L-asparaginase fatal toxic encephalopathy during consolidation treatment in an adult with acute lymphoblastic leukemia

Central nervous system complications during treatment in childhood acute leukemia

OBJECTIVE

Central nervous system (CNS) complications can be seen in patients with leukemia, depending on the disease itself and the chemotherapeutic agents used. This study focused on CNS complications during treatment in children with acute leukemia in a single pediatric institution.

METHODS

CNS complications were evaluated retrospectively in 115 patients with ALL and AML. Patients with CNS leukemia infiltration at the time of diagnosis or during a neurological event, late-onset encephalopathy, peripheral neuropathy, or a previous history of neurological abnormalities were excluded from the study.

RESULTS

A total of 115 children's clinical records with acute leukemia over a four-year period were reviewed. Acute CNS complications developed in 23.1% of acute myeloid leukemia (AML) patients and in 13.5% of acute lymphoblastic leukemia (ALL) patients. CNS complications developed most frequently during the induction phase of the treatment (66.7%). Seizures were the most common symptom (9 patients, 50%), followed by hemiparesis (4 patients, 22.2%) and headache (4 patients, 22.2%). Six patients (33.3%) had chemotherapy-induced toxic leukoencephalopathy, two (11.1%) had Wernicke's encephalopathy, and one patient (5.6%) each had sinus vein thrombosis, posterior reversible encephalopathy syndrome, and CNS infection. Sequelae occurred in three patients (16.7%), and only one patient (5.6%) died due to a CNS complication.

CONCLUSION

A wide variety of symptoms can be observed in childhood leukemia, depending on the disease itself, the chemotherapeutic agents used and a lot of other conditions such as nutritional problems. Our research shows that several CNS complications might manifest with similar symptoms; differentiated diagnosis between the underlying etiological reasons can be made by neuroimaging.

Asparaginase: How to Better Manage Toxicities in Adults

PURPOSE OF REVIEW

This review aims to help oncologists who predominantly treat adults better understand and manage asparaginase associated toxicities and prevent unnecessary discontinuation or reluctance of its use.

RECENT FINDINGS

Given the data supporting the benefit of incorporating multiple doses of asparaginase in pediatric type regimens, it is prudent to promote deeper understanding of this drug, particularly its toxicities, and its use so as to optimize treatment of ALL. Although asparaginase is associated with a variety of toxicities, the vast majority are not life threatening and do not preclude repeat dosing of this important drug. Understanding the pharmacology and toxicity profile of asparaginase is critical to dosing asparaginase appropriately in order to minimize these toxicities.

In vivo stabilization of a less toxic asparaginase variant leads to a durable antitumor response in acute leukemia

Asparagine is a non-essential amino acid since it can either be taken up via the diet or synthesized by asparagine synthetase. Acute lymphoblastic leukemia (ALL) cells do not express asparagine synthetase or express it only minimally, which makes them completely dependent on extracellular asparagine for their growth and survival. This dependency makes ALL cells vulnerable to treatment with L-asparaginase, an enzyme that hydrolyzes asparagine. To date, all clinically approved L-asparaginases have significant L-glutaminase co-activity, associated with non-immune related toxic side effects observed during therapy. Therefore, reduction of L-glutaminase co-activity with concomitant maintenance of its anticancer L-asparaginase effect may effectively improve the tolerability of this unique drug. Previously, we designed a new alternative variant of Erwinia chrysanthemi (ErA; Erwinaze) with decreased L-glutaminase co-activity, while maintaining its L-asparaginase activity, by the introduction of three key mutations around the active site (ErA-TM). However, Erwinaze and our ErA-TM variant have very short half-lives in vivo. Here, we show that the fusion of ErA-TM with an albumin binding domain (ABD)-tag significantly increases its in vivo persistence. In addition, we evaluated the in vivo therapeutic efficacy of ABD-ErA-TM in a B-ALL xenograft model of SUP-B15. Our results show a comparable long-lasting durable antileukemic effect between the standard-of-care pegylated-asparaginase and ABD-ErA-TM L-asparaginase, but with fewer co-glutaminase-related acute side effects. Since the toxic side effects of current L-asparaginases often result in treatment discontinuation in ALL patients, this novel ErA-TM variant with ultra-low L-glutaminase co-activity and long in vivo persistence may have great clinical potential.

Acute central nervous system complications and ammonium levels in adult patients with acute lymphoblastic leukemia receiving l-asparaginase

We analyzed ammonium levels and acute central nervous complications in adult patients receiving chemotherapy for acute lymphoblastic leukemia with or without asparaginase (l-asp). Twenty patients with a median age of 40.3 years were included. Ammonium-levels were measured during 88 chemotherapy cycles, 60 cycles (68%) with l-asp, and 28 cycles (32%) without l-asp. Ammonium was elevated in 87% of all l-asp containing cycles, with median ammonium levels of 169 μmol/l (interquartile range (IQR) 91-269 μmol/l). These values were higher when compared to ammonium levels at baseline (31.5 μmol/l, IQR 24-40 μmol/l, p < .001), and when compared to levels in cycles without l-asp (30 μmol/l, IQR 19-41 μmol/l, p < .001). Acute hyperammonemic encephalopathy was diagnosed in one patient, and encephalopathy for other reasons, but with hyperammonemia as a possible contributing factor in four patients. In conclusion, ammonium levels are elevated in all adult patients receiving l-asparaginase, but only some patients will present symptoms of encephalopathy.

Asparaginase-associated toxicity in children with acute lymphoblastic leukemia

Asparaginase is an integral component of multiagent chemotherapy regimens for the treatment of children with acute lymphoblastic leukemia. Positive outcomes are seen in patients who are able to complete their entire prescribed course of asparaginase therapy. Toxicities associated with asparaginase use include hypersensitivity (clinical and subclinical), pancreatitis, thrombosis, encephalopathy, and liver dysfunction. Depending on the nature and severity of the toxicity, asparaginase therapy may be altered or discontinued in some patients. Clinical hypersensitivity is the most common asparaginase-associated toxicity requiring treatment discontinuation, occurring in up to 30% of patients receiving Escherichia coli-derived asparaginase. The ability to rapidly identify and manage asparaginase-associated toxicity will help ensure patients receive the maximal benefit from asparaginase therapy. This review will provide an overview of the common toxicities associated with asparaginase use and recommendations for treatment management.