July 23, 2008

Nabi Biopharmaceuticals Announces Positive Interim Results of NicVAX Immunogenicity Study; Revised Schedule Significantly Increases Antibody Response in Vast Majority of Subjects

ROCKVILLE, Md., July 23, 2008 (PRIME NEWSWIRE) -- Nabi Biopharmaceuticals (Nasdaq:NABI) announced today positive interim results from its Phase 2 NicVAX(r) (Nicotine Conjugate Vaccine) schedule optimization immunogenicity study to assess the antibody response and safety of a 400 microgram, six dose immunization schedule.

Interim results from the study indicate that significantly higher anti-nicotine antibody levels can be generated three months earlier and in a much higher percentage of subjects than observed in previous NicVAX studies. Nabi's new immunization schedule, which included an additional injection at three months, resulted in an immune response at 14 weeks that was higher than the peak antibody level achieved following the six month booster in the Phase 2b proof of concept study. Significantly, the data indicated that more than 80% of subjects achieved the target antibody level at 14 weeks compared to 50% of subjects in the Phase 2b proof of concept study at the same time point. The revised schedule was well tolerated with an adverse event profile comparable to previous NicVAX clinical studies.

"We are excited that these initial results strongly support our hypothesis that production of anti-nicotine antibodies can be accelerated and elevated with this revised regimen," stated Dr. Raafat Fahim, President and Chief Executive Officer of Nabi Biopharmaceuticals. "The Phase 2b proof-of-concept trial results, completed in November 2007, demonstrated a clear and positive correlation between antibody levels and the ability of patients to quit smoking and remain abstinent. We believe that significantly enhancing the antibody levels in the majority of immunized subjects would increase the likelihood of success in the upcoming pivotal studies. The final results of the current immunogenicity study will provide critically important information that will be incorporated into the design of the Phase 3 clinical trials. Phase 3 is on track to be initiated before the end of this year."

About NicVAX

NicVAX(r) is an innovative and proprietary investigational vaccine being developed by Nabi to treat nicotine addiction and prevent smoking relapse. NicVAX(r) is designed to stimulate the immune system to produce antibodies that bind to nicotine. A nicotine molecule attached to an antibody is too large to cross the blood-brain barrier. Therefore, NicVAX(r) blocks nicotine from reaching its receptors in the brain and prevents the highly-addictive pleasure sensation experienced by smokers and users of nicotine products. Pre-clinical and previous clinical data, as well as the study reported here, show that NicVAX(r)'s ability to block nicotine from reaching the brain could help people quit smoking. Because the body's immune system can be boosted to produce long-lasting antibodies, Nabi believes NicVAX(r) also could be effective in preventing smoking relapse. Relapse is a significant challenge facing smokers and, with currently-available smoking cessation therapies, relapse rates can be as high as 90% in the first year after a smoker quits.

About Nabi Biopharmaceuticals

Nabi Biopharmaceuticals leverages its experience and knowledge in powering the immune system to develop products that target serious medical conditions in the areas of nicotine addiction and gram-positive bacterial infections. Nabi Biopharmaceuticals is currently developing NicVAX(r) (Nicotine Conjugate Vaccine), an innovative and proprietary investigational vaccine for treatment of nicotine addiction and prevention of smoking relapse, and PentaStaph(tm) (Pentavalent S. aureus Vaccine), a vaccine designed to prevent the most dangerous and prevalent strains of S. aureus bacterial infections. The company is headquartered in Rockville, Maryland. For additional information about Nabi Biopharmaceuticals, please visit our Web site:http://www.nabi.com.

Forward-Looking Statements

Statements in this release that are not strictly historical are forward-looking statements including statements about NicVAX. You can identify these forward-looking statements because they involve our expectations, beliefs, projections, anticipations or other characterizations of future events or circumstances. These forward-looking statements are not guarantees of future performance and are subject to risks and uncertainties that may cause actual results to differ materially from those in the forward-looking statements as a result of any number of factors. These factors include, but are not limited to, risks relating to our ability to: successfully pursue strategic and other alternatives; conduct clinical trials and obtain successful clinical trial results; receive PhosLo milestone and royalty proceeds; successfully partner with third parties to fund, develop, and manufacture our pipeline products, including NicVAX and our gram-positive infections products; realize anticipated cost saving; attract and maintain the human and financial resources to bring to market products in development; depend upon third parties to manufacture our products; achieve approval and market acceptance of our products; enter into and maintain arrangements with third parties to market and sell our products; comply with reporting and payment obligations under government rebate and pricing programs; raise additional capital on acceptable terms, or at all; and re-pay our outstanding convertible senior notes when due. Many of these factors are more fully discussed, as are other factors, in the company's Annual Report on Form 10-K for the fiscal year ended December 29, 2007 and our Quarterly Report for the quarter ended March 29, 2008 on form 10-Q that have been filed with the Securities and Exchange Commission.

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 CONTACT:  Nabi Biopharmaceuticals           Investor Relations           301-770-3099           www.nabi.com