Comparative pharmacokinetic/pharmacodynamic characterisation of a new pegylated recombinant E. coli l-asparaginase preparation (MC0609) in Beagle dog

Evaluation of PEG-L-asparaginase in asparagine suppression and anti-drug antibody development in healthy Beagle dogs: A multi-phase preclinical study

L-asparaginase is a frequently used drug in the treatment of canine malignant lymphoma. Since production and availability of native E. coli-derived L-asparaginase are limited, PEG-L-asparaginase (PEG-ASP) is an alternative. However, recommended doses and dosing intervals are mainly empirically determined. A multi-phase clinical dose-finding study with seven healthy Beagle dogs was conducted to find the minimum effective dose and, potentially, a dosing interval for PEG-ASP in dogs. Plasma concentrations of amino acids and PEG-ASP activity were measured at various time points after administration of different doses of PEG-ASP. Anti-PEG and anti-asparaginase antibody titres were measured. Administration of 10 IU/kg PEG-ASP resulted in asparagine depletion in all dogs, albeit for various durations: for 9 days in all dogs, 15 days in five dogs, 21 days in three dogs and 29 days in one dog. Asparagine suppression occurred at PEG-ASP plasma concentrations < 25 IU/L. Subsequent administrations of a second and third dose of 20 IU/kg and 40 IU/kg PEG-ASP resulted in asparagine suppression at < 9 days in five dogs, accompanied by the development of antibodies against PEG and L-asparaginase. Two dogs with prolonged asparagine suppression after the second and third administration did not develop antibodies. Marked individual variation in the mechanism and duration of response to PEG-ASP was noted. Antibody formation against PEG-ASP was frequently observed and sometimes occurred after one injection. This study suggests that PEG-ASP doses as high as the currently used dose of 40 IU/kg might not be needed in treatment of canine malignant lymphoma.

Improved pharmacokinetic and pharmacodynamic profile of a novel PEGylated native Erwinia chrysanthemi L-Asparaginase

Introduction. Erwinase® (native Erwinia chrysanthemi L-Asparaginase (nErA)) is an approved second-line treatment for acute lymphoblastic leukaemia (ALL) in children and adolescents, who develop hypersensitivity or neutralising antibodies to E.coli derived L-Asparaginases (ASNases). However, nErA has a short in vivo half-life requiring frequent dosing schedules in patients. In this study, nErA was covalently conjugated to PEG molecules with the aim of extending its half-life in vivo. Methods. Firstly, efficacy of this novel product PEG-nErA was investigated on human ALL cell lines (Jurkat, CCRF-CEM and CCRF-HSB2), in vitro. Secondly, its pharmacokinetic (PK) and pharmacodynamic (PD) characteristics were determined, in vivo (12 rats in each group). Results. It was found that the specific activity (U/mg of enzyme) and the kinetic constant (K_M) of nErA remained unaltered post PEGylation. PEG-nErA was shown to have similar cytotoxicity to nErA (IC₅₀: 0.06–0.17 U/mL) on human ALL cell lines, in vitro. Further, when compared to nErA, PEG-nErA showed a significantly improved half-life in vivo, which meant that L-Asparagine (Asn) levels in plasma remained depleted for up to 25 days with a four-fold lower dose (100 U/kg) compared with 72 h for nErA at 400 U/kg dose. Conclusion. Overall, this next generation product PEG-nErA (with improved PK and PD characteristics compared to nErA) would bring a significant advantage to the therapeutic needs of ALL patients and should be further explored in clinical trials.

Efficacy and adverse events of continuous l-asparaginase administration for canine large cell lymphoma of presumed gastrointestinal origin

We examined the efficacy and adverse events of continuous l-asparaginase administration in dogs with large cell lymphoma of presumedgastrointestinal (GI) origin. We retrospectively reviewed medical records of dogs with large cell lymphoma of presumed GI origin treated with continuous l-asparaginase administration from 2009 to 2018. We collected information on the signalment, lesion site, complete blood count, serum biochemical profile, diagnostic imaging findings, cytological and histopathological findings, immunophenotype, l-asparaginase administration frequency, treatment response, adverse events, rescue protocol, and patient outcomes. Clinical outcomes were assessed using medical records or by contacting the owner or referring veterinarian. Thirty-two dogs with large cell lymphoma of presumed GI origin received weekly l-asparaginase administration. The median number of l-asparaginase injections was seven (range: 1-30). Although two of the 32 dogs had GI toxicity of grade 3 or higher, none developed a hypersensitivity reaction. The response rate based on ultrasonographic findings was 18/32 (56%) and that based on clinical signs was 30/32 (94%). The median overall progression-free survival was 50 days (range: 2-214 days), and median overall survival was 147 days (range: 2-482 days). Adverse events associated with continuous l-asparaginase administration were rare. Clinical signs at diagnosis improved in most cases. Based on these results, continuous l-asparaginase administration appears to be a reasonable treatment option for dogs with large cell lymphoma of presumed GI origin.

Development of a Lyophilized Formulation of Pegaspargase and Comparability Versus Liquid Pegaspargase

INTRODUCTION

Pegaspargase, a pegylated asparaginase, is a core component in the treatment of acute lymphoblastic leukemia. Pegaspargase in liquid form has a limited shelf life of 8 months due to depegylation, leading to changes in purity and potency over time. Lyophilization is an approach that can improve the stability of biological drug conjugates.

METHODS

Here we describe the development of a lyophilized formulation of pegaspargase and present results of a series of tests demonstrating that the lyophilized form has comparable physicochemical properties to the liquid form.

RESULTS

Stability tests of critical quality attributes, including purity, potency, aggregates and total free polyethylene glycol, demonstrate that lyophilized pegaspargase remains stable for at least 3 years, with optimum stability achieved with storage under refrigerated conditions (2-8 °C).

CONCLUSIONS

Lyophilization improved the stability of pegaspargase without altering other physicochemical properties, permitting a prolonged shelf life of at least 2 years when stored at 2-8 °C. This may enable greater storage flexibility and allow for better management of pegaspargase.

FUNDING

Study Sponsor: Baxalta (now part of Takeda). Publication Sponsor: Servier Affaires Médicales.