The researchers assessed the ability of an enhanced interferon (IFN) to maintain an IFN concentration sufficient to suppress viral replication.
The enhanced molecule was produced by the covalent attachment of a branched 40-kd polyethylene glycol (PEG) moiety to IFN alpha-2a. This molecule exhibits sustained absorption, a restricted volume of distribution, and reduced clearance compared with unmodified IFN alpha-2a.
The team enrolled 159 patients with chronic hepatitis C in the randomized, ascending-dose (45, 90, 180, or 270µg) study. PEG IFN alpha-2a administered once weekly was compared with 3 MIU IFN alpha-2a administered 3 times weekly for 48 weeks.
Measurement of hepatitis C virus RNA following a 24-week treatment-free period was used to assess efficacy.
The findings of the trial were reported in February's issue of Hepatology.
|Sustained virological responses for PEG IFN alpha-2a:|
Response for IFN alpha-2a: 3%
Sustained virological responses for PEG IFN alpha-2a once weekly were 10% (45 µg), 30% (90 µg), 36% (180 µg), and 29% (270 µg), compared with 3% for the 3-times-weekly 3-MIU IFN alpha-2a regimen.
The types and frequencies of adverse events and laboratory abnormalities were similar among all groups.
Researcher K. Rajender Reddy of Miami, Florida concluded, "Once-weekly PEG IFN alpha-2a was associated with a higher number of sustained virological responses compared with IFN alpha-2a 3 times weekly in patients with chronic hepatitis C, but had a similar safety profile.
"180-µg PEG IFN alpha-2a appeared to be the optimal dose based on sustained virological response and its associated side-effect profile."