PEGASYS® (Peginterferon Alfa-2a [40KD]) Fixed Dose
The volume of distribution for PEG-IFN a-2a (40KD)
varies little with body weight
180 mg
180 mg
180 mg
Lamb MW, Martin NE. Ann Pharmacother. 2002;36:933-935.
Slide 5. PEGASYS® (Peginterferon Alfa-2a [40KD])
Need Not Be Dosed by Weight
PEGASYS® (peginterferon alfa-2a [40KD]) has a restricted distribution and is predominantly found in the bloodstream and interstitial fluid rather than in the tissues.1 Its volume of distribution is small (8 to 12 L).2
Because its maximum tolerated and minimum effective doses are widely separated, PEGASYS® has a broad therapeutic index.1
In an analysis of patient variability in volume of distribution and clearance of PEGASYS® in relation to body surface, body weight, and body mass index, body weight accounted for less than 1% of the observed between-patient variability in these pharmacokinetic parameters.1
Moreover, the efficacy and safety of PEGASYS® are not altered by variations
in patient body weight.1

   1. Lamb MW, Martin NE. Ann Pharmacother. 2002;36:933-935.  2. Perry CM, Jarvis B. Drugs. 2001;61:2263-2288.