Page 15 - The Flying Publisher Guide to Hepatitis C Treatment

Antiviral Therapy: The Basics
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There are two FDA and EMA approved formulas of PegIFN that
can be administered subcutaneously once weekly, with different
dosing regimens and pharmacokinetics (Table 1.1):
– PegIFN alfa-2a (PEGASYS™, manufactured by Hofmann La-
Roche) in which standard IFN alfa-2a is covalently linked to
a 40-kDa branched Peg molecule, administered at a fixed
dose (180 µg/week), with a plasma half-life of 80 -160 hours.
– PegIFN alfa-2b (PegIntron™, manufactured by Schering–
Plough/Merck) in which standard IFN alfa-2b is covalently
linked to a 12-kDa linear Peg molecule, dosed according to
body weight (1.5 µg/kg/week), with a mean elimination
half-life of 40 hours.
Table 1.1 – Different characteristics of the available PegIFNs*
Characteristic PegIFN alfa-2a PegIFN alfa-2b
Trade name/ Pegasys/ PegIntron/
Manufacturer Hoffmann-La Roche Schering Corporation-
now Merck
Structure large, branched, 40 kD small, linear, 12 kD
Volume of distribution 8-12 L 0.99 L/kg body
Clearance 60-100 mL/hr 22mL/hr/kg
Absorption half-life (hrs) 50-60 4,6
Elimination half-life (hrs) 65 40
Time to reach maximum 80 15-44
concentration
Peak to trough ratio 1.5-2 >10
Cost of combination treatment 5019 6743
(PegIFN + RBV) for 24 wks £ †
Cost of treatment 48 wks £ † 10963-11889‡ 13468
* According to data from Foster 2010
† according to British national formulary, 50th edition, excluding VAT
‡ depending on body weight
These differences do not affect significantly the treatment
outcomes. Current evidence does not allow for a definitive
recommendation of one of the two forms of PegIFNs. A Cochrane
systematic review of head-to-head randomized trials (Awad