Development and characterization of a novel anti-IgE monoclonal antibody

Characterization and pre-clinical assessment of a proposed biosimilar to its originator Omalizumab

Omalizumab is an anti-IgE monoclonal antibody (mAb) approved for the treatment of moderate-to-severe asthma. Herein, we report physicochemical, biological, pharmacological, and toxicological characteristics of an Omalizumab biosimilar mAb named KA. We show that KA and its originator present only minimum differences. Their charge heterogeneity and primary, secondary structures are similar. The two molecules are comparable regarding in vitro activity, including molecular binding and cell-based inhibition. Pharmacological and toxicological properties were assessed using a mouse model of allergy and cynomolgus monkeys, and we determined that the efficacy, safety, and pharmacokinetic characteristics of KA are comparable to its originator. Our data, which demonstrated that KA has similar activity to the Omalizumab reference product in relevant preclinical models, calls for a clinical evaluation of its bio-similarity.

An update on anti-allergic patents granted in China: 2009 - 2011

INTRODUCTION

The prevalence of allergic diseases has increased dramatically in recent decades. Therefore, there is a pressing need for the development of effective anti-allergic services worldwide.

AREAS COVERED

In previous studies, the authors had analyzed a total of 789 anti-allergic patents granted in China from 1988 to 2008. Herein, they report a further 151 anti-allergic patents issued in China during 2009 - 2011. The current analysis covers the scientific progress in supporting anti-allergic patent applications and granted patent literature, in China, for the last 3 years.

EXPERT OPINION

The 151 anti-allergic patents granted from 2009 to 2011 mainly focus on seven types of products. They are: traditional Chinese medicines (TCM), plant extracts, biological products, synthetic compounds, pharmaceutical preparations, medical apparatus and new treatment modalities. Although the overall number of anti-allergic patent applications made between 2009 and 2011 in China is less than that of the USA and Europe, patents on TCM have increased. This suggests that there are demands for modernization of TCMs. Recently, studies of interesting new immunomodulators have also been conducted, and some of these are likely to represent clinically useful advances. In the last 3 years, several patents on these novel potential drugs have also been granted in China. The large number of anti-allergic patents issued in China, in recent times, suggests that the Chinese market is relatively competitive one that will help pharmaceutical companies make proper decisions for their research and development strategies.

Is there a regulatory role of immunoglobulins on tissue forming cells relevant in chronic inflammatory lung diseases?

Epithelial cells, fibroblasts and smooth muscle cells together form and give structure to the airway wall. These three tissue forming cell types are structure giving elements and participate in the immune response to inhaled particles including allergens and dust. All three cell types actively contribute to the pathogenesis of chronic inflammatory lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). Tissue forming cells respond directly to allergens through activated immunoglobulins which then bind to their corresponding cell surface receptors. It was only recently reported that allergens and particles traffic through epithelial cells without modification and bind to the immunoglobulin receptors on the surface of sub-epithelial mesenchymal cells. In consequence, these cells secrete pro-inflammatory cytokines, thereby extending the local inflammation. Furthermore, activation of the immunoglobulin receptors can induce proliferation and tissue remodeling of the tissue forming cells. New studies using anti-IgE antibody therapy indicate that the inhibition of immunoglobulins reduces the response of tissue forming cells. The unmeasured questions are: (i) why do tissue forming cells express immunoglobulin receptors and (ii) do tissue forming cells process immunoglobulin receptor bound particles? The focus of this review is to provide an overview of the expression and function of various immunoglobulin receptors.

Bacterial expression and characterization of a novel human anti-IgE scFv fragment

Antibodies highly specific to human immunoglobulin (Ig) E are capable of selectively blocking the IgE interaction or eliminating IgE-producing cells, thus providing valuable agents for diagnostics and treatment of various allergic illness. An example is omalizumab, a humanized monoclonal anti-IgE antibody that is approved for the treatment of patients with moderate-to-severe allergic diseases in the United States, European Union and other countries. Here, we describe the generation and characterization of a novel human anti-IgE as a single-chain antibody fragment (scFv). The bacterially-synthesized scFv showed high affinity (86 nM) and specificity to the Fc region of human IgE. To our knowledge, this is the first report of the production of a human anti-IgE scFv in E. coli. Its further development as a potential candidate for medical applications is discussed.

Food allergy herbal formula 2 protection against peanut anaphylactic reaction is via inhibition of mast cells and basophils

BACKGROUND

Mast cells and basophils are key effector cells of IgE-mediated anaphylactic reactions. The Chinese herbal formula, food allergy herbal formula 2 (FAHF-2), protects against peanut anaphylaxis in mice. However, the mechanisms underlying this effect are not fully elucidated.

OBJECTIVE

To investigate whether FAHF-2 inhibits mast cell/basophil numbers and IgE-mediated activation.

METHODS

Mice with peanut allergy (PNA mice) were treated with FAHF-2 intragastrically for 7 weeks and challenged intragastrically with peanut 1 day and 4 weeks posttreatment. Peripheral blood basophil numbers and peritoneal mast cell numbers and FcεRI expression were determined. Direct effects of FAHF-2 on the murine mast cell line MC/9, and effects of 4 fractions and 3 compounds isolated from FAHF-2 on rat basophilic leukemia cells (RBL-2H3) and human skin mast cells degranulation and on the IgE-mediated spleen tyrosine kinase signaling pathway, were determined.

RESULTS

Although all sham-treated PNA mice developed anaphylaxis, FAHF-2-treated PNA mice were protected against anaphylaxis after peanut challenge at 1 day and 4 weeks posttherapy. Reduction of peripheral blood basophils began after 1 week of treatment and continued for at least 4 weeks posttherapy. The number and FcεRI expression of peritoneal mast cells were also significantly decreased 4 weeks posttherapy. FAHF-2-treated MC/9 cells showed significantly reduced IgE-induced FcεRI expression, FcεRI γ mRNA subunit expression, proliferation, and histamine release on challenge. Fraction 2 from FAHF-2 inhibited RBL-2H3 cell and human mast cell degranulation. Three compounds from fraction 2-berberine, palmatine, and jatrorrhizine-inhibited RBL-2H3 cell degranulation via suppressing spleen tyrosine kinase phosphorylation.

CONCLUSION

Food allergy herbal formula 2 reduction of basophils and mast cell numbers as well as suppression of IgE-mediated mast cell activation may contribute to FAHF-2's persistent protection against peanut anaphylaxis.