A multifunctional bispecific antibody protects against Pseudomonas aeruginosa

Abstract

Widespread drug resistance due to empiric use of broad-spectrum antibiotics has stimulated development of bacteria-specific strategies for prophylaxis and therapy based on modern monoclonal antibody (mAb) technologies. However, single-mechanism mAb approaches have not provided adequate protective activity in the clinic. We constructed multifunctional bispecific antibodies, each conferring three mechanisms of action against the bacterial pathogen Pseudomonas aeruginosa by targeting the serotype-independent type III secretion system (injectisome) virulence factor PcrV and persistence factor Psl exopolysaccharide. A new bispecific antibody platform, BiS4, exhibited superior synergistic protection against P. aeruginosa-induced murine pneumonia compared to parent mAb combinations or other available bispecific antibody structures. BiS4αPa was protective in several mouse infection models against disparate P. aeruginosa strains and unexpectedly further synergized with multiple antibiotic classes even against drug-resistant clinical isolates. In addition to resulting in a multimechanistic clinical candidate (MEDI3902) for the prevention or treatment of P. aeruginosa infections, these antibody studies suggest that multifunctional antibody approaches may be a promising platform for targeting other antibiotic-resistant bacterial pathogens.

Insertion of scFv into the hinge domain of full-length IgG1 monoclonal antibody results in tetravalent bispecific molecule with robust properties

“…Bs4Ab technology is versatile in that it can yield molecules targeting soluble disease mediators, such as Bs4Ab-VA described here; membrane-bound targets on the surface of pathogens, as demonstrated by the clinical candidate MEDI3902 13 targeting the virulence factor PcrV and the persistence factor Psl exopolysaccharide of Pseudomonas aeruginosa; or receptors, as shown by a Bs4Ab that targets the EGFR and IGF1R described in the patent USPTO 20140302038. In the case of MEDI3902, it was determined that, for this combination of targets, the intermediate paratopic distance offered by the Bs4Ab format was optimal, and the molecule demonstrated significantly superior activity and efficacy compared with other bispecific antibody formats and antibody combination.…”

“…In the case of MEDI3902, it was determined that, for this combination of targets, the intermediate paratopic distance offered by the Bs4Ab format was optimal, and the molecule demonstrated significantly superior activity and efficacy compared with other bispecific antibody formats and antibody combination. 1,13 The Bs4Ab platform maintains intact Fc, which is important for maintaining IgG1 Fc-like functions, such as half-life and effector functions. Moreover, the Bs4Ab platform allows Fc modifications to modulate half-life and effector functions similar to IgG1.…”

“…The Bs4Ab platform was previously used to construct MEDI3902, 13 which targets Pseudomonas aeruginosa PcrV and Psl and is currently in a Phase 2 study (ClinicalTrials.gov NCT02696902), and a Bs4Ab targeting EGFR and IGF1R (USPTO 20140302038). To further demonstrate the applicability of the Bs4Ab technology, we constructed a bispecific tetravalent antibody, Bs4Ab-VA, that concurrently neutralizes VEGF and Ang2.…”

“…Among the plethora of BsAb formats, 3,9 only Bs4Ab is engineered for bispecificity via the insertion of an additional binding unit into the IgG1 hinge. Bs4Ab can be efficiently produced in mammalian cells, purified using traditional methods and has demonstrated IgG1-like biochemical and biophysical properties, as evidenced by MEDI3902, 13 which is a Bs4Ab targeting the Pseudomonas aeruginosa serotype-independent type III secretion system virulence factor PcrV and persistence factor Psl exopolysaccharide. MEDI3902 is currently in a Phase 2 clinical study (ClinicalTrials.gov Identifier: NCT02696902) in mechanically ventilated patients for the prevention of nosocomial pneumonia caused by Pseudomonas aeruginosa.…”

Structural investigation of humanS. aureus-targeting antibodies that bind wall teichoic acid

“…The use of animal serum containing antibodies that target bacterial antigens was a common therapeutic approach pre-dating the development of small molecule antibiotics, 7 but technological advances in antibody discovery, including B-cell cloning from human patients, 8 has invigorated research into monoclonal antibody (mAb)-based antibiotics. Anti-infective biologics with novel mechanisms of action targeting S. aureus alpha toxin, 9,10 protective antigen of Bacillus anthracis , 11 toxins A and B from Clostridium difficile , 12 and Pseudomonas aeruginosa cell wall components 13,14 are currently approved or in clinical development. The presence of cell wall glycopolymers, particularly in Gram-positive bacteria, shields many epitopes that might confer bactericidal activity from antibodies and other host-defense molecules, 15 but these cell wall polysaccharides also represent a potential target for mAb therapeutics.…”