Clinical Studies

Before a new drug can be approved to treat a disease, it must go through a long and rigorous testing process to establish that it is safe and effective. This usually takes several years and is done in several phases. (Visit the Genzyme corporate website for an introduction to the clinical study process.)

Before it was commercially available to people with Fabry disease, Fabrazyme^® (agalsidase beta) was tested in clinical studies.

^{Clinical Studies of Fabrazyme}

^{Phase 1/2 Study}

The phase 1/2 clinical study of Fabrazyme involved 15 male patients with Fabry disease. In this study, Fabrazyme was tested at five different dosing regimens: 0.3, 1.0 or 3.0 milligrams (mg) per kilogram (kg) of body weight administered by IV infusion every 2 weeks or 1.0 or 3.0 mg per kg of body weight administered every 48 hours. Patients received a total of 5 infusions. This small study provided preliminary information on how Fabrazyme acts in the body, as well as information about the safety of Fabrazyme infusions.

^{Phase 3 Study}

The phase 3 clinical study involved 58 patients (56 males and 2 females) from around the world. In this 5 month study, Fabrazyme was tested at a dose of 1.0 mg per kg of body weight administered by IV infusion every 2 weeks. Half of the patients received Fabrazyme, and half of the patients received a placebo (inactive substance). The goals of the phase 3 study were to see how well Fabrazyme worked to reduce the amount of GL-3 in certain cells of the kidney, heart, and skin.

In patients who received Fabrazyme, GL-3 was reduced to normal or near normal levels in certain types of cells in the kidney (20 of 29, or 69%), heart (21 of 29, or 72%), and skin (29 of 29, or 100%). In patients who received a placebo, GL-3 was not reduced in these cells. Treatment with Fabrazyme may improve the signs and symptoms of Fabry disease; however, the relationship of between GL-3 reduction and the improvement of specific signs and symptoms has not been established.

All patients received anti-fever medications and an antihistamine prior to their infusions. The most common side effects reported with Fabrazyme were chills, fever, and skeletal pain. Skeletal pain reported during the study was most likely due to Fabry disease and not due to the Fabrazyme infusion. When chills and fever occurred, they were managed by slowing down the infusion and by treatment with additional anti-fever medications and antihistamines.

^{Phase 3 Extension Study}

All 58 patients from the phase 3 study chose to enroll in an extension study in which all patients received Fabrazyme at a dose of 1.0 mg per kg of body weight administered by IV infusion every 2 weeks. After 6 months in the phase 3 extension study, the amount of GL-3 in certain cells of the kidney, heart, and skin remained reduced to normal or near-normal in patients who originally received Fabrazyme and was decreased to normal or near-normal in patients who originally received placebo during the phase 3 study.

All patients received anti-fever medications and some patients received an antihistamine prior to their infusions. After 36 months of treatment in the extension study, the most common side effects reported with Fabrazyme were infusion reactions and included chills, drowsiness, feeling cold / warm, fever, nasal congestion, nausea, and headache. These side effects were managed by slowing down the infusion and by treatment with anti-fever medications, antihistamines, and oral steroids. Infusion reactions occurred in some patients after receiving anti-fever medications, antihistamines, and oral steroids. Infusion reactions declined in frequency with continued use of Fabrazyme; however, serious infusions reactions occurred after extended durations of Fabrazyme treatment. In this study, overtime, a majority of patients completed one or more full infusions in 2.0 hours or less. Individual results with Fabrazyme infusion times may vary. Some patients experienced allergic reactions to Fabrazyme, and some of these patients successfully received Fabrazyme after experiencing an allergic reaction to Fabrazyme.