Arno Therapeutics to Present Data Further Validating Diagnostic Development of CDx for Onapristone at San Antonio Breast Cancer Symposium 2014

Abstract #5567
Poster #P5-02-13
Poster Session 5
Friday, December 12; 5:00 – 7:00 p.m. CT
Track: Diagnostic Pathology, Hall A-B

FLEMINGTON, N.J., Dec. 9, 2014 (GLOBE NEWSWIRE) -- Arno Therapeutics, Inc. (OTCQB:ARNI), a clinical stage biopharmaceutical company focused primarily on the development of oncology therapeutics, today announced that data from a study supporting diagnostic development for its lead compound onapristone will be presented at a poster session at the 2014 San Antonio Breast Cancer Symposium (SABCS), being held December 9-13, 2014 in San Antonio, Texas. The symposium is hosted by The Cancer Therapy & Research Center (CTRC) at The University of Texas Health Sciences Center at San Antonio, the American Association for Cancer Research (AACR) and Baylor College of Medicine.

Findings from the study "Impact of Progesterone Receptor Isotype-Specific Immunohistochemistry on the Diagnosis of Triple Negative Breast Cancer" (Abstract #5567; P5-02-13) will be presented during Poster Session 5 on Detection and Diagnosis: Diagnostic Pathology on Friday, December 12 from 5:00 – 7:00 p.m. CT in Exhibit Hall A-B of the Henry B. Gonzalez Convention Center.

Alex Zukiwski, MD, Chief Executive Officer of Arno Therapeutics, commented, "Using isotype specific progesterone receptor antibodies as part of a diagnostic technique may offer a useful and potentially important method of detecting progesterone receptor-positive tumors for personalized treatment of cancer. Furthermore, use of the two specific isotype-specific antibodies, PRA and PRB, may reveal breast cancer cases that are not necessarily triple negative and could benefit from treatment with anti-progestins, like our lead compound onapristone – which is an oral, anti-progestin hormone blocker that has been shown in previous Phase II clinical trials to exhibit anti-tumor activity in patients with breast cancer."

Poster Title: Impact of Progesterone Receptor Isotype-Specific Immunohistochemistry on the Diagnosis of Triple Negative Breast Cancer

Study Authors: Bonneterre J, Bosq J, Alleaume C, Gilles E, Jamme P and Zukiwski A

The study evaluated the impact of using a progesterone receptor (PR) isotype-specific immunohistochemical (IHC) diagnostic technique on the diagnosis of triple-negative breast cancer tumors, which are defined as estrogen receptor (ERα), PR and HER2 negative. PR cellular expression is thought to be linked to ERα expression in breast cancer. Triple-negative breast cancer may express PR when tested with two forms of the PR: PRA and PRB antibodies. Routine IHC determination of PR utilizes "bispecific" antibodies which recognize epitopes common to both PRA and PRB. Ultimately, the accuracy of triple-negative phenotype determination depends in part on the ability of the antibody to detect both PRA and PRB expression in the tumor.

The study evaluated 775 archived breast cancer tumor samples from female patients diagnosed with invasive ductal breast cancer provided by Oscar Lambret Hospital in Lille, France. The samples were analyzed for ERα, PRA and PRB. Of the samples, 89 cases were determined to be ERα negative (by retesting) and HER2 negative (from patient records).

Evaluating the PR status with IHC staining demonstrated that 53 of the 89 cases (60%) were found to be "true" triple negative using isotype specific antibodies for PRA and PRB. Furthermore, results showed that 21 of the 89 (24%) were PR positive using the PRA and PRB antibodies tested and 15 of the 89 (17%) were found to be PR positive with either the PRA or PRB antibody and not with the PR bispecific antibody used in standard PR testing. The use of PRA and PRB isotype-specific antibodies may reveal breast cancer cases that are not necessarily triple negative.

The results demonstrate the potential of this diagnostic approach to more accurately detect breast cancers that are PR positive and therefore not truly triple negative. Ultimately this could allow for the detection of PR-positive breast cancers that may be amenable to treatment with anti-progestins, such as onapristone.

About Breast Cancer

In the United States, over 232,670 new cases of invasive breast cancer are expected to be diagnosed in women and over 2,360 new cases are expected in men during 2014.i After cancers of the skin, breast cancer is the most frequently diagnosed cancer in women.i More than 40,430 breast cancer deaths are expected in 2014, with the vast majority in women. Breast cancer ranks second as a cause of cancer death in women, following lung cancer.i

About Arno Therapeutics

Arno Therapeutics is a clinical stage biopharmaceutical company developing innovative products for the treatment of cancer. Arno has exclusive worldwide rights to develop and market three innovative anti-cancer product candidates. These compounds are in clinical or preclinical development as product candidates to treat hematologic malignancies and solid tumors. 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, statements regarding the potential of onapristone as a treatment for prostate and other cancers, statements regarding Arno's use and development of a diagnostic test to identify patients with APR tumors, as well as Arno's strategy, future operations, outlook, milestones, future financial position, future financial results, plans and objectives. We 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 we make. Various important factors could cause actual results or events to differ materially from the forward-looking statements that we make. Such factors include, among others, risks that the results of clinical trials will not support our claims or beliefs concerning the effectiveness of onapristone or any of our other product candidates, our ability to successfully develop a diagnostic to identify APR tumors, our ability to finance the development of our product candidates, regulatory risks, and our 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, 2013 and its Quarterly Report for the quarter ended September 30, 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.


i American Cancer Society. Cancer Facts & Figures 2014. Available at:

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.