Former Idun Management team to expand efforts in liver disease and oncology

SAN DIEGO, July 30, 2010 — Conatus Pharmaceuticals Inc. announced today that Conatus acquired the Idun Pharmaceuticals subsidiary of Pfizer Inc. Financial terms were not disclosed. Conatus Pharmaceuticals is a privately-held drug development company focused on liver disease and oncology.

Conatus Pharmaceuticals is led by Steven J. Mento, Ph.D., the former CEO of Idun Pharmaceuticals, which was acquired by Pfizer Inc. in 2005. “The addition of Idun to Conatus continues our important work in liver disease and expands our therapeutic reach into oncology,” said Dr. Mento. “Conatus plans to leverage its scientific and drug development expertise and resources to continue to advance potentially important therapeutic candidates in liver disease and oncology.”

Idun Pharmaceuticals was a privately-held biopharmaceutical company engaged in the discovery and development of drug candidates to control apoptosis. At the time of the acquisition by Pfizer, Idun had a Phase 2 drug candidate in liver disease (emricasan/IDN-6556), preclinical drug candidates including IDN-13389 for oncology, a development agreement with Abbott for an oncology drug candidate, and key intellectual property in the field of apoptosis. Conatus’ SVP Corporate Development, Jennifer Giottonini Cayer added, “We appreciate the contributions of Pfizer’s colleagues on these potentially important drug candidates. Conatus is excited to have the opportunity to work on these programs.”

Conatus Pharmaceuticals Inc. is a privately-held pharmaceutical company engaged in the development of innovative human therapeutics to treat liver disease and oncology. The lead drug candidate, CTS-1027 is in multiple Phase 2 clinical trials for the treatment of hepatitis C virus (HCV). Conatus was founded by the executive management team of Idun Pharmaceuticals in July 2005 following the sale of Idun to Pfizer. For additional information, please visit www.conatuspharma.com.

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