Prescient Therapeutics debuts CellPryme-A at world’s largest CAR-TCR meeting in Boston

At the world’s largest CAR-TCR meeting, Prescient Therapeutics (ASX: PTX) has debuted CellPryme-A, which is a novel adjuvant designed to be administered to cancer patients in combination with cellular immunotherapy such as CAR-T.

CellPryme-A was unveiled at the CAR-TCR Summit in Boston this week.

According to Prescient, CellPryme-A makes a tumour microenvironment more amenable to cellular immunotherapy by “significantly” improving tumour killing and survival.

This was demonstrated in pre-clinical studies, and Prescient noted its impact was even greater when used with its CAR-T manufacturing technology: CellPryme-M.

“Prescient is delighted to finally unveil CellPryme-A as a distinct but complementary addition to CellPryme-M to expand our stable of cell therapy enhancements,” Prescient managing director and chief executive officer Steven Yatomi-Clarke said.

“Together with Prescient’s next-generation CAR platform, OmniCAR, Prescient has placed itself enviably at the forefront of cellular immunotherapy by creating technologies that overcome the challenges facing the field,” he said.

Mr Yatomi-Clarke said CellPryme-A has third-party commercialisation potential. As a result, the company is seeking to licence the adjuvant to external parties for incorporation in their own cell therapy programs.

Initial discussions with potential collaborators are already underway.

CellPryme-A

Prescient will also incorporate CellPryme-A into its own next generation CAR-T therapy OmniCAR-T programs – particularly those that target solid tumours.

The company currently has a clinical grade supply of CellPryme-A, regulatory documentation and a “compelling body” of pre-clinical data. The material also has GMP-ready status.

Prescient envisages CellPryme-A can be administered to patients via intravenous infusion either prior to, or just after starting cellular immunotherapy such as CAR-T.

The treatment has been designed to counteract the “hostile cold tumour microenvironment”, which Prescient says is known to dampen the tumour killing ability of CAR-T cells and other similar immunotherapies.

This is achieved by reducing the number of suppressive regulatory T cells (Tregs) that infiltrate the tumour.

Pre-clinical trials in an immune-competent mouse model of HER2+ colon cancer and a conventional CAR-T cell therapy targeting HER2 tumour cells was able to reduce the number of Tregs.

After only one week of treatment, twice-weekly administration of CellPryme-A reduced the number of Tregs per milligram of tumour by two-thirds.

As a result, CAR-T infiltration of tumours was increased.

When CellPryme-A was added to CellPryme-M pre-treated CAR-T cells, it showed “impressive” synergies in the aggressive colon cancer model.

Only one model in the group that received CellPryme-A and CellPryme-M pre-treated CAR-T cells had a detectable tumour by day 15.

Prescient senior vice president of scientific affairs Dr Rebecca Lim said solid tumours such as colon cancer continue to pose a challenge to traditional CAR-T therapies.

“It is crucial that we address the immunosuppressive contributions of regulatory T cells as they significantly inhibit the efficacy of even the best-in-class CAR-T cells.”

“The synergies between CellPryme-A and our CellPryme-M platform, gives cellular immunotherapy the best chance at success based on these animal studies,” Dr Lim added.