Pegademase bovine: replacement therapy for severe combined immunodeficiency disease.

Severe combined immunodeficiency (SCID) represents a syndrome characterized by abnormal function of cellular and humoral immunity. Of the various types of SCID, approximately one-fourth are associated with adenosine deaminase (ADA) deficiency. Treatment consists of bone marrow transplantation, red blood cell transfusions, enzyme replacement, and, more recently, gene therapy. Pegademase bovine is the sole agent available for enzyme replacement therapy of SCID associated with ADA deficiency. The drug is administered intramuscularly to infants from birth and to children of any age at time of diagnosis. At present, few adverse effects or drug interactions have been documented. Although it is expensive (approximately $60,000 annually), pegademase bovine offers an alternative to standard means of therapy.