title: Identification of a candidate therapeutic antibody for treatment of canine B-cell lymphoma.
abstract: B-cell lymphoma is one of the most frequently observed non-cutaneous neoplasms in dogs. For both human and canine BCL, the standard of care treatment typically involves a combination chemotherapy, e.g. "CHOP" therapy. Treatment for human lymphoma greatly benefited from the addition of anti-CD20 targeted biological therapeutics to these chemotherapy protocols; this type of therapeutic has not been available to the veterinary oncologist. Here, we describe the generation and characterization of a rituximab-like anti-CD20 antibody intended as a candidate treatment for canine B-cell lymphoma. A panel of anti-canine CD20 monoclonal antibodies was generated using a mouse hybridoma approach. Mouse monoclonal antibody 1E4 was selected for construction of a canine chimeric molecule based on its rank ordering in a flow cytometry-based affinity assay. 1E4 binds to approximately the same location in the extracellular domain of CD20 as rituximab, and 1E4-based chimeric antibodies co-stain canine B cells in flow cytometric analysis of canine leukocytes using an anti-canine CD21 antibody. We show that two of the four reported canine IgG subclasses (cIgGB and cIgGC) can bind to canine CD16a, a receptor involved in antibody-dependent cellular cytotoxicity (ADCC). Chimeric monoclonal antibodies were assembled using canine heavy chain constant regions that incorporated the appropriate effector function along with the mouse monoclonal 1E4 anti-canine CD20 variable regions, and expressed in CHO cells. We observed that 1E4-cIgGB and 1E4-cIgGC significantly deplete B-cell levels in healthy beagle dogs. The in vivo half-life of 1E4-cIgGB in a healthy dog was ∼14 days. The antibody 1E4-cIgGB has been selected for further testing and development as an agent for the treatment of canine B-cell lymphoma.
authors.affiliation: Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, United States.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Rue
authors.affiliation: Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, United States.
authors.forename: Brendan P
authors.initials: BP
authors.lastname: Eckelman
authors.affiliation: Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, United States.
authors.forename: Jem A
authors.initials: JA
authors.lastname: Efe
authors.affiliation: Elanco Animal Health US, Inc., 2729 Toby Drive, Brighton, MI 48114, United States.
authors.forename: Kristin
authors.initials: K
authors.lastname: Bloink
authors.affiliation: Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, United States.
authors.forename: Quinn L
authors.initials: QL
authors.lastname: Deveraux
authors.affiliation: Elanco Animal Health US, Inc., 3200 Northline Ave. Suite 300, Greensboro, NC 27408, United States. Electronic address: david.lowery@novartis.com.
authors.forename: David
authors.initials: D
authors.lastname: Lowery
authors.affiliation: Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, United States.
authors.forename: Marc
authors.initials: M
authors.lastname: Nasoff
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D000920:Antibody-Dependent Cell Cytotoxicity; D018951:Antigens, CD20 / Q000276:immunology*; D004283:Dog Diseases / Q000188:drug therapy* / Q000276:immunology; D004285:Dogs; D006801:Humans; D016393:Lymphoma, B-Cell / Q000188:drug therapy / Q000276:immunology / Q000662:veterinary*; D000069283:Rituximab / Q000627:therapeutic use
chemical_list: D000911:Antibodies, Monoclonal; D018951:Antigens, CD20; D000069283:Rituximab
keywords: Antibody; CD20; Canine; Immunoglobulin; Lymphoma