Panacos Appoints Scott McCallister, M.D., Chief Medical Officer.

WATERTOWN, Mass. -- Panacos Pharmaceuticals, Inc. (Nasdaq:PANC), a biotechnology company dedicated to developing the next generation of antiviral therapeutic products, today announced that Scott McCallister, M.D. has joined the Company as Chief Medical Officer. Dr. McCallister will be responsible for medical affairs and will spearhead the Company's Phase 3 development efforts for bevirimat. He will report to Graham Allaway, Ph.D., Panacos' President and COO.

Before joining Panacos, Dr. McCallister was Director of Virology, Global Medical Affairs for Bristol Myers Squibb Company (BMS). In this role, he was responsible for the global medical strategy of the anti-HIV protease inhibitor, atazanavir (REYATAZ), and coordinated the review and approval of other virology studies, both internal and external, at BMS. Prior to BMS, Dr. McCallister held positions of increasing responsibility at Boehringer Ingelheim Pharmaceuticals (BI), leading the international clinical development program and regulatory review process for its anti-HIV protease inhibitor, tipranivir (APTIVUS). At BI, Dr. McCallister coordinated the design, conduct, and analysis of more than 20 Phase I, II, and III tipranavir development trials, culminating in the FDA and EMEA approval of APTIVUS for the treatment of HIV infection in treatment-experienced patients. Dr. McCallister has also served as an Assistant Professor of Medicine at Rush Medical College, Medical Director of the Howard Brown Health Center, and Associate Chief of HIV Medicine at the Illinois Masonic Medical Center in Chicago, where he established a general HIV clinic, a drop-in sexually transmitted disease clinic, and a women's health clinic for indigent patients. Dr. McCallister completed his studies at St. George's University School of Medicine and the University of California, Los Angeles.

Graham Allaway commented, "We are pleased to welcome Scott to the Panacos team. The expertise and experience he has gained in bringing an HIV drug from Phase 2 through regulatory approval will be extremely valuable to Panacos. His background will be a great addition to the bevirimat development program and to our HIV pipeline programs. Scott will work closely with Dr. David Martin, our Senior Vice President of Drug Development, as bevirimat moves toward Phase 3 development."

About Panacos

Panacos is developing the next generation of anti-infective products through discovery and development of small molecule oral drugs for the treatment of HIV and other major human viral diseases. HIV infects approximately 1.7 million people in North America and Western Europe and approximately 40 million people worldwide. Approximately 650,000 patients are treated annually for HIV in the United States and Western Europe. Resistance to currently available drugs is one of the most pressing problems in HIV therapy and the leading cause of treatment failure. Panacos' proprietary discovery technologies are designed to combat resistance by focusing on novel targets in the virus life cycle, including virus maturation and virus fusion.

Panacos' lead candidate, bevirimat (PA-457), is the first in a new class of oral HIV therapeutics under development called maturation inhibitors, discovered by Panacos scientists and their academic collaborators. Based on its novel mechanism of action, bevirimat is designed to have potent activity against a broad range of HIV, including strains that are resistant to existing classes of drugs. The Company has completed seven clinical studies of bevirimat in over 300 subjects, showing significant reductions in viral load in HIV-infected subjects and a promising safety profile, and is currently in Phase 2b clinical trials.

REYATAZ is a registered trademark of Bristol-Myers Squibb Company and APTIVUS is a registered trademark of Boehringer Ingelheim Pharmaceuticals.

Except for the historical information contained herein, statements made herein, including those relating to bevirimat's clinical development, the potential results of treatment with bevirimat and future clinical trials and clinical practice are forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements involve risks as set forth in the Company's filings with the Securities and Exchange Commission, including, but not limited to, the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2005. These risks and uncertainties could cause actual results to differ materially from any forward-looking statements made herein. The Company undertakes no obligation to publicly update forward-looking statements, whether because of new information, future events or otherwise, except as required by applicable law.