What is Actimmune®?

Actimmune® is a bioengineered protein approved by the FDA for treatment of certain diseases. The protein, a form of interferon gamma, affects the immune system. It is used to treat chronic granulomatous disease (CGD), particularly serious infections that occur as a result of that disease. Actimmune® also is approved for treating malignant osteopetrosis. Treatment often occurs in conjunction with antibiotics.

CGD is an autoimmune condition in which certain immune cells, called phagocytes, do not work correctly. An inherited disorder, it usually diagnosed is early, with about 75 percent of cases diagnosed before the patient turns 5 years old. Because of the underlying malfunction in the immune system, those afflicted with this condition suffer from recurring bacterial and fungal infections. These recurring infections result in chronic granulomas, or areas of inflammation, in affected areas, which often include the lungs and spleen. Actimmune® can be used to treat both adults and children suffering from this disorder.

CGD appears to be more common in males than in females. When the disease was first discovered, most patients died in childhood. Even with modern medicine and use of Actimmune®, mortality tends to be high. While many more patients live to adulthood now than in previous years, many still succumb to the disease before turning 30.

First described by doctors in 1904, osteopetrosis is an inherited disorder in which the bones are both extremely dense and abnormally brittle. This occurs because old bone cells are not properly reabsorbed as new bone tissue continues to be created. Though mild cases produce few symptoms, more severe cases can lead to increased frequency of infections because of a reduction in the size of the bone marrow. Osteopetrosis also can lead to stunted growth and even blindness, deafness or some forms of paralysis if nerves are compressed by the abnormally dense bones.

Benign osteopetrosis usually is diagnosed in adults, but another form, called malignant osteopetrosis, is apparent in infancy, or shortly after birth. Symptoms include easily fractured bones as well as anemia, blindness and deafness. Malignant osteopetrosis must be treated with bone marrow transplants to prevent early death.

A bone marrow transplant is the only known cure for osteopetrosis, although Actimmune® has been shown to slow progression of the disease. Slowing the disease can be particularly important in cases of malignant osteopetrosis, because it can take time to find an appropriate donor for a bone marrow transplant. Other drugs also have shown a slowing effect on osteopetrosis, but Actimmune® was the first drug with FDA approval for this treatment.