Local reaction due to pegvisomant (Somavert ®)

RATIONALE: Pegvisomant, the first growth hormone-receptor antagonist for the treatment of acromegaly, is usually well tolerated. METHODS: We report a case of a 54 year-old woman who 24-48 hours after the first subcutaneous injection of 20 mg of Somavert®, presented a erythemato-violaceous, purpuric and pruriginous lesion in the site of the injection.Ten mg produced the same lesion.It disappeared in one week without treatment, leaving a transitory hyperpigmentation. Prick test, intradermal test and a single blind controlled challange were performed. RESULTS: Prick (20 mg/ml) and intradermal test (0,02; 0,2; 2; 20 mg/ml) to Somavert® were negative on inmediate and delayed readings. A single blind controlled subcutaneous challenge with increasing doses of Somavert®, with 24 hours-intervals was positive. Six to 8 hours after the 14 mg dose, the lesion was reproduced. (10 x 6 cm). A cutaneous biopsy revealed an eosinophilic inflammatory infiltrate, and capillary vasodilatation in the deep dermis. Epidermis and superficial and intermediate dermis were intact. CONCLUSIONS: 1- We report a case of local delayed reaction caused by Somavert®, confirmed by controlled challenge. 2- The presence of eosinophilies in the skin biopsy could suggests a possible hypersensitivity mechanism.