The coordinating center will immediately notify ANVISA and subsequently the Department of Science and Technology in the Ministry of Health (DECIT/SCTIE/MS). PregnancyThe occurrence of pregnancy during the study will need to be communicated immediately to the coordinating center via a pregnancy report formulary and Rufloxacin hydrochloride reported concomitantly to the system CEP-CONEP. effective dose, a clinical protocol was developed to be applied in a multicenter, non-randomized and open phase I/II clinical trial. Twenty participants with more than five stings, aged more than 18?years, of both sexes, who have not previously received the heterologous serum against bee stings, will be included for 24?months. The proposed dose was based on the antivenom neutralizing capacity and the number of stings. Treatment will be administered only in a hospital environment and the participants will be evaluated for a period up to 30?days after discharge for clinical and laboratory follow-up. Results This protocol, approved by the Brazilian regulatory agencies for ethics (National Commission for Ethics on Research C CONEP) and sanitation (National Health Surveillance Agency C ANVISA), is a guideline constituted by specific, adjuvant, symptomatic and complementary treatments, in addition to basic orientations for conducting a clinical trial involving heterologous sera. Conclusions This is the first clinical trial protocol designed specifically to evaluate the preliminary efficacy and safety of a new antivenom against stings E1AF from the Africanized honeybee bees were introduced into the southeastern region of Brazil in 1956. Twenty-six queens swarmed and initiated the Africanization of the American continent. These new hybrids, known as Africanized honeybees, are very defensive and attack honeybees, to evaluate safety and preliminary efficacy, and to standardize the lowest dose of the new antivenom. The absence of a previous standardized clinical protocol justifies its publication in order to open a discussion on the relevance of antivenom strategy and methodology proposed. Methods Antivenom development and dose proposal Researchers from the Center for Studies of Venoms and Venomous Animals (CEVAP) of the S?o Paulo State University (UNESP) in partnership with the Vital Brazil Institute (IVB), Brazil, developed the apilic antivenom. For this, the principal toxins from the venom of Africanized honeybee maintained at the Lageado Experimental Farm, UNESP campus in Botucatu, S?o Paulo, Brazil, were extracted and purified. Next, previously selected horses were immunized with increasing doses of the chosen antigens. These protocols are described in detail in the developed guide for researchers and in the patent submitted [7, 11]. The proposed dose of the new antivenom was calculated taking into account the premises of the [12] that prioritize the quantity of venom inoculated in the host, neutralization potency and the proposed antivenom dose. For these calculations, the authors relied on the fact that one bee inoculates during one sting approximately 0.1?mg of venom [1]. According to the serum neutralization tests, each milliliter of standardized antivenom neutralizes 1.25?mg of venom. Therefore, 10?mL of antivenom should neutralize the venom of 100 stings. The experimental validation of antivenom efficacy and preclinical tests are detailed in a paper in progress. Design of the study This is a multicenter, non-randomized and open phase I/II clinical trial study to evaluate the Rufloxacin hydrochloride safety, determine the pharmacokinetic and proteomic profile, and confirm the lowest antivenom dose, according to the severity of each case. It will include 20 adult individuals, of both sexes, afflicted with multiple stings from Africanized honeybees. The study population will be of the type non-probabilistic by convenience (or accidental) sample, given the low demographic density of the studied phenomenon and the extreme geographic decentralization of this event. The sample size was estimated by considering examples of phase I/II clinical studies proposing to study the safety and neutralizing power and to confirm the minimum required dose of antivenom [12]. Not performing the sample calculation is justified by the fact that the efficacy outcome is not the target at this moment given that there are no data on safety and adequate dose. The study will last 36?months, with 24?months for recruitment. Objectives Primary objectives: to evaluate the safety of the antivenom including number and severity of acute adverse events, as well as deaths suspected to be related to the intervention; and to confirm the lowest effective dose when faced with different Rufloxacin hydrochloride quantities of venom inoculated in patients exposed to multiple stings from Africanized honeybees. Secondary objectives: to correlate the severity of the initial clinical condition with number of stings. Explanatory objectives: to evaluate the antivenom neutralizing power by pharmacokinetic and proteomic studies; and to evaluate the antivenom pharmacokinetics and immunogenicity. Outcomes Primary outcomes: to evaluate the antivenom safety profile through laboratory and clinical adverse events; to verify the proportion of individuals with improvement in the initial clinical picture by monitoring signs, symptoms and laboratory exams. Secondary outcomes: to evaluate the degree de correlation between the number.