October 31, 2008

Nabi Reports Positive Results From Phase II NicVAX Immunogenicity Study

Nabi Biopharmaceuticals has announced positive final results from its Phase II NicVAX schedule optimization immunogenicity study to assess the antibody response and safety of a 400mcg, six dose immunization schedule. The vaccine lot used in this study is from the same lot used in the Phase IIb proof-of-concept trial whose results were announced in November 2007.

Final results from the study confirmed the positive interim results announced in July 2008 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 two-fold higher than those achieved at the same time point in the Phase IIb study as a result of the added injection. Moreover, greater than 80% of subjects who completed the six- dose 400mcg 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 has 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 the planned Phase III 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 IIb proof-of-concept trial and the vaccine lot manufactured for the planned Phase III 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.