Development of an ELISA to detect circulating anti-asparaginase antibodies in dogs with lymphoid neoplasia treated with Escherichia coli l-asparaginase

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.

L-Asparaginase, Doxorubicin, Vincristine, and Prednisolone (LHOP) Chemotherapy as a First-Line Treatment for Dogs with Multicentric Lymphoma

Cyclophosphamide exhibits the weakest therapeutic effect compared with vincristine and doxorubicin in the CHOP (C, cyclophosphamide; H, doxorubicin; O, vincristine; and P, prednisolone) chemotherapeutic protocol for the treatment of canine lymphoma. Twenty dogs with multicentric lymphoma were treated using the LHOP protocol, which used l-asparaginase in place of cyclophosphamide, and the outcomes were historically compared with those of dogs that received CHOP chemotherapy in the same institution. No significant differences were found in age (p = 0.107), body weight (p = 0.051), sex (p = 0.453), clinical stage V (p = 1), substage b (p = 0.573), T-cell phenotype (p = 0.340), overall response (p = 1), and hypercalcaemia status (p = 1) between the LHOP and CHOP groups. The adverse effects of l-asparaginase were well tolerated and self-limiting. The median PFS (progression-free survival) and median ST (survival time) in the LHOP group were 344 days (range: 28-940 days) and 344 days (range: 70-940 days), respectively. The median PFS and median ST in the CHOP group were 234 days (range: 49-1822 days) and 314 days (range: 50-1822 days), respectively. The dogs that received LHOP chemotherapy had a significantly longer PFS than the dogs that received CHOP chemotherapy (p = 0.001). No significant difference was observed in ST between the LHOP and CHOP groups (p = 0.131). Our study findings thus indicate that the LHOP protocol can be used as a first-line chemotherapeutic protocol in canine multicentric lymphoma.

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.

Hypersensitivity reactions associated with L-asparaginase administration in 142 dogs and 68 cats with lymphoid malignancies: 2007-2012

Clinically significant hypersensitivity reactions (HSRs) to the chemotherapy drug L-asparaginase are reported in humans and dogs, but frequency in small animals is not well-defined. This study retrospectively evaluated the frequency of HSR to L-asparaginase given by IM injection to dogs and cats with lymphoid malignancies. The medical records of all dogs and cats treated with at least 1 dose of L-asparaginase chemotherapy over a 5-year period were reviewed. A total of 370 doses of L-asparaginase were administered to the dogs, with 88 of 142 dogs receiving multiple doses, and 6 dogs experiencing an HSR. A total of 197 doses were administered to the cats, with 33 of 68 cats receiving multiple doses, and no cats experiencing an HSR. Hypersensitivity reactions were documented in 4.2% of dogs, and in association with 1.6% of L-asparaginase doses administered. These results show that HSRs occur uncommonly among dogs and cats, even with repeated dosing.