Single-Arm, Multicenter Phase I/II Clinical Trial for the Treatment of Envenomings by Massive Africanized Honey Bee Stings Using the Unique Apilic Antivenom

We evaluated the safety, optimal dose, and preliminary effectiveness of a new-approach Africanized honeybee (Apis mellifera) Antivenom (AAV) in a phase I/II, multicenter, non-randomized, single-arm clinical trial involving 20 participants with multiple stings. Participants received 2 to 10 vials of AAV depending on the number of stings they suffered, or a predefined adjuvant, symptomatic, and complementary treatment. The primary safety endpoint was the occurrence of early adverse reactions within the first 24 h of treatment. Preliminary efficacy based on clinical evolution, including laboratory findings, was assessed at baseline and at various time points over the four following weeks. ELISA assays and mass spectrometry were used to estimate venom pharmacokinetics before, during, and after treatment. Twenty adult participants, i.e., 13 (65%) men and 7 (35%) women, with a median age of 44 years and a mean body surface area of 1.92 m2 (median = 1.93 m2) were recruited. The number of stings ranged from 7 to > 2,000, with a median of 52.5. Symptoms of envenoming were classified as mild, moderate, or severe in 80% (16), 15% (3), and 5% (1) of patients, respectively; patients with mild, moderate, or severe envenoming received 2, 6, and 10 vials of AAV as per the protocol. None of the patients had late reactions (serum sickness) within 30 d of treatment. There was no discontinuation of the protocol due to adverse events, and there were no serious adverse events. One patient had a moderate adverse event, transient itchy skin, and erythroderma. All participants completed the intravenous antivenom infusion within 2 h, and there was no loss to follow-up after discharge. ELISA assays showed venom (melittin and PLA2) concentrations varying between 0.25 and 1.479 ng/mL prior to treatment. Venom levels decreased in all patients during the hospitalization period. Surprisingly, in nine cases (45%), despite clinical recovery and the absence of symptoms, venom levels increased again during outpatient care 10 d after discharge. Mass spectrometry showed melittin in eight participants, 30 d after treatment. Considering the promising safety results for this investigational product in the treatment of massive Africanized honeybee attack, and its efficacy, reflected in the clinical improvements and corresponding immediate decrease in blood venom levels, the AAV has shown to be safe for human use. Clinical Trial Registration: UTN: U1111-1160-7011, identifier [RBR-3fthf8].

A Novel Apilic Antivenom to Treat Massive, Africanized Honeybee Attacks: A Preclinical Study from the Lethality to Some Biochemical and Pharmacological Activities Neutralization

Massive, Africanized honeybee attacks have increased in Brazil over the years. Humans and animals present local and systemic effects after envenomation, and there is no specific treatment for this potentially lethal event. This study evaluated the ability of a new Apilic antivenom, which is composed of F(ab’)2 fraction of specific immunoglobulins in heterologous and hyperimmune equine serum, to neutralize A. mellifera venom and melittin, in vitro and in vivo, in mice. Animal experiments were performed in according with local ethics committee license (UFRJ protocol no. DFBCICB072-04/16). Venom dose-dependent lethality was diminished with 0.25–0.5 μL of intravenous Apilic antivenom/μg honeybee venom. In vivo injection of 0.1–1 μg/g bee venom induced myotoxicity, hemoconcentration, paw edema, and increase of vascular permeability which were antagonized by Apilic antivenom. Cytotoxicity, assessed in renal LLC-PK1 cells and challenged with 10 μg/mL honeybee venom or melittin, was neutralized by preincubation with Apilic antivenom, as well the hemolytic activity. Apilic antivenom inhibited phospholipase and hyaluronidase enzymatic activities. In flow cytometry experiments, Apilic antivenom neutralized reduction of cell viability due to necrosis by honeybee venom or melittin. These results showed that this antivenom is effective inhibitor of honeybee venom actions. Thus, this next generation of Apilic antivenom emerges as a new promising immunobiological product for the treatment of massive, Africanized honeybee attacks.

A phase I/II trial to treat massive Africanized honeybee (Apis mellifera) stings using the new apilic antivenom

ABSTRACTSafety, optimal minimum dose, and, preliminary effectiveness of a new generation Africanized honeybees (Apis mellifera) antivenom (AAV) were evaluated. A phase I/II, multicenter, non- randomized, single-arm clinical trial involving 20 participants showing multiple stings were studied. Participants have received either 2 to 10 vials of AAV based on the stings number together with a predefined adjuvant, symptomatic, and complementary treatment schedule. The primary safety endpoint was the presence of early adverse reactions within the first 24 hours after treatment. Preliminary efficacy through clinical evolution, including laboratory tests, was assessed at baseline and over the following four weeks. ELISA assays and mass spectrometry estimated the venom pharmacokinetics before, during, and after treatment. Twenty adult participants, 13 (65%) males, and 7 (35%) females, with a median age of 44 years and a mean body surface of 1.92 m2 (median = 1.93 m2) were recruited. The median number of stings was 52.5 ranging from 7 to more than 2,000. Envenoming severity was classified as 80% mild, 15% moderate, and 5% severe. According to the protocol, 16 (80%) participants received two AAV vials, 3 (15%) six vials, and one (5%) 10 vials. There was no discontinuation of the treatment due to acute adverse events and there were no late adverse reactions. Two patients showed mild adverse events with only transient itchy skin and erythroderma. All participants completed the infusion within two hours and there was no loss of follow-up after discharge. ELISA assays showed venom concentrations varying between 0.25 ng/mL and 1.479 ng/mL prior to treatment. Venom levels decreased in all cases during the hospitalization period. Surprisingly, in nine cases (45%), despite clinical recovery and without symptoms, the venom levels increased again during outpatient care 10 days after discharge. Mass spectrometry showed melittin in eight participants 30 days after the treatment. Considering the promising safety results of the investigational product for the treatment of massive Africanized honeybee attacks, added to efficacy in clinical improvement and immediate decrease in blood venom level, the AAV has shown to be safe for human use.Trial registrationUniversal Trial Number (UTN): U1111-1160-7011, Register Number: RBR-3fthf8 (http://www.ensaiosclinicos.gov.br/rg/RBR-3fthf8/).