Question and Answer session with T. Kuramochi (CPR)
Taichi Kuramochi (CPR) described Chugai’s patented antibody sweeping technology. This comprises of two components, an antibody binding site that is being rendered pH sensitive for binding, such that antigen is bound at pH 7.4 but released at pH 5.8. This means that when the antibody-antigen complex is internalized into the endosome, the antigen is released and is degraded by the lysosome, while the antibody is recycled through the FcRn back into the circulation. The second modifications are to the Fc region of the antibody to enhance the binding activity against FcgRIIb and pI modification. Antibodies engineered to have both of these properties are able to remove soluble antigen from the circulation with remarkable efficiency. This opens up many new targets for therapy.
Dr Samuel Gan of APD Lab (p53Lab-BII) presented a fascinating talk challenging the assumptions within the reductionist analysis of antibody domains. Showing the need of a holistic view of antibodies on examples of IgG, IgM and most importantly IgE, he demonstrated distal effects between the variable and constant regions of antibodies in antigen and antigen antibody binding. Notably, the effects on IgE could underlie VH biases in specific allergic pathogenesis and also the activation of allergy by superantigens. At the end, there was also a preview of unpublished work on IgM that revealed the importance of epitope location affecting the interaction of IgM with Her2 in Pertuzumab and Trastuzumab models.
Dr Koh Xin Yu (p53Lab) presented her studies on the production of panel of antibodies to the RON receptor tyrosine kinase. In a comprehensive study2, she showed that antibodies recognized epitopes that are differentially expressed on cells treated with different fixatives and that this could be explained by the cryptic nature of some epitopes that appear absent from the surface of RON but are clearly exposed following protein conformational changes. Surprisingly, an antibody called 6E6 directed to the alpha chain of RON, though it bound poorly to RON in tissue culture based assays, proved remarkably effective as an imaging agent and as a therapeutic antibody in xenograft studies. Xin Yu determined that the epitope of 6E6 was created by a small sulfhydryl loop and that this covalent link was necessary to create the epitope. She suggested that the straightforward assumption that strong surface expression was necessary for anti-tumour efficacy may not be correct and that in vivo imaging work at an early point in the development workstream may be crucial.
Dr Keith Breinlinger, CTO of Berkeley Lights Inc. (https://www.berkeleylights.com/), presented his company’s extraordinary progress in developing the Beacon platform, which is able to manipulate individual cells under computer control on a small chip surface containing up to 14,000 pens. This allowed the successful examination of the product of individual B cells to be studied within one to two days, in remarkable detail. Their standard antibody discovery workflow can screen 25,000 plasma cells for soluble or membrane bound antigens but the flexibility of the platform allows for other functional screens on chip. For example, using a 3500 pen chip, they were able to distinguish antibodies that could inhibit virus infection from those that merely bound the virus in an integrated assay that operated within a given pen. The machine was then able to identify the individual cells responsible for the antibody with the desired neutralization properties and move the cell out of the machine into a new vessel where the heavy and light chain sequence of the antibody could be determined. The audience’s enthusiasm for the amazing performance for this machine was palpable.
Rounding off the meeting was a talk by Dr Khoo Kian Hoe, a former A*STAR NSS-PhD scholar and member of the p53 Lab, and now Senior Associate of Davies Collison Cave Asia Pte Ltd. He gave a very clear presentation on the challenges of antibody patenting in the light of recent US legislation. He illustrated his points by describing the portfolio of patents that protects the best-selling antibody drug, Humira. It was of interest to see that while the composition of matter patent expired in 2016, patents protecting its use, formulation and production are in place until 2031. Clearly the message to all of us was to engage suitable advice on patenting as our projects develop.
At the end of the meeting, the conclusion that antibody research in A*STAR and in Singapore was becoming highly successful was inescapable. It was particularly heartening to see the large enthusiastic audience and the easy relationship between those working in academia and industry. This collaborative, informative and enthusiastic meeting will certainly bolster the chances of a blockbuster antibody drug emerging from research and development efforts in Singapore.
- Research List of Guidance Documents: https://www.fda.gov/media/72570/download
- Immunogenicity testing of therapeutic antibody products: https://www.fda.gov/media/119788/download
- Immunogenicity Assessment for Therapeutic Protein Products https://www.fda.gov/media/85017/download
- Preclinical Safety Evaluation of Biotechnology-derived pharmaceuticals: https://www.fda.gov/media/78034/download
- Points to Consider in the Manufacture and Testing of monoclonal antibodies for human use: https://www.fda.gov/media/76798/download
- Bispecific Antibody Development Programs: https://www.fda.gov/media/123313/download
2) Koh XY et al, Oncogene. 2019 Aug 15. doi: 10.1038/s41388-019-0946-8
The 5th Antibody Symposium. 5 to 6 March 2018.
- The 17th International p53 Workshop. 8 to 12 July 2017.
- 4th Antibody Symposium. 14 November 2016.
- The 7th International Peptide Symposium. 9 to 11 December 2015.
- 3rd Antibody Symposium. 14 January 2015.
- Peptide Symposium. 28 February 2014.
- 2nd Antibody Symposium. 10 September 2013.
- Antibody Symposium. 17 September 2012.
- IFOM-p53Lab Symposium. 2 March 2011.