Karolinska Development AB Aprea Announces First Patient Enrolled In Phase Ib/II Clinical Study

STOCKHOLM August 2, 2017. Karolinska Development portfolio company Aprea Therapeutics today announces First Patient Enrolled in Phase Ib/II Clinical Study of APR-246 for the Treatment of Platinum-Resistant High-Grade Serous Ovarian Cancer

Aprea Therapeutics, a privately held, clinical stage biopharmaceutical company developing novel anticancer therapies targeting the tumor suppressor protein p53, announced today that the first patient was enrolled in a Phase Ib/II clinical study of APR-246 in platinum-resistant high-grade serous ovarian cancer (HGSOC).

"We are excited to begin this important clinical study in a subset of high-grade serous ovarian cancer patients with few treatments options," said Christian S. Schade, President and Chief Executive Officer of Aprea Therapeutics. "This study complements our ongoing randomized Phase II study in platinum sensitive HGSOC patients and further enhances our growing clinical strategy of testing APR-246 with various combinations and in multiple tumor types, all with a high prevalence of mutated p53 protein. We look forward to seeing the results of this study in first half of 2018."

Professor Charlie Gourley, Chair of Medical Oncology at the Edinburgh Cancer Research Center of the University of Edinburgh, commented, "High-grade serous ovarian cancer is the most deadly form of ovarian cancer and nearly always carries one or more mutations in the p53 gene. The majority of patients with this cancer develop tumors that are resistant to platinum-based chemotherapy and there are very limited treatment options for platinum-resistant disease. By targeting mutated p53 and restoring its normal function, APR-246 may provide a much-needed therapeutic benefit for this difficult-to-treat, platinum-resistant patient population."

About p53 and APR-246

The p53 tumor suppressor gene is the most frequently mutated gene in human cancer, occurring in approximately 50% of all human tumors. These mutations are often associated with resistance to anticancer drugs and poor overall survival, representing a major unmet medical need in the treatment of cancer.

APR-246 has been shown to reactivate mutant p53 protein - by reconverting mutant p53 into wild-type p53 conformation and function - and thereby induce programmed cell death in human cancer cells. APR-246 has demonstrated compelling pre-clinical antitumor activity in a wide variety of solid and hematological (blood) tumors, including ovarian cancer, small cell lung cancer, oesophageal cancer and acute myeloid leukemia (AML), among others. Additionally, strong synergy has been seen with both traditional anticancer agents, such as chemotherapy, as well as newer mechanism-based anticancer drugs and immuno-oncology checkpoint inhibitors. In addition to pre-clinical testing, a Phase I/Ib clinical program with APR-246 has been completed, demonstrating a favorable safety profile and both biological and confirmed clinical responses in hematological malignancies and solid tumors with mutations in the p53 gene. The Company is enrolling a randomized Phase II study in platinum-sensitive ovarian cancer, a Phase Ib/II study in myelodysplastic syndrome and is expecting to initiate additional clinical studies of APR-246 in 2017.

About Aprea Therapeutics

Aprea Therapeutics is a Boston, Massachusetts- and Stockholm, Sweden-based biopharmaceutical company focused on the discovery and development of novel anticancer compounds reactivating the tumor suppressor protein, p53. The Company's lead program, APR-246, a first-in-class small molecule drug candidate, is in Phase II clinical development in ovarian cancer patients, and additional clinical studies with APR-246 in other cancer indications are planned. In March 2016, Aprea completed a EUR 46 million Series B financing with an international syndicate co-led by Versant Ventures and 5AM Ventures, with additional participation by Sectoral Asset Management, HealthCap, acting as local lead investor, and existing investor, Karolinska Development. For more information, please visit www.apreatherapeutics.com

About High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) is an aggressive and high-mortality form of ovarian cancer that accounts for as much as 70% of all ovarian cancer diagnoses, with nearly 90% of cases presenting at an advanced stage of disease. Treatment of HGSOC typically involves surgical debulking followed by chemotherapy, most commonly with platinum-containing agents. Platinum-sensitive HGSOC responds to treatment with platinum-containing chemotherapy regimens but relapse is common and the majority of patients develop platinum-resistant disease within 3-5 years. Platinum-resistant HGSOC is associated with diminished response to chemotherapeutic intervention and lower overall survival. Mutations in the p53 tumor suppressor protein occur in more than 96% of HGSOC patients and these mutations may contribute to the development of platinum-resistance and increased disease severity.

For further information, please contact:

Viktor Drvota, CEO, Karolinska Development AB
Phone: +46 73 982 52 02, e-mail: viktor.drvota@karolinskadevelopment.com

David Dible/Mark Swallow/Pip Batty, Citigate Dewe Rogerson
Phone: +44 20 7638 9571; e-mail: KDev@citigatedr.co.uk

TO THE EDITORS

About Karolinska Development AB
Karolinska Development AB (Nasdaq Stockholm: KDEV) is a Nordic life sciences investment company. The company focuses on identifying breakthrough medical innovations in the Nordic region that are developed by entrepreneurs and leadership teams. The Company invests in the creation and growth of companies that advance these assets into commercial products that are designed to make a difference to patients' lives while providing an attractive return on investment to shareholders.

Karolinska Development has access to world-class medical innovations at the Karolinska Institutet and other leading universities and research institutes in the Nordic region. The Company aims to build companies around scientists who are leaders in their fields, supported by experienced management teams and advisers, and co-funded by specialist international investors, to provide the greatest chance of success.

Karolinska Development has established a portfolio of nine companies targeting opportunities in innovative treatment for life-threatening or serious debilitating diseases.

The Company is led by an entrepreneurial team of investment professionals with a proven track record as company builders and with access to a strong global network..

For more information, please visit www.karolinskadevelopment.com

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