Pieris Signs Broad Collaboration With Sanofi-Aventis and Sanofi Pasteur to Develop Anticalin Therapeutics

FREISING-WEIHENSTEPHAN, Germany, September 28, 2010 - Pieris AG (www.pieris-ag.com/) announced today the signature of a
collaboration and license agreement with both Sanofi-Aventis and Sanofi
Pasteur, the vaccines division of the sanofi-aventis Group (EURONEXT: SAN and
NYSE: SNY), under which Pieris will apply its proprietary Anticalin
technology to discover novel Anticalin drugs against multiple targets, with
further development undertaken by Sanofi-Aventis and Sanofi-Pasteur. The
collaboration will initially involve two targets nominated by Sanofi-Aventis
and Sanofi-Pasteur, and includes the option for four additional targets.

Anticalins (www.pieris-ag.com/technology/anticalins.php) are a
novel generation of targeted therapeutics and are sourced from Pieris'
proprietary libraries. They have the potential to overcome some of the
constraints of monoclonal antibodies, thereby allowing novel therapeutic
approaches.

"This multi-year collaboration underscores our strategy of developing a
broad pipeline of therapeutic Anticalin drug candidates comprising partnered
programs in addition to our proprietary drug portfolio," noted Stephen Yoder,
CEO of Pieris. "The opportunity to collaborate with a pharmaceutical company
of sanofi-aventis' caliber is an exciting step as we continue to demonstrate
the diverse applicability of the Anticalin technology."

"Sanofi-Aventis' basic objective of finding new solutions to address
patients' needs is furthered in this collaboration by exploiting innovative
technology which focuses on some of the fundamental mechanisms of disease
processes," commented Leopold Bertea, VP of the Scientific Core Platform,
Biologics Center at sanofi-aventis. "Pieris' Anticalin technology will allow
sanofi-aventis to take a more comprehensive approach to developing targeted
therapeutics, as we believe the Anticalin technology will complement our
existing suite of more conventional technologies."

Under the terms of the agreement, Pieris will receive EUR 3.5 million in
an upfront payment for the first two targets, plus committed research funding
and payments for the achievement of research, preclinical, regulatory and
commercial milestones. Overall, the agreement could encompass for Pieris, per
each product resulting from the collaboration, up to EUR 26.5 million in
development milestones for the first therapeutic application and EUR 18
million in commercial milestones. Further milestones would be received by
Pieris with respect to the same product in the case of development of that
product in additional therapeutic applications. Payments will also include
tiered royalties on sales of products resulting from the collaboration.
Sanofi-Aventis and Sanofi Pasteur will have exclusive marketing rights
worldwide for all such products.

About Sanofi-Aventis

Sanofi-Aventis, a leading global pharmaceutical company, discovers,
develops and distributes therapeutic solutions to improve the lives of
everyone. Sanofi-aventis is listed in Paris (EURONEXT: SAN) and in New York
(NYSE: SNY).

About Sanofi Pasteur

Sanofi Pasteur, the vaccines division of Sanofi-Aventis Group, provided
more than 1.6 billion doses of vaccine in 2008, making it possible to
immunize more than 500 million people across the globe. A world leader in the
vaccine industry, Sanofi Pasteur offers the broadest range of vaccines
protecting against 20 infectious diseases. The company's heritage, to create
vaccines that protect life, dates back more than a century. Sanofi Pasteur is
the largest company entirely dedicated to vaccines. Every day, the company
invests more than EUR 1 million in research and development. For more
information, please visit: www.sanofipasteur.com or
www.sanofipasteur.us.

About Pieris

Pieris AG is an independent biotechnology company advancing its
proprietary Anticalin(r) technology to create safer, more efficacious and
more convenient protein therapeutics. Exclusive to Pieris, Anticalin-based
drugs promise to address high-unmet medical needs and expand the therapeutic
potential of current targeted approaches. Pieris' pipeline ranges from its
lead compound (anti-VEGF, oncology), which entered the clinic in the first
half of 2010, to multiple Anticalins in preclinical development. Pieris will
commercialize Anticalin therapeutics through strategic partnerships,
involving both its proprietary pipeline and its de novo drug discovery
capabilities. Apart from today's announced deal, its most recent partnership
is with Allergan, Inc. (NYSE: AGN), focusing on novel treatments for eye
diseases. Privately held, Pieris has been funded by premier
biotechnology-focused venture capital, including lead investors OrbiMed
Advisors and Global Life Science Ventures. For more information, please
visit: www.pieris-ag.com.

For more information, please contact: Pieris AG, Stephen Yoder, CEO
+49(0)8161-1411-400, info@pieris-ag.com

For more information, please contact: Pieris AG, Stephen Yoder, CEO +49(0)8161-1411-400, info at pieris-ag.com