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

Alexandre Naime Barbosa, Rui Seabra Ferreira, Francilene Capel Tavares de Carvalho, Fabiana Schuelter-Trevisol, Mônica Bannwart Mendes, Bruna Cavecci Mendonça, José Nixon Batista, Daisson José Trevisol, Leslie Boyer, Jean Philippe Chippaux, Natália Bronzatto Medolago, Claudia Vilalva Cassaro, Márcia Tonin Rigotto Carneiro, Ana Paola Piloto de Oliveira, Daniel Carvalho Pimenta, Luís Eduardo Ribeiro da Cunha, Lucilene Delazari dos Santos, Benedito Barraviera

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


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].

Original languageEnglish (US)
Article number653151
JournalFrontiers in immunology
StatePublished - Mar 23 2021


  • Apis mellifera (Africanized)
  • antivenom
  • clinical trial
  • enzyme-linked immunosorbent assay (ELISA)
  • safety assessment

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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