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Double-Blind, Alacramyn® vs. Placebo in Pediatric Patients

This study has been completed.
University of Arizona
Universidad Nacional Autonoma de Mexico
Information provided by:
Instituto Bioclon S.A. de C.V. Identifier:
First received: May 23, 2008
Last updated: June 1, 2011
Last verified: June 2011

There is no FDA approved therapy for the treatment of scorpion envenomation, Centruroides scorpion envenomation produces a pattern of neurotoxicity with a spectrum of severity ranging from trivial to life threatening. Patients stung by Centruroides scorpions develop a clinical syndrome which may require sedation with benzodiazepines and observation for 6 to 28 hours of intensive care monitoring. A safe therapy is necessary to halt the progression of symptoms early in the clinical course while avoiding the clinical deterioration that can occur en route to a tertiary facility. Alacramyn® is anticipated to be safer and more effective than the present standard of care, midazolam, and faster-acting such that the need for transport of most rural patients will be eliminated and will reduce hospitalization time.

The working hypotheses are as follows:

  1. The investigational antivenom is safe as treatment of scorpion sting envenomation.
  2. The investigational antivenom is effective as treatment of scorpion sting envenomation.

Condition Intervention Phase
Scorpion Sting Envenomation Biological: Antivenin Centruroides (scorpion) equine immune F(ab)2 Other: Placebo Phase 2 Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Prospective, Randomized, Double-Blind, Controlled Study of Alacramyn® vs. Placebo in Pediatric Patients With Systemic Signs of Scorpion Sting Envenomation

Further study details as provided by Instituto Bioclon S.A. de C.V.:

Primary Outcome Measures:
  • The primary study endpoint is the resolution of clinically important signs of scorpion envenomation [ Time Frame: 4 hours ]

Secondary Outcome Measures:
  • Alacramyn®-treated patients require significantly less benzodiazepine sedation than placebo controls, for control of agitation [ Time Frame: 4 hours ]
  • Venom blood levels decrease after Alacramyn® treatment, while the placebo group continues to have elevated blood venom levels [ Time Frame: 1 hour ]

Enrollment: 15
Study Start Date: May 2004
Study Completion Date: October 2005
Primary Completion Date: August 2005 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1
Alacramyn and midazolam as needed
Biological: Antivenin Centruroides (scorpion) equine immune F(ab)2
3 vials of Alacramyn reconstitued in 50 ml of normal saline as a IV infusion over 10 minutes.
Other Name: Anascorp
Placebo Comparator: 2
placebo and midazolam as needed
Other: Placebo
Placebo reconstituted in 50 ml of normal saline administered over 10 min

Detailed Description:

The purpose of this Prospective, Randomized, Double-Blind, Controlled, Multicenter Treatment Protocol, phase III trial is to examine the safety and efficacy of Alacramyn® for treatment of patients envenomed by scorpion sting.

This study will take place in two pediatric Intensive care units in Tucson, Arizona.

Patients who arrive at the emergency clinic presenting with scorpion sting symptoms will be evaluated for treatment with respect to the inclusion/exclusion criteria according to the study procedures. Only patients with clinically important systemic signs of scorpion sting envenomation will be included in the study. Baseline measures will include severity evaluation of the scorpion sting envenomation. The patient's vital signs, concomitant medication, medical history and demographic data will be collected. Blood tests will be done for haematology, chemistry, venom and anti-venom levels and urine test.

After informed consent and inclusion7exclusion criteria have been obtained and verified, and the baseline measurements have been done, three vials of Alacramyn® or placebo will be administered. During the following 3 hours, midazolam will continue, if indicated for control of agitation.

Patients off midazolam sedation after receiving study drug and no longer manifesting clinically important systemic signs of scorpion envenomation will be discharge at 4 hours, or 2 hours following cessation of midazolam drip, whichever occurs later. Prior to discharge repeat lab work, physical assessments, and vital signs will be done. Patients still requiring midazolam sedation and/or manifesting clinically important systemic signs of scorpion envenomation will be treated with standard of care for the duration of clinical symptoms. Those remaining for extended care undergo final study assessments at time of hospital discharge or at 24 hours after study drug infusion if hospitalization continues.

All patients who participated in the study will be contacted 7 and 14 days after treatment, looking for symptoms suggestive of ongoing venom effect, delayed serum sickness as well as for any other adverse event reported by the patient.


Ages Eligible for Study:   6 Months to 18 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Males and females of 6 months to 18 years of age
  • Presenting for emergency treatment within 5 hours with clinically important systemic signs of scorpion sting envenomation.
  • Signed written Informed Consent by patient or legal guardian.
  • No participation in a clinical drug trial within the last month or concomitantly.

Exclusion Criteria:

  • Allergy to horse serum.
  • Use within the past 24 hours of drugs expected to alter immune response: H1 or H2 blockers, corticosteroids.
  • Use of any antivenom within the last month or concomitantly.
  • Underlying medical conditions that significantly alter immune response: bone marrow suppression congenital or acquired immuno-deficiency state, chemotherapy and chronic corticosteroid use.
  • Allergy to midazolam.
  • More than 0.3mg/kg of body weight of midazolam administered during the hour prior to study drug infusion.
  • Concurrent medical condition involving a baseline neurologic status mimicking envenomation (chorea, tardive dyskinesia, uncontrolled epilepsy).
  • Pregnant and nursing women.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00685230

United States, Arizona
Tucson Medical Center
Tucson, Arizona, United States, 85712
University Medical Center
Tucson, Arizona, United States, 85724
Sponsors and Collaborators
Instituto Bioclon S.A. de C.V.
University of Arizona
Universidad Nacional Autonoma de Mexico
Principal Investigator: Leslie Boyer, MD Poison and Drug Center
Study Director: Walter Garcia, MD Instituto Bioclon S.A. de C.V.
Study Chair: Alejandro Alagon, PhD Universidad Nacional Autonoma de Mexico
  More Information

Additional Information:
Connor, D.A., Seldon, B.S., Scorpion Envenomation. Chapter in Wilderness Medicine; Management of Wilderness and Environmental Emergencies. 3rd edition. Auerbach PS, ed., Mosby Yearbook, Inc. St. Louis, MO. pp 831-842
Chavez-Haro A., Gonzalez J., Paniagua nJ., Efficiency and Security Comparison between Two Different Scorpion-derived Antivenom in Mexico, Abstract, Leon Study Data Analysis.
Gonzalez, C., et al, Development of an Immunoenzymatic Assay for the Quantification of Scorpion Venom in Plasma, Abstract, Cuernavaca, 2000
Alagon Cano, A., Gozalez Juarez, C., From Serotherapy to Fabotherapy, Abstract, Cuernavaca, 1998.
Cabral-Soto, J., et al, Comparison of Efficacy between Two Antiscorpion Antivenoms, Abstract, Cuernavaca, 2000, Clinical Study Report, Randomized, Double-Blind, Variable dosing of Alacramyn in Patients With Scorpion Sting (this was done with two approved products in Mexico, Alacramyn and Birmex), March 2002.
Madrazo Navarro, M., et al, Animales Ponzoñosos en la Población Derechohabiente del IMSS 1990-1996.
Dart, R.C., Horowitz, R.S., Use of Antibodies as Antivenoms: A primitive Solution for Complex Problem? Rocky Mountain Poison and Drug Center, Denver Co, USA.
TESS Data Collection Manual (available upon request)

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Dr. Walter Garcia Ubbelohde/Clinical Research Manager, Instituto Bioclon Identifier: NCT00685230     History of Changes
Other Study ID Numbers: AL-02/03
Study First Received: May 23, 2008
Last Updated: June 1, 2011

Keywords provided by Instituto Bioclon S.A. de C.V.:
scorpion sting

Additional relevant MeSH terms:
Bites and Stings
Scorpion Stings
Chemically-Induced Disorders
Wounds and Injuries
Immunologic Factors
Physiological Effects of Drugs processed this record on September 20, 2017