Repligen Reports Phase 3 Clinical Trial Results of RG1068 in Pancreatic Imaging

Repligen Reports Phase 3 Clinical Trial Results of RG1068 in Pancreatic Imaging

WALTHAM, MA - December 9, 2009 - Repligen Corporation (NASDAQ: RGEN) reported today top-line results from a Phase 3 clinical trial to evaluate the safety and efficacy of RG1068, synthetic human secretin, to improve magnetic resonance imaging (MRI) of the pancreas in patients with a history of pancreatitis. The study's co-primary endpoints were improvements in sensitivity of detection of structural abnormalities of the pancreatic ducts using RG1068 in combination with MRI compared to MRI alone with minimal loss in specificity (<7.5%). The study design used endoscopy as the standard for determination of structural abnormalities. The predetermined criteria for a successful study were achievement of a statistically significant improvement in sensitivity with minimal loss in specificity from two of the three central radiologists reading the MRI images. In this study, one radiologist achieved a statistically significant improvement in sensitivity with RG1068 (p<0.001) while a second radiologist showed a trend but did not achieve statistical significance (p=0.088). There was minimal loss in specificity for all radiologists. While it was not a pre-specified endpoint, pooled data from all three radiologists resulted in a statistically significant improvement in sensitivity with RG1068 (p=0.005) with minimal loss in specificity.

The RG1068-enhanced MRI images showed highly statistically significant improvements on other endpoints for all radiologists including improvements in image quality (p<0.001), ability to see all three segments of the pancreatic duct (p<0.001), and physician confidence in their ability to identify pancreatic duct abnormalities (p<0.001), when compared to MRI alone. There were no serious adverse events (SAEs) associated with the RG1068-MRI procedures compared to 55 SAEs associated with the endoscopy procedures. The most commonly reported SAE following endoscopy was acute pancreatitis requiring hospitalization.

"Although this study did not achieve the pre-specified statistical outcome for the primary endpoint, it provides further evidence of the benefits of RG1068 in MRI imaging of the pancreas," stated Walter C. Herlihy, President and Chief Executive Officer of Repligen Corporation. "Further development plans for RG1068 will be determined following discussion of these results with the FDA next quarter."

This was a multi-center, baseline controlled, single dose study in which 258 patients with a history of pancreatitis at 23 clinical sites within the U.S. and Canada received an MRI of the pancreas with and without RG1068, and independently an endoscopic procedure called ERCP. The MRI imaging results were randomized and independently evaluated by three radiologists blinded to the details of the MRI procedures for evaluation of pancreatic duct abnormalities, image quality, number of duct segments visualized and confidence in diagnosis. The use of MRI is attractive for patient care as it can obviate the need for more risky invasive procedures such as ERCP.

RG1068 is a synthetic version of human secretin, a natural gastrointestinal hormone involved in the process of digestion. Secretin has been used for many years by gastroenterologists in conjunction with ERCP, an invasive procedure to evaluate and treat diseases of the pancreas and gallbladder. There are risks associated with the use of ERCP, which have generated interest in the development of safer non-invasive tests to diagnose gastrointestinal disorders. The use of RG1068 in combination with a non-invasive procedure such as MRI can improve the detection of abnormalities and increase the diagnostic quality of the MRI image of the pancreas. The FDA has granted RG1068 Orphan Drug status and Fast Track Designation, a process designed to facilitate the development and expedite the review of drugs that treat serious diseases and fill an unmet medical need based on the need for safer non-invasive tests to diagnose pancreatic disorders. There are more than 300,000 MRI procedures conducted in the U.S. and Europe each year that could directly benefit by the addition of RG1068.

About Repligen Corporation
Repligen Corporation is a biopharmaceutical company focused on the development of novel therapeutics for neurological disorders. In addition, we are the world's leading supplier of recombinant Protein A, the sales of which partially fund the advancement of our development pipeline while supporting our financial stability. Repligen's corporate headquarters are located at 41 Seyon Street, Building #1, Suite 100, Waltham, MA 02453. Additional information may be requested from www.repligen.com.

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