Kiadis announces new data related to its K-NK cell therapy platform presented today at the ISCT Annual Meeting

• Data presented demonstrates improved ex vivo PM21 expansion of NK cells when pre-activated with cytokines.

Amsterdam, The Netherlands, May 28, 2020 – Kiadis Pharma N.V. (“Kiadis” or the “Company”) (Euronext Amsterdam and Brussels: KDS), a clinical stage biopharmaceutical company, announces that new data related to its K-NK cell therapy platform will be presented today at the International Society of Cell & Gene Therapy (ISCT) virtual annual meeting. Poster #228, from the lab of Alicja Copik, Ph.D., at the University of Central Florida, will present data that shows how cytokine pre-activation enhances Kiadis’ PM21-particle driven NK cell expansion.

Dr. Copik’s group performed preclinical research to understand how both the expansion and the activity of ex vivo expanded NK cells can be further enhanced by coupling the PM21 expansion process with cytokine pre-activation prior to the expansion. This results in high-scale expansion of NK cells with a “memory-like” phenotype that can be re-activated upon detection of stimuli, resulting in a more potent response upon tumor detection. Other methods for producing NK cells with “memory-like” features have been developed and applied clinically, but cell yields were low and manufacturing processes were not amenable to scalable, commercial development.

Results presented as part of Dr. Copik’s poster at ISCT demonstrate that high-scale expansion of “memory-like” NK cells can be obtained with a combined pre-activation with cytokines followed by expansion with Kiadis’ PM21-platform. NK cells from healthy donor-derived peripheral blood mononuclear cell (PBMCs) were stimulated overnight with IL-12, IL-18 and IL-15 and then expanded with PM21 particles. The new methodology resulted in a significantly further increased expansion of NK cells than with PM21 alone. Also, the NK cells that were preactivated produced even larger amounts of IFNγ and were very responsive to activation by K562 tumor cells or cytokines.

In addition, receptor expression was similar for both cytokine preactivated NK and PM21 activated NK cells and demonstrated that both are in a highly activated state as compared to IL-2 activated NK cells. In vitro and in vivo data are also presented that confirm their anti-leukemic effects.

In summary, pre-activation with IL-12, IL-18 and IL-15 followed by PM21 particle expansion leads to significantly further increases of NK cells. Such NK cells have further enhanced IFNγ production upon stimulation with cytokines or tumor cells compared to PM21-NK cells without pre-activation, to yield a unique NK cell phenotype with a hyper-functional phenotype and potent therapeutic potential.