Cell therapy is an emerging treatment with great potential because, unlike small molecules, cells are dynamic. They can migrate, proliferate, differentiate, and respond to their environment both in vitro and in vivo.
Cell therapy company Refuge Biotechnologies, based in Menlo Park, CA is leveraging gene engineering technologies known as CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) to develop therapeutic cells that are programmed to make decisions inside the patient’s body. This commitment is aptly summarized by the company’s mission statement: Designing Intelligent Cell Therapies to Fight Cancer.
Refuge’s platform connects cell membrane receptors to CRISPR a/i systems, creating a genetically programmable switch that can control multiple gene expressions. Refuge is seeking to enable the integration of multiple therapies into a single type of therapeutic cells, one that combines greater efficacy with fewer side effects.
Refuge’s technology enables cells to sense their surroundings and conditionally activate or repress multiple genes when they encounter specific external antigens. In particular, with receptor-dCas, immune cells can now be engineered to conditionally turn on/off certain genes, such as PD-1, to generate more potent CAR-T immune cells when it senses the presence of a tumor cell.
Leading Refuge’s research programs is CEO and Co-founder Dr. Bing Wang. Dr. Wang co-founded the company following nearly a decade of life science investment banking experience. He most recently served as director of healthcare investment banking at Barclays Capital. Dr. Wang, a cancer survivor who is passionate about bringing forth “smarter” medicines that will transform cancer care, earned a B.S. in Applied Physics from Columbia University, an MBA from Columbia Business School, and a Ph.D. in Electrical Engineering from Princeton University.
WuXi AppTec communications asked Dr. Wang to explain how Refuge’s unique cell therapy platform can fight cancer in vivo and the future benefits of and challenges in developing cell therapies.
WuXi AppTec: How has cell therapy research progressed over the past 10 years? Do you anticipate a wave of new approvals coming over the next five to 10 years?
Dr. Bing Wang: Absolutely, the expectation is that cell therapies will become much more prominent as a treatment modality across many diseases over the next five to ten years. There has been an immense amount of progress in the cell therapy field over the last decade building on original research into using cells to treat diseases, especially as the Novartis and Kite/Gilead products have come to the forefront to treat hematological malignancies. At Refuge, we are building on this progress and hope to further apply the cell therapy modality with other mechanisms to make cell therapies more effective in oncology and beyond.
WuXi AppTec: What kinds of diseases are targeted with cell therapies?
Dr. Bing Wang: Recently, cell therapies have been most prominently linked to oncology, but there is a wide range of applications for which cell therapies can be targeted, including regenerative medicine, rare diseases, and metabolic and cardiovascular diseases. Refuge initially focused on furthering cell therapy efficacy in solid tumors, but now we are exploring the potential ways to utilize the Refuge platform beyond oncology indications.
WuXi AppTec: What scientific advances are needed to make cell therapies more effective?
Dr. Bing Wang: As research progresses further into how cell therapies work and act within the tumor microenvironment, it is expected that better control over these mechanisms will improve the efficacy of cell therapies. Refuge is uniquely positioned to be able to tackle these issues together as its platform technology has the ability to target multiple pathways that underpin these mechanisms at the same time by modulating multiple genes simultaneously in addition to a cell therapy itself, such as CAR-T. This effectively designs an intelligent cell that is fitter and can react to its environment.
WuXi AppTec: Will cell therapies ever be commonplace? If so, how soon?
Dr. Bing Wang: At the current rate of advancement across various cell therapy fields, it would be expected that cell therapies would become much more common in the clinic and industry. Within the next five to ten years, cell therapies could likely become a common treatment modality in addition to traditional small molecule medicines and antibody-based therapies.
WuXi AppTec: What are the risks and limitations of cell therapies?
Dr. Bing Wang: As with all medical treatments, there are safety and efficacy risks that need to be managed for cell therapies. With further use in the clinic, as we have seen with the evolution of therapy management in dealing with CRS (Cytokine Release Syndrome), many of the risks can be effectively managed so that patients can really benefit from curative cell therapies.
For current cell therapy products on the market, the obvious limitation today is that they are only indicated in hematological malignancies. There are various challenges for getting CAR-T (cell surface chimeric antigen receptor) therapy to perform better in solid tumors, including improving the ability to have CAR-T get into the tumor microenvironment and improving the persistence and fitness of CAR-T therapy cells, which many research and development institutions, including Refuge Biotech, are working towards solving.
The field of oncology presents a highly complex range of biology and manifestations that are still being discovered and understood today. It is likely that there are unknown limitations that will cap the ability to have a single solution for all cancers, so combination therapy across cell therapies and other treatments may still be needed.
WuXi AppTec: What cell therapies are you developing?
Dr. Bing Wang: Our mission at Refuge Biotech is to “Design Intelligent Cell Therapies To Fight Cancer” based on Stanley Qi’s original research in CRISPR interference and activation to allow cells to make decisions in vivo. When the cell therapy comes in contact with a tumor, different genes within the T cell are expressed to react and enhance the attack against cancer cells. To do this, we are leveraging a synthetic biology circuit that combines cell surface signaling with specific multiplexed gene modulation through use of a deactivated CRISPR system. This capability enables us to combine many different cancer therapeutic mechanisms in a single therapy.
As it relates to our initial clinical developments, we are applying known cancer biology, combining CAR-Ts against targets such as HER2, among others, with simultaneous modulation of genes responsible for various pathways involved in cancer pathogenesis. This includes checkpoint genes as well as targets in various other co-immunostimulatory and co-immunoinhibitory pathways. Our lead pipeline asset is a HER2 CAR-T plus PD-1 knockdown system for various solid tumor indications. We are also developing various additional pipeline assets focused on other CAR-T targets, with modulation of different genetic target combinations derived through intensive bioinformatics analysis to treat a wide range of cancers. Additional oncology indications will be disclosed in due course.
WuXi AppTec: How does your approach differ from other cell therapy companies?
Dr. Bing Wang: Our technology platform connects cell membrane receptors to CRISPR interference / activation to facilitate inducible gene modulation of multiple genes simultaneously with cell therapies such as CAR-T therapy.
CRISPR interference / activation is very different from standard gene editing technology, such as standard CRISPR, Talens and Zinc fingers, etc., in which there is no cutting of the genome. The CRISPR is “deactivated” to mute the cleavage site while maintaining all the gene targeting specificity through short guide RNA (sgRNA). At the same time a transcription that either down-regulates or up-regulates gene expression is combined to the deactivated CRISPR, so that the cell therapy can use the GPS mechanism of the CRISPR to pinpoint a targeted strand of DNA and switch that gene on or off to varying degrees. This structure is tethered to the cell surface so that it is released only in response to engagement of tumor antigen through activation of a CAR-T on the T-cell surface. On release, the structure travels to the cell nucleus guided by sgRNA to effect specific gene modulation, where gene targeting can be multiplexed through adding multiple sgRNAs.
Most DNA editing technologies snip out genes entirely and have an all-or-none effect, but we are able to control gene modulation and up-or-down-regulate multiple gene expressions at different levels. This will be important in combination therapy situations where you may not want to completely knockout endogenous genes since doing so can lead to long term permanent changes to the genome after tumor cells disappear.
The advantages of our platform consist of no cutting of genetic material, the ability to multiplex gene modulation through the addition of more sgRNAs, and the capability to simultaneously versus sequentially enhance this process, thereby providing better efficiency for manufacturing. Comparable editing technologies need to be more careful with concurrent edits due to potential translocation and genotoxicity risks, which are irrelevant issues for our technology.
By effectively being able to combine multiple cancer treatment modalities together, the Refuge platform will be able to provide better efficacy in the treatment of various cancers while simultaneously achieving a better safety profile.
WuXi AppTec: What are your major regulatory and commercial challenges? What lessons have you learned?
Dr. Bing Wang: We have a very novel approach to treating cancer that effectively incorporates synthetic biology, cell therapy and gene engineering. Therefore, familiarizing health authorities and regulatory bodies with our technology is essential, especially before we increase the complexity by using multiplexed targets. In parallel, we need to be diligent in manufacturing, as it is central to development and commercialization, alongside impeccable planning.
WuXi AppTec: The drug industry is already under enormous pressure in Congress to hold down prices. And as with other, new medicines, prices for some cell therapies seem to generate “sticker-shock” among patients. What are ways can we make new cell therapies more accessible to patients especially in these times?
Dr. Bing Wang: As with any new and complex class of treatments, we must find ways make them effective and ensure patients can access them. One key element to consider is manufacturing. The complexity of manufacturing and delivering cell-based therapies, compared to traditional biologics and small molecules, leads to higher costs. Cell therapies require greater precision and regulatory inspections to ensure quality grade practices, and we face a shortage of capacity in GMP-grade manufacturing facilities to support new cell-based products coming to market. But as more products advance toward the market, the resulting growth in manufacturing capacity and other innovations may help reduce cost.