Search Results (6)

Bothrofav, a monospecific antivenom, was introduced in June 1991 and has shown excellent effectiveness against life-threatening and thrombotic complications of Bothrops lanceolatus envenoming. Because of the reoccurrence of cerebral stroke events despite the timely administration of antivenom, new batches of Bothrofav were produced and introduced into clinical use in January 2011. This study’s aim was to evaluate the effectiveness of Bothrofav generations at treating B. lanceolatus envenoming. During the first period of the study (2000–2010), 107 patients were treated with vials of antivenom produced in June 1991, while 282 envenomed patients were treated with vials of antivenom produced in January 2011 in the second study period (2011–2023). Despite timely antivenom administration, thrombotic complications reoccurred after an interval free of thrombotic events, and a timeframe analysis suggested that the clinical efficacy of Bothrofav declined after it reached its 10-year shelf-life. In of the case of an antivenom shortage due to the absence of regular batch production, no adverse effects were identified before the antivenom reached its 10-year shelf-life, which is beyond the accepted shelf-life for a liquid-formulation antivenom. While our study does not support the use of expired antivenom for potent, life-threatening B. lanceolatus envenoming, it can be a scientific message to public entities proving the necessity of new antivenom production for B. lanceolatus envenoming. Full article

Antivenoms contain either pure animal IgGs or their fragments as an active substance, and are the only specific therapeutics against envenomation arising from snakebites. Although they are highly needed, the low sustainability of such preparations’ manufacture causes constant global shortages. One reason for this is the stability of the product, which contributes not only to the manufacture sustainability, but the product safety as well. It has been hypothesized that the roughness of conditions to which IgGs are exposed during downstream purification disturbs their conformation, making them prone to aggregation, particularly after exposure to secondary stress. The aim of this research was to investigate how the roughness of the downstream purification conditions influences the stability properties of purified IgGs. For this purpose, equine IgGs were extracted from unique hyperimmune plasma by two mild condition-based operational procedures (anion-exchange chromatography and caprylic acid precipitation) and three rougher ones (ammonium sulphate precipitation, cation-exchange chromatography and protein A affinity chromatography). The stability of the refined preparations was studied under non-optimal storage conditions (37 °C, 42 °C, and a transiently lower pH) by monitoring changes in the aggregate content and thermal stability of the pure IgGs. Mild purification protocols generated IgG samples with a lower aggregate share in comparison to the rougher ones. Their tendency for further aggregation was significantly associated with the initial aggregate share. The thermal stability of IgG molecules and the aggregate content in refined samples were inversely correlated. Since the initial proportion of aggregates in the samples was influenced by the operating conditions, we have shown a strong indication that each of them also indirectly affected the stability of the final preparations. This suggests that mild condition-based refinement protocols indeed generate more stable IgGs. Full article

Vipera ammodytes (V. ammodytes) is the most venomous European viper. The aim of this study was to compare the clinical efficacy and pharmacokinetic values of intravenous Vipera berus venom-specific (paraspecific) Fab fragments (ViperaTAb) and intramuscular V. ammodytes venom-specific F(ab’)₂ fragments (European viper venom antiserum, also called “Zagreb” antivenom) in V.ammodytes-envenomed patients. This was a prospective study of V.ammodytes-envenomed patients that were treated intravenously with ViperaTAb or intramuscularly with European viper venom antiserum that was feasible only due to the unique situation of an antivenom shortage. The highest venom concentration, survival, length of hospital stay and adverse reactions did not differ between the groups. Patients treated with intravenous Fab fragments were sicker, with significantly more rhabdomyolysis and neurotoxicity. The kinetics of Fab fragments after one or more intravenous applications matched better with the venom concentration in the early phase of envenomation compared to F(ab’)₂ fragments that were given intramuscularly only on admission. F(ab’)₂ fragments given intramuscularly had 25-fold longer apparent total body clearance and 14-fold longer elimination half-time compared to Fab fragments given intravenously (2 weeks vs. 24 h, respectively). In V.ammodytes-envenomed patients, the intramuscular use of specific F(ab’)₂ fragments resulted in a slow rise of antivenom serum concentration that demanded their early administration but without the need for additional doses for complete resolution of all clinical signs of envenomation. Intravenous use of paraspecific Fab fragments resulted in the immediate rise of antivenom serum concentration that enabled their use according to the clinical progress, but multiple doses might be needed for efficient therapy of thrombocytopenia due to venom recurrence, while the progression of rhabdomyolysis and neurotoxic effects of the venom could not be prevented. Full article

Snakebites are a relatively rare medical emergency in Europe. In more than half of the annual cases caused by Vipera ammodytes, Vipera berus, and Vipera aspis, immunotherapy with animal-derived antivenom is indicated. Among eight products recently identified as available against European medically relevant species, only Zagreb antivenom, Viperfav, and ViperaTAb have been used almost exclusively for decades. Zagreb antivenom comprises V. ammodytes-specific F(ab′)₂ fragments. Viperfav is a polyspecific preparation based on F(ab′)₂ fragments against V. aspis, V. berus, and V. ammodytes venoms. ViperaTAb contains Fab fragments against the venom of V. berus. In 2014 the production of Zagreb antivenom was discontinued. Additionally, in the period of 2017 to 2018 a shortage of Viperfav occurred. Due to a lack of the product indicated for the treatment of V. ammodytes bites, other antivenoms were implemented into clinical practice without comparative assessment of their eligibility. The aim of our work was to identify a high-quality antivenom that might ensure the successful treatment of V. ammodytes and V. berus bites at the preclinical level. Differentiation between bites from these two species is difficult and unreliable in clinical practice, so the availability of a unique antivenom applicable in the treatment of envenoming caused by both species would be the most advantageous for Southeastern Europe. Zagreb antivenom, Viperfav, and ViperaTAb, as well as Viper venom antitoxin for V. berus envenoming and the in-development Inoserp Europe, which was designed to treat envenoming caused by all medically important European snakes, were comparatively tested for the first time. Emphasis was placed on their physicochemical properties, primarily purity and aggregate content, as well as their in vivo protective efficacies. As Zagreb antivenom is no longer available on the European market, Viperfav is the highest-quality product currently available and the only antivenom whose neutralisation potency against V. ammodytes and V. berus venoms was above regulatory requirements. Full article

Second generation antivenomics is a translational venomics approach designed to complement in vivo preclinical neutralization assays. It provides qualitative and quantitative information on the set of homologous and heterologous venom proteins presenting antivenom-recognized epitopes and those exhibiting impaired immunoreactivity. In a situation of worrying antivenom shortage in many tropical and sub-tropical regions with high snakebite mortality and morbidity rates, such knowledge has the potential to facilitate the optimal deployment of currently existing antivenoms and to aid in the rational design of novel broad specificity antidotes. The aim of the present work was to expand the analytical capability of the immunoaffinity second-generation antivenomics platform, endowing it with the ability to determine the maximal binding capacity of an antivenom toward the different toxins present in a venom, and to quantify the fraction of venom-specific antibodies present in a given antivenom. The application of this new platform, termed third generation (3G) antivenomics, in the preclinical evaluation of antivenoms is illustrated in this paper for the case of antivenom EchiTAb-Plus-ICP^® reactivity towards the toxins of homologous (B. arietans) and heterologous (N. melanoleuca) venoms. Full article

Snakebite envenoming represents a neglected tropical disease that has a heavy public health impact worldwide, mostly affecting poor people involved in agricultural activities in Africa, Asia, Latin America and Oceania. A key issue that complicates the treatment of snakebite envenomings is the poor availability of the only validated treatment for this disease, antivenoms. Antivenoms can be an efficacious treatment for snakebite envenoming, provided they are safe, effective, affordable, accessible and administered appropriately. The shortage of antivenoms in various regions, particularly in Sub-Saharan Africa and some parts of Asia, can be significantly alleviated by optimizing the use of current antivenoms and by the generation of novel polyspecific antivenoms having a wide spectrum of efficacy. Complementing preclinical testing of antivenom efficacy using in vivo and in vitro functional neutralization assays, developments in venomics and antivenomics are likely to revolutionize the design and preclinical assessment of antivenoms by being able to test new antivenom preparations and to predict their paraspecific neutralization to the level of species-specific toxins. Full article