Gaucher disease is a genetic disease caused by the lack of an enzyme that breaks down a certain fat molecule, which accumulates spleen, liver, and bone marrow, potentially causing spleen and liver enlargement, anemia, excessive bleeding and bruising, bone disease, and other issues. Gaucher disease affects fewer than 10,000 people worldwide.
In a 40-patient trial, dubbed Engage, eliglustat tartrate decreased spleen volume by a mean of 28%, compared with a mean increase of 2% in patients who received placebo. Eliglustat tartrate met three secondary endpoints: increasing platelet levels, increasing hemoglobin levels, and decreasing liver volume.
A second trial, dubbed Encore, enrolled 160 patients who were stable on Sanofi's Cerezyme, and then either switched to eliglustat tartrate, or remained on Cerezyme. The trial was considered successful because 84% of patients taking eliglustat tartrate for a year remained stable in all four parameters -- spleen volume, platelet levels, hemoglobin levels, and liver volume -- compared to 94% of patients taking Cerezyme.
Despite the numerical difference, eliglustat tartrate was considered non-inferior to Cerezyme. Eliglustat tartrate is taken orally, while Cerezyme must be injected, so proving that eliglustat tartrate is equivalent to the currently available treatment should be sufficient for FDA approval.