Arno Therapeutics Advances Phase I/II Trial Evaluating Onapristone in Prostate Cancer to Phase II

- Phase II to include study of onapristone in combination with abiraterone -

FLEMINGTON, N.J., March 21, 2016 -- 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 enrolled the first patient in the second stage of its Phase I/II clinical trial evaluating onapristone in men with advanced castration-resistant prostate cancer (CRPC), after failure of abiraterone or enzalutamide.

The Phase II portion of this study will evaluate onapristone in combination with Zytiga® (abiraterone acetate) in patients with CRPC.  Stage 2 of the study also includes a Phase II cohort of patients with CRPC who will receive single agent onapristone.  An independent data review committee has determined the recommended Phase 2 dose of single agent onapristone to be 50mg extended release tablets, taken twice daily. 

Alex Zukiwski, MD, Chief Executive Officer of Arno Therapeutics, remarked, “Enrollment of the first patient in the Phase II portion of the trial is an important milestone as we look forward to determining the safety profile and potential antitumor activity of onapristone in combination with abiraterone, one of the most prescribed prostate cancer drugs on the market. Research shows that the progesterone receptor (PR) is moderately to highly expressed in CRPC and that progesterone can activate androgen receptor genes in prostate cancer cell lines with certain androgen receptor mutations, indicating that an anti-progestin like onapristone may have clinical benefit in inhibiting tumor growth in certain patients with CRPC. We believe the modified CRPC stage 2 protocol will enable us to more fully determine the potential benefits of onapristone in this patient population.”

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. 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 any antitumor activity.  This multi-site trial is taking place initially in the United Kingdom and is expected to enroll a total of approximately 75 patients. Arno is working with Biotrial S.A.S., a drug evaluation and pharmacology research company, as its contract research organization for this trial.  

About Prostate Cancer

In the United States, prostate cancer is the most frequently diagnosed cancer in men aside from skin cancer. Approximately 180,890 new cases of prostate cancer are estimated to be diagnosed in 2016 in the U.S. alone. With an estimated 26,120 deaths expected to occur in 2016, 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 www.arnothera.com. 

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 ability to identify and treat those patients most likely to benefit from onapristone, 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 successfully develop a diagnostic to identify APR tumors, 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. 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.

The Ruth Group
Lee Roth (investors) 
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Kirsten Thomas (media)
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