ANASCORP® [centruroides (scorpion) immune F(ab')2 (equine) injection] is an equine-derived antivenom indicated for treatment of patients with clinical signs of scorpion envenomation.

For Intravenous use only.

Initiate treatment with ANASCORP as soon as possible after scorpion sting in patients who develop clinically important signs of scorpion envenomation, including but not limited to loss of muscle control, roving or abnormal eye movements, slurred speech, respiratory distress, excessive salivation, frothing at the mouth and vomiting.(2)

Initial Dose: 3 vials

• The initial dose of ANASCORP is 3 vials.
• Reconstitute the contents of each vial with 5 milliliters of sterile normal saline (0.9% NaCl) and mix by continuous gentle swirling.
• Combine the contents of the reconstituted vials promptly and further dilute to a total volume of 50 milliliters with sterile normal saline (0.9% NaCl).
• Inspect the solution visually for particulate matter and discoloration prior to administration. Do not use if turbid.
• Infuse intravenously over 10 minutes.
• Monitor patient closely during and up to 60 minutes following the completion of infusion to determine if clinically important signs of envenomation have resolved.
• Discard partially used vials.

Additional Dosing

• Additional doses may be used if needed.
• Infuse one vial at a time at intervals of 30 to 60 minutes.
• Reconstitute the contents with 5 milliliters of sterile normal saline (0.9% NaCl) and mix by continuous gentle swirling.
• Further dilute to a total volume of 50 milliliters with sterile normal saline (0.9% NaCl). Inspect the solution visually for particulate matter or discoloration prior to administration.
• Infuse intravenously over 10 minutes.
• Monitor patient closely during and up to 60 minutes following the completion of infusion to determine if clinically important signs of envenomation have resolved.
• Discard partially used vials.

Each vial of ANASCORP contains a sterile, lyophilized preparation containing not more than 35 milligrams total protein and not less than 150 LD50 (mouse) neutralizing units.

None.

5.1 Hypersensitivity Reactions

Severe hypersensitivity reactions, including anaphylaxis, may occur with ANASCORP. Close patient monitoring for hypersensitivity reactions and readiness with intravenous therapy using epinephrine, corticosteroids, and diphenhydramine hydrochloride is recommended during the infusion of ANASCORP. If an anaphylactic reaction occurs during the infusion, terminate administration at once and administer appropriate emergency medical care.

Patients with known allergies to horse protein are particularly at risk for an anaphylactic reaction. Patients who have had previous therapy with ANASCORP or another equine antivenom/antitoxin may have become sensitized to equine protein and be at risk for a severe hypersensitivity reaction.

5.2 Delayed Allergic Reactions (Serum Sickness)

Monitor patients with follow-up visit(s) for signs and symptoms of delayed allergic reactions or serum sickness (e.g., rash, fever, myalgia, arthralgia), and treat appropriately if necessary. Eight out of 1,534 (0.5%) patients in the clinical trials exhibited symptoms suggestive of serum sickness. (6.1)

5.3 Transmissible Infectious Agents

ANASCORP is made from equine (horse) plasma, it may therefore carry a risk of transmitting infectious agents, e.g., viruses.

5.4 Reaction to Cresol

Trace amounts of cresol from the manufacturing process are contained in ANASCORP. Localized reactions and generalized myalgias have been reported with the use of cresol as an injectable excipient.

The most common adverse reactions observed in ≥ 2% of patients in the clinical studies for ANASCORP were: vomiting, pyrexia, rash, nausea and pruritus.

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

A total of 1534 patients were treated with ANASCORP, ranging from less than one month to 90 years old. The patient population was comprised of 802 males and 732 females. Patients were monitored for signs and symptoms of adverse reactions, including acute hypersensitivity reactions and serum sickness. Follow-up telephone interviews were conducted at 24 hours, 7 days, and 14 days after treatment to assess symptoms suggestive of ongoing venom effect, serum sickness, and any other adverse reactions.

Table 1 shows the adverse reactions occurring in patients across all clinical trials for ANASCORP. Twenty-seven percent (421/1534) of patients receiving ANASCORP reported at least one adverse reaction.

No patients died or discontinued study participation for severe adverse reactions.

Eight patients were considered to have serum sickness (Type III hypersensitivity); no patient manifested the full serum sickness syndrome. Three patients were treated with systemic corticosteroids and five others received either no treatment or symptomatic therapy.

34 patients experienced a total of 39 severe adverse reactions such as respiratory distress, aspiration, hypoxia, ataxia, pneumonia, and eye swelling. It is not clear whether these adverse reactions were related to ANASCORP envenomation or a combination of both2.

6.2 Postmarketing Experience

The following adverse reactions have been identified during post approval use of ANASCORP . Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Chest tightness, palpitations, rash and pruritus.

No drug interaction studies have been conducted with ANASCORP.

8.1 Pregnancy

Risk Summary
Animal reproduction studies have not been conducted with ANASCORP. It is also not known whether ANASCORP can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. ANASCORP should be given to a pregnant woman only if clearly needed.

8.2 Lactation

Risk Summary
It is not known whether ANASCORP is excreted in human breast milk. Because many drugs are excreted in human milk, caution should be exercised when ANASCORP is administered to a nursing woman.

8.4 Pediatric Use

Seventy-eight percent of the patients enrolled in the clinical studies were pediatrics subjects(1204/1534), with ages ranging from less than one month to 18.7 years of age. Patient age groups were as follows: < 2 years of age, 29%, 2 to 5 years, 37%, 5 to 18 years, 34%. The efficacy and safety of ANASCORP is comparable in pediatric and adult patients.

8.5 Geriatric Use

Specific studies in elderly patients have not been conducted, ANASCORP was administered to 77 patients over the age of 65 years with comparable efficacy and safety to the overall patient population.

12.1 Mechanism of Action

ANASCORP is composed of venom-specific F(ab')2 fragments of immunoglobulin G (IgG) that bind and neutralize venom toxins, facilitating redistribution away from target tissues and elimination from the body.1

12.3 Pharmacokinetics

Eight clinically healthy volunteers (6 males and 2 females, age: 17 to 26 years) received a bolus intravenous dose of 47.5 mg of centruroides (scorpion) immune F(ab’)2, (equine) injection. Blood samples were collected till 504 hours (21 days) and pharmacokinetic parameters were estimated by non-compartmental analysis which are summarized in Table 2.3