Arno Therapeutics Receives Authorization to Proceed With Modified Phase I/II Trial Evaluating Onapristone in Prostate Cancer

FLEMINGTON, N.J., Aug. 18, 2015 (GLOBE NEWSWIRE) -- Arno Therapeutics, Inc. (OTCQB:ARNI), a clinical stage biopharmaceutical company focused on the development of therapeutics for cancer and other life threatening diseases, today announced that it has received authorization from the Medicines and Healthcare products Regulatory Authority (MHRA) to begin enrolling patients in the United Kingdom in the second stage of its Phase I/II clinical trial evaluating lead compound onapristone in men with advanced castration-resistant prostate cancer (CRPC). An independent data review committee has determined the recommended Phase II dose of single agent onapristone to be 50mg extended release tablets, taken twice daily. The second stage protocol has been modified to evaluate onapristone in combination with abiraterone (Zytiga®) in patients with CRPC that expresses the progesterone receptor (PR) or the T878A androgen receptor (AR) mutation. The AR T878 receptor mutation has been demonstrated to bind progesterone. The second stage of the study also includes a Phase II cohort of patients with PR-positive CRPC who will receive single agent onapristone.

Alex Zukiwski, MD, Chief Executive Officer of Arno Therapeutics, remarked, "The safety profile of onapristone in the dose escalation stage of the CRPC study has been consistent with our expectations in this group of heavily pretreated patients, and matches the Phase II dose for onapristone in the Company's other Phase II study, in women with recurrent or metastatic endometrioid tumors. With the modification to the CRPC stage 2 protocol, we are looking to determine the potential benefits of using single agent onapristone and the combination of onapristone plus abiraterone in patients with CRPC that would not otherwise benefit from continued use of abiraterone as a single agent. We are pleased to announce that patient screening has commenced."

The ongoing, open-label Phase I/II study is currently enrolling patients and is designed to evaluate the safety of onapristone in the selected patient population, determine the recommended Phase II dose and assess the potential benefits of single-agent onapristone and the combination of onapristone with abiraterone. This multi-site trial is being conducted at three centers in the United Kingdom and is expected to enroll a total of approximately 75 patients.

Onapristone is an oral, anti-progestin hormone blocker that has been shown in previous Phase II clinical trials (not sponsored by Arno) to exhibit anti-tumor activity in patients with breast cancer. In pre-clinical testing, onapristone has been shown to block the activation of the progesterone receptor (PR), which is believed to be a mechanism that inhibits the growth of activated progesterone receptor (APR) driven breast, endometrial and other, primarily gynecological tumors, in addition to castration resistant prostate cancer tumors. APR has the potential to function as a biomarker of anti-progestin activity, as detected by a companion diagnostic currently under development. Arno Therapeutics has improved the manufacturing process for onapristone and developed a proprietary, sustained release formulation to avoid the high peak concentrations associated with previously investigated immediate release type formulations, and to allow the continuous suppression of the APR.

About Prostate Cancer

According to the International Agency for Research on Cancer, in the United States, prostate cancer is the most frequently diagnosed cancer in men aside from skin cancer. An estimated 233,000 new cases of prostate cancer were diagnosed during 2014 in the U.S. alone. With an estimated 29,500 deaths expected to occur in 2014, prostate cancer is the second-leading cause of cancer death in men.

On the global scale, prostate cancer is the fourth most common cancer in both sexes combined and the second most common cancer in men. Worldwide in 2012, an estimated 1.1 million men were diagnosed – accounting for 15 percent of the cancers diagnosed in men – and there were an estimated 307,000 deaths, making prostate cancer the fifth leading cause of death from cancer in men (6.6% of the total men deaths).

About Arno Therapeutics

Arno Therapeutics is a clinical stage biopharmaceutical company developing innovative products for the treatment of cancer and other life threatening diseases. Arno has exclusive worldwide rights to develop and market three innovative product candidates. These compounds are in clinical or preclinical development as product candidates to treat hematologic malignancies and solid tumors, as well as infectious diseases. For more information about the company, please visit

Forward-Looking Statements

This press release contains forward-looking statements that involve substantial risks and uncertainties. These statements are often, but not always, made through the use of words or phrases such as "anticipates," "expects," "plans," "believes," "intends," and similar words or phrases. These forward-looking statements include, without limitation, statements regarding the timing, progress and anticipated results of the clinical development of onapristone, including the expected enrollment of Arno's Phase I/II study in patients with CRPC, the potential benefits of using onapristone in combination with abiraterone, as well as Arno's strategy, future operations, outlook, milestones, future financial position, future financial results, plans and objectives. Arno may not actually achieve these plans, intentions or expectations and Arno cautions investors not to place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements made here. Various important factors could cause actual results or events to differ materially from these forward-looking statements. Such factors include, among others, risks that the results of clinical trials will not support claims or beliefs concerning the safety or effectiveness of onapristone or any other product candidates, the ability to finance the development of Arno's product candidates, regulatory risks, and reliance on third party researchers and other collaborators. Additional risks are described in the company's Annual Report on Form 10-K for the year ended December 31, 2014 and its Quarterly Report on Form 10-Q for the quarter ended June 30, 2015. Arno is providing this information as of the date of this press release and does not undertake any obligation to update any forward-looking statements as a result of new information, future events or otherwise.

CONTACT: The Ruth Group Lee Roth (investors) (646) 536-7012 Kirsten Thomas (media) (646) 536-7014 Arno Therapeutics Lawrence Kenyon (862) 703-7171

Source:Arno Therapeutics Inc.