Engineering and design considerations for next-generation snakebite antivenoms

Knudsen, Carsten; Ledsgaard, Line; Dehli, Rasmus Ibsen; Ahmadi, Shirin; Soerensen, Christoffer Vinther; Laustsen, Andreas Hougaard

doi:10.1016/j.toxicon.2019.06.005

Cited by 46 publications

(52 citation statements)

References 91 publications

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“…The advantages of repurposing licensed medicines (e.g., DMPS and dimercaprol) or phase II-approved drug candidates (e.g., marimastat and varespladib) are that these molecules have demonstrated safety profiles and thus drug development times could be significantly shortened as these agents have extensive pharmacokinetic, bioavailability and tolerance data already associated with them [23,61,62]. The small size of these compounds, compared with conventional antibodies, confer desirable drug-favorable properties enabling rapid and effective tissue penetration and, depending on the pharmacokinetics and physicochemical properties of specific inhibitors, often make them amenable for oral delivery [61,63,64].…”

Section: Discussionmentioning

confidence: 99%

Neutralizing Effects of Small Molecule Inhibitors and Metal Chelators on Coagulopathic Viperinae Snake Venom Toxins

et al. 2020

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Animal-derived antivenoms are the only specific therapies currently available for the treatment of snake envenoming, but these products have a number of limitations associated with their efficacy, safety and affordability for use in tropical snakebite victims. Small molecule drugs and drug candidates are regarded as promising alternatives for filling the critical therapeutic gap between snake envenoming and effective treatment. In this study, by using an advanced analytical technique that combines chromatography, mass spectrometry and bioassaying, we investigated the effect of several small molecule inhibitors that target phospholipase A2 (varespladib) and snake venom metalloproteinase (marimastat, dimercaprol and DMPS) toxin families on inhibiting the activities of coagulopathic toxins found in Viperinae snake venoms. The venoms of Echis carinatus, Echis ocellatus, Daboia russelii and Bitis arietans, which are known for their potent haemotoxicities, were fractionated in high resolution onto 384-well plates using liquid chromatography followed by coagulopathic bioassaying of the obtained fractions. Bioassay activities were correlated to parallel recorded mass spectrometric and proteomics data to assign the venom toxins responsible for coagulopathic activity and assess which of these toxins could be neutralized by the inhibitors under investigation. Our results showed that the phospholipase A2-inhibitor varespladib neutralized the vast majority of anticoagulation activities found across all of the tested snake venoms. Of the snake venom metalloproteinase inhibitors, marimastat demonstrated impressive neutralization of the procoagulation activities detected in all of the tested venoms, whereas dimercaprol and DMPS could only partially neutralize these activities at the doses tested. Our results provide additional support for the concept that combinations of small molecules, particularly the combination of varespladib with marimastat, serve as a drug-repurposing opportunity to develop new broad-spectrum inhibitor-based therapies for snakebite envenoming.

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Section: Discussionmentioning

confidence: 99%

Neutralizing Effects of Small Molecule Inhibitors and Metal Chelators on Coagulopathic Viperinae Snake Venom Toxins

et al. 2020

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“…specific antibodies in horses, tested for neutralizing activity, rapidly cloned/synthesized and humanized to produce the next generation of antivenoms 14,16,77 . Alternatively, recombinant venom proteins can be used as baits against antibody phage libraries to obtain toxinneutralizing, activity-tested humanized synthetic antibodies 16,72,78 .…”

Section: Nature Geneticsmentioning

confidence: 99%

The Indian cobra reference genome and transcriptome enables comprehensive identification of venom toxins

Suryamohan¹,

Krishnankutty

Guillory³

et al. 2020

Nat Genet

140

152

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ossil remains from ~100 million years ago (Ma) show that snakes were widely distributed across the world by the late Cretaceous period 1. During the course of their evolution, snakes lost their limbs, acquiring a serpentine body 2. Some also evolved or co-opted venom systems to help subdue, capture and digest their prey 2,3. The Colubroides clade of advanced snakes encompasses >3,000 extant species including >600 venomous species 4. The most venomous snakes include the true vipers and pit vipers, both members of the Viperidae family, and cobras, kraits, mambas and sea snakes from the Elapidae family 5. Although humans are not an intended target, accidental contact with venomous snakes can be deadly. Snakebite envenoming is a serious neglected tropical disease that affects ~5 million people worldwide annually, leading to ~400,000 amputations and >100,000 deaths 6. In India alone, the high rural population density combined with the presence of the 'big four' deadly snakes, namely the Indian cobra (Naja naja), Russell's viper (Daboia russelli), sawscaled viper (Echis carinatus) and common krait (Bungarus caeruleus), results in >46,000 snakebite-related deaths annually 7. Snake venom is a potent lethal cocktail rich in proteins and peptides, secreted by specialized venom gland cells. Venom components can be broadly classified as neurotoxic, cytotoxic, cardiotoxic or hemotoxic, and the composition can vary both between and within species 8-11. Currently, snake antivenom is the only treatment effective in the prevention or reversal of the effects of envenomation. Since 1896, antivenom has been developed by immunization of large mammals, such as the horse, with snake venom to generate a cocktail of antibodies that are used for therapy 12. Given the heterologous nature of these antibodies, they often elicit adverse immunological responses when treating snakebite victims 13. Moreover, the antivenom composition is not well defined and its ability to neutralize the venom

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“…IgG antibodies have many advantages, such as a long serum half-life, extensive clinical validation, and established manufacturing strategies. Yet, other smaller formats, including Fabs, scFvs, DARPins, nanobodies, and Avimers, have their own set of advantages ( Jenkins et al, 2019 ; Knudsen et al, 2019 ). Indeed, these formats have more binding sites per mass unit due to their smaller molar mass, which could have a favorable influence on cost dynamics, as the amount of antitoxin required for neutralizing a given venom may be less (in terms of gram).…”

Section: Resultsmentioning

confidence: 99%

“…However, one of the challenges that sets snakebite envenoming aside from other indications that are treatable with antibodies is that exceptionally high amounts of antibodies are needed for effective treatment ( Laustsen, 2019 ). Therefore, the cost of manufacture should be a key focal point for recombinant antivenom developers ( Laustsen and Dorrestijn, 2018 ; Knudsen et al, 2019 ). Yet, so far, this has remained largely unexplored.…”

Section: Introductionmentioning

confidence: 99%

Cost of Manufacturing for Recombinant Snakebite Antivenoms

Jenkins

Laustsen

2020

Front. Bioeng. Biotechnol.

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Snakebite envenoming is a neglected tropical disease that affects millions of people across the globe. It has been suggested that recombinant antivenoms based on mixtures of human monoclonal antibodies, which target key toxins of medically important snake venom, could present a promising avenue toward the reduction of morbidity and mortality of envenomated patients. However, since snakebite envenoming is a disease of poverty, it is pivotal that next-generation therapies are affordable to those most in need; this warrants analysis of the cost dynamics of recombinant antivenom manufacture. Therefore, we present, for the first time, a bottom-up analysis of the cost dynamics surrounding the production of future recombinant antivenoms based on available industry data. We unravel the potential impact that venom volume, abundance of medically relevant toxins in a venom, and the molecular weight of these toxins may have on the final product cost. Furthermore, we assess the roles that antibody molar mass, manufacturing and purification strategies, formulation, antibody efficacy, and potential cross-reactivity play in the complex cost dynamics of recombinant antivenom manufacture. Notably, according to our calculations, it appears that such next-generation antivenoms based on cocktails of monoclonal immunoglobulin Gs (IgGs) could be manufacturable at a comparable or lower cost to current plasma-derived antivenoms, which are priced at USD 13-1120 per treatment. We found that monovalent recombinant antivenoms based on IgGs could be manufactured for USD 20-225 per treatment, while more complex polyvalent recombinant antivenoms based on IgGs could be manufactured for USD 48-1354 per treatment. Finally, we investigated the prospective cost of manufacturing for recombinant antivenoms based on alternative protein scaffolds, such as DARPins and nanobodies, and highlight the potential utility of such scaffolds in the context of low-cost manufacturing. In conclusion, the development of recombinant antivenoms not only holds a promise for improving therapeutic parameters, such as safety and efficacy, but could possibly also lead to a more competetive cost of manufacture of antivenom products for patients worldwide.

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Engineering and design considerations for next-generation snakebite antivenoms

Cited by 46 publications

References 91 publications

Neutralizing Effects of Small Molecule Inhibitors and Metal Chelators on Coagulopathic Viperinae Snake Venom Toxins

Neutralizing Effects of Small Molecule Inhibitors and Metal Chelators on Coagulopathic Viperinae Snake Venom Toxins

The Indian cobra reference genome and transcriptome enables comprehensive identification of venom toxins

Cost of Manufacturing for Recombinant Snakebite Antivenoms

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