Questionable Efficacy of Therapeutic Antibodies in the Treatment of Anthrax

Abstract

Inhalational anthrax caused by Bacillus anthracis, a spore-forming Gram-positive bacterium, is a highly lethal infection. Antibodies targeting the protective antigen (PA) binding component of the toxins have recently been authorized as an adjunct to antibiotics, although no conclusive evidence demonstrates that anthrax antitoxin therapy has any significant benefit. We discuss here the rational basis of anti-PA development regarding the pathogenesis of the disease. We argue that inductive reasoning may induce therapeutic bias. We identified anthrax animal model analysis as another bias. Further studies are needed to assess the benefit of anti-PA antibodies in the treatment of inhalational anthrax, while a clearer consensus should be established around what evidence should be proven in an anthrax model.

Anthrax Toxin Detection: From In Vivo Studies to Diagnostic Applications

“…4) It makes it possible to monitor the effectiveness of treatment and seroconversion, either by directly measuring the toxins or by searching for anti-toxin antibodies, as applied in human cases of cutaneous, gastrointestinal, and inhalation anthrax [ 52 , 53 ]. Measuring toxin levels may help to monitor the efficiency of anti-toxin, as it is still the only specific authorized treatment to complement antibiotics [ 61 ].…”

Case Report of an Injectional Anthrax in France, 2012

“…Unfortunately, a retrospective analysis of the toxin levels in the serum and the hydro-electrolytic losses was not possible for this patient. The administration of adjunct anti-toxin therapy was evaluated in the Scotland cohort with an ambiguous success [8,9], and this would have probably not changed the prognosis.…”

You Can’t B. cereus – A Review of Bacillus cereus Strains That Cause Anthrax-Like Disease

“…As with the vaccine, it is assumed that the anthrax toxins produced by B. cereus are homologous to those produced by B. anthracis and the treatment should be similarly effective. However, there is a wider debate ongoing as to whether anti-toxin therapy adds value to the treatment of anthrax disease ( Vietri, 2018 ; Tournier et al, 2019 ).…”