Enzyme Replacement Therapy for Fabry Disease: A Model for the Integration of Rare Disease Therapeutics Into the Canadian Health Care System

CFDI STUDY with ENZYME REPLACEMENT THERAPY (ERT)

Fabry disease is a rare, inherited, genetic condition due to a deficiency of an enzyme called alpha-galactosidase A. This enzyme deficiency causes the small blood vessels to accumulate a substance called glycolipid. Without sufficient levels of the enzyme, alpha-galactosidase A, persons with Fabry Disease develop severe neuropathic pain, kidney disease, heart disease, stroke and/or premature death; often before the age of 60.

Fabry Disease is estimated to affect approximately one out of every 40,000 males and up to twice as many females in Canada. We do not have the exact number of persons in Canada who have this disease. A common problem in studying rare conditions is the difficulty in identifying the majority of people suffering from such a disease. Gathering their health information in order to better understand the natural disease progression and its response to treatment is difficult.

Until recently, treating symptoms was all that was available for people with Fabry Disease. In 2001, enzyme replacement therapy (ERT) was developed as a treatment for this rare condition. ERT provides the deficient enzyme and may be beneficial in Fabry Disease. The Canadian Fabry Disease Initiative (CFDI) will determine the impact of Enzyme Replacement Therapy (ERT) on the development of complications of Fabry Disease in males and females currently on, or who have received ERT; and to assess which of these complications respond to the ERT therapy. Another purpose of this study is to establish a national registry which will collect information on all persons with Fabry Disease in Canada.

Early ERT studies involving humans had small numbers of subjects and the studies were of short duration. The results of these clinical studies did lead to approval of the therapy in many countries around the world including Canada. To date though, evidence of the usefulness of ERT and its direct impact on the natural course of Fabry disease has been limited, while its cost continues to be very high. As a result of these issues, there will need to be continued and long-term collection of information related to the effectiveness of ERT to better document its true clinical outcomes in Canadian people with Fabry disease.