6ER-005 Effectiveness of omalizumab and bee venom immunotherapy combination: case report

Background and importance Bee venom immunotherapy (b-VIT) is an established therapeutic option for anaphylaxis by hymenoptera venom. Some cases of omalizumab (anti-IgE monoclonal antibody) and b-VIT combination have been reported to suppress systemic reactions developing due to b-VIT itself. Aim and objectives To describe the efficacy of omalizumab in avoiding the anaphylaxis risks due to b-VIT. Material and methods A 33-year-old beekeeper woman, asthmatic, with a diagnosis of severe anaphylaxis due to hymenoptera venom, presented b-VIT management difficulties, suffering systemic reactions. b-VIT was initiated weekly and over 4 weeks, from 40 µg (0.4 mL) to 100 µg (1 mL), divided into two equal doses, separated by 30 min, each injected into a different arm, increasing progressively to 20 µg per week. The patient then received doses of 50 µg (0.5 mL) in each arm, with 30 min between injections, per month over another 3 months. The following month she received 100 µg (1 mL) in one arm, suffering grade III anaphylaxis. It was decided to continue with the divided and spaced doses, presenting good tolerance. She suffered a new bee sting anaphylaxis and therefore 5 months later the off-label use of omalizumab 300 mg monthly was authorised to allow a dose increase in b-VIT. Results After two single doses of omalizumab 300 mg in 1 month intervals she had a bee sting with just a local reaction. After that, omalizumab 300 mg plus 100 µg (50 µg in each arm) of b-VIT monthly was started. The dose of one arm was increasing while the other arm was decreasing proportionally until reaching the dose of 100 µg in one arm. Shortly after she had a completely asymptomatic new bee sting. Conclusion and relevance The omalizumab and b-VIT combination was effective in suppressing undesirable systemic reactions in our patient. The last asymptomatic sting implies good expectations for its use. However, as there is little evidence of this off-label use, it is necessary to observe if the patient can continue the treatment without omalizumab in the future, even at higher b-VIT doses if necessary. References and/or acknowledgements No conflict of interest.