Prescient Therapeutics unveiled a novel adjuvant/neoadjuvant named CellPryme-A. CellPryme-A is designed to be administered to cancer patients as an intravenous infusion in combination with cellular immunotherapy, such as CAR-T cell therapy, to address the hostile tumour microenvironment that cellular immunotherapies face. In animal models CellPryme-A reduces the number of suppressive regulatory T cells surrounding solid tumours that counteract the effectiveness of CAR-T and other cancer therapies. Whilst CellPryme-A demonstrated superior tumour killing and survival in pre-clinical studies, its effects were even greater when used together with Prescient's CAR-T manufacturing technology, CellPryme-M. This exciting new data was presented at the 7th Annual CAR-TCR Summit (Boston, MA), the world's pre-eminent forum in the CAR and TCR fields of cellular immunotherapy.

CellPryme-A is now ready for clinical testing and can be incorporated into clinical studies of existing cell therapies. For Prescient this opens up another avenue for collaboration with external parties and potential commercialisation. CellPryme-A has been developed by Prescient in collaboration with the Peter MacCallum Cancer Centre (Peter Mac), with Prescient owning the resultant intellectual property, which is the subject of a patent application.

CellPryme-A increased in CAR-T infiltration into the tumours. Specifically, there was a three-fold increase in CD4+ helper CAR-T cell and a four-fold increase in CD8+ cytotoxic CAR-T cells. These changes were not associated with changes to the CAR-T phenotype.

CellPryme-A treatment on its own had no impact on T cell exhaustion. This suggests that CellPryme-A could work in synergy with CellPryme-M. The addition of CellPryme-A to CellPryme-M pre-treated CAR-T cells showed impressive and demonstrable synergies in the aggressive MC38 colon cancer model. Notably, only one animal in the group that received the combination of CellPryme-A and CellPryme-M pre-treated CAR-T cells had detectable tumour by day 15.

Unsurprisingly, the combination of CellPryme-M pre-treated CAR-T cells and CellPryme-A also improved the predicted survival of these animals. Administration of conventionally manufactured CAR-T cells did not improve the probability of survival in this model. The addition of CellPryme-A alone extended this to day 28.

The combination of CellPryme-M pre-treated CAR-T cells and CellPryme-A saw 4 out of 7 animals survive beyond the intended length of study (i.e. beyond day 30). CellPryme-A doubled the numbers of CD8+ cytotoxic CAR-T cells in the spleen, which is a secondary lymphoid organ and known to be a site of CAR-T cell accumulation. The greatest CAR-T cell expansion was seen when CellPryme-M pre-treated CAR-T cells were administered alongside CellPryme-A, where CD4+ CAR-T cells expanded more than 6-fold and CD8+ CAR-T cells expanded more than 9-fold.

It is evident that these proprietary technologies can work synergistically to enable even conventional CAR-T cells to deliver an unprecedented level of potency in the setting of solid cancer.