Anti-PEG antibody bioanalysis: a clinical case study with PEG-IFN--1a and PEG-IFN-2a in naive patients

Background: Extensive use of polyethylene glycol (PEG) in consumer products necessitates the assessment of anti-PEG antibodies (APAb). Methods: In clinical trials comparing PEG-IFN- to PEG-IFN-, conventional bridge and direct assays were assessed. Results & Conclusion: The bridge assay detected IgM and IgG APAb reactive with common PEG sizes and derivatives at sufficient sensitivity, 15-500 ng/ml. Of subjects evaluated, 6% of PEG-IFN- and 9% of PEG-IFN- subjects had persistent APAb while 60% of PEG-IFN- and 33% of PEG-IFN- subjects had persistent anti-interferon antibodies (AIAb). Pre-existing APAb and AIAb prevalence was comparable (approximately 10% of subjects). APAb were earlier onset, less frequent, less persistent and lower titer than AIAb. No associated hypersensitivity events were reported.