“Before anthrax infections are being diagnosed, valuable hours have been lost and the window of opportunity for treatment with antibiotics might have closed. Having antibodies directed against the toxins will save lives in such instances, especially highly effective antibodies which can be administered after distinctive symptoms have appeared and diagnosed.”
IQ-DAA is an antibody countermeasure for anthrax, focusing on treatment of symptomatic . It is a clinical development stage product based on the combination of two monoclonal antibodies. It has demonstrated compelling animal efficacy results and the first antibody is currently in Phase I clinical study.
Bacillus anthracis, the causative agent for anthrax, is a Category A pathogen and its ability to be used as a bio-terror agent was confirmed by the October 2001 postal attacks in the United States in which finely ground anthrax was mailed to political offices and news stations at the East coast. This resulted in 18 confirmed cases of anthrax (11 inhalation, 7 cutaneous), caused US Congress to be shut-down for several days and led to general public panic about possible other anthrax attacks. Since these events the US government is in search of countermeasures and has made available significant funds for development and stockpiling.
Current treatment
Recommended post-exposure treatment of anthrax consists of giving patients one or several of the following therapies: antibiotics, specific immunoglobulin for anthrax lethal toxin (Anthrax ImmunoGlobulin, AIG) derived from immunized donors, and licensed human vaccine (AVA).
Human monoclonal antibodies as medical countermeasures for anthrax
Human monoclonal antibodies (humAbs) are ideal candidates for the treatment of individuals exposed to a bio-threat agent. The advantage of human monoclonal antibodies is that they are not subject to concerns regarding potential transmission of pathogens, and that they have more favorable pharmacokinetics and lower immunogenicity than antibodies of xenogenic origin. In terms of efficacy, they will confer immediate protection, are effective pre and post exposure, and are also effective against strains genetically engineered to be resistant to multiple antibiotics. Treatment can effectively be limited to only those who have been exposed, are suspected to have been exposed, or are at risk of becoming exposed to an agent. In addition, also those with a weakened immune system will be helped with antibody treatment. Such exposure-guided treatment avoids the need for costly mass vaccination programs and avoids the health risks associated with large-scale prophylactic vaccination.
IQ-DAA – Dual Antibody Approach
Since the major virulence factor of the anthrax disease is composed of the concerted action of combined toxin components, it makes sense to design a therapy that addresses two components. Chances of survival will increase when fully human monoclonal antibody (humAb) directed against PA (IQNPA) are combined with humAb directed against LF (IQNLF). Both antibodies can fully neutralize the Lethal Toxin. This has been successfully demonstrated in vitro and in animal challenge models by IQ Therapeutics and its collaborators, by testing a combination of IQNPA and IQNLF, respectively humAb against PA and LF, and using pre and post-exposure settings. Interestingly, it was found that the combined application of the two antibodies provides a higher degree of protection than either antibody alone. It is currently under investigation whether the effect is an added or a synergistic effect, but it is already clear that the finding is very important with respect to the ability of actually saving people from death due to anthrax. In addition, and highly noteworthy, it was also found that by the combination of the two antibodies IQNPA and IQNLF, the post-exposure window of successful treatment could be extended. As it will not always be possible to treat those exposed to anthrax immediately or shortly after exposure, the latter is a very important finding, as it may save lives that would have otherwise been lost due to delayed treatment.
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