The US Food and Drug Administration (FDA) has approved Elelyso (taliglucerase alfa) for long-term enzyme replacement therapy to treat a form of Gaucher disease, a rare genetic disorder.

Gaucher disease occurs in people who do not produce enough of an enzyme called glucocerebrosidase. The enzyme deficiency causes fatty materials (lipids) to collect in the spleen, liver, kidneys, and other organs. The major signs of Gaucher disease include liver or spleen damage, low red blood cell counts (anemia), low blood platelet counts, and bone problems.

Elelyso is an injection that replaces the missing enzyme in patients with a confirmed diagnosis of Type 1 (non-neuropathic) Gaucher disease and should be administered by a health care professional every other week. Type 1 Gaucher disease is estimated to affect about 6,000 people in the United States.

“Today’s approval provides for a new enzyme replacement therapy for the select number of patients with Type 1 Gaucher disease,” said Julie Beitz, MD, director of the Office of Drug Evaluation III in FDA’s Centre for Drug Evaluation and Research. “It also demonstrates FDA’s commitment to developing treatments for rare diseases.”

Due to the small number of affected patients, the efficacy of Elelyso was evaluated in a total of 56 patients with Type 1 Gaucher disease enrolled in two clinical trials. Many of these patients continued treatment on a longer-term extension study.

In one multi-centre, double-blind, parallel-dose trial, the efficacy of Elelyso for use as an initial therapy was evaluated in 31 adult patients who had not previously received enzyme replacement therapy. Patients were randomly selected to receive Elelyso at a dose of either 30 units per kilogram or 60 units/kg.

At both doses, Elelyso was effective in reducing spleen volume, the study’s primary endpoint, from baseline by an average of 29 per cent in patients receiving the 30 units/kg dose and by an average of 40 per cent in patients receiving the 60 units/kg dose after nine months of treatment. Improvements in liver volume, blood platelet counts, and red blood cell (hemoglobin) levels also were observed.

In the other study, the efficacy of Elelyso was assessed in 25 patients with Type 1 Gaucher disease who were switched from imiglucerase, another enzyme replacement therapy product. In this multi-centre, open-label, single-arm trial, patients who had been receiving treatment with imiglucerase for at least two years were switched to Elelyso infusions every other week at the same dose of imiglucerase. Results showed Elelyso was effective in maintaining spleen and liver volumes, blood platelet counts, and hemoglobin levels over a nine month evaluation period.

The most common side effects reported during clinical studies were infusion reactions and allergic reactions. Symptoms of infusion reactions include headache, chest pain or discomfort, weakness, fatigue, hives, skin redness, increased blood pressure, back pain, joint pain, and flushing. As with other intravenous protein products, anaphylaxis has been observed in some patients during Elelyso infusions.

Other commonly observed side effects observed in greater than 10 per cent of patients treated with Elelyso included upper respiratory tract infection, common cold-like symptoms (nasopharyngitis), joint pain (arthralgia), influenza, headache, extremity pain, back pain, and urinary tract infections.

Elelyso is manufactured and distributed by New York City-based Pfizer Inc., under license from Protalix BioTherapeutics Inc.

The FDA, an agency within the US Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.