SAN DIEGO, June 11, 2008 — Conatus Pharmaceuticals Inc. announced today that an independent investigator at the Mayo Clinic reported that treatment with CTS-1027 in a preclinical model of liver disease resulted in an attenuation of hepatic fibrosis. These data were presented at the May 2008 Digestive Disease Week (DDW) meeting held in San Diego, CA, by Drs. Alisan Kahraman and Gregory Gores from the Mayo Clinic.

CTS-1027 is an oral, small molecule drug candidate and is being studied as a treatment for the inflammatory damage to the liver resulting from infection by HCV. CTS-1027 inhibits the activity of key members of a class of protease enzymes, the matrix metalloproteinases or MMPs. In the liver and in other solid organs, MMPs play an important role in regulating inflammation as well as in maintaining the integrity of the extracellular matrix. CTS-1027 has been shown to be effective in multiple other preclinical models of liver disease.

“The preclinical data from the Mayo Clinic reinforces other compelling observations from our laboratory and those of other independent collaborators, said Steven J. Mento, Ph.D., President and CEO, of Conatus.

CTS-1027 is currently being studied in a Phase 2a clinical trial of patients with chronic infection of hepatitis C virus. For more information, please visit (Identifier: NCT00570336).

Conatus Pharmaceuticals Inc. is a privately-held specialty pharmaceutical company engaged in the development of innovative human therapeutics to treat liver disease. Chronic liver disease affects millions of people worldwide and can be caused by many different conditions or “insults” to the liver including viral infection, obesity, chronic alcohol abuse or autoimmune diseases. Conatus lead drug candidate, CTS-1027, is currently being evaluated in a Phase 2 study in patients infected with the Hepatitis C virus (HCV). Conatus was founded by the executive management team of Idun Pharmaceuticals in July 2005 following the successful sale of Idun to Pfizer. For additional information, please visit