Current Highlights

6th Antibody Symposium

“Antibody Engineering: The Next Wave"

Z. Lin and D.P. Lane


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The 6th Antibody Symposium was held on 23 September 2019, organized and sponsored by the p53Lab and Chugai Pharmabody Research. 344 people attended the meeting, with a strong showing from the local research community; 45% of the audience came from Industry, hospitals, tertiary institutions as well as other research organisations. The audience heard a very exciting set of presentations from both academic groups and industrial researchers, as well as key members of the national platform, EDDC. The meeting was introduced by Prof. Sir David Lane who reminded the audience that the current global market for monoclonal antibodies exceeded sales of $155 billion dollars in 2018, and that 182 molecules were currently in stage 3 clinical trials. Antibody treatments have transformed the treatment of cancer and inflammatory diseases and more recently, genetic diseases. The recent success of “Hemlibra”, Chugai’s bi-specific antibody treatment for Hemophilia, is an example of the extended potential that antibody molecules can have in the future.

The first talk was given by Dr Ang Hwee Ching from the Experimental Drug Development Centre (EDDC), who introduced the new national platform for development of both small molecule and biologics-based therapies. She shared that collaboration was important for the EDDC – its three legacy units had partnered with over 70 academic institutions and 25 companies, with EDDC’s lead asset originating from a partnership with Duke-NUS. Hwee Ching explained that newly established Target Translation Consortium (https://www.a-star.edu.sg/EDDC/Partnership/Target-Translation-Consortium) is a partnership initiative that brings together the resources and expertise of a network of public research performers in Singapore to facilitate the preclinical validation of potential drug targets arising from publicly funded research. Scientists in Singapore can get expert advice on their ideas for drug development. In addition, selected projects may receive seed funding to support key experiments to gather critical data. In the question time, she emphasized that EDDC was interested in all disease areas and not just in treatments of cancer.

The next speaker, Dr John Connolly, is currently the CSO of Tessa Therapeutics, one of Singapore’s more successful biotech company. He described exciting new work on developing a bi-specific antibody mimic of the interleukin 2 (IL-2) growth factor, which grew out from core technology licensed from Dr Wang Cheng-I’s lab at SIgN (A*STAR). This molecule was designed to reduce some of the side effects of delivery of IL-2 itself by having a more restricted receptor engagement. Exciting evidence for anti-cancer activity was shown in a number of models and the molecule looks poised for clinical development.

Dr Walter Stunkel (EDDC) gave an excellent overview of the antibody drug discovery process and emphasized that enormous challenge of developing a molecule from its initial discovery through to clinical approval. Whilst it is often thought that this is more easily achieved with antibodies than with small molecules, Walter explained clearly the complexities of development, and increased expenditure necessary to take a molecule to first in man studies. Using the case history of TGN1412, a CD28 superagonist antibody tested in a phase I clinical trial in 2006, he showed the risks that accompany antibody development and shared with us the latest FDA guidance on the development of antibody therapies. He urged us all to read these documents1 as they provide a strong reality check for our future work. He also shared the recent establishment of an antibody discovery and –development workflow at EDDC, that is available on a collaborative basis to the Singapore community.

Hummingbird Bioscience Singapore is another success story in the Singapore Biotech sector. Their founder and CEO, Dr Piers Ingram, has recently inked deals with both Amgen and Cancer Research UK that will see two of the company’s molecules enter clinical trials in 2020. Piers explained how his company’s platform has developed antibodies recognizing precise epitopes on both HER-3 and VISTA. Both of these antibodies showed very promising pre-clinical activity as their detailed mechanism of action allowed them to function to precisely block the desired signaling pathways.

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Collage of past and present p53 lab staff speaking at the symposium – clockwise from top left: Dr Ang Hwee Ching, Dr Christopher Brown, Dr Khoo Kian Hoe, Dr Koh Xin Yu

Dr Christopher Brown of the p53 Lab described how VHH domain antibodies can be used to validate protein:macromolecular interaction targets. He has been working on the control of translation and its aberrant upregulation in many cancers. Focusing on the eIF4E protein as a target, his team have developed a number of potent peptide inhibitors of two different binding sites on eIF4E. One site is the docking site for another component (eIF4G) of the eIF4F translational complex, while the other site is the docking site for the 5’ cap structure of a subclass of mRNAs. By using a VHH library, Chris’s team, was able to identify a potent and novel inhibitor of the eIF4G interaction, and solve its crystal structure. In another approach, Chris was able to graft a novel peptide optimally onto the surface of a VHH scaffold that mimicked the cap-structure using yeast display. Again a potent inhibitor of this interaction site was obtained. Chris explained that these two VHH molecules were functional in cell-based assays, and would go on to be tested in preclinical models to determine which site on eIF4E was most suitable for future drug development. He also outlined how this system termed PELE could be used to generate novel reagents against targets of significant biological interest for the wider community.

Dr Paul MacAry gave a rousing introduction to his talk where he highlighted the pivotal role that antibody engineers will play in the future of Medicine. This is in recognition of the fact that antibody medicines have replaced traditional small molecule drugs as preferred modalities for treating many of the most common malignant and inflammatory diseases that afflict human populations. In a beautifully detailed study, he showed how antibodies to HLA antigens of the donor could limit the efficacy of organ transplantation. Tragically, sometimes after a successful initial transplant, the donated organ starts to fail slowly due to the production by the host of damaging antibodies recognizing the graft. Using a phage antibody library prepared by Dr Wang Cheng-I (SIgN), Paul identified the type of antibody that was responsible for this antibody-dependent graft rejection and in collaboration with colleagues at NTU, solved the structure of these fascinating molecules. He was able to show that the current mechanisms for clinically determining which patient may have a greater likelihood of making these damaging antibodies are inadequate and his work offers a promise of improved methods for matching the donated organ to recipient in a way that will minimize the chance of the production of these donor-specific antibodies (DSAs).

Dr Andre Choo (BTI) described his team’s recent work on identifying monoclonal antibodies using phenotypic screens following whole cell immunization. This approach has led to the discovery of an exceptionally interesting class of antibodies that recognize epitopes created by glycan modification at particular amino acid sequences. This dual specificity gives the antibodies an exceptional preference for binding the antigenic protein on tumour cells and one of the antibodies developed by Andre’s team is now going forward for further development with EDDC. The BTI platform to study glycan modifications on proteins is proving exceptionally valuable in understanding how these modifications are recognized immunologically.

Dr Tatsushi Kodama (Chugai Pharmabody Research) presented work on the development of the T-cell redirecting antibody (TRAB) program. TRABs recognizing multiple tumour antigens have been developed including one that recognizes a peptide derived from the HPV-E7 protein docked into the HLA protein. The most advanced program, which he described in detail, uses a bi-specific antibody directed towards GPRC5D, which is expressed only on multiple myeloma cells and at very low levels on plasma cells and B-cells. Bi-specific antibodies showed exceptional potency in suppression of tumour growth both in in vitro and in vivo xenograft models and suggest that GPRC5D is an antigen specific to multiple myeloma and a good potential target for clinical TRAB therapy.

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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.

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Participants at the networking session

Photography: He Ping Ping

References:

1) FDA GUIDANCE DOCUMENTS:

2) Koh XY et al, Oncogene. 2019 Aug 15. doi: 10.1038/s41388-019-0946-8