Anti-CD20/CD3 T cell–dependent bispecific antibody for the treatment of B cell malignancies

Abstract

Bispecific antibodies and antibody fragments in various formats have been explored as a means to recruit cytolytic T cells to kill tumor cells. Encouraging clinical data have been reported with molecules such as the anti-CD19/CD3 bispecific T cell engager (BiTE) blinatumomab. However, the clinical use of many reported T cell-recruiting bispecific modalities is limited by liabilities including unfavorable pharmacokinetics, potential immunogenicity, and manufacturing challenges. We describe a B cell-targeting anti-CD20/CD3 T cell-dependent bispecific antibody (CD20-TDB), which is a full-length, humanized immunoglobulin G1 molecule with near-native antibody architecture constructed using "knobs-into-holes" technology. CD20-TDB is highly active in killing CD20-expressing B cells, including primary patient leukemia and lymphoma cells both in vitro and in vivo. In cynomolgus monkeys, CD20-TDB potently depletes B cells in peripheral blood and lymphoid tissues at a single dose of 1 mg/kg while demonstrating pharmacokinetic properties similar to those of conventional monoclonal antibodies. CD20-TDB also exhibits activity in vitro and in vivo in the presence of competing CD20-targeting antibodies. These data provide rationale for the clinical testing of CD20-TDB for the treatment of CD20-expressing B cell malignancies.

CODV-Ig, a universal bispecific tetravalent and multifunctional immunoglobulin format for medical applications

“…Engineering interaction with FcRn gives control over the pharmacokinetic/pharmacodynamic profiles of biotherapeutic drugs, whether linear or non-linear pharmacokinetics will determine clearance. 29,33,34,69,70 Thereby administration and dosing strategy can be tailored in function of disease requirements, which may differ widely in chronic and ad-hoc treatments. Systematic pharmacokinetic studies show that increased FcRn affinity leads to increased elimination half-life of IgGs; however, modulation of in vitro affinity does not result in predictive modification of the in vivo elimination profile.…”

“…As a consequence, they may have extended serum half-lifes by endocytic salvage via neonatal FcR (FcRn), which may compensate for slow tissue penetration. [30][31][32][33][34][35] Furthermore, they may elicit antibody-dependent cell-mediated cytotoxicity or phagocytosis (ADCC or ADCP, respectively) via Fcg receptors (FcgRs), which is important for cancer biotherapeutics. 3,[36][37][38][39] Fully functional Fc domains may also confer the potential to trigger the classical pathway of complementdependent humoral response, and thereby elicit complementdependent cytotoxicity (CDC).…”

bisFabs: Tools for rapidly screening hybridoma IgGs for their activities as bispecific antibodies

“…9,10,11 Unlike full-length bispecific Abs, bisFabs showed a minor population (< 12%) with incomplete heavy-light chain disulfide formation, originating from disulfide scrambling in the heavy chain during reoxidation of the Fab's. While the presence of a fraction of bisFabs with scrambled disulfide did not affect the potency of bisFabs in T-cell redirected cell killing, the effect on other mechanisms of actions remains to be studied.…”

“…Production and characterization of full-length bispecific antibodies was done as described elsewhere. 9,10,11 To explore potential differences between the 2 formats in the context of different binding geometries and antigen densities, we used 10 different antibodies directed against 5 different antigens: human epidermal growth factor receptor 2 (HER2); B-cell antigens CD20, CD79, and antigen A; and melanoma antigen B. A description of the isotypes, enzymes used and yields obtained for those 10 clones is shown in Table S1.…”

“…10,11 Briefly, PBMCs were isolated form whole blood of healthy donors by Ficoll separation. Target cells were incubated with PBMCs at 1:5 ratio for 24-48 hr.…”