Summary of pharmacokinetics (PK)
*Varies according to patient bodyweight.; †Does not vary according to patient bodyweight.
3–8
Infinity
77
»40
Elimination
half-life, h1,3,4,7
1/1.5–2.1
100:1
Peak-to-trough ratio6
50
4.6
2.3
Absorption
half-life, h2-5
80
1540*
11 800
Clearance, mL/h1-3
6–14†
80*
31–73
Volume of distribution, L1-3,6
PEGASYS® (40KD)
Pegylated interferon alfa-2b (12KD)
Interferon alfa
Pharmacokinetic parameter
1. Perry C, Jarvis B. Drugs 2001; 61: 2263 5. Reddy K. Ann Pharmacother 2000; 34: 915
2. Glue P, et al. Clin Pharmacol Ther 2000; 68: 556 6. Hoffmann-La Roche. PEGASYS® Monograph
3. PEG-Intron® PDR® 7. INTRON® A PDR®
4. ROFERON®-A PDR®
Slide 6: Summary of pharmacokinetics (PK)
•This table compares the pharmacokinetics of three molecules: conventional interferon alfa, small linear pegylated interferon alfa-2b (12KD) and PEGASYS®.
•Conventional interferon alfa has a very short half-life of 3–8 hours, so within 24 hours there is little interferon alfa left in the serum. The peak-trough ratio is infinity which means that there are huge fluctuations in interferon alfa serum concentrations which are associated with side effects of therapy and viral rebound. Pegylated interferon alfa-2b (12KD) has a longer serum half-life of approximately 40 hours and approximately a 10-fold reduced clearance rate compared with conventional interferon alfa. This molecule has a peak-trough ratio of approximately 100:1 which still indicates wide fluctuation in serum concentrations across the dosing interval.
•With the use of a 40KD PEG in PEGASYS®, the resulting molecular entity has a much lower volume of distribution, reduced clearance, an increased half-life of approximately 80 hours and a low peak-to-trough ratio. PEGASYS® exhibits sustained plasma levels over the entire dosing interval.

1. Perry C, Jarvis B. Drugs 2001; 61: 2263
2. Glue P, et al. Clin Pharmacol Ther 2000; 68: 556
3. PEG-Intron™ PDR®
4. ROFERON®-A PDR®
5. Reddy K. Ann Pharmacother 2000; 34: 915
6. Hoffmann-La Roche. PEGASYS® Monograph
7. INTRON® A PDR®