A double-blind study comparing monomethoxy polyethylene glycol-modified honeybee venom and unmodified honeybee venom for immunotherapy. I. Clinical results.

Thirty-five patients were allocated at random to immunotherapy (IT) in a double-blind way with either monomethoxy polyethylene glycol (mPEG)-modified honeybee venom (HBV) or HBV. The two groups were well matched regarding age, sex, skin sensitivity, HBV-specific serum IgE and IgG antibodies, and history of reactions after a field sting; mPEG-HBV-treated patients received doses that increased more steeply than doses of the HBV-treated patients. The maintenance dose of the former group (200 micrograms) was greater than that of the latter group (100 micrograms). During IT, both groups had the same frequency of local swellings after injections. Four patients receiving mPEG-HBV developed one mild systemic reaction (SR) during dose increase, whereas 10 patients receiving HBV demonstrated one or more of these reactions, compelling two patients to stop therapy. Following challenge with a honeybee sting after about 14 weeks of IT, six patients with SR were observed, four in the mPEG-HBV-treated group and two in the HBV-treated group. In the HBV-treated group, three patients were not challenged, one because of an insufficient IgG increase and two other patients because they dropped out of IT before reaching maintenance dose because of repeated SRs. Since the mPEG-HBV is extremely well tolerated during IT and the success rate is not significantly lower than with unmodified HBV, we suggest it as an attractive alternative to HBV for the treatment of HBV hypersensitivity. Increase of the maintenance dose may result in an even better clinical efficacy.