Arno Therapeutics Announces Data Validating Continued Onapristone and Companion Diagnostic Development at ASCO Annual Meeting 2015

FLEMINGTON, N.J., May 13, 2015 (GLOBE NEWSWIRE) -- Arno Therapeutics, Inc. (OTCQB:ARNI), a clinical stage biopharmaceutical company primarily focused on the development of therapeutics for cancer and other life threatening diseases, today announced promising data supporting the ongoing clinical development program for lead compound onapristone to be presented at the upcoming 2015 American Society of Clinical Oncology (ASCO) Annual Meeting, being held May 29-June 2 in Chicago, IL.

Alex Zukiwski, MD, Chief Executive Officer of Arno Therapeutics, commented, "Results from our Phase 1 study in women with progesterone (PR) positive tumors have been immensely informative and critical to the advancement of our onapristone clinical development program. In addition to demonstrating clinical benefit in a group of heavily pre-treated patients, the study demonstrated that Arno's highly purified onapristone extended-release formulation has a very manageable safety profile, providing the recommended dose for the Phase 2 study currently underway. Additionally, results from the first portion of our Phase 1/2 study in men with advanced castration-resistant prostate cancer (CRPC) confirm the very acceptable safety profile of onapristone. We look forward to sharing details of these two studies and providing an update on our ongoing Phase 2 trial in women with recurrent or metastatic endometrioid cancer that expresses the APR at the upcoming ASCO Annual Meeting."

Data from the three accepted abstracts are outlined below.

Abstract TPS5616 (Poster 168b) Phase 2 clinical study of onapristone (ONA) in patients (pts) with uterine endometrioid adenocarcinoma (EC) expressing the activated progesterone receptor (APRpos)

Presenting Author: Jacques Bonneterre, MD, PhD, Centre Oscar Lambret
Poster Session: Gynecologic Cancer
Date, Time, Location: Saturday, May 30; 1:15 - 4:45 p.m. CDT; S Hall A, McCormick Place

An ongoing Phase 2 clinical trial is evaluating the safety and efficacy of onapristone in post-menopausal women with recurrent or metastatic uterine endometrioid cancer that is APR positive. In addition, the trial is evaluating the companion diagnostic, which is being developed to detect APR in patients with endometrioid cancer to identify those patients more likely to respond to onapristone.

The ongoing Phase 2 study is actively recruiting post-menopausal women (≥18 years) with recurrent or metastatic uterine endometrioid cancer that is APR positive. At study entry, patients' APR status is determined by immunohistochemistry (IHC) on biopsy with slides stained using a technically-validated procedure and interpreted by trained pathologists. Patients are treated with the recommended Phase 2 dose (RP2D) of 50mg extended-release onapristone twice daily (BID) – as determined by the Phase I portion of the trial – until progressive disease or intolerability.

The primary endpoint is objective response rate by RECIST 1.1, with secondary endpoints including relationship between extent of APR expression and onapristone activity, safety and tolerability, duration of response, progression-free survival (PFS) and overall survival (OS). The Simon 2-stage design of the Phase 2 study includes 10 patients in the first stage. If two or more patients respond, the study will recruit an additional 19 patients (stage 2) to confirm anti-tumor activity.

Abstract 5593 (Poster 151) – Onapristone (ONA) in progesterone receptor (PR)-expressing tumors: efficacy and biomarker results of a dose-escalation phase 1 study

Presenting Author: Paul H. Cottu, MD, MSc, Institut Curie
Poster Session: Gynecologic Cancer
Date, Time, Location: Saturday, May 30; 1:15 - 4:45 p.m. CDT; S Hall A, McCormick Place

Data from 52 patients in a completed open-label, multi-center, randomized, parallel-group Phase I study of onapristone in women with PR-positive tumors (endometrial, breast, ovarian or other) demonstrated observed clinical benefit in these heavily pre-treated patients and data support ongoing onapristone development at the RP2D in APR-positive endometrioid cancer. The study showed eight patients had clinical benefit, with one patient experiencing a partial response (duration of response 32 weeks) and seven patients with protracted (≥ 24 weeks) stable disease.

The safety findings were reviewed by an independent Data Review Committee (DRC) and no dose limiting toxicities were observed. The RP2D was determined by the DRC to be 50mg extended-release onapristone BID.

The study explored the role of APR as a predictive immunohistochemical (IHC) biomarker. APR analysis was performed on archival tumor tissue for each patient. Of 11 PR-positive endometrial tumors, six were APR positive; of 8 PR-positive breast cancer tumors, three were APR-positive; of five ovarian cancer tumors, one was APR-positive. To date, the diagnostic assay for APR has been optimized for endometrioid cancer and validation in additional tumor types is currently ongoing.

Abstract 5051 (Poster 44) Phase 1-2 study of progesterone receptor (PR) inhibition with extended-release (ER) onapristone (ONA) in patients (pts) with castration-resistant prostate cancer (CRPC) - PK, safety and PR testing results from the dose escalation cohort

Presenting Author: Anuradha Jayaram, The Institute of Cancer Research & The Royal Marsden NHS Foundation Trust
Poster Session: Genitourinary (Prostate) Cancer
Date, Time, Location: Saturday, May 30; 1:15 - 4:45 p.m. CDT; S Hall A, McCormick Place

Data from 21 patients in the Stage 1a dose-escalation portion of an ongoing, open-label, Phase 1/2 clinical trial in men with advanced CRPC whose tumors have progressed on treatment with abiraterone or enzalutamide demonstrated that there were no dose-limiting toxicities or significant liver function test abnormalities at the doses evaluated (10, 20, 30, 40 or 50mg BID ER formulation).

Safety results from the Stage 1a portion of the study show the most common related adverse events were fatigue, anorexia, constipation, weight loss and grade 1 transient AST elevation. While serious adverse events were reported, none were considered related to onapristone, and there were no treatment discontinuations for adverse events.

About Onapristone

Onapristone is an oral, anti-progestin hormone blocker that has been shown in previous Phase II clinical trials (not sponsored by Arno) to exhibit considerable anti-tumor activity in patients with breast cancer. In pre-clinical testing, onapristone has been shown to block the activation of PR, which is believed to be a mechanism that inhibits the growth of APR driven breast, endometrial and other gynecological tumors. APR has the potential to function as a biomarker of anti-progestin activity, as detected by a companion diagnostic currently under development with Arno's partner, Leica Biosystems.

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 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.

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.