The engineered human anti-tumor necrosis factor-alpha antibody CDP571 inhibits inflammatory pathways but not T cell activation in patients with rheumatoid arthritis.

OBJECTIVE: We investigated the effect of an engineered human anti-tumor necrosis factor-alpha antibody, CDP571, on immune functions as well as bone and cartilage turnover in patients with rheumatoid arthritis (RA) in a placebo controlled trial. We also assessed the effects of repeated treatment with CDP571 in an open label continuation study. METHOD: Thirty-six patients were treated with either placebo or 0.1, 1, or 10 mg/kg of CDP571 given as an intravenous infusion. The followup period was 8 weeks. Lymphocyte phenotype, soluble CD4 (sCD4), soluble interleukin 2 receptor (sIL-2R), IL-6, and stromelysin levels in the blood were measured before and after treatment; bone and cartilage markers (pyridinoline, deoxypyridinoline, N-terminal telopeptide) were similarly assessed in the urine. Patients who completed a placebo controlled trial of CDP571 were offered further treatment with CDP571. They received a maximum of 2 further doses of 1 mg/kg (7 patients) or 10 mg/kg (9 patients) in an open study. RESULTS: Plasma IL-6 level was statistically significantly reduced in the 1 and 10 mg/kg groups. In the 10 mg/kg group, there were also reductions in plasma stromelysin and urine bone markers, although there was no change in sCD4 and sIL-2R levels. Repeat doses of CDP571 were well tolerated and continued to suppress the acute phase response and disease activity. CONCLUSION: Treatment with 10 mg/kg of CDP571 reduced IL-6 and surrogate markers of bone turnover in RA, suggesting that CDP571 might prevent joint damage in RA. Since there was no effect on lymphocyte markers despite the marked reduction in inflammation, CDP571 appears to have no effect on ongoing CD4 T cell activation.

F(ab')2 molecules made from Escherichia coli produced Fab' with hinge sequences conferring increased serum survival in an animal model.

Fab's with hinges based on the human gamma1 sequence containing 1, 2, or 4 cysteines have been produced by high level Escherichia coli periplasmic secretion, and coupled in vitro by reduction/oxidation to form F(ab')2. We find that the F(ab')2 made with hinges containing 2 or 4 cysteines have a high level (approximately 70%) of multiple disulphide bonds. These F(ab')2 molecules have an increased pharmacokinetic stability as measured by area under the curve compared to those made by direct coupling through a single disulphide bond. One particular molecule containing 4 hinge cysteines has a greater pharmacokinetic stability than a F(ab')2 formed by chemical cross-linking. F(ab')2 made from the Fab' with 4 hinge cysteines is also relatively resistant to chemical reduction in vitro allowing partial reduction to expose reactive hinge thiols. These hinge sequences provide a simple method for producing robust F(ab')2 in vitro, obviating the need to use chemical cross-linkers, and provide a route to hinge specific chemical modification with thiol-reactive conjugates.

Comprehensive pharmacokinetics of a humanized antibody and analysis of residual anti-idiotypic responses.

A murine antibody to human tumour necrosis factor-alpha (TNF-alpha) (CB0010) was complementarity-determining region (CDR)-grafted using human IgG4 heavy and kappa light chain constant regions. In cynomolgus monkeys, the grafted antibody (CDP571) was eliminated with a half-life of 40-90 hr, two to three times longer than CB0010, and immunogenicity was reduced by > 90%. Responses to the constant regions were almost entirely eliminated and responses to the CDR loop (anti-idiotype) were lowered. CDP571 was given to 24 human volunteers in doses from 0.1 to 10.0 mg/kg. It was well tolerated, with a half-life of approximately 13 days. Anti-CDP571 antibodies were low or undetectable at higher doses. At lower doses, anti-CDP571 peaked at 2 weeks and then declined. The response was primarily IgM (in contrast to the cynomolgus monkey, where by 5 weeks IgG predominated) and was against a conformational epitope comprising heavy and light chain CDR loops. No antibodies were detected against the gamma 4/kappa domains or frameworks. The response had little or no effect on CDP571 binding to TNF-alpha or on plasma clearance.