Nabi Biopharmaceuticals Announces Successful Final Results of NicVAX(r) Immunogenicity Study

Nabi Biopharmaceuticals (Nasdaq:NABI) announced today positive final 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. The vaccine lot used in this study is from the same lot used in the Phase 2b proof-of-concept trial whose results were announced in November 2007.

Final results from the study confirmed the positive interim results announced in July that significantly higher anti-nicotine antibody levels can be generated three months earlier and in a much higher percentage of subjects for sustained periods of time than observed in previous NicVAX studies. Antibody levels achieved at 14 weeks were more than 2-fold higher than those achieved at the same time point in the Phase 2b proof-of-concept study as a result of the added injection. Moreover, greater than 80% of subjects who completed the six- dose 400 ug NicVAX regimen had anti-nicotine antibody levels above the target threshold at the planned week 14 "quit date." The revised six-dose schedule, after all six doses were administered, continued to be well tolerated with an adverse event profile comparable to previous NicVAX clinical studies.

The Company also evaluated NicVAX in a second cohort of subjects in an ongoing identical immunogenicity study using the vaccine lot that has been manufactured for use in our planned Phase 3 clinical trial. While the results from this second cohort are not yet finalized, the interim results are virtually identical to those of the first cohort described above. This indicates that the quality of the vaccine is nearly identical between the vaccine lot used in the Phase 2b proof-of-concept trial and the vaccine lot manufactured for our planned Phase 3 trial. In addition, to confirm that the anti-nicotine antibodies generated in response to these two lots are functional, the lots were tested in animal models. Data from these functional animal models indicated that both vaccine lots effectively blocked nicotine from entering the brain of rats, confirming the quality, specificity and effectiveness of those lots.

"We are very excited that NicVAX can generate high anti-nicotine antibody levels earlier with the revised dosing regimen. These early and high levels will support smokers during their most critical time -- when they are instructed to quit," stated Dr. Raafat Fahim, President and Chief Executive Officer of Nabi Biopharmaceuticals. "In addition, we are also encouraged that the clinical data and the functional assays confirm that the phase III manufactured vaccine is of high quality, before we proceed with the phase 3 studies."

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 that has been filed with the Securities and Exchange Commission.

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SOURCE: Nabi Biopharmaceuticals

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

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