Deploy repurposed small-molecule toxin inhibitors as broad-spectrum early therapy
#00134
Use varespladib (PLA2 inhibitor), marimastat (SVMP inhibitor), and DMPS/dimercaprol (Zn2+ chelators) as cheap, heat-stable, species-agnostic first-line treatment that buys time before or alongside antivenom, particularly in the pre-hospital window.
Parent issue
#00133 Antivenoms are species- and region-specific, so the available product often fails against the local snake
Sustainable Development Goals
Location
Description
The proposal
Repurpose small-molecule inhibitors that block whole classes of venom toxin as a species-agnostic first-line therapy deliverable in the field or at a first clinic before definitive antivenom. Lead candidates: varespladib (inhibits secretory phospholipase A2), marimastat (inhibits snake-venom metalloproteinases), and DMPS/dimercaprol (chelate the Zn2+ metalloproteinases require).
Why it would work
These drugs target conserved enzyme families near-ubiquitous across venoms rather than species-specific epitopes, so a single agent acts against many snakes. As small molecules they are cheap, heat-stable (no cold chain), and — for varespladib — orally bioavailable, directly addressing the pre-hospital gap during which neurotoxic and coagulopathic envenoming does its damage.
Evidence
The BRAVO phase II RCT (India and USA, BMJ Global Health 2024) tested oral varespladib plus standard care in 95 patients. The primary Snakebite Severity Score endpoint was not statistically significant overall (difference −0.4, p=0.13), but a prespecified subgroup treated within 5 hours showed clinically important benefit, and the drug was safe and well tolerated. Preclinically, marimastat and DMPS neutralize hemorrhagic and lethal effects of Echis and Bothrops venoms, and marimastat + varespladib combined counter Russell's viper toxicity.
Implementation path
Combine class-complementary inhibitors (PLA2 + SVMP inhibitor) to broaden coverage; formulate for oral/field use; run larger trials powered on early-treatment windows and viper-dominant settings; position as an adjunct/bridge to antivenom, not a replacement.
Trade-offs and limitations
BRAVO did not meet its overall primary endpoint, so efficacy as standalone therapy is unproven and the signal is confined to early treatment. Each inhibitor covers only its toxin class, requiring combinations; toxins that are not enzyme-based (e.g., three-finger neurotoxins) are not addressed by any of these agents.
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