Optimisation of omalizumab dosage in patients with severe persistent allergic asthma using recoveryELISA.

ABSTRACT

BACKGROUND: The objective of this study was to investigate the suitability of recoveryELISA as a method to monitor treatment with therapeutic antibodies using the example of omalizumab. METHODS: The recoveryELISA is a newly developed immunoassay technology that measures three parameters in one test the free level of antigen, the level of therapeutic antibody and the specific dose-response interaction which represents the actual activity of the drug. A retrospective and observational analysis was performed on 197 serum samples from 17 patients (13 ± 4 years of age) with severe persistent allergic asthma who received add-on treatment with omalizumab. RESULTS: The mean omalizumab serum level during antibody therapy was 59 ± 45 µg/mL; the kit's upper detection limit of 140 µg/mL was exceeded in 27 samples. Antibody concentrations between 50 and 140 µg/mL were found in 64 samples. Independent of the omalizumab dosage, nearly all measurements were in a range of absolute saturation as regards the IgE binding rate. Almost complete binding of IgE with a recovery of added labelled IgE of <1% was reached within a maximum of 11 days. CONCLUSIONS: The biochemical activity of therapeutic antibodies can be examined by recoveryELISA and their residual activity can be determined. Thus, further individualisation of therapy with biologics is possible using this test which seems to be suitable to diminish side effects and reduce costs.