A Comparison of Crotalinae Equine Immune F(ab)2 Antivenom (Anavip) and Crotalidae Polyvalent Immune Fab,

Completed · Phase 2

Conditions studied: Snake Bite, Blood Coagulation Disorders

In brief

This phase II study was a prospective, randomized, open-label, multi-center study in the United States, involving patients from 18 to 70 years of age, comparing Anavip (Antivenin Crotalinae \[pit viper\] equine immune F(ab)2; Instituto Bioclon, Mexico City, Mexico) against CroFab (Protherics Inc., Nashville, Tennessee), the only currently approved product for treatment of Crotalinae (pit viper) envenomation in the US. The study was designed to evaluate the hypothesis that lasting correction of snakebite induced thrombocytopenia and hypofibrinogenemia are possible following correction with F(ab)2 antivenom, by analyzing in detail the relationships among platelet count, fibrinogen, venom levels, and antivenom levels in subjects presenting with thrombocytopenia following crotaline viper envenomation. In the study we expected to see a fall in platelet count following Fab treatment, commensurate with that reported in the past. We hypothesized that following F(ab)2 treatment there would be a slower drop in post-treatment platelet counts, with a relatively higher platelet count at any given point in the follow-up period. We further hypothesized that an initial rise and later fall in platelet count would correspond with rise and fall in antivenom levels, and would be mirrored by concurrent drop and rise in levels of unbound circulating venom.

Key facts

Study ID

NCT00868309

Run by

Instituto Bioclon S.A. de C.V.

People needed

12

Starts

2005-01-01

Expected to finish

2007-02-01

Last updated by the study team

2016-04-18

Who can join

Age: 18 and older, up to 70. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• men and women 18 to 70 years of age
• presenting for emergency treatment of pit viper bite
• informed consent document read and signed by subject

You may not qualify if…

• allergy to horse serum, sheep serum, or papaya
• current use of any antivenom, or use within the last month
• current participation in a clinical drug study, or participation within the last month
• pregnancy or breast-feeding
• underlying medical conditions that significantly alter blood coagulation: thrombocytopenia, hemophilia, familial dysfibrinogenemia, leukemia, recent ingestion of superwarfarin compounds (rat poison)
• use of any medication expected to affect platelet count, coagulation factors, or fibrinogen: chemotherapeutic agents, warfarin, heparin, aspirin
• No clinical indications of snake bite envenomation

Where it is running

• Tucson snakebite investigational site — Tucson, Arizona, United States

Full record on ClinicalTrials.gov

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