Repligen Corporation Reports Positive Phase 2 Clinical Trial Results of Secretin for MRI Imaging of the Pancreas WALTHAM, Mass., May 10 -- Repligen Corporation announced today positive results from a Phase 2 clinical trial to evaluate the use of RG1068, synthetic human secretin, as an agent to improve the assessment of pancreatic duct structures by magnetic resonance imaging (MRI). The study showed an improvement in sensitivity of detection of structural abnormalities of the pancreatic duct of approximately 20% with no loss in specificity, consistent with prior data and expectations. In addition, the study showed highly significant increases in the following three assessments: physician confidence in their ability to identify structural abnormalities, the number of pancreatic duct segments visualized and improvement in the overall quality of the MRI images. Detailed visual assessment of the pancreatic ducts and identification of structural abnormalities is important in the assessment, diagnosis and treatment of diseases such as acute and chronic pancreatitis. This was a multi-center, baseline controlled, single dose study in which 80 patients with a history of pancreatitis received a secretin-enhanced MRI and an unenhanced MRI of the pancreas. All study operations and data analyses were conducted with protocols previously discussed with the U.S. Food and Drug Administration (FDA). "We are pleased with the successful outcome of our first prospectively defined, blinded, multi-center clinical study to assess the use of secretin to aid in the detection of structural abnormalities of the pancreas," stated Walter C. Herlihy, President and Chief Executive Officer of Repligen. "These quantitative results confirm what has previously been reported by physicians, and establishes a sound basis for discussions with the FDA regarding a clinical plan to receive marketing approval for secretin for MRI imaging of the pancreas. We believe there may be more than 100,000 potential MRI images of the pancreas in the U.S. each year that could benefit from the use of secretin." Secretin is a natural gastrointestinal hormone involved in the process of digestion. Secretin has been used for many years by gastroenterologists in combination with endoscopy, an invasive procedure to evaluate and treat diseases of the pancreas and gallbladder. There are risks associated with the use of endoscopy, which have generated interest in the development of safer non-invasive tests to diagnose gastrointestinal disorders. The use of secretin in combination with a non-invasive procedure such as MRI to improve the detection and delineation of normal and abnormal structures of the pancreas and to quantify pancreatic fluid production, harnesses the natural biologic properties of the hormone to increase the diagnostic quality of the MRI image. The use of MRI is attractive for patient care as it can obviate the need for more risky invasive procedures. The use of secretin in abdominal imaging may have application beyond improvements in detection of structural abnormalities. We are conducting several pilot studies to evaluate the use of secretin with MRI to assess among other things, the function of the pancreas. This study is based on the clinical observation that patients with pancreatic diseases have a reduced fluid production response to secretin stimulation and will be designed to confirm and quantify this observation. The Office of Orphan Products Development of the FDA granted Repligen orphan drug designation for RG1068, synthetic human secretin, for use with MRI of the pancreas. Orphan drug designation qualifies Repligen for seven years of exclusive marketing rights in the United States if the company is first to receive marketing approval for RG1068 for MRI imaging of the pancreas. About Repligen Corporation Repligen Corporation is a biopharmaceutical company focused on the development of novel therapeutics for diseases that affect the central nervous system. 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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