A Trial of Equine F (ab')2 Antivenom for Treatment of Scorpion Envenomation in Morocco

This study has the objective to demonstrate the effectiveness of Alacramyn NAMO in the treatment of North Africa and Middle East scorpions envenomation by reducing the severity of envenomation. The primary endpoint is make a comparison between antivenom and placebo groups, at 4 hours after study drug, of the number of cases showing improvement in class of envenomation.

In an effort to shorten hospital stay and to further decrease mortality, a new antivenom has been developed. This antivenom is a third generation F(ab')2 "fabotherapeutic" agent.It is administered intravenously which should lead to rapid neutralization of circulating venom. This study will demonstrate whether or not use of the new antivenom in children receiving standardized supportive care leads to resolution of the syndrome within 4 hours of treatment.The onset of clinical symptoms following a scorpion envenomation is usually within 5 to 30 minutes following the sting.

Established a classification of the patient status to differentiate a simple scorpion sting from a severe envenomation. A simple sting (class I) is characterized by signs that are local only: pain at the inoculation point, redness, edema, and numbness.

A class II envenomation is characterized by the presence of some systemic signs: hypothermia, hyperthermia, chills, nausea, abdominal pain and diarrhea. Being 15 years old or younger or the presence of priapism, vomiting, sweating, or a body temperature greater than 39°C are factors predictive of severity.

A severe envenomation (class III) is characterized by cardiovascular failure, often leading to death; respiratory failure related to the cardiac failure; and neurologic failure due to hypoxia.

• Biological: equine F(ab')2 antivenom

  Calculation of the expected dose of Study Drug for effective treatment of envenomation by the species tested, assuming maximal venom injection and treatment of children within 5 hours of sting, projects a range of effective dose between 1 and 4 vials administered intravenously. Because it is not currently possible to judge, on an individual clinical basis, which patients have received the largest doses of scorpion venom, this protocol uses a single dose of 4 vials, intravenous, as the most likely dose to ensure efficacy in the largest number of subjects.

  Lyophilized placebo consisting of inactive excipient materials, and its packaging will be indistinguishable from the active drug.

  Other Names:

  • Alacramyn NAMO
  • Scorpion North Africa and Middle East Immune F(ab')2(Equine)
• Other: Standard of care plus placebo
  Intensive care support as needed plus placebo

• Experimental: Active treatment
  Standard of care and active antivenom
  Intervention: Biological: equine F(ab')2 antivenom
• Placebo Comparator: Placebo control
  Standard of care plus placebo
  Intervention: Other: Standard of care plus placebo

Inclusion Criteria:

• Male or female 6 months to 15 years
• Class II B or III scorpion envenomation
• Presenting within 5 hours of sting
• Informed consent read and signed by parent or legal guardian

Exclusion Criteria:

• Unable to provide informed consent
• Prior use of antivenom for this envenomation
• Allergy to horse serum
• Pregnant or breast-feeding
• Patients with underlying condition mimicking symptoms of scorpion envenomation (congenital heart disease, chronic oxygen therapy, etcetera)

• Centre Antipoison et de Pharmacovigilane du Maroc
• University of Arizona
• Institut Pasteur du Maroc
• Universidad Nacional Autonoma de Mexico