The decision was based on conclusions from an outside advisory panel’s review of Nabi Biopharmaceuticals’ assessment of the StaphVAX confirmatory phase III clinical study results. The assessment revealed marked differences in the effectiveness of the lot of vaccine used in this study compared to the lot used in the previous phase III clinical study.
On November 1, 2005, Nabi Biopharmaceuticals announced that this study had failed to meet its primary endpoint. Because these results were not consistent with previous positive clinical data for StaphVAX, the company developed an investigation plan and formed an outside advisory panel of experts to conduct an assessment to determine the factors that led to the unexpected results.
In collaboration with the panel, Nabi Biopharmaceuticals has reached two important conclusions related to the future development of StaphVAX and Altastaph. The first was that the quality or functional characteristics of the antibodies generated by the vaccine used in the confirmatory clinical study was inferior to those antibodies generated by vaccine lots used in previous and subsequent clinical studies.
The second conclusion was that medical factors associated with kidney disease in dialysis patients impaired their immune response to the vaccine. When considered in combination with an increase in the virulence of the bacteria, these factors also contributed to the observed lack of protection in this study population.
Nabi Biopharmaceuticals now intends to find a partner for its vaccines development program. The company said an ideal partner would contribute additional experience and expertise in vaccine development and commercialization, as well as the financial resources to advance these programs.
A partner with the relevant vaccine expertise could, the company believes, also support broadening the use of the vaccine to prevent infections in populations such as children, the elderly, athletes and prisoners who are at increasing risk for community- acquired S. aureus infections.