Aragon Pharmaceuticals Inc., a leader in developing drugs for hormone driven cancers, has signed a definitive agreement with Johnson & Johnson whereby Aragon will be acquired for $650 million in cash up front along with $350 million in contingent development milestone payments that could bring the total transaction value to $1 billion. The acquisition includes Aragon's androgen receptor antagonist programme, including its most advanced compound, ARN-509, a second generation androgen receptor signaling inhibitor that is currently being evaluated in a phase II trial in patients with castration-resistant prostate cancer.

Prior to closing, Aragon will spin off an independent, newly formed corporation called Seragon Pharmaceuticals, which will be focused primarily on Aragon's Selective Estrogen Receptor Degrader (SERD) platform, including ARN-810, its lead SERD currently being evaluated in a phase I trial for ER+ metastatic breast cancer. Seragon will be based in San Diego, California and will be financed by the current Aragon investors. It will retain members of the management team including, Richard Heyman, current chief executive officer of Aragon, who will become Seragon's CEO. Johnson & Johnson will not have an ownership stake in Seragon nor retain any rights to its technology or product development pipeline.

"This agreement represents seamless transition between biotech and Pharma and will provide an optimal outcome for the ARN-509 programme and the prostate cancer patient community. The Aragon team is passionate about bringing game changing therapies to cancer patients and is excited to have Johnson & Johnson carry forward this innovative prostate cancer treatment. Johnson & Johnson is clearly a recognised leader in the oncology field, and their development and commercial capabilities in the prostate cancer area are unparalleled," said Richard A Heyman, Ph.D., chief executive officer and one of the co-founders of Aragon Pharmaceuticals.

"I would like to thank Rich and the entire team at Aragon for their commitment and steadfast belief in the ground breaking science behind ARN-509. In just four years since the founding of Aragon the company has advanced ARN-509 from an early preclinical asset through phase II as well as building a strong pipeline of novel therapeutics targeting hormone dependent cancers. I would also like to thank Dr Charles Sawyers for his pioneering work, which made the founding of Aragon possible. This is an ideal path which will hopefully translate to improving the lives of patients in the near-term as well as providing a new opportunity to advance the Aragon pipeline in the newly created spin off structure of Seragon," said Peter Svennilson, founder and managing partner of The Column Group and chairman of Aragon.

BofA Merrill Lynch served as exclusive financial advisor and Wilson Sonsini Goodrich & Rosati served as legal advisor to Aragon Pharmaceuticals in this transaction.