In the phase 3 trial of eliglustat in patients with Gaucher disease type 1 already stabilized with enzyme therapy (ENCORE), at one year, eliglustat was non-inferior to imiglucerase enzyme therapy in maintaining stable platelet counts, hemoglobin concentrations, and spleen and liver volumes. After this primary analysis period, patients entered a long-term extension phase in which all received eliglustat. Duration on eliglustat ranged from 2 to 5 years, depending on timing of enrollment (which spanned 2 years), treatment group to which patients were randomized, and whether they lived in the United States when commercial eliglustat became available. Here we report long-term safety and efficacy of eliglustat for 157 patients who received eliglustat in the ENCORE trial; data are available for 46 patients who received eliglustat for 4 years. Mean hemoglobin concentration, platelet count, and spleen and liver volumes remained stable for up to 4 years. Year to year, all four measures remained collectively stable (composite endpoint relative to baseline values) in ≥85% of patients, as well as individually in ≥92%. Mean bone mineral density Z-scores (lumbar spine and femur) remained stable and were maintained in the healthy reference range throughout. Eliglustat was well-tolerated over 4 years; 4 (2.5%) patients withdrew due to adverse events that were considered related to the study drug. No new or long-term safety concerns were identified. Clinical stability assessed by composite and individual measures was maintained in adults with Gaucher disease type 1 treated with eliglustat who remained in the ENCORE trial for up to 4 years.The ENCORE trial was funded and conducted by Sanofi Genzyme
