Dose Levels in Particulate-Containing Formulations Impact Anti-drug Antibody Responses to Murine Monoclonal Antibody in Mice

Dosage levels and particulate contents of therapeutic protein formulations are potential factors that impact immunogenicity of protein therapeutics. Here, we evaluated the effect of dose levels on the immunogenicity of protein particulates formed by adsorbing a murine monoclonal IgG2c/κ antibody (mAb1) onto silicone oil microdroplets, glass, or aluminum hydroxide (Alhydrogel®) microparticles. Immune responses to these particulate-containing preparations were compared against responses to solutions of mAb1 that had been ultracentrifuged to minimize particle levels. Formulations containing 5 or 500 μg of adsorbed mAb1 were administered subcutaneously to C57BL/6 J or BALB/c mice. Antidrug antibodies (ADAs) were detected using an isotype-specific enzyme-linked immunosorbent assay (ELISA) method or a chemiluminescence method. Sera from BALB/c mice showed greater ADA responses to administration of particles at the 5-μg dose level than at the 500-μg dose level. In sera from C57BL/6 J mice, ADA levels detected by ELISA were independent of the particle dose levels tested. ADAs were not detected in sera from C57BL/6 J mice performing the chemiluminescence technique. In conclusion, mice administered formulations of a murine antibody adsorbed onto silicone oil microdroplets, glass microparticles, or Alhydrogel® showed greater ADA responses that those that received particle-free mAb1 preparations, and responses were greater for formulations containing lower doses of antibody.