Arno Therapeutics, Inc. and Leica Biosystems (LBS) have announced that the companies have entered into a co-development agreement for the development of a companion diagnostic (CDx) for Arno's lead compound and personalized therapy, onapristone.
Onapristone is an oral, anti-progestin hormone blocker that has been shown to have anti-tumor activity in breast cancer. Onapristone appears to selectively block the activation of the progesterone receptor (APR). This is believed to inhibit the growth of APR-driven breast, endometrial and other tumors.
The CDx will be an immunohistochemical (IHC) in vitro diagnostic (IVD) test used to detect APR in various women's cancers, including endometrioid and breast cancer. This CDx test will help to identify patients who are APR positive and therefore most likely to respond to treatment with onapristone. This also has potential application in castration-resistant prostate cancer (CRPC).
In preclinical work sponsored by Arno, IHC testing on archived specimens has shown that approximately 40% of archived endometrioid cancer specimens and approximately 25% of archived breast cancer specimens were APR positive.
Initial findings by Arno indicate that progesterone receptor (PR) was present in CRPC specimens and potentially active in a subset of tumors. Further investigation is underway to determine the frequency of APR positive tumors in CRPC specimens.
Under the terms of the co-development agreement, Arno will sponsor and conduct clinical trials for onapristone. Leica will develop and validate the CDx for APR with responsibility for ensuring the investigational CDx kit is ready, available and meets FDA and other health authority standards for a planned Phase II trial of onapristone in endometrioid cancer. The co-development program aims to achieve simultaneous approval and launch of onapristone and the CDx IVD for APR.
"This agreement with Leica Biosystems is a significant milestone for Arno and an important step forward in the development of onapristone. We believe that partnering with a world-class organization such as Leica will enable us to quickly and effectively get to reliable, reproducible and practical APR positive tumor detection. This will help identify the patients most likely to benefit from treatment with onapristone," said Glenn Mattes, Chief Executive Officer of Arno Therapeutics. "We are excited about what the future holds for Arno as we enter a critical period for the Company with the commencement of our first Phase I trial which will evaluate onapristone in progesterone receptor positive tumors."
"We are pleased to partner with Arno to co-develop this companion diagnostic for onapristone," added Dr. Matthias Weber, President of Leica Biosystems. "Personalized medicine is a key development in oncology. We believe that diagnostics such as the APR test will play a critical role in the broader effort to improve quality of care for patients."