StemBioSys Announces Launch of CELLvo™ Atrial Cardiomyocyte, a Technological Leap Forward in Cardiotoxicity Screening Developed in collaboration with REPROCELL, CELLvo™ Atrial Cardiomyocyte delivers non-genetically modified human heart cells that are chamber specific and derived from iPS (stem) cells

SAN ANTONIO, TX – June 13, 2023 – StemBioSys, Inc. (StemBioSys) announced today the launch of CELLvo™ Atrial Cardiomyocyte, a “chamber specific” human induced pluripotent stem cell derived cardiomyocyte (hiPSC-CM) designed to function identically to human atrial cardiomyocytes. StemBioSys developed CELLvo™ Atrial Cardiomyocyte to empower pharmaceutical companies and academics with a more precise, efficient and cost-effective platform for screening new drug products in vitro for cardiotoxicity compared to animal models and other in-vitro methods currently in use. “Having access to mature, human atrial cells derived from human induced pluripotent stem cells (hiPSCs) is a breakthrough in many ways,” said Bob Hutchens, CEO of StemBioSys. “The chamber-specificity of CELLvo™ Atrial Cardiomyocyte is a significant advance because the electrophysiology of each heart chamber is distinct, and there are drug compounds that are known to cause arrhythmia in only the atria or ventricles. Thus, these mature human atrial cells mirror those found in a natural, beating heart and should be better predictors of drug effects and toxicity. This thesis was affirmed by data published in a peer-reviewed journal, which demonstrated that hiPSC-CMs cultured on Matrix Plus are a more accurate predictor for cardiac toxicity than the ion-channel invitro testing method commonly in use.” CELLvo™ Atrial Cardiomyocyte builds upon prior research published in Nature Scientific Reports in which scientists with StemBioSys and the University of Michigan produced mature human cardiomyocytes in seven (7) days via CELLvo™ Matrix Plus platform, StemBioSys’ extracellular matrix. Further, the resulting cardiomyocytes promoted electrophysiological function and enabled the in vitro visualization of reentrant arrhythmia responsible for fatal cardiac events in humans. Comparatively, competing technologies require 30 to 100 days for only partial hiPSC-CM maturation.

Travis Block, Ph.D., Chief Technology Officer of StemBioSys, added, “hiPSC-CMs offer substantial promise in pre-clinical drug discovery, however the technology’s adoption has been hindered by hiPSC-CM immaturity and inconsistencies in cell production and functionality. CELLvo™ Atrial Cardiomyocyte combined with CELLvo™ Matrix Plus addresses this challenge by providing researchers with a highly efficient, ‘all-in-one’ system that enables experiments with greater reliability which can successfully predict the cardiac safety of drugs in the early development stage.” CELLvo™ Atrial Cardiomyocytes are being produced from hiPSCs licensed from REPROCELL. REPROCELL uses a proprietary technique to reprogram adult cells into stem cells without permanently altering the genome of the cells. Additionally, CELLvo™ ` Atrial Cardiomyocyte cells are purified prior to cryopreservation for long term storage using magnetic beads to eliminate unwanted cell types. This approach is relevant for therapeutic translation and provides a more biologically relevant cell than competing approaches that require genetic engineering of cells or other harsher methods that kill off unwanted cells but can induce a heart failure phenotype in the remaining cardiomyocytes. CELLvo™ iPSC-CMs, in contrast, are healthy, chamber-specific, and biologically relevant.

REPROCELL’s Chief Executive Officer, Chika Yokoyama, noted, “As one of the first companies to market iPSC-derived human cardiomyocytes, our cells are renowned for their stability and translatability using our latest RNA reprogramming technology. We are excited that they are being used to address this critical problem. We look forward to continued collaboration with StemBioSys.” Mr. Hutchens concluded, “CELLvo™ Atrial Cardiomyocyte is the first of several anticipated product launches utilizing our groundbreaking hiPSC technology. In the coming months, StemBioSys will be launching a companion hiPSC-CM product for developing ventricular cardiomyocytes. Our vision is for StemBioSys to be a driving force in a new era of drug discovery which relies on data from cultured, iPS-derived human cells, while reducing and replacing the use of animals in the drug discovery and toxicity testing fields.”

About StemBioSys, Inc. StemBioSys, Inc., a privately held, San Antonio-based biomedical company, manufactures and develops innovative, advanced stem cell technologies to meet the promise of regenerative medicine in a surging global market. Its patented and proprietary technology platforms – licensed from the University of Texas System – overcome key obstacles to creating clinically useful stem cell therapies. StemBioSys markets its products to the global research community under the CELLvo™ brand name.

About REPROCELL REPROCELL is a publicly traded (TYO:4978) Yokohama-based company that are experts in iPSC and human tissue technology. Its cutting-edge Stemgent StemRNA Reprogramming Technology provides business partners with high quality iPSCs for commercial and non-commercial use in both the clinical and research space. Its Biopta human tissue services predicts clinical success by using the closest possible model of drug behavior in humans. Human tissue testing is a translational approach to drug discovery that bridges the gap between animal studies and clinical trials. Find out more at: https://www.reprocell.com.

Contact StemBioSys, Inc.

Bob Hutchens (210) 877-9323

bob.hutchens@stembiosys.com

Media Tiberend Strategic Advisors, Inc.

Bill Borden (732) 910-1620

bborden@tiberend.co