Nabi Biopharmaceuticals has completed enrollment for its phase IIB "proof-of-concept" study for NicVAX (Nicotine Conjugate Vaccine), the company's novel, innovative and proprietary investigational vaccine being developed to treat nicotine addiction and prevent smoking relapse. enrolment for the trial was completed three months earlier than anticipated, paving the way for the release of trial results early in the second quarter of 2007.

Thomas H. McLain, chairman of the board, chief executive officer and president, Nabi Biopharmaceuticals, stated, "We are extremely pleased to have completed patient enrolment for this trial ahead of schedule and consider it a testament to the hard work and dedication of our clinical team and our ability to execute on the key milestones we have established for our company. The successful completion of patient enrolment also puts us in a highly advantageous position to rapidly advance partnering efforts for NicVAX. We look forward to sharing these trial results early in the second quarter of 2007."

McLain continued, "This achievement is also greatly supported by the physician and patient communities who maintain a strong interest in the development of a new and innovative smoking cessation approach such as NicVAX."

Henrik S. Rasmussen, M.D., Ph.D., senior vice president, clinical, medical and regulatory affairs, Nabi Biopharmaceuticals, stated, "According to the US Centers for Disease Control and Prevention, tobacco use is the single leading preventable cause of death in the U.S. and is responsible for more than 440,000 deaths each year, and yet optimal treatments are still not available. We believe NicVAX is poised to address one of today's most pressing healthcare challenges, nicotine addiction, in a way that could offer distinct therapeutic advantages over both marketed and development-stage smoking cessation treatments. We look forward to advancing NicVAX to the next stage of development and to the continuing support of the physician and patient communities committed to innovative solutions for smoking addiction."

Dr. Rasmussen continued, "Completion of patient enrolment for this proof-of-concept phase IIB trial is evidence that NicVAX is the most advanced smoking cessation vaccine in development. The clinical advancement of NicVAX is supported by both a strong and global intellectual property position and our ability to manufacture the vaccine at commercial-scale, a position unmatched by any other company with a smoking cessation vaccine in development. We believe the results of this phase IIB trial will enable us to identify the optimal formulation for the upcoming phase III pivotal trials, and allow us to initiate these trials with a development partner in the second half of 2007."

The main reason it is so difficult to stop smoking is that smokers crave the 'rush' they get when nicotine reaches and binds to receptors in the brain. That releases dopamine, which creates the positive stimulus in the brain and at the same time is very addictive. NicVAX is designed to prevent the 'rush' and the associated addiction by preventing nicotine from entering the brain. The vaccine stimulates the immune system to produce antibodies that bind to nicotine. Nicotine attached to the antibodies is too large to cross the blood brain barrier, preventing nicotine from reaching the receptors in the brain. The rush that is normally caused by nicotine should no longer be present, thereby eliminating the addictive properties of nicotine and, consequently, helping people to quit. in essence, it is believed that these nicotine antibodies can act like a "sponge" soaking up nicotine as it circulates in the bloodstream and preventing it from reaching the brain.

Further, because the ability of the body's immune system to produce these antibodies is expected to be long lasting, it is believed NicVAX will also be effective in preventing smoking relapse. Relapse is a significant challenge with existing smoking cessation therapies and can range as high as 90% in the first twelve months after quitting. This is expected to be an important differentiator between NicVAX and existing smoking treatment options.