News Release

Nabi reports successful reduction in S. aureus bacteremias at Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC)

Peer-Reviewed Publication

Kureczka/Martin Associates

Toronto, Canada , September 19, 2000 -- Nabi (Nasdaq: NABI) announced preliminary results from the phase III clinical trial for StaphVAX™ (Staphylococcus aureus conjugate vaccine) at the 40th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Toronto, Canada. The data from the trial demonstrated a dramatic reduction in S. aureus bacteremias (blood stream infections) during the first ten months of the study. However, the decrease in bloodstream infections after one-year follow up, the primary endpoint for the study, did not achieve statistical significance. The study was performed by the Kaiser Permanente Vaccine Study Center based in Oakland, CA, and the preliminary results were presented by the principal investigators from that institution, Steven Black, M.D. and Henry Shinefield, M.D.

"We are excited by the data from this trial," said David J. Gury, Chairman, President and Chief Executive Officer of Nabi. "Based on the protection exhibited for StaphVAX treated patients during the first ten months of the trial, we strongly believe that a CPS-conjugated vaccine against S. aureus is feasible. Moreover, the demonstration that StaphVAX-induced antibodies can protect against bloodstream infections has very positive implications for the success of Nabi's entire Gram-positive program."

In reviewing the preliminary results from the trial, Dr. Black stated, "Through ten months, the study results found 57% fewer cases of Staph aureus disease in these immune compromised study participants who received the vaccine. Staph aureus is an increasing, lethal bacteria, which causes significant morbidity and mortality."

Dr. Shinefield affirmed, "These results are particularly important at a time of growing resistance of Staph aureus to antibiotics."

StaphVAX consists of capsular polysaccharides (CPS) from the two most common serotypes of S. aureus (Type 5 and Type 8), each conjugated to a carrier protein. The double-blinded, placebo-controlled trial involved 1,804 end-stage renal disease patients on hemodialysis who were randomly assigned so that approximately half were vaccinated with a single intramuscular injection of StaphVAX and half received a placebo vaccination. After a patient was vaccinated, the investigators observed them for at least one year to collect information on bloodstream infections that might occur. In the group of patients that received placebo there were 17 S. aureus bacteremias at approximately six months of follow-up, compared to 7 bacteremias in the group that received StaphVAX or a 58% reduction in S. aureus bacteremias (p= 0.0438). At ten months, there were 26 S. aureus bacteremias in the placebo group and 11 bacteremias in the group that received StaphVAX or a 57% reduction in bacteremias (p=0.015). At one year there were 37 S. aureus bacteremias in the placebo group and 27 bacteremias in the group that received StaphVAX or a 26% reduction in bacteremias (p=0.228). Geometric mean titers of StaphVAX-induced antibodies at six months post-vaccination were approximately 50% of peak titers (peak titer measured at 42 days post-vaccination). Antibody titers at one year post-vaccination were approximately 33% of peak titers.

Mr. Gury said, "We plan to discuss these data with the Food and Drug Administration before determining the next steps in the development of StaphVAX. Based on the very encouraging results in this trial, Nabi will increase its research activities at our Rockville, Maryland facility. For that reason, we expect that a reserve of approximately $3 million, originally recorded in 1998 for future lease costs associated with reducing pre-clinical activities at this location, will be reversed into income in the third quarter of this year."

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A conference call to review this and other recent business developments is scheduled for 2:30 PM EST today and can be accessed on the Internet at http://www.streetfusion.com. A replay of this teleconference will be available for 30 days and can be accessed through the company's website.

Nabi, a fully integrated biopharmaceutical company, has a broad product portfolio and significant R&D capabilities focused on the development and commercialization of drugs that prevent and treat infectious and autoimmune diseases. Nabi currently has several clinical trials underway in these areas and has four marketed pharmaceutical products. Nabi has its corporate headquarters in Boca Raton, Florida, with principal R&D offices and laboratories in Rockville, Maryland. Additional information about Nabi may be obtained on the Company's website at: http://www.nabi.com.

This press release contains forward-looking statements that reflect the Company's current expectations regarding future events. While these statements reflect the Company's best current judgment, they are subject to risks and uncertainties. Actual results may differ significantly from the results projected herein due to a number of factors, including, but not limited to, the impact on the Company of current industry supply and demand factors and the supply of and demand for the Company's individual products; margin pressure on the Company's non-specific antibody product line; future sales growth prospects for its pharmaceutical products; the likelihood that Nabi-StaphVAX or any other product in the research pipeline can receive regulatory approval in the U.S. or abroad or be successfully developed, manufactured and marketed; failure to receive licensure for the Boca Raton manufacturing facility; and dependence upon third parties to manufacture product. These factors are more fully discussed in the Company's most recent Form 10-K filed with the Securities and Exchange Commission.

Contacts:

David J. Gury
Chairman, President and CEO
(561) 989-5800

Thomas H. McLain
Sr. V.P. Corporate Services and CFO
(561) 989-5800



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