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Anti-Infliximab Antibodies May Interfere With Drug Efficacy
Anti-Infliximab Antibodies May Interfere With Drug Efficacy J Rheumatol 2006;33:31-36.
In patients with rheumatoid arthritis (RA) who are treated with the TNF-alpha inhibitor infliximab (Remicade), development of anti-infliximab antibodies may reduce clinical efficacy of the drug in some patients, research suggests.
Dr. Boulos Haraoui from the University of Montreal and colleagues Evaluated baseline characteristics and anti-infliximab antibody levels in 51 consecutive RA patients treated with infliximab at a single center. Nineteen of the patients achieved and maintained clinical responses to infliximab at a dose of 3 mg/kg every 8 weeks, whereas 32 (63%) required higher doses of the drug.
According to the team, anti-infliximab antibodies occurred in 47% of patients who required higher doses of infliximab compared with 27% of those who did not. They also found that concentrations of anti-infliximab antibodies were more than twice as high in patients needing infliximab dose escalation (18.3 vs 7.5 g/mL).
Individuals who developed anti-infliximab antibodies were younger and were taking less prednisone when infliximab was initiated. No other differences in baseline or clinical characteristics at the time of infliximab initiation were identified between the two groups, including methotrexate doses and infliximab starting doses.
Dr. Haraoui's team also observed that median serum trough levels of infliximab were significantly lower in patients with anti-infliximab antibodies as opposed to those without these antibodies or in those with equivocal samples (0 vs 2.2 micrograms/ml; p< 0.001). This suggests, they offer in the Journal of Rheumatology this month, that "high concentrations of anti-infliximab antibodies may have neutralized infliximab in this subset of patients."
Taken together, these data suggest that anti-infliximab antibodies may interfere with infliximab efficacy, Dr. Haraoui and colleagues write.
"Our study," they add, "is the first to raise a possible causal relationship between the presence of high concentrations of antibodies to infliximab and the need for infliximab dose escalation in patients with RA."
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