Deriving health utility values from a randomized, double-blind, placebo-controlled trial of siltuximab in subjects with multicentric Castleman's disease.

AbstractPurpose: To estimate health utility values, explore predictors of utility values, and estimate the quality-adjusted life years (Q.A.L.Y.s) gained by treatment in multicentric Castleman’s disease (M.C.D.). Methods: The SF-36 was administered to 79 patients enrolled in a randomized, double-blind, placebo-controlled, multi-national study to determine the safety and efficacy of siltuximab plus best supportive care (B.S.C.) compared with B.S.C., in subjects with symptomatic M.C.D. Utility (SF-6D) scores were derived from the SF-36. Sensitivity analyses using utilities obtained by mapping the SF-36 to the EQ-5D were also conducted. Repeated measures, mixed effects models were conducted to estimate effects of treatment, responder status and ≥ Grade 3 adverse events (A.E.s) on changes in utility values over time, controlling for baseline utility value. Additionally, differential Q.A.L.Y. gain was assessed in the trial using multiple regression. Results: Patients on siltuximab and those who experienced a c...