Title: Deriving a dose and regimen for anti-glucosaminidase antibody passive-immunisation for patients with Staphylococcus aureus osteomyelitis

Authors: CC Lee, RD Southgate, C Jiao, E Gersz, JR Owen, SL Kates, CA Beck, C Xie, JL Daiss, V Post, TF Moriarty, S Zeiter, EM Schwarz, G Muthukrishnan

Address: Centre for Musculoskeletal Research, University of Rochester Medical Centre, Rochester, NY, USA

E-mail: Edward_schwarz at urmc.rochester.edu

Abstract: Staphylococcus aureus (S. aureus) osteomyelitis remains a major clinical problem. Anti-glucosaminidase (Gmd) antibodies (1C11) are efficacious in prophylactic and therapeutic murine models. Feasibility, safety and pharmacokinetics of 1C11 passive immunisation in sheep and endogenous anti-Gmd levels were quantified in osteomyelitis patients.
3 sheep received a 500 mg intravenous (i.v.) bolus of 1C11 and its levels in sera were determined by enzyme-linked immunosorbent assay (ELISA) over 52 d. A humanised anti-Gmd monoclonal antibody, made by grafting the antigen-binding fragment (Fab) portion of 1C11 onto the fragment crystallisable region (Fc) of human IgG1, was used to make a standard curve of mean fluorescent intensity versus concentration of anti-Gmd. Anti-Gmd serum levels were determined in 297 patients with culture-confirmed S. aureus osteomyelitis and 40 healthy controls.
No complications or adverse events were associated with the sheep 1C11 i.v. infusion and the estimated circulating half-life of 1C11 was 23.7 d. Endogenous anti-Gmd antibody levels in sera of osteomyelitis patients ranged from < 1 ng/mL to 300 µg/mL, with a mean concentration of 21.7 µg/mL. The estimated circulating half-life of endogenous anti-Gmd antibodies in sera of 12 patients with cured osteomyelitis was 120.4 d.
A clinically relevant administration of anti-Gmd (500 mg i.v. = 7 mg/kg/70 kg human) was safe in sheep. This dose was 8 times more than the endogenous anti-Gmd levels observed in osteomyelitis patients and was predicted to have a half-life of > 3 weeks.
Anti-Gmd passive immunisation has potential to prevent and treat S. aureus osteomyelitis. Further clinical development is warranted.

Key Words: Orthopaedic infections, immunoassay, Staphylococcus aureus, osteomyelitis, peri-prosthetic joint infection, 2-stage revision surgery, passive immunisation.

Publication date: January 31st 2020

Article download: Pages 96-107 (PDF file)
DOI: 10.22203/eCM.v039a06