Acetylon Pharmaceuticals and Celgene Corporation Announce an Exclusive Strategic Collaboration to Advance the Science of Epigenetics

Acetylon Pharmaceuticals, Inc., the leader in development of selective histone deacetylase (HDAC) inhibitors for enhanced therapeutic outcomes (the “Company”), today announced a strategic collaboration and option agreement with Celgene Corporation

, which supports the development of Acetylon's portfolio of oral, selective HDAC inhibitors in oncology, hematology, immunology, and neurologic disease indications. The agreement includes an exclusive option for the future acquisition of Acetylon by Celgene. The collaboration will focus on the continued clinical advancement of Acetylon's lead candidate, ACY-1215, an oral first-in-class selective HDAC6 inhibitor being developed for hematological malignancies, ACY-738 for neurological diseases, an HDAC1/2 inhibitor, and a yet unnamed project, spanning cancer and non-cancer disease indications. Under the terms of the agreement, Acetylon will receive a $100 million upfront cash payment. In return, Celgene receives an exclusive option to acquire Acetylon at a cash purchase price that will be within a defined value range and based upon future independent valuations of Acetylon. Acetylon will retain control of its drug development programs during the option period. If Celgene exercises its option to acquire Acetylon, an upfront payment determined from the valuation process and subject to a minimum of $500 million will be paid at the time of closing. Additionally, Acetylon shareholders will be eligible to receive potential future milestone payments for either approvals or additional indications of drugs developed by Acetylon and for accomplishing defined sales targets. If all the milestones are achieved, the additional value accruing to Acetylon shareholders would be $1.1 billion, comprised of $250 million for regulatory milestones and $850 million for sales milestones. “Acetylon's work in epigenetics and resultant pipeline has shown significant promise,” said Mark Alles, Celgene's Executive Vice President, Global Head of Hematology and Oncology and observer to the Acetylon Board of Directors. “The expansion of our relationship with Acetylon from our original equity investment to this exciting strategic collaboration demonstrates our belief that Acetylon's highly selective HDAC inhibitors have the potential to meaningfully improve clinical outcomes for patients with a variety of diseases, including hematology, oncology, diseases of the immune system, and neurodegenerative diseases.” “Celgene has been an enthusiastic investor and supporter of Acetylon's mission since completing its equity investment in our company early last year,” said Walter C. Ogier, President and Chief Executive Officer and co-founder of Acetylon. “We are excited to be able to work with Celgene under the expanded framework of this new development and option agreement. The $100 million in up-front, non-dilutive funding should enable us to aggressively advance our drug pipeline and create substantial value for our patients and investors.” About Acetylon Pharmaceuticals Acetylon Pharmaceuticals, Inc., based in Boston, Massachusetts, is a leader in the development of novel small molecule drugs targeting epigenetic mechanisms for the enhancement of therapeutic outcomes in cancer and other critical human diseases. The Company's epigenetic drug discovery platform has yielded a proprietary portfolio of optimized, orally-administered Class I and Class II histone deacetylase (HDAC) selective compounds. Alteration of HDAC regulation through selective HDAC inhibition is thought to be applicable to a broad range of diseases including cancer, sickle cell disease and beta-thalassemia, and autoimmune and neurodegenerative diseases. Acetylon's lead drug candidate, ACY-1215, is a selective HDAC6 inhibitor currently in Phase 1b clinical development for the treatment of multiple myeloma. Acetylon's scientific founders are affiliated with the Harvard University, the Dana-Farber Cancer Institute, the Massachusetts General Hospital, and Harvard Medical School. www.acetylon.com