"Modulation of Immune Checkpoints by Self Deliverable RNAi for Adoptive Cell Transfer"

Two of the most promising approaches to cancer immunotherapy are immune checkpoint blockade by monoclonal antibodies and the adoptive transfer of immune cells The recent successes in treating melanoma with anti PD and anti CTLA antibodies as well as the extremely successful application of T cells engineered to express the CAR receptor targeting CD to treat B cell lymphomas initiated a waterfall of research in identifying new indications and targets for both antibodies and immune cells While highly effective in treating hematological malignancies adoptive transfer of natural or engineered T cells is much more challenging to implement for the treatment of solid tumors in large part due to the immunosuppressive tumor microenvironment Advirna is proposing to improve the efficacy of adoptive cell transfer therapies by pre treatment of immune cells ex vivo with RNAi reagents to prevent immunosuppression Our approach is based on the use of unique self deliverable RNAi sdRNAi molecules that have been chemically modified conferring them stability and the inherent ability to enter immune cells without the need for exogenous reagents or methods Because of its simplicity self deliverable RNAi technology is perfectly compatible with existing cell growth protocols sdRNAs are used as media component and is very easy to implement sdRNAi high efficiency of delivery andgt lack of toxicity and strong and long lasting effect of gene suppression enables knockdown of multiple immune checkpoint and or regulatory molecules involved in immunosuppression This may protect the adoptively transferred immune cells in the tumor microenvironment and enhance their efficacy as antitumor agents sdRNAs can be applied to a broad variety of ACT technologies CAR T engineered TCR TIL NK The unique properties of sdRNAi technology makes it a method of choice for multiplexed immune check point modulation in CAR T cells We have generated lead sdRNA compounds targeting a number of immune checkpoints PD LAG TIGIT etc Our preliminary results in tumor infiltrating lymphocytes TILs enhancing their cytotoxicity to melanoma tumor cells and in mesothelin targeting CAR T cells increasing their efficacy in a mouse model of ovarian cancer show promise for the success of the approach We propose to further optimize the existing chemical modification pattern of sdRNAs to improve the knockdown efficiency and longevity of the RNAi effect and to evaluate the effect of simultaneous knockdown of multiple immune checkpoints in vitro and in vivo using mesothelin CAR T cells Our overall goal is to create a series of optimized sdRNAs targeting most of the known immune checkpoints to allow customizable combinatorial RNAi cocktails for specific tumor and ACT cell types to protect immune cells and increase their efficacy Future in vivo studies in collaboration with academic groups and biotech companies will further evaluate this concept with a goal to move this technology to clinic as a general approach for enhancement of efficacy of any cell based therapies to treat solid tumors Two of the most promising approaches to immunotherapy of cancer are immune checkpoint blockade by monoclonal antibodies and adoptive transfer of immune cells targeting tumors We are proposing to use our novel self delivering RNAI technology to improve the efficacy of adoptive cell transfer therapies by pre treatment of immune cells ex vivo with to prevent immunosuppression Successful implementation of this approach will allow moving this technology to the clinic as a general complementary approach enhancing any existing cell based therapy to treat solid tumors