Pieris Pharmaceuticals Presents Positive Preclinical Data on Lead Bispecific Immuno-Oncology Program

BOSTON, MA–(Marketwired – September 21, 2015) – 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 for its Anticalin-based CD137/HER2 bispecific drug candidates in the PRS-343 immuno-oncology program. The data demonstrate potent CD137-driven T cell activation that is dependent upon drug-mediated HER2 engagement on the tumor cell surface. The Company reconfirmed its intent to achieve drug candidate nomination for this program by the end of the year.

Presented September 18, 2015 during a poster session at CRI-CIMT-EATI-AACR — The Inaugural International Cancer Immunotherapy Conference, the data provide an overview of the drug-like properties and pharmacodynamic activity of four distinct CD137/HER2 bispecific molecules comprised of an anti-HER2 monoclonal antibody genetically linked to an agonist CD137-targeting Anticalin® protein. All four bispecific molecules demonstrated not only desired biophysical properties, but also the ability to activate T cells ex vivo as a function of HER2 engagement. Importantly, the unique geometries of each drug candidate led to pronounced differences in levels of T cell activation, highlighting the importance of structure in designing bispecifics. A copy of the poster can be viewed and downloaded by clickinghttp://c.eqcdn.com/pierisag/db/164/1975/pdf/150914+CRI+Poster+postFinal.pdf.

Pieris President and CEO, Stephen Yoder, commented, “In contrast to traditional bispecific antibody efforts that utilize a one-size-fits-all format, Anticalin-based bispecifics enable tailored approaches to derive drug candidates with superior structure and function. We look forward to advancing our PRS-343 program through IND-enabling studies and into clinical trials.”

CD137 is a costimulatory immunoreceptor and a highly promising target for cancer therapy. However, conventional CD137-targeting antibodies suffer from a lack of tumor-selective activity, which may lead to peripheral toxicity, reducing the available therapeutic window. Pieris’ bispecifics are designed to promote CD137 clustering by bridging T cells with HER2-positive tumor cells, and to thereby provide a localized costimulatory signal to tumor antigen-specific T cells.

About Pieris Pharmaceuticals:
Pieris is a clinical-stage biotechnology company advancing its proprietary Anticalin® technology to create differentiated drugs that have the potential to be safer and more effective than conventional approaches. Anticalins show promise in addressing high-unmet medical needs and expanding the potential of targeted therapeutics. The company currently has a diverse proprietary pipeline and has ongoing R&D collaborations with Daiichi Sankyo, the Sanofi Group, Zydus Cadila, Stelis Biopharma and Allergan. Anticalin®, Anticalins® are registered trademarks of Pieris. For more information visit www.pieris.com.

Forward Looking Statements
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