A phase 1, randomized study to assess the pharmacokinetic comparability of siltuximab derived from two different cell lines in healthy subjects.

Siltuximab, a monoclonal antibody (mAb) against interleukin (IL-6), is under development by Janssen Research & Development, LLC. During early clinical development, siltuximab was produced in a murine Sp2/0 myeloma cell line. The production cell line was switched to stably transfected Chinese hamster ovary (CHO) cell line for subsequent clinical development. A two-part, parallel-group, phase 1 study was designed to evaluate the safety and pharmacokinetics (PK) of a single IV administration of Sp2/0- and CHO-derived siltuximab in healthy subjects. The results from this study demonstrated PK comparability of siltuximab produced from Sp2/0 and CHO cell lines. The 90% confidence interval of the ratios of geometric means of Cmax and AUC0-84day following 1.4 mg/kg doses was (99.4%, 111.3%) and (98.1%, 109.6%), respectively, both within the pre-specified comparability range of 80-125%. Siltuximab derived from either the Sp2/0 or CHO cell lines was in general well tolerated and was not found to be immunogenic in this study.