Biological standardization of human interferon beta: Establishment of a replacement world health organization international biological standard for human glycosylated interferon beta

CIS 00/572, containing CHO cell-derived, glycosylated IFN-β, was clearly shown to be suitable to serve as a primary standard for glycosylated forms of IFN-β, especially clinical grade IFN-β-1a products. It was further shown to exhibit high thermal and long-term stability. Since the CHO cell-derived IFN-β used for preparation of 00/572 was of a greater purity than the IFN-β used for the 2nd IS of IFN-β, Gb23-902-531, it was recommended by the WHO Informal Consultation on the Standardisation of Cytokines, Growth Factors and Other Endocrinological Substances, which met in October 2003, that 00/572 should replace Gb23-902-531 as the IS for glycosylated IFN-β. This recommendation was accepted by the WHO Expert Committee on Biological Standardization (ECBS) at its annual meeting in November 2003 and 00/572 was established as the 3rd IS for human glycosylated IFN-β with an assigned potency of 40,000 IU. As this study identified no advantage to replacing the existing 1st IS for IFN-β Ser 17 mutein, Gxb02-901-535, WHO ECBS accepted that this should continue to serve as the IS for this material.