Aragon Pharmaceuticals, Inc. Announces First Patient Dosed in Phase I Study of ARN-810 in Estrogen Receptor Positive Breast Cancer

SAN DIEGO, CA--(Marketwired - April 04, 2013) - Aragon Pharmaceuticals Inc., a leader in developing drugs for hormone driven cancers, today announced that the first patient has been dosed in a Phase I clinical study of ARN-810, an oral selective estrogen receptor degrader (SERD), for the treatment of locally advanced or metastatic estrogen receptor positive breast cancer in post-menopausal women.

Approximately 70% of breast cancers are dependent on estrogen for growth and survival. Current treatment generally involves antihormonal therapies, such as tamoxifen or aromatase inhibitors. Although these therapies are initially effective, acquired resistance is common, leading to disease progression. ARN-810 is a potent, orally bioavailable nonsteroidal agent, which functions by binding to the estrogen receptor, inducing a conformational change resulting in the degradation of the receptor. As such, its novel profile represents a new treatment that may circumvent resistance seen in traditional therapies.

The Phase 1 dose escalation study is designed to assess safety and tolerability of ARN-810. The study will be conducted at Vanderbilt University, Mass General Hospital and Memorial Sloan-Kettering Cancer Center.

"We are thrilled to announce the initiation of trials in ARN-810, the most advanced of our novel SERD program," said Richard A. Heyman, CEO of Aragon Pharmaceuticals. "Today's announcement represents a landmark step for us, as our SERD program originated within Aragon and is wholly-owned. We are hopeful that ARN-810's novel approach to breast cancer therapy will prove to be a more effective, sustained treatment option for this important patient population."

"We are excited to be able to contribute to the development of this novel oral antagonist of the estrogen receptor," said Dr. Carlos L. Arteaga, Associate Director for Clinical Research and Director of the Breast Cancer Program at the Vanderbilt-Ingram Cancer Center. "This drug may become another treatment option for many women with breast cancer."

About SERD Program

Aragon Pharmaceuticals' orally active selective estrogen receptor degraders represent a new treatment for progressive metastatic breast cancer that may circumvent the problem of resistance to anti-hormonal therapies. SERDs bind to the estrogen receptor, and induce a conformational change that results in the degradation of the receptor.

Aragon has identified multiple SERDs that have pharmacokinetic profiles sufficient to drive a robust therapeutic response and result in degradation of the receptor and anti-tumor activity. The novel profile of these potent, orally bioavailable, nonsteroidal agents may result in greater efficacy and response rates in patients with hormone-refractory breast cancer compared to other drugs in development. Aragon's most advanced leads induce tumor regressions in both tamoxifen sensitive and tamoxifen resistant tumor models in vivo. Based on these results and others, the company is currently advancing multiple, distinct lead SERD chemical scaffolds toward clinical development.

Aragon's SERDs are initially being developed for the treatment of women with late-stage, progressive metastatic disease, but these SERDs also have tremendous potential in treating patients with early-stage disease.

About Aragon Pharmaceuticals

Aragon Pharmaceuticals is focused on the development of 2nd generation anti-hormonal agents for hormone-driven cancers. The company's portfolio of small molecule therapeutics is based upon pioneering research identifying key molecular events that lead to drug resistance to traditional anti-hormonal therapies. This work has broad implications for the development of breakthrough medicines for prostate cancer and other hormone-dependent cancers such as breast, ovarian and endometrial cancer. Aragon Pharmaceutical's most advanced compound, ARN-509, is an androgen receptor antagonist that is currently being evaluated in a Phase 2 trial in patients with castration-resistant prostate cancer. In addition, Aragon Pharmaceuticals has a selective estrogen receptor degrader (SERD) for hormone-sensitive and hormone-resistant estrogen receptor positive breast cancer targeted to begin clinical trials in 2013. Aragon is a private company founded in 2009 and headquartered in San Diego, California. For more information, visit

For further information, please contact:

Laura Forman
Blueprint Life Science Group
(415) 375-3340, ext 103

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