SAN DIEGO, CA – October 31, 2005 – Mpex Pharmaceuticals, Inc. today announced that Michael Dudley, Pharm.D., has joined the company as Vice President, Drug Development. Dr. Dudley will be an integral part of Mpex's executive management team and will be responsible for the preclinical development and clinical pharmacology of Mpex's anti-bacterial drug candidates. "We're delighted Michael has joined our company," states Bill Gerhart, President and CEO. "We are assembling a world-class management team skilled at developing novel antibacterial drug products, and Michael is a very important addition to that team."

Dudley brings to Mpex a highly relevant background of experience in both industry and academic research. Prior to joining Mpex pharmaceuticals he was the Vice President, Preclinical and Clinical Sciences at Diversa Corporation where he was responsible for all aspects of an antifungal development program, and the development of an internal preclinical scientific department to support discovery and preclinical programs. Prior to Diversa, Dudley spent six years at Microcide where he became the Vice President, Pharmacology and Microbiology. His responsibilities at Microcide included oversight of all discovery drug evaluation, preclinical, and clinical pharmacology of novel antiinfectives. Prior to Microcide, Dudley served as a professor and led academic research programs at the University of Rhode Island and Brown University in nonclinical and clinical (Phases I-IV) investigations for several classes of antibacterial and antiviral agents that are currently in clinical use. He also served as a consultant to the pharmaceutical industry, FDA, and currently serves on the Antimicrobial Susceptibility Testing Subcommittee of the Clinical Laboratory Standards Institute (formerly known as NCCLS).

About Mpex Pharmaceuticals:

Mpex Pharmaceuticals, Inc. is a San Diego-based pharmaceutical company focused on the discovery and development of new antibacterial drugs to meet the growing clinical need created by multi-drug resistant bacterial pathogens. Resistance to multiple antibiotics has resulted in unacceptably high morbidity and mortality rates that costs the U.S. healthcare system $5 billion annually and kills more than 90,000 Americans each year. Despite the efforts of drug development companies, new antibiotics have failed to significantly improve these worsening statistics. To address this medical need, Mpex is developing inhibitors of bacterial resistance that can be combined with proven antibiotics to significantly increase their potency against resistant bacteria. For more information: www.mpexpharma.com