SAN DIEGO, June 24, 2009 — Conatus Pharmaceuticals Inc. announced today the initiation of a second Phase 2 clinical trial with a novel drug candidate for the treatment of liver disease associated with Hepatitis C Virus (HCV) infection. The trial will enroll patients for whom treatment with approved standard of care treatments is not currently advised. Results from an earlier clinical trial in HCV patients who failed standard of care treatment are expected to be reported later this year.

CTS-1027 is an oral, small molecule compound that inhibits the activity of key members of a class of protease enzymes, the matrix metalloproteinases or MMPs. CTS-1027 had previously been shown to be effective in multiple preclinical models of inflammatory liver disease and HCV infection.

The clinical trial is a double-blind, placebo-controlled trial testing an optimized dose of CTS-1027 alone or in combination with ribavirin. Dosing will last for up to twenty four weeks. The Company expects approximately 70 patients to be enrolled. The clinical trial will be conducted at up to twenty five medical centers in the U.S. Additional information about the trial can be found at: www.clinicaltrials.gov (Identifier NCT00925990) or www.clinicaltrials.gov/ct2/show/NCT00925990?term=cts1027&rank;=2.

“Our recent preclinical studies suggest that CTS-1027 treatment has the potential to impact the second phase of HCV virus inhibitory kinetics in patients. This phase is associated with the gradual reduction and replacement of HCV infected cells by uninfected liver cells. Interestingly, ribavirin is also postulated to have the greatest impact on HCV second phase inhibition, leading us to evaluate CTS-1027 in combination with ribavirin,” said Steven J. Mento, President and CEO of Conatus. “We believe that CTS-1027 represents a novel approach to treating HCV disease and look forward to developing this drug candidate to fill an important medical need in HCV-infected patients.”

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 Hepatitis C and other viral infections, obesity, chronic alcohol abuse or autoimmune diseases. 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 www.conatuspharma.com