SBIR-STTR Award

Direct to Phase II

Snake bite envenomation is a significant problem in the US and worldwide that can result in substantial morbidity and evendeath. Snake venom contains a complex mixture of toxins including neurotoxins and myotoxins, as well as toxins thatdisrupt normal hemostasis and can produce fatal hemorrhage. Snake venoms also include several classes of digestive andproteolytic enzymes that are responsible for the extensive local tissue destruction from snake bites that can result inpermanent disability or require limb amputation. Current antivenom products consist of antibody fragments raised in horsesor sheep and are generally effective at stabilizing envenomation patients, however they come with several limitations in thatthey are not effective against all species of N. American venomous snakes in mitigating tissue damage, and there are adverseeffects such as serum sickness, hypersensitivity, and recurrent coagulopathy. In addition, antibody-based formulations havean extremely high cost, with the cost of the drug ranging from $20,000 to $40,000 per patient treatment.We propose to develop a novel antivenom therapeutic based on high-affinity aptamers, which consist of single-strandedoligodeoxynucleotides that form stem-loop structures to bind to their targets. Our proprietary X-Aptamer selectiontechnology utilizes bead-based oligo DNA combinatorial libraries in which certain bases contain protein-like sidemodifications to enhance binding affinity. In this project, we will generate X-Aptamers against a set of major toxin classesfound in N. American venomous snakes, to develop novel antivenom formulation with a better safety profile than currentantibody-based antivenoms. Our preliminary studies have demonstrated selection of aptamers capable of neutralizingmyotoxin from Southern Pacific rattlesnakes (C. o. helleri) in a hind limb paralysis model in mice.The project aims are: 1) Generate high-affinity oligonucleotide X-Aptamers against the five major classes of N. Americansnake venom toxins and measure the dissociation constant for each X-Aptamer and its target toxin; 2) Demonstrate in vivoefficacy of X-Aptamers against snake venom toxins and crude venom, using mouse models of hemorrhagic activity, creatinekinase activity, hind-limb paralysis, and lethality, to determine the effective dose for each aptamer; 3) Perform dose-rangingand toxicology studies in rats with the blended aptamer antivenom formulation. The completion of these studies willdemonstrate safety and efficacy of a novel aptamer-based formulation which will have a strong impact and market potentialin the emergency treatment of snake bite envenomation.

Public Health Relevance Statement:
Snake bites are a significant emergency care concern, as current serum-based antivenom products are often not effective at reducing the severe tissue damage resulting from snake venom. We propose to develop a novel antivenom therapeutic based on high-affinity aptamers, which consist of single-stranded DNA segments that form stem-loop structures to bind to their targets. Our aptamer-based antivenom formulation will be targeted to neutralize the major toxin classes found in N. American venomous snakes, to provide a safe and consistent emergency treatment for snake bites.

Project Terms:
Antibodies ; Antivenins ; antivenom ; Blood ; Blood Reticuloendothelial System ; Blood Coagulation Disorders ; Coagulation Disorder ; Coagulopathy ; bleeding disorder ; clotting disorder ; Body Weight ; Creatine Kinase ; ADP Phosphocreatine Phosphotransferase ; ATP Creatine Phosphotransferase ; Creatine Kinase-B ; Creatine Kinase-B Chain ; Creatine Phosphokinase ; Cessation of life ; Death ; DNA ; Deoxyribonucleic Acid ; Single-Stranded DNA ; Emergency treatment ; Emergency Therapy ; Enzymes ; Enzyme Gene ; Limb structure ; Extremities ; Limbs ; Non-Trunk ; Family ; Female ; Hemorrhage ; Bleeding ; blood loss ; Hemostatic function ; Hemostasis ; Equus caballus ; Domestic Horse ; Equine ; Equine Species ; Equus przewalskii ; Horses ; Hypersensitivity ; Allergy ; Immunoglobulin Fragments ; Antibody Fragments ; Libraries ; male ; Metalloproteases ; Metallopeptidases ; Metalloproteinases ; Morbidity - disease rate ; Morbidity ; Mus ; Mice ; Mice Mammals ; Murine ; Neurotoxins ; neurotoxicant ; Oligonucleotides ; Oligo ; oligos ; Ophthalmology ; Clinical Pathology ; Patients ; Peptide Hydrolases ; Esteroproteases ; Peptidases ; Protease Gene ; Proteases ; Proteinases ; Proteolytic Enzymes ; Drug Kinetics ; Pharmacokinetics ; Phospholipase A2 ; EC 3.1.1.4 ; Lecithinase A2 ; PLA2 ; lecithinase A ; phosphatidase ; phosphatidolipase ; phosphatidylcholine 2 acylhydrolase ; Proteins ; Rattus ; Common Rat Strains ; Rat ; Rats Mammals ; Recurrence ; Recurrent ; Safety ; Serine Protease ; Serine Endopeptidases ; Serine Protein Hydrolases ; Serine Proteinases ; Serum Sickness ; Sheep ; Ovine ; Ovis ; Snake Bites ; Snake Envenomation ; Snake Venoms ; Snakes ; Technology ; Tissues ; Body Tissues ; Toxicology ; Toxin ; Venoms ; Measures ; Drug Costs ; Dissociation ; Treatment Cost ; proteinase B ; Targeted Toxins ; base ; Site ; Cottonmouth ; Copperheads ; Crotalus ; Rattlesnake ; Serum ; Blood Serum ; disability ; Individual ; Measurement ; Therapeutic ; Side ; Palsy ; Plegia ; paralysis ; paralytic ; Paralysed ; American ; aptamer ; Histopathology ; Structure ; novel ; Modeling ; Adverse effects ; C-Type Lectins ; Molecular Interaction ; Binding ; Complex Mixtures ; polypeptide ; Dose ; Affinity ; in vivo ; Hindlimb ; Modification ; Emergency Care ; ED care ; ER care ; Emergency Department care ; Emergency Room care ; Emergency health care ; Emergency healthcare ; Emergency medical care ; cost ; novel strategies ; new approaches ; novel approaches ; novel strategy ; combinatorial ; mouse model ; murine model ; stem ; limb amputation ; amputated limb ; Formulation ; nanomolar ; nano-molar ; efficacy study ; Immunize ;