Somavert

OB/GYN News, May 15, 2003 by Elizabeth Mechcatie

(pegvisomant for injection, Pharmacia)

A growth hormone receptor antagonist for acromegaly, in people who have had an inadequate response to existing treatments (surgery, radiation treatment, and other medical therapies), or when these treatments are not appropriate. The first drug in this new class of drugs to be approved.

* Recommended Dosage: Subcutaneous 40-mg loading dose, followed by a 10-mg subcutaneous injection daily, adjusting dose based on serum insulin-like growth factor-I (IGF-I) levels, with dose not to exceed 30 mg a day.

* Special Considerations: Injection site reactions, sweating, headache, and fatigue were the most common side effects associated with treatment in trials. Monitor liver function for the first 6 months of therapy; in trials, two patients (fewer than 1%) had liver function tests above 10 times the upper limit of normal.

* Comment: The goal of treatment with Somavert, which blocks the effects of growth hormone, is to normalize serum levels of IGF-1, a biochemical measure of the severity of acromegaly. In patients with acromegaly, oversecretion of growth hormone, usually due to a pituitary tumor, results in overproduction of IGF-1. Treatment with Somavert normalized IGF-I levels in up to 92% of patients treated for a mean of 1 year in one study, and up to 82% of patients in a 12-week study. Compared with those on placebo, treatment was associated with improvements in signs and symptoms of the condition, such as ring size, soft tissue swelling, arthralgia, headache, perspiration, and fatigue.

Dr. Keith Friend, medical director at Pharmacia, said that there is "scientific interest" in Somavert for treating cancer and diabetic complications because growth hormone and IGF-I are involved in the pathogenesis of diabetic nephropathy and retinopathy, and in the promotion of tumor growth.