The U.S. Food and Drug Administration yesterday approved Elelyso (taliglucerase alfa) for long-term enzyme replacement therapy to treat a form of Gaucher disease, a rare genetic disorder.
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, M.D., director of the Office of Drug Evaluation III in FDA’s Center 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-center, 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 percent in patients receiving the 30 units/kg dose and by an average of 40 percent 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-center, 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 percent 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.