Biologic anti-TNFs in India have improved the patient management. Signiﬁcant proportions of patients lose response over time or do not respond. Possible explanations are suboptimal trough anti-TNFa concentrations or antibodies to anti-TNFs. The aim of this project was to set up and standardize an independent laboratory to test immunogenicity of anti-TNF biologics (inﬂiximab and etanercept).
Three rheumatologists piloted this project approved by independent ethics committee and carried out in compliance with ICH/GCP guidelines. Pﬁzer supplied immunogenicity kits (Promonitor® - ELISA) to the independent laboratory (SRL labs). After informed consent, blood (5 mL) was collected before infusion of inﬂiximab (n=8) or injection of etanercept (n=8).
Mean age of 16 patients was 42.06 ± 12.89 years. While 4 patients tested negative for inﬂiximab, one patient tested low positive and 3 patients were positive. Anti-inﬂiximab antibody was detected in 1/8 patient (12.5%) and the blood level of inﬂiximab was negligible.
Anti-inﬂiximab antibodies are found in 12%-44% of patients vis-a`-vis anti-etanercept antibodies (0%-18%). Anti-etanercept antibodies are without apparent effect on effectiveness or adverse events. When anti-TNFa are used, therapeutic drug monitoring is of help for optimal clinical outcomes. It might be more cost effective to adjust anti TNFa dosages according to serum drug concentrations. Clinicians should have access to immunogenicity testing facility in India. The results of the study were as per the observed percentages across the world.
This study met its objective of setting up and standardizing an independent laboratory for immunogenicity testing of anti-TNF biologics in India.