IgG Antibodies Against Polyethylene Glycol (PEG) in Patient with Hemophilia A

In recent years, PEGylated factor VIII (FVIII) has become one of the mainstay therapeutic agents for hemophilia A. In the present study, the frequency and characteristics of anti-PEG IgG antibodies were investigated in 177 hemophilia A patients in Japan. Twenty-five patients (14.1%) were determined to be anti-PEG IgG antibody-positive by ELISA using three PEGylated proteins (Rurioctocog alfa pegol, Damoctocog alfa pegol, and PEGylated BSA) as antigens. The anti-PEG IgG antibody-positive rates in the groups with and without administration of PEGylated therapeutic drugs for hepatitis were 8.2% and 16.4%, respectively. Similarly, the antibody-positive rates in the groups with and without administration of Rurioctocog alpha pegol were 8.7% and 14.9%, respectively, and a causal relationship with history of PEGylated agent use could not be confirmed. The results suggested that anti-PEG IgG antibodies were more commonly observed in younger patients than in older patients, and may be continuously retained. Anti-PEG IgG antibodies did not inhibit the activity of FVIII. In one patient with anti-PEG IgG antibody positivity, the expected recovery rate and half-life-prolonging effect of Rurioctocog alfa pegol were not obtained.