Analysis of relationship between baseline body weight and efficacy/safety of yttrium 90 (90Y) ibritumomab tiuxetan radioimmunotherapy in patients (pts) with non-Hodgkin's lymphoma (NHL)

Abstract

6700 Background: 90Y ibritumomab tiuxetan (Zevalin®) has produced high response rates and durable remissions in pts w/relapsed or refractory low-grade, follicular, or transformed B-cell NHL. Increased stability and favorable pharmacokinetic profile (ie, predictable urinary clearance and absence of dehalogenation) associated w/the 2nd-generation chelator tiuxetan enables simple weight-based dosing and obviates need for determining whole body clearance. Standard dose 90Y ibritumomab tiuxetan is 0.4 mCi/kg in pts w/plts ≥ 150,000/μL, to maximum recommended dose (MRD) 32 mCi. Pts >80 kg, therefore, receive a dose/kg that is less than that received by pts ≤ 80 kg. The objective of this analysis was to determine whether this difference in dose impacts efficacy or safety. Method/Results: Analysis of efficacy and safety data of pts (n=170) who received 90Y ibritumomab tiuxetan 0.4 mCi/kg from 3 registrational trials was performed. 103 pts ≤ 80 kg w/median wt 70 kg (range, 45–80 kg) were compared w/67 pts >80 kg w...