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Pieris Pharmaceuticals Presents Data at SITC Conference on Lead Immuno-Oncology Program Demonstrating Selective Tumor-Targeted Immune Responses

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Tumor-Targeting CD137/HER2 Bispecifics Exhibit Differentiation Over Anti-CD137 Monoclonal Antibodies and Possess Desired Drug-Like Properties

BOSTON, MA -- (Marketwired) -- 11/06/15 -- Pieris Pharmaceuticals, Inc. (NASDAQ: PIRS), a biotechnology company advancing novel biotherapeutics through its proprietary Anticalin® technology platform, announced today the presentation of new preclinical data from its lead immuno-oncology program demonstrating that its Anticalin-based CD137/HER2 bispecific PRS-343 drug candidates stimulate tumor-targeted immune responses distinct from conventional anti-CD137 monoclonal antibodies and possess desirable drug-like properties.

Pieris' PRS-343 bispecifics, which simultaneously target the inducible T-cell costimulatory receptor CD137 and the HER2 tumor antigen, are designed to promote CD137 clustering by bridging T cells with HER2-positive tumor cells, thereby providing a selective activation signal to tumor-specific T cells. They are in development for immunotherapy of HER2-positive cancers.

To be presented today at a poster session during the 2015 Annual Meeting for the Society for Immunotherapy of Cancer (SITC), the data demonstrate that PRS-343 drug candidates drive tumor-targeted T cell activation on multiple HER2 high-expressing tumor cell lines but not on HER2 low-expressing tumor cell lines, confirming the requirement of tumor-expressed HER2 binding to trigger the CD137-mediated anti-tumor immune response. In contrast, a reference anti-CD137 monoclonal antibody was demonstrated to activate T cells independent of tumor cell HER2 expression.

In additional presented studies, the PRS-343 drug candidates exhibited desirable drug-like properties with respect to stability, pharmacokinetic, and immunogenicity profiles. These included retaining full activity after four weeks at 40°C, as well as having both a predicted serum half-life equivalent to a monoclonal antibody and low immunogenicity risk.

A copy of the poster can be viewed and downloaded by clicking

Pieris Senior VP and Chief Development Officer, Louis Matis, M.D, commented, "CD137 is a highly promising target for cancer immunotherapy. However, conventional CD137-targeting antibodies lack tumor-selective activity, which may increase the risk of systemic toxicity. In contrast, by promoting CD137-induced immune activation that is localized to sites of HER2-positive tumor involvement, Pieris' bispecifics have the potential to enhance the therapeutic window for the target, affording greater safety and efficacy. We are actively advancing this program toward clinical studies as a top priority."

About Pieris Pharmaceuticals:

Pieris is a clinical stage biotechnology company that discovers and develops Anticalin-based drugs to target validated disease pathways in a unique and transformative way. Our pipeline includes immuno-oncology multi-specifics tailored for the tumor micro-environment, an inhaled Anticalin to treat severe asthma and a half-life-optimized Anticalin to treat anemia. Proprietary to Pieris, Anticalins are a novel class of protein therapeutics validated in the clinic and by partnerships with leading pharmaceutical companies. Anticalin®, Anticalins® are registered trademarks of Pieris. For more information visit

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This press release contains forward-looking statements as that term is defined in Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Statements in this press release that are not purely historical are forward-looking statements. Such forward-looking statements include, among other things, references to novel technologies and methods; our business and product development plans; our liquidity and ability to fund our future operations; or market information. Actual results could differ from those projected in any forward-looking statements due to numerous factors. Such factors include, among others, our ability to raise the additional funding we will need to continue to pursue our business and product development plans; the inherent uncertainties associated with developing new products or technologies and operating as a development stage company; our ability to develop, complete clinical trials for, obtain approvals for and commercialize any of our product candidates; competition in the industry in which we operate and market conditions. These forward-looking statements are made as of the date of this press release, and we assume no obligation to update the forward-looking statements, or to update the reasons why actual results could differ from those projected in the forward-looking statements, except as required by law. Investors should consult all of the information set forth herein and should also refer to the risk factor disclosure set forth in the reports and other documents we file with the SEC available at, including without limitation the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2014 and the Company's Quarterly Reports on Form 10-Q.

Company Contact:
Pieris Pharmaceuticals, Inc.
Darlene Deptula-Hicks
SVP and Chief Financial Officer

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Thomas Hoffmann

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The Del Mar Consulting Group, Inc.
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Source: Pieris Pharmaceuticals, Inc.