This video poster, “End-to-end discovery to support the development of safe and efficacious engineered cell therapies” by Katherine Vousden, Large Molecule Director at Charles River Laboratories, discusses how downstream characterization enables identification of the best lead candidate for optimal therapeutic outcome.

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  • Video Transcript

    Katherine Vousden (00:00):

    Hello. My name is Katherine Vousden, and I'm a Science Director with Charles River, at one of our early discovery sites based in the UK.

    Katherine Vousden (00:10):

    Today I'm going to talk you through our poster, 'End-to-end Discovery to support the development of safe and efficacious engineered cell therapies'. The global market for cell and gene therapy including CAR-T is expanding, with many success stories in the lymphoma space. With more and more products in development, the associated safety and tox risks identified with some of the earlier clinical candidates has helped to inform the design of newer and safer therapies. A number of factors in the CAR design have been identified as influencing the safety and efficacy of CAR-T therapies. In particular, the selection of the tumor-targeting moiety, with its exquisite specificity and desirable biophysical attributes, along with appropriate affinity, and all that coupled with robust downstream workflows to identify off-target binding, are all really key in developing a successful therapy.

    Katherine Vousden (01:05):

    At Charles River, we have access through our newly acquired partners, Distributed Bio, to industry-leading phase display libraries, both single chain and VHH. These display libraries have been used successfully by a large number of clients in the CAR-T space. In fact, a significant minority of Distributed Bio's successful programs have been exactly for targets engineering binding modalities that have ultimately ended up in CAR-T. One reason for this is that the libraries have been designed to be biophysically stable and non-immunogenic. They're also incredibly large, which enables the delivery of large panels of unique binders with a range of affinities which can then all be assessed to determine the appropriate affinity, as well as finding that exquisite specificity that's required to enable the successful translation of that binder to a CAR-T construct with therapeutic value.

    Katherine Vousden (02:17):

    Once those binders have been identified within Distributed Bio, they can be engineered into the whole CAR construct and then taken to our additional work streams located elsewhere in our vast discovery network. Illustrated on this slide on the right, is one such example of the kind of in vitro validation that we can do. Once multiple binders have been identified, the next step is to compare the functionality and potency of the binders in CAR format. Here illustrated is a co-culture assay, which allows you to screen CAR-T cells containing various binders to identify the best lead candidate. This assay can assess potency, efficacy, and specificity at a high level of your CAR-T candidates.

    Katherine Vousden (03:08):

    In the figure illustrated, we can see a cytotoxicity co-culture assay example result. In this assay, different effector target cell ratios were tested to allow quantification of lower and upper limits of the cellular therapy. In this experiment anti-HER2 CAR-T cells were co-cultured with cell lines expressing high levels of HER2, or with cells lacking the expression of the target antigen.

    Katherine Vousden (03:32):

    At four different effector to target cell ratios, after 24 hours, the co-cultured cells were collected and stained with Hoechst and PI to analyze cell death by flow cytometry. In this case, a clear CAR-T dose dependent and anti-HER2 specific effect can be observed across the various effector to target cell ratios. For additional assays of how we can support CAR-T in vitro assessment, I'd like to direct you towards a second poster, 'Abstract ID 294 In-vitro efficacy studies to support engineered T-cell therapies'. So to conclude this poster, ultimately we believe that by combining our full end-to-end capabilities, the discovery platform afforded by Distributed Bio, coupled with the vast amount of experience and expertise we have elsewhere in discovery, to really balance efficacy and safety of your CAR-T therapy, we can help you with identifying your optimal therapeutic.

    Katherine Vousden (04:32):

    Thank you.