Aprea announces positive data from a clinical Phase I/II study with APR-246 in patients with advanced cancers

STOCKHOLM – September 18, 2012. Aprea today announced positive data from a
completed Phase I/II clinical study with its investigational drug APR-246. The
results from the study have been published in the Journal of Clinical Oncology.
Based on the positive data, Aprea is planning to advance APR-246 into a Phase II
proof-of-concept study in ovarian cancer. Aprea is a Karolinska Development
portfolio company.
In the Phase I/II-trial, escalating doses of APR-246 were administered as
monotherapy to 22 patients with advanced blood- or prostate cancer during up to
four consecutive days. Dose limiting toxicity was shown at plasma levels well
above predicted therapeutic plasma levels. The study also demonstrated dose
-proportional and time-independent pharmacokinetics for APR-246 over the dose
range studied.

The results from the study have been published in the Journal of Clinical
Oncology. In addition to reporting that the drug was well tolerated, the authors
conclude from the study that APR-246 induces biological effects and that there
are cases of clinical effects on tumor burden. One patient with advanced blood
cancer demonstrated a 50 percent reduction in the number of blast cells in the
bone marrow.

Ulf Björklund, CEO, Aprea:

“These are very encouraging study results. We are now planning to take the p53
-activating compound APR-246 forward into a Phase II-trial in epithelial ovarian
cancer with mutated p53 in combination with conventional chemotherapy.”

In the new proof-of-concept study, APR-246 will be administered in combination
with the reintroduction of a carboplatin-based regimen. A striking synergistic
effect between APR-246 and the very active and frequently used cancer product
carboplatin has been observed in pre-clinical experiments.

Torbjörn Bjerke, CEO, Karolinska Development:

“This is indeed promising data. Although it was primarily a safety trial, the
data indicates that APR-246 has an anti-tumor effect. APR-246 was well tolerated
and, importantly, the safety profile is different from traditional cytostatic
drugs. With these new results we can see a clear path forward for APR-246,
especially in carboplatin-resistant patients.”

For further information, please contact:
Ulf Björklund, CEO, Aprea AB
Phone: +46 (0)8 508 845 04, e-mail: ulf.bjorklund@aprea.com

Torbjörn Bjerke, CEO, Karolinska Development AB
Phone: +46 (0)72 744 41 23, e-mail: torbjorn.bjerke@karolinskadevelopment.com

TO THE EDITORS

About Aprea
Aprea AB is a Swedish biotech company focusing on discovery and development of
novel anticancer compounds targeting the tumor suppressor protein p53.
Aberrations in p53 are common in many various cancer forms and are associated
with increased resistance to standard chemotherapy and thus poor prognosis.
Aprea is a Karolinska Development AB (publ) portfolio company. The other main
owners are Östersjöstiftelsen, Praktikerinvest and KCIF Co-Investment Fund KB.
For more information, please visit www.aprea.com .

About Karolinska Development AB
Karolinska Development aims to create value for investors, patients, and
researchers by developing innovations from world class science into products
that can be sold or out-licensed with high returns. The business model is to:
SELECT the most commercially attractive medical innovations; DEVELOP innovations
to the stage where the greatest return on investment can be achieved; and
COMMERCIALIZE the innovations through the sale of companies or out-licensing of
products. An exclusive deal flow agreement with Karolinska Institutet
Innovations AB, along with other cooperation agreements with leading Nordic
universities, delivers a continuous flow of innovations. Today, the portfolio
consists of 35 projects, of which 15 are in clinical development. For more
information, please visit www.karolinskadevelopment.com.

Karolinska Development is listed on NASDAQ OMX. Karolinska Development may be
required to disclose the information provided herein pursuant to the Securities
Markets Act.