CELLULAR DYNAMICS INTERNATIONAL AND ROCHE PALO ALTO ENTER AGREEMENT
TO SCREEN DRUG COMPOUNDS FOR CARDIOTOXICITY


MADISON, Wis., March 5, 2008 Cellular Dynamics International (CDI) announced today that
it has entered an agreement with Roche Palo Alto, one of Roches five research facilities, to
test candidate drug compounds for cardiotoxicity, or damage to heart tissue.

Under the agreement, Roche will supply CDI with 2 sets of 25 well-characterized drug
compounds to validate CDIs current toxicology products and services. CDI will test those
compounds using human cardiomyocytes, or heart muscle cells, derived from human
embryonic stem cells in cytotoxicity and electrical physiology. The goal of the project is to
detect drug-induced changes in the electrical activity of the heart (for example, prolongation of
the QT interval), noting abnormalities that cause the heart to beat faster, slower, or more
irregular than normal. CDI will also work with Roche on cytotoxicity testing of the compounds in
hopes of building predictive models of toxicology.

We are very excited to be working with Roche in pioneering the use of human cardiomyocytes
derived from human embryonic stem cells for cardiotoxicity testing, said Nick Seay, Chief
Technology Office at CDI. Because over 30% of all drug failures are a direct result of
cardiotoxicology problems, our goal is to build the next generation of biological models.

Chris Kendrick-Parker, CDIs Vice President, Business Development, continued, CDI is
dedicated to developing solutions that will bridge the gap between in vitro testing of drug
candidates and in vivo testing using animal models. Validating our unique platform for
differentiated cells derived from human embryonic stem cells with a world leader in toxicology
testing is the first step in using these cells in routine toxicology testing.


About Cellular Dynamics International, Inc.
Cellular Dynamics International, Inc. (CDI) is a leading developer of next-generation tools and
services for drug discovery, screening and predictive toxicology. CDI combines the power of
human embryonic stem cells and cardiac toxicity for world class drug development including a
GLP facility for hERG testing for FDA submissions. CDI was founded in 2006 by Jamie
Thomson a pioneer in human embryonic stem cells from the University of Wisconsin-Madison.
CDIs facilities are located in Madison, Wisconsin.