Fc-Mediated Anomalous Biodistribution of Therapeutic Antibodies in Immunodeficient Mouse Models

Abstract

A critical benchmark in the development of antibody-based therapeutics is demonstration of efficacy in preclinical mouse models of human disease, many of which rely on immunodeficient mice. However, relatively little is known about how the biology of various immunodeficient strains impacts the in vivo fate of these drugs. Here we used immunoPET radiotracers prepared from humanized, chimeric and murine monoclonal antibodies against four therapeutic oncologic targets to interrogate their biodistribution in four different strains of immunodeficient mice bearing lung, prostate, and ovarian cancer xenografts. The immunodeficiency status of the mouse host as well as both the biological origin and glycosylation of the antibody contributed significantly to the anomalous biodistribution of therapeutic monoclonal antibodies in an Fc receptor-dependent manner. These findings may have important implications for the preclinical evaluation of Fc-containing therapeutics and highlight a clear need for biodistribution studies in the early stages of antibody drug development.

WITHDRAWN: Positron Emission Tomographic imaging of tumor cell death using Zirconium-89-labeled APOMAB® following cisplatin chemotherapy in lung and ovarian cancer xenograft models

“…3D). As has been shown in other studies of immuno-incompetent NSG mice receiving radiolabeled antibodies [35][36][37], signi cant accumulation of activity in the spleens of A2780 tumor-bearing mice was observed, regardless of prior chemotherapy.…”

The Impact of FcγRI Binding on Immuno-PET

“…Activity measurements were made using a CRC-15R Dose Calibrator (Capintec), and experimental samples were counted on an Automatic Wizard 3 g-counter (Perkin-Elmer). The synthesis, purification, electrophoresis, matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry, and lectin culinaris agglutinin (LCA) blot analysis of DFO-nss trastuzumab, DFO-nss trastuzumab-PNGaseF, DFO-nss trastuzumab-EndoS, and DFO-ss trastuzumab-EndoS were performed according to previously published methods (17)(18)(19)(20). Likewise, the radiolabeling and stability analysis of the 89 Zr-labeled radioimmunoconjugates were performed according to established protocols (21).…”

“…To this end, we turned to a highly immunodeficient strain: NOD scid g-(NOD.Cg-Prkdc scid Il2rg tm1Wjl /SzJ), or NSG, mice. This strain of mice lacks endogenous immunoglobulins that can compete with radioimmunoconjugates for unoccupied mFcgRI on myeloid cells such as monocytes, neutrophils, and eosinophils, as well as tissueresident macrophages in the liver, spleen, and bone (18).…”

Pharmacokinetic and Pharmacodynamic Considerations in the Design of Therapeutic Antibodies

“…Consequently, glycoengineering (modifying glycosylation patterns) and protein engineering (modifying the amino acid sequence using display libraries and/or structure‐guided design) have been adopted to either enhance or reduce/abrogate Fc effector function depending on the desired therapeutic activity of the mAb. Because the screening for Fc activity of IgG mAbs is performed in vitro (such as ADCC, ADCP, and CDC assays) as well as in vivo (such as antitumor efficacy in murine models or toxicology studies in nonhuman primates), the species differences in expression of FcγRs and in affinities should be taken into account, because they can complicate the contribution of Fc activity, and the clinical translation of preclinical activity …”

“…Because the screening for Fc activity of IgG mAbs is performed in vitro (such as ADCC, ADCP, and CDC assays) as well as in vivo (such as antitumor efficacy in murine models or toxicology studies in nonhuman primates), the species differences in expression of FcγRs and in affinities should be taken into account, because they can complicate the contribution of Fc activity, and the clinical translation of preclinical activity. [76][77][78] Enhancing Fc effector functions. Enhanced Fc-mediated effector functions are highly desirable when the removal of the mAb-targeted cell is crucial to clinical efficacy, such as tumor cells or virally infected cells.…”