Clinical trial NCT00247078: The Efficacy and Safety of Aracmyn in Patients With Systemic Latrodectism
Official title: The Efficacy and Safety of Aracmyn® [Antivenin Latrodectus (Black Widow)Equine Immune F(ab)2], in Patients With Systemic Latrodectism: A Phase II, Multi-center, Randomized, Double-Blind Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE2
Conditions: Arachnidism
Latrodectism
Keywords: black
widow
spider
antivenom
Lead sponsor: Instituto Bioclon S.A. de C.V.
Sponsor class: INDUSTRY
Collaborators: name: Rocky Mountain Poison and Drug Center
First posted: 2005-11-01
Enrollment: 24
Sex: ALL
Minimum age (years): 10
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: The purpose of this study is to compare the safety and effectiveness of an investigational antivenom and the current standard of care (pain management with opioid analgesics) for treating patients with a widow spider bite. The working hypotheses are as follows:

1. the investigational antivenom is more promptly effective at alleviating the pain associated with a widow spider bite than routine management with opioid pain medication
2. the investigational antivenom is as safe a treatment as opioid pain medication in treating patients with a widow spider bite.

Detailed description: The purpose of this randomized, double-blind, multi-center phase II trial is to examine the safety and efficacy of Aracmyn® \[Antivenin Latrodectus (Black Widow) Equine Immune F(ab)2\], a new antivenom, for treatment of patients envenomed by the widow spider. Twenty-four subjects will be randomized to receive either the study drug or control (normal saline) through intravenous (IV) infusion. Following infusion, subjects will be monitored for changes in pain and clinical signs during a two-hour observation period. A standard dose of IV fentanyl will be offered to all subjects as pain medication at specific intervals following treatment. Vital signs, blood samples, and pain intensity scores (using a visual analog scale, VAS) will be collected before and after the infusion, as well as during the observation period. This study uses a treatment failure protocol, which involves administration of Merck Antivenin to subjects who do not obtain adequate pain relief from the study drug or control. Primary efficacy and safety endpoints for this 12-month trial will be improvement in pain intensity and clinical signs and incidence of adverse events, respectively.

Eligibility criteria: Inclusion Criteria:

* patient presents for treatment within 72 hours from time of symptoms onset
* clinical diagnosis of widow spider envenomation
* patient has moderate to severe pain intensity

Exclusion Criteria:

* history of significant cardiac, respiratory, hepatic, or renal disease
* distracting injury or chronic pain syndrome that would obscure pain intensity assessment
* history of asthma or known sensitivity to fentanyl, morphine, diazepam, or equine serum
* pregnant or lactating

Primary outcomes:
measure: between-treatment groups difference in pain intensity (pre- and post-treatment)
timeFrame: within first two hours
Secondary outcomes:
measure: between-treatment groups difference in proportion of treatment failures (absence of pain relief or return to hospital)
timeFrame: within 24 hours after discharge from emergency department
measure: between-treatment groups difference in incidence of drug-related adverse events.
timeFrame: onset of adverse events within 21 days
Other outcomes:
Locations:
city: Denver
country: United States
facility: Denver Health and Hospital Authority
state: Colorado
Study officials:
affiliation: Rocky Mountain Poison and Drug Center
name: Richard C Dart, MD PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: Instituto Bioclon S.A. de C.V.
name: Walter Garcia, MD
role: STUDY_DIRECTOR
References: