase injection. Cats showing an objective response were eligible to continue therapy with pegaspargase incorporated into a modified COP protocol and had their survival analysed using the Kaplan-Meier method and log-rank test.

RESULTS

Objective response to pegaspargase was reported in 46 cats (82%), including 21 (38%) complete and 25 (44%) partial responses. Thirty-four responders continued therapy with pegaspargase-COP as the first-line treatment. Of these, 31 cats (92%) achieved complete remission with a median duration of the first remission (disease-free survival [DFS]) of 816 days. The median overall survival time (OST) for all 34 cats treated with pegaspargase-COP was 181 days. Response to the initial pegaspargase injection before COP initiation was significantly associated with DFS (P = 0.04) and OST (P = 0.001). Median DFS/OST for cats with complete response to initial pegaspargase injection was significantly longer compared with those with partial remission (>1273 days/>2066 days vs 77 days/108 days, respectively). Cats with gastric lymphoma showed a significantly longer survival (OST 854 days, 1- and 2-year survival rate 57.1%) compared with cats with intestinal lymphoma (OST 102 days, 1-year survival rate 0%). The pegaspargase-COP protocol was generally well tolerated, but two deaths were likely attributable to treatment-related toxicity during the maintenance phase. Importantly, none of the cats experienced hypersensitivity, despite multiple repeated treatments with pegaspargase.

CONCLUSION AND RELEVANCE

Pegaspargase is an effective agent for feline lymphoma. Its incorporation into a COP chemotherapy protocol may confer a survival benefit, especially in cats with complete response to pegaspargase. Treatment is generally well tolerated, but careful monitoring is recommended. Further studies are required to assess the benefits of pegaspargase as monotherapy or as part of different multi-agent chemotherapy regimens.

Asparaginase in the Treatment of Acute Lymphoblastic Leukemia in Adults: Current Evidence and Place in Therapy

Acute lymphoblastic leukemia (ALL) is a rare hematologic malignancy resulting in the production of abnormal lymphoid precursor cells. Occurring in B-cell and T-cell subtypes, ALL is more common in children, comprising nearly 30% of pediatric malignancies, but also constitutes 1% of adult cancer diagnoses. Outcomes are age-dependent, with five-year overall survival of greater than 90% in children and less than 20% in older adults. L-asparaginase, an enzyme not found in humans, depletes serum levels of L-asparagine. As leukemic cells are unable to synthesize this amino acid, its deprivation results in cell death. The success of asparaginase-containing regimens in the treatment of pediatric ALL, and poor outcomes with conventional cytotoxic regimens in adults, have led to trials of pediatric or pediatric-inspired regimens incorporating asparaginase in the adolescent and young adult (AYA) and adult populations. Initially purified from Escherichia coli, newer formulations of asparaginase have been developed to address short half-life, high immunogenic potential, and manufacturing difficulties. Unfamiliarity with asparaginase use and management of its unique toxicities may result in treatment-decisions that negatively impact outcomes. In this review, we address the current use of asparaginase in the treatment of ALL, with an emphasis on its role in the treatment of adults, key clinical trials, recognition and management of toxicities, and ongoing directions of study.

Gut and liver involvement in pediatric hematolymphoid malignancies

Hematolymphoid malignancies are common neoplasms in childhood. The involvement of the gastrointestinal (GI) tract, liver, biliary system, pancreas, and peritoneum are closely interlinked and commonly encountered. In leukemias, lymphomas, and Langerhans cell histiocytosis (LCH), the manifestations result from infiltration, compression, overwhelmed immune system, and chemotherapy-induced drug toxicities. In acute leukemias, major manifestations are infiltrative hepatitis, drug induced gastritis, neutropenic typhlitis and chemotherapy related pancreatitis. Chronic leukemias are rare. Additional presentation in lymphomas is cholestasis due to infiltration or biliary obstruction by lymph nodal masses. Presence of ascites needs a thorough workup for the underlying pathophysiology that may modify the therapy and affect the outcome. Uncommon hematolymphoid malignancies are primary hepatic, hepatosplenic, and GI lymphomas which have strict definitions. In advanced diseases with extensive spread, it may be impossible to distinguish these diseases from the primary site of origin. LCH produces biliary strictures that mimic as sclerosing cholangitis. Liver infiltration is associated with poor liver recovery even after chemotherapy. The heterogeneity of gut and liver manifestations in hematolymphoid malignancies has a clinical impact on their management. Though chemotherapy is the mainstay of therapy in all hematolymphoid malignancies, debulking surgery and radiotherapy have an adjuvant role in specific clinical scenarios. Rare situations presenting as liver failure or end-stage liver disease require liver transplantation. At their initial presentation to a primary care physician, given the ambiguity in clinical manifestations and the prognostic difference with time-bound management, it is vital to recognize them early for optimal outcomes. Pooled data from robust registries across the world is required for better understanding of these complications.

Novel Insights on the Use of L-Asparaginase as an Efficient and Safe Anti-Cancer Therapy

Simple Summary

L-asparaginase (L-ASNase) therapy is key for achieving the very high cure rate of pediatric acute lymphoblastic leukemia (ALL), yet its use is mostly confined to this indication. One main reason preventing the expansion of today’s FDA-approved L-ASNases to solid cancers is their high toxicity and side effects, which become especially challenging in adult patients. The design of optimized L-ASNase molecules provides opportunities to overcome these unwanted toxicities. An additional challenge to broader application of L-ASNases is how cells can counter the pharmacological effect of this drug and the identification of L-ASNases resistance mechanisms. In this review, we discuss recent insights into L-ASNase adverse effects, resistance mechanisms, and how novel L-ASNase variants and drug combinations can expand its clinical applicability, with a focus on both hematological and solid tumors.

Abstract

L-Asparaginase (L-ASNase) is an enzyme that hydrolyses the amino acid asparagine into aspartic acid and ammonia. Systemic administration of bacterial L-ASNase is successfully used to lower the bioavailability of this non-essential amino acid and to eradicate rapidly proliferating cancer cells with a high demand for exogenous asparagine. Currently, it is a cornerstone drug in the treatment of the most common pediatric cancer, acute lymphoblastic leukemia (ALL). Since these lymphoblasts lack the expression of asparagine synthetase (ASNS), these cells depend on the uptake of extracellular asparagine for survival. Interestingly, recent reports have illustrated that L-ASNase may also have clinical potential for the treatment of other aggressive subtypes of hematological or solid cancers. However, immunogenic and other severe adverse side effects limit optimal clinical use and often lead to treatment discontinuation. The design of optimized and novel L-ASNase formulations provides opportunities to overcome these limitations. In addition, identification of multiple L-ASNase resistance mechanisms, including ASNS promoter reactivation and desensitization, has fueled research into promising novel drug combinations to overcome chemoresistance. In this review, we discuss recent insights into L-ASNase adverse effects, resistance both in hematological and solid tumors, and how novel L-ASNase variants and drug combinations can expand its clinical applicability.