Serum Control for Therapeutic Antibody and IgE during Treatment - - PowerPoint PPT Presentation

International Conference Advances in Pneumology Bonn 2011

Serum Control for Therapeutic Antibody and IgE during Treatment with Omalizumab

• Dr. Gunther Becher, BecherConsult GmbH
• Dr. Pavel Strohner, BioTeZ Berlin-Buch GmbH

Target is not measurable by traditional antibody based tests in presence of a therapeutic antibody Because components of test system are already in the sample! New immunoassay for antibody therapies developed:

recoveryELISA

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Comparison of IgE determinations during Omalizumab therapy

In presence of therapeutic antibody, conventional Sandwich ELISA systematically measures false high levels of IgE.

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Comparison of IgE determination during Omalizumab therapy

The efficiency of Omalizumab therapy can not be controlled by conventional tests; they rarely measure the goal of therapy (< 50 ng IgE / mL).

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There is no correlation between concentration of target antigen and therapeutic antibody in serum, also not with respect to initial values .

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c) Function 3: Recovery curve (main result of assay)

Basis: b1 = q1*p/(1/k1+q1) Binding rate of target protein:b1/p=q1/(1/k1+q1) Recovery of free target protein: rec = 1 –b1/p = 1 – q1/(1/k1+q1)

rec = 1 / (1+k1*q1) + NSB

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Recovery of IgE after TAb addition in relation to reference curve without TAb

Calculation of IgE from O.D. with inverse of function 1 for spiked samples Slope of lines = Recovery (rec)

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Function 3: Recovery curve:

It shows the neutralization rate of target protein dependent on TAb. Higher the TAb lower the neutralization of added TAb.

Y = rec; X = TAb

Y = 1 / (1 + 2,7628 * X) + 2,0753E-04

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recoveryELISA avoids massive interference of conventional tests in samples during antibody therapy

• Free antigen (target protein), if available in serum
• Available therapeutic antibody (TAb) in serum
• Effective interaction between antigen and TAb

(binding / neutralization rate of target protein)

recoveryELISA measures 3 parameters for a sample:

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Comparative studies from the example IgE / Omalizumab show:

• Conventional immunoassays are not suitable for

measurement of antigen during antibody therapies

• Traditional assays are massively disrupted by the

presence of therapeutic antibodies in the sample

recoveryELISA provides the solution

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Taking the general assumption in account, we could establish the following recoveryELISAs which allow to analyze the interaction between target protein and therapeutic antibody.

Further recoveryELISAs in progress (in-house versions available) :

• 3. TNF- / Infliximab
• 4. TNF- / Eternacept
• 5. Her2 / Trastuzumab
• 6. VEGF / Bevacizumab
• 1. IgE / Omalizumab „RIO“ -

Registered IVD

• 2. TNF- / Adalumimab
• For research use only