The VISYT trial: Venom Immunotherapy Safety and Tolerability with purified vs nonpurified extracts.

BACKGROUND

Venom immunotherapy (VIT) is a highly effective treatment but can induce systemic adverse effects.

OBJECTIVE

To evaluate the safety and tolerability of VIT with purified and nonpurified extracts for treating yellow jacket and honeybee allergy.

METHODS

Ninety-four patients (mean age, 46 years) with a history of insect venom allergy were randomly allocated to undergo purified extract VIT (group A [44 patients]) or nonpurified extract VIT (group B [50 patients]). Fifty-six patients were allergic to yellow jacket venom (group A: 25; group B: 31) and 38 to honeybee (19 per group). The induction phase was performed using a 2- or 7-day ultrarush scheme. The maintenance phase lasted 11 weeks. Local and systemic reactions were recorded after each injection.

RESULTS

A total of 1,401 VIT injections were performed. Six systemic reactions were observed in 4 patients (honeybee-allergic patients only) (4% of patients; 0.4% of injections): 1 patient in group A (2%) and in 3 in group B (6%) (P = .57). Local extensive reactions were recorded after 5 injections in 4 patients (9%) in group A (2 yellow jacket- and 2 honeybee-allergic patients) and after 17 injections in 12 patients (24%) in group B (8 yellow jacket- and 4 honeybee-allergic patients) (P = .02). Total reactions (systemic and large local) numbered 6 in group A (0.9% of injections; 11% of patients) and 20 in group B (2.7% of injections; 30% of patients) (P = .001).

CONCLUSION

In patients with honeybee or yellow jacket venom allergy, VIT with purified extracts has a significantly lower propensity toward severe local reactions compared with VIT with nonpurified extracts.