PharmAbcine Presents Updated Preclinical Data of Its Anti-VISTA Antibody Candidate at AACR 2022

DAEJEON, South Korea, April 11, 2022 /PRNewswire/ -- PharmAbcine Inc. (KOSDAQ: 208340ks), a clinical-stage biotech company focusing on the development of next-generation antibody therapeutics, announced today that the Company presented an updated preclinical data PMC-309, the Company's anti-VISTA antibody candidate at AACR (American Association for Cancer Research) 2022 Annual Meeting currently taking place both online and offline in New Orleans.

PMC-309, one of the company's first immuno-oncology drug candidates, is a monoclonal IgG (Immunoglobulin G) that targets human VISTA (V-domain Ig Suppressor of T cell Activation), an immune checkpoint regulator. VISTA is found overexpressed on MDSC (Myeloid-Derived Suppressor Cells) and M2 macrophages both of which are immunosuppressive cells found abundantly around TME (Tumor Microenvironment).

The new findings from the poster presentation are as follows:

1) PMC-309 indirectly activates T cells by inhibiting VISTA expressions on immunosuppressive cells.
2) It has shown to inhibit MDSCs and M2 macrophages.
3) It activates monocytes, one of key factors in innate immunity, which also led to the proliferation of pro-inflammatory M1 macrophages.
4) The animal model study showed significantly improved tumor growth inhibition when PMC-309 is used in combo with an anti-PD1 drug.

The in vitro studies confirmed that PMC-309 inhibits MDSCs and M2 macrophages which created a pro-inflammatory environment. The MDSC inhibition showed dose dependent increase of IFN-y, a pro-inflammatory cytokine, similar to an anti-PD1 drug but higher than an anti-CTLA4 drug. The M2 macrophage inhibition decreased the proliferation of Tregs (regulatory T cells) while boosted the number of NK (Natural Killer) cells compared to the control group. Both data from Treg and NK cell experiments were superior to that of an anti-PD1 drug.

PMC-309 has also shown to activate innate immunity as it increased TNF-alpha, a pro-inflammatory cytokine released by monocytes. The elevated level of TNF-alpha has also led to polarization of M1 macrophages, which release pro-inflammatory cytokines. On the other hand, anti-PD1, anti-PDL1, and anti-CTLA4 drugs showed lower elevation of TNF-alpha and M1 macrophage than PMC-309.

Lastly in vivo studies, the experimental mice were administered with PMC-309 to evaluate tumor growth inhibition. PMC-309 showed notable tumor growth reduction similar to an anti-PD1 drug, but when used in combo with an anti-PD1 drug, there was a significantly improved anti-tumor effects than either monotherapies. Likewise, the combo therapy showed better T cell infiltration and MDSC reduction in the tumor microenvironment.

"Our latest data reveals that PMC-309 can activate adaptive immunity (T cells) like the existing drugs, but also can activate innate immunity (monocytes), where the existing drugs show low performance," said Dr. Cheon Ho Park, Head of Drug Discovery Team at PharmAbcine. "This allows PMC-309 to fill in the role of complementary mode of action that the existing drugs need for better anti-tumor effects,"

"We are confident that PMC-309 can be a promising immunotherapeutic strategy in both mono and combo therapies for patients who do not respond to other immuno-oncology drugs," said Dr. Jin-San Yoo, CEO of PharmAbcine. "To establish safety profile, we initiated GLP-Tox studies in April 2021. We received a notice from our CRO partner that the toxicology studies are completed and the final report will be ready in 2Q22. In 2Q22, the Company will also submit a clinical trial application to the HREC (Human Research Ethics Committee) in Australia for a Phase 1 study."

The poster presentation is currently available on the AACR website. The details of the presentation are as follows:

Title: PMC-309, a highly selective anti-VISTA antibody reverses immunosuppressive TME to immune-supportive TME
Session category/title: Preclinical Immunotherapy
Presentation Type: Online (E-poster)
Poster Number: 5557
Date: April 8-13, 2022

About PharmAbcine Inc.

PharmAbcine is a clinical-stage biotech company focusing on the development of fully human antibody therapeutics to treat neovascular disorders, tumors, and other medically unmet diseases. It provides therapeutic antibodies for a wide spectrum of indications from oncology, immuno-oncology, ophthalmology, pulmonology, to renal pathology.

PharmAbcine has its own HuPhage library and innovative selection system. PharmAbcine's advanced 3G expression system accommodates high levels of antibody production and steady reproducibility. With these cutting-edge technology platforms, it provides state-of-the art antibody generation services.

PharmAbcine also has unique knowhow in the area of the antibody production, early drug development, and clinical development.

For additional information about PharmAbcine, visit http://www.pharmabcine.com or follow us on Youtube and Linkedin.

For licensing deals, co-development, and collaboration in research or antibody discovery inquiries, please contact:

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Sungjun Park, Associate
E-mail: sungjun.park@pharmabcine.com 
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