Repligen Receives Complete Response Letter from FDA for RG1068 NDA

WALTHAM, MA  – June  22, 2012 – Repligen Corporation (NASDAQ:RGEN) today announced that it has received a Complete Response Letter (CRL) from the U.S. Food & Drug Administration (FDA) regarding the Company's New Drug Application (NDA) for RG1068 (synthetic human secretin).  RG1068 was evaluated in a Phase 3 study to improve detection of pancreatic duct abnormalities in combination with MRI in patients with known or suspected pancreatitis. The CRL indicates that the FDA has completed its review of the RG1068 NDA and has determined that additional clinical efficacy and safety trial data will be required to support potential approval of the NDA. There were no specific safety concerns cited in the CRL, although safety will continue to be monitored in conjunction with any future clinical trial. No deficiencies were cited in the CRL with respect to the manufacturing, pharmacology or toxicology sections of the NDA.

"We will continue to engage in dialogue with the FDA to determine the design and scope of a clinical program that will address the agency's requirements for approval of RG1068," said Walter C. Herlihy, Ph.D., President and Chief Executive Officer of Repligen. "We believe that RG1068, if approved, will provide a safe and effective means to non-invasively image the pancreas with MRI and will meet an important unmet medical need for patients with pancreatitis." 

Repligen filed its NDA for RG1068 on December 21, 2011 based on the re-read of Phase 3 clinical trial data. On February 21, 2012, the FDA accepted the NDA filing and granted it priority review based on its prior Fast Track designation. In addition, on March 5, 2012, Repligen submitted a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) that was successfully validated for full review by the EMA's Committee for Medicinal Products for Human
Use.

About Repligen Corporation

Repligen Corporation is a leading supplier of critical biologic products used to manufacture biologic drugs. Repligen also applies its expertise in biologic product development to RG1068, a synthetic hormone being developed as a novel imaging agent for the diagnosis of a variety of pancreatic diseases. In addition, the Company has two central nervous system (CNS) rare disease programs in Phase 1 clinical trials. Repligen's corporate headquarters are located at 41 Seyon Street, Building #1, Suite 100, Waltham, MA 02453.  Additional information may be requested at www.repligen.com.