The data were presented in an oral presentation at the Lysosomal Disease Network (LDN) World Symposium in Miami, Florida. Data from a pediatric subgroup of this study and five year follow-up results from a long-term phase I/II extension study (TKT025 EXT) conducted in adults were also reported. They add to the available data on the long-term safety and efficacy of velaglucerase alfa in patients with Type 1 gaucher disease. Both studies (TKT032 and TKT025 EXT) met their primary end-points.
Additionally, Shire reported important findings from a study that compared patient antibody response to velaglucerase alfa and imiglucerase. All patients enrolled in the velaglucerase alfa phase III clinical studies underwent a comprehensive panel of tests that were developed and validated to assess antibody response.
In each study, samples were first screened using an electrochemiluminescence (ECL) assay. Positive samples were confirmed using a quantitative radioimmunoprecipitation (RIP) assay. Positive cut-points were established for the ECL assay as 5ng/mL, as well as in terms of fixed raw counts, and for the RIP assay as 4ng/mL. The results suggest significant antigenic differences between velaglucerase alfa and imiglucerase, with only 1% seroconversion rates against velaglucerase alfa.
Pramod Mistry, professor of pediatrics and internal medicine at Yale University School of Medicine, said: “The combined data presented today provides additional and compelling support for the long-term clinical efficacy and safety of velaglucerase alfa. The Gaucher community is very fortunate to have velaglucerase alfa as an option for patients.