Use of Tissue Cross-reactivity Studies in the Development of Antibody-based Biopharmaceuticals

Abstract

Tissue cross-reactivity (TCR) studies are screening assays recommended for antibody and antibody-like molecules that contain a complementarity-determining region (CDR), primarily to identify off-target binding and, secondarily, to identify sites of on-target binding that were not previously identified. At the present time, TCR studies involve the ex vivo immunohistochemical (IHC) staining of a panel of frozen tissues from humans and animals, are conducted prior to dosing humans, and results are filed with the initial IND/CTA to support first-in-human clinical trials. In some cases, a robust TCR assay cannot be developed, and in these cases the lack of a TCR assay should not prevent a program from moving forward. The TCR assay by itself has variable correlation with toxicity or efficacy. Therefore, any findings of interest should be further evaluated and interpreted in the context of the overall pharmacology and safety assessment data package. TCR studies are generally not recommended for surrogate molecules or for comparability assessments in the context of manufacturing/cell line changes. Overall, the design, implementation, and interpretation of TCR studies should follow a case-by-case approach.

A High-Affinity Native Human Antibody Neutralizes Human Cytomegalovirus Infection of Diverse Cell Types

“…In tissue reactivity profiling, only sporadic staining was observed, all of which was intracellular and thus unlikely to be relevant to clinical use in which the MAb will be administered systemically. Freezing, cutting, and fixation of the tissues disrupt cells and expose intracellular epitopes that are not normally accessible in vivo and that may be denatured during processing of the tissue; positive staining of some or many tissues that do not correlate with any known epitope or any in vivo effects are common (68). Consistent with the absence of binding to normal tissues, normal pharmacokinetics was observed (69).…”

“…TRL345 was applied at 1 and 20 g/ml to a panel of cryosections of 38 adult and 21 fetal (0 to 6 months) human tissue samples of diverse origins (Charles River Laboratories, Reno, NV) (68). Various types of nonspecific staining occurred, including incompletely quenched endogenous peroxidase staining (cytoplasmic staining of a few individual cells).…”

Antibody Drug Conjugates for Cancer Therapy

“…The toxicities are probably target dependent, but the specific tissue(s) involved in eliciting the adverse events were not identified. Although GLP compliant tissue cross reactivity studies were performed, this practice involves the immunohistochemical application of the drug itself, in this case MEDI-547, to frozen tissue sections as a means of detecting potential sites of reactivity (Leach et al, 2010). Accordingly, some weak staining restricted to tonsilar and esophageal epithelium was noted for MEDI-547.…”

When Tissue Antigens and Antibodies Get Along

“…204 These pharmaceutical compounds, intended as vehicles of biologically active molecules, are incubated with microarrays of human or animal tissues (frozen or, less commonly, fixed); TCR studies supplement but do not replace in vivo studies. 204 In some laboratories, the same MAb (same clone and antibody presentation) from 2 different companies is used in the same IHC procedure for validation purposes. We have experienced aberrant immunoreactivity using an antibody to CK8/18 from one company, whereas the same clone from a different company produced the expected results (Figs.…”