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Validation of an Immunoassay for Anti-thymidine Phosphorylase Antibodies in Patients with MNGIE Treated with Enzyme Replacement Therapy.

Levene, M; Pacitti, D; Gasson, C; Hall, J; Sellos-Moura, M; Bax, BE (2018) Validation of an Immunoassay for Anti-thymidine Phosphorylase Antibodies in Patients with MNGIE Treated with Enzyme Replacement Therapy. Mol Ther Methods Clin Dev, 11. pp. 1-8. ISSN 2329-0501 https://doi.org/10.1016/j.omtm.2018.08.007
SGUL Authors: Bax, Bridget Elizabeth Levene, Michelle Pacitti, Dario

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Abstract

Erythrocyte encapsulated thymidine phosphorylase is recombinant Escherichia coli thymidine phosphorylase encapsulated within human autologous erythrocytes and is under development as an enzyme replacement therapy for the ultra-rare inherited metabolic disorder mitochondrial neurogastrointestinal encephalomyopathy. This study describes the method validation of a two-step bridging electrochemiluminescence immunoassay for the detection of anti-thymidine phosphorylase antibodies in human serum according to current industry practice and regulatory guidelines. The analytical method was assessed for screening cut point, specificity, selectivity, precision, prozone effect, drug tolerance, and stability. Key findings were a correction factor of 129 relative light units for the cut-point determination; a specificity cut point of 93% inhibition; confirmed intra-assay and inter-assay precision; assay sensitivity of 356 ng/mL; no matrix or prozone effects up to 25,900 ng/mL; a drug tolerance of 156 ng/mL; and stability at room temperature for 24 hr and up to five freeze-thaws. Immunogenicity evaluations of serum from three patients who received erythrocyte encapsulated thymidine phosphorylase under a compassionate treatment program showed specific anti-thymidine phosphorylase antibodies in one patient. To conclude, a sensitive, specific, and selective immunoassay has been validated for the measurement of anti-thymidine phosphorylase antibodies; this will be utilized in a phase II pivotal clinical trial of erythrocyte encapsulated thymidine phosphorylase.

Item Type: Article
Additional Information: © 2018 The Authors. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Keywords: MNGIE, assay validation, bridging immunoassay, enzyme replacement therapy, thymidine phosphorylase
SGUL Research Institute / Research Centre: Academic Structure > Molecular and Clinical Sciences Research Institute (MCS)
Journal or Publication Title: Mol Ther Methods Clin Dev
ISSN: 2329-0501
Language: eng
Dates:
DateEvent
14 December 2018Published
28 August 2018Published Online
21 August 2018Accepted
Publisher License: Creative Commons: Attribution 4.0
Projects:
Project IDFunderFunder ID
MR/K025406/1Medical Research Councilhttp://dx.doi.org/10.13039/501100000265
PubMed ID: 30294618
Go to PubMed abstract
URI: https://openaccess.sgul.ac.uk/id/eprint/110090
Publisher's version: https://doi.org/10.1016/j.omtm.2018.08.007

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