title: CD19-/CD3-bispecific antibody of the BiTE class is far superior to tandem diabody with respect to redirected tumor cell lysis.
abstract: Many kinds of bispecific antibodies recruiting T cells for cancer therapy have been developed. Side-by-side comparison has shown that CD19-/CD3-bispecific antibodies of the diabody, tandem diabody (Tandab) and quadroma format had similar cytotoxic activity, with Tandab being the most active format. Tandab has also been claimed to be superior to single-chain (sc) Fv-based bispecific constructs although data from a side-by-side comparison are not available. In this study, we compared side-by-side MT103 (bscCD19xCD3), a single-chain bispecific antibody of the BiTE class, with a CD19-/CD3-bispecific representative of the Tandab class. Based on literature data, we have constructed, produced and characterized the LL linker version of Tandab, which was reported to be the most active version of Tandab proteins. A dimeric protein of 114kDa was obtained that showed proper bispecific binding to CD3- and CD19-positive cells and could redirect both pre-stimulated and unstimulated human T cells for lysis of human B lymphoma lines Raji, MEC-1 and Nalm-6. Raji cells were lysed at a half-maximal concentration (EC50) of 10 nM Tandab using pre-stimulated T cells, which closely matched the published activity of LL-Tandab with this particular cell line. MT103 had between 700- and 8000-fold higher efficacy than Tandab for redirected lysis of the three human B lymphoma lines. These data demonstrate that under identical experimental conditions, the BiTE format has far superior activity compared to the Tandab format and is also superior to conventional diabody and quadroma formats. The extraordinary potency of the BiTE class and its representative MT103 may translate into improved anti-tumor activity, lower dosing and lower costs of production compared to other bispecific antibody formats.
authors.affiliation: Micromet AG, Staffelseestr. 2, 81477 Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Mølhøj
authors.forename: Sandrine
authors.initials: S
authors.lastname: Crommer
authors.forename: Klaus
authors.initials: K
authors.lastname: Brischwein
authors.forename: Doris
authors.initials: D
authors.lastname: Rau
authors.forename: Mirnaalini
authors.initials: M
authors.lastname: Sriskandarajah
authors.forename: Patrick
authors.initials: P
authors.lastname: Hoffmann
authors.forename: Peter
authors.initials: P
authors.lastname: Kufer
authors.forename: Robert
authors.initials: R
authors.lastname: Hofmeister
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Baeuerle
mesh_terms: D000818:Animals; D018033:Antibodies, Bispecific / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology / Q000627:therapeutic use; D000920:Antibody-Dependent Cell Cytotoxicity; D018941:Antigens, CD19 / Q000276:immunology*; D000970:Antineoplastic Agents / Q000276:immunology* / Q000494:pharmacology / Q000627:therapeutic use; D017252:CD3 Complex / Q000276:immunology*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008223:Lymphoma / Q000188:drug therapy / Q000276:immunology*; D051379:Mice; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D018033:Antibodies, Bispecific; D018941:Antigens, CD19; D000970:Antineoplastic Agents; D017252:CD3 Complex; D011994:Recombinant Proteins