Recommendations on risk-based strategies for detection and characterization of antibodies against biotechnology products

doi:10.1016/j.jim.2008.01.001

Journal of Immunological Methods

Volume 333, Issues 1–2, 20 April 2008, Pages 1-9

https://doi.org/10.1016/j.jim.2008.01.001 Get rights and content

Abstract

The appropriate evaluation of the immunogenicity of biopharmaceuticals is of major importance for their successful development and licensure. Antibodies elicited by these products in many cases cause no detectable clinical effects in humans. However, antibodies to some therapeutic proteins have been shown to cause a variety of clinical consequences ranging from relatively mild to serious adverse events. In addition, antibodies can affect drug efficacy. In non-clinical studies, anti-drug antibodies (ADA) can complicate interpretation of the toxicity, pharmacokinetic (PK) and pharmacodynamic (PD) data. Therefore, it is important to develop testing strategies that provide valid assessments of antibody responses in both non-clinical and clinical studies. This document provides recommendations for antibody testing strategies stemming from the experience of contributing authors. The recommendations are intended to foster a more unified approach to antibody testing across the biopharmaceutical industry. The strategies proposed are also expected to contribute to better understanding of antibody responses and to further advance immunogenicity evaluation.

Introduction

Evaluation of the immunogenicity of therapeutic proteins and peptides remains an important part of product development. There is increasing evidence that immune responses to biotechnology products can have a wide variety of effects on non-clinical and clinical studies. In some non-clinical studies, anti-drug antibodies may affect the pharmacokinetics, pharmacodynamics, bioavailability and efficacy of the product. Therefore, antibodies can alter the activity of the product in a way that leads to altered exposure in toxicology studies, by reducing or extending half lives, altering the rate at which a product reaches its target etc. Anti-drug antibodies can also cause their own toxicity by cross-reacting with endogenous molecules in animal models.

Antibody-related clinical sequelae that can occur in humans range from no apparent or mild side effects to altered efficacy, immune complex mediated symptoms, and allergic reactions. In the most severe examples, autoimmune syndromes, such as thrombocytopenia (Zipkin, 1998, Li et al., 2001) or pure red cell aplasia (PRCA) (Casadevall et al., 2002) may develop in patients with drug-induced antibodies capable of neutralizing the biological activity of both the drug and its endogenous counterpart (i.e. thrombopoietin or erythropoietin respectively). Thus, it is necessary to collect appropriate data regarding the appearance and characteristics of antibodies induced over time and assess how these findings may be associated with clinical outcomes.

A previously published paper (Mire-Sluis et al., 2004) describes the design and optimization of immunoassays used to determine if a sample contains antibodies that bind to the product. It discusses in detail important assay parameters such as assay cut point, sensitivity, precision, specificity and relative antibody level. Validation of immunoassays for detection of antibodies directed against therapeutic antibodies has been described in a recently published paper (Geng et al., 2005) and recommendations for the design optimization and qualification of cell-based assays for detection of neutralizing antibodies have also been published recently (Gupta et al., 2007).

This manuscript provides recommendations for the host antibody testing and characterization strategies for non-clinical and clinical studies based upon risk assessment of the drug and the study conditions in which the antibodies were generated. Such an approach is primarily intended to encourage proactive antibody-monitoring strategies in order to minimize patients' safety risks. However, the authors also assume that sponsors will establish the most appropriate antibody screening schemes as well as the extent of antibody characterization on a case-to-case basis, and in agreement with regulatory agencies (Rosenberg and Worobec, 2004).

Section snippets

Antibody monitoring based on risk assessment

The premise of the risk assessment strategy is to consider the severity of consequences of an antibody response to a protein therapeutic if it is induced. The critical factors to be considered are related to the biological function of the product or its endogenous counterpart(s) the target of the product, the mode of administration and the health status of the subject. Because of its complexity, the risk assessment should be carried out in a collaborative fashion between toxicologists,

Examples of risk-based antibody characterization

There are compelling reasons to design antibody-monitoring strategy in accordance with the risk-based approach. The utility of such an approach became quite apparent during development of recombinant human thrombopoietin (r-HuTpo) analogues. In one development program, r-HuTpo was shown to be highly immunogenic and was deemed to be a high-risk molecule. This assessment was initially made based on the non-clinical immunogenicity data. Severe thrombocytopenia in animals positive for neutralizing

Antibody testing

On the basis of the above risk assessments we recommend a two-step antibody testing and characterization strategy as well as reporting scheme that is applicable to both non-clinical and clinical studies.

Fig. 1 illustrates the first step where all pre- and post-dosing samples are analyzed for antibodies. Two essential tests here are the screening assay and confirmation by drug inhibition and/or immunoglobulin depletion. Mire-Sluis et al. (2004) have recommended the use of the upper bound of a

Concluding remarks

The first paper in this series described common approaches for developing and optimizing immunoassays for antibodies to biotechnology products (Mire-Sluis et al., 2004). The second describes development and optimization of cell-based assays for neutralizing antibodies (Gupta et al., 2007). This paper recommends a tiered, risk-based strategy to evaluate antibody responses to therapeutic proteins and peptides. The proposed strategy for clinical studies is based on risk assessment that factors in

Acknowledgements

This work was sponsored by The Ligand Binding Assay Bioanalytical Focus Group (LBABFG0) of the American Association of Pharmaceutical Scientists (AAPS). The authors thank to the members of the LBABFG for their review and comments. The authors also thank Dr. Amy Rosenberg, CDER, FDA for her review of the manuscript.

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¹: The views expressed here represent those of the author and not necessarily those of the Food and Drug Administration.

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ReviewRecommendations on risk-based strategies for detection and characterization of antibodies against biotechnology products

Abstract

Introduction

Section snippets

Antibody monitoring based on risk assessment

Examples of risk-based antibody characterization

Antibody testing

Concluding remarks

Acknowledgements

Blood

J. Pharm. Biomed. Anal.

J. Immunol. Methods

Cytokine

Blood

J. Immunol. Methods

J. Immunol. Methods

J. Biol. Chem.

J. Immunol. Methods

J. Biol. Chem.

Influence of immunogenicity on the long-term efficacy of infliximab in Crohn's disease

N. Engl. J. Med.

Immunogenicity, efficacy and adverse events of adalimumab in RA patients

Rheumatol. Int.

Increased IgA antibodies to cytokeratins in the spondyloarthropaties

Ann. Rheum. Dis.

Pure red-cell aplasia and antierythropoietin antibodies in patients treated with recombinant erythropoietin

N. Engl. J. Med.

Effect of aerosolized anti-IgE (E25) on airway responses to inhaled allergen in asthmatic subjects

Am. J. Respir. Crit. Care Med.

Review
Recommendations on risk-based strategies for detection and characterization of antibodies against biotechnology products