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Two tumor necrosis factor (TNF) antagonists infliximab (a chimeric monoclonal antibody) and etanercept (a p75 TNF receptor/Fc fusion protein) have been approved for treatment of rheumatoid arthritis. However, these agents have shown differ-

Objective. To investigate the relationship between serum concentrations of infliximab, a monoclonal antitumor necrosis factor ␣ antibody, and clinical improvement from infliximab therapy for rheumatoid arthritis (RA).Methods. Multiple blood samples were obtained from each of 428 subjects with active RA who were enrolled in a multicenter, randomized, double-blind, placebo-controlled trial (ATTRACT [Anti-Tumor Necrosis Factor Trial in Rheumatoid Arthritis with Concomitant Therapy]) evaluating the clinical efficacy and safety of infliximab therapy. Serum levels of infliximab were measured by enzyme-linked immunosorbent assay. Dose-response trends were analyzed using generalized logistic regression techniques. Pharmacokinetic modeling was used to predict the serum concentrations of infliximab after simulated infusions using doses and dosing intervals not evaluated in the trial.Results. At week 54, 26% of the subjects receiving 3 mg/kg infliximab every 8 weeks had undetectable trough serum levels of infliximab, a significantly greater proportion than in the other 3 treatment groups (P < 0.001). Increased magnitude of American College of Rheumatology (ACR) response (measured by the ACR-N, a continuous measure of clinical improvement derived from the ACR 20% response criteria) and greater reduction from baseline in serum C-reactive protein level were both associated with higher trough serum concentrations of infliximab (P < 0.001), as was less progression of radiographic joint damage (P ‫؍‬ 0.004), providing support for a dose-response relationship. Pharmacokinetic models predicted that decreasing the dosing interval from 8 weeks to 6 weeks would yield higher trough serum levels of infliximab than increasing the dose by 100 mg.Conclusion. These results suggest that some patients with RA may benefit from infliximab given at higher doses than 3 mg/kg or more frequently than every 8 weeks.

The delay or reversal of inflammatory and joint-destructive mechanisms in patients with early RA was already apparent following 18 weeks of treatment with infliximab + MTX and was reflected in radiologic changes at 54 weeks.

Objective. To assess the efficacy, safety, and pharmacology of subcutaneous administration of golimumab in patients with active rheumatoid arthritis (RA) despite treatment with methotrexate (MTX).Methods. Patients were randomly assigned in a double-blinded manner to receive injections of placebo plus MTX or 50 mg or 100 mg golimumab every 2 or 4 weeks plus MTX through week 48. Patients originally assigned to receive injections every 2 weeks had the interval increased to every 4 weeks starting at week 20. The primary end point was the proportion of patients meeting the American College of Rheumatology 20% improvement criteria (achieving an ACR20 response) at week 16. The study was powered to detect a difference in the primary end point when the combined golimumab groups and at least 1 of the individual dose groups were compared with placebo.Results. The primary end point was attained. Sixty-one percent of patients in the combined golimumab plus MTX dose groups achieved an ACR20 response at week 16 compared with 37% of patients in the placebo plus MTX group (P ‫؍‬ 0.010). In addition, 79% of patients in the group receiving 100 mg golimumab every 2 weeks achieved an ACR20 response (P < 0.001 versus placebo). Through week 20 (after which patients receiving placebo were switched to active infliximab therapy), serious adverse events were reported in 9% of patients in the combined golimumab groups and in 6% of patients in the placebo group.Conclusion. Golimumab plus MTX effectively reduces the signs and symptoms of RA and is generally well tolerated in patients with an inadequate response to MTX.

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Summary Background  Benefits and risks of concomitant immunomodulators and maintenance infliximab in inflammatory bowel disease (IBD) patients have not been adequately evaluated. Aim  To assess the effect of concomitant immunomodulator and infliximab maintenance therapy using data from four prospective, randomized Phase 3 trials in IBD patients. Methods  Overall, 1383 patients from ACCENT I and ACCENT II [luminal and fistulizing Crohn’s disease trials] and ACT 1 and ACT 2 [ulcerative colitis trials] were analysed. Patients were treated with placebo or infliximab 5 or 10 mg/kg at weeks 0, 2 and 6 followed by every‐8‐week maintenance therapy. Clinical response, clinical remission, fistula response, complete fistula response, infection and infusion reaction rates; serum infliximab concentrations and immunogenicity were summarized by baseline concomitant immunomodulator subgroup (use or non‐use). Results  Overall, almost 40% of evaluated IBD patients received concomitant immunomodulators. Efficacy, infection, and serious infection rates were generally similar in patients who received maintenance therapy with or without concomitant immunomodulators. There were no consistent differences in serum infliximab concentrations with or without immunomodulators in patients who received scheduled maintenance therapy. Concomitant immunomodulators reduced infusion reactions and immunogenicity. Conclusion  Concomitant immunomodulators did not improve efficacy or pharmacokinetics in IBD patients who received maintenance infliximab.

These results are consistent with continuous reequilibration of abciximab among circulating platelets and may explain the gradual recovery of platelet function and long-term prevention of ischemic complications by abciximab after coronary intervention.