Evidence continues to accumulate that rapid virological
response (RVR) at week 4 may offer an even earlier criterion for stopping treatment
in patients who are unlikely to become sustained responders, thereby sparing side
effects and expense.
French researchers assessed rapid (week 2 and 4) and
early (week 12) virological response among 323 HIV-HCV coinfected patients in
the RIBAVIC
(ANRS HC02) trial, which compared pegylated interferon alpha-2b (PegIntron)
versus conventional interferon, both in combination with 800 mg/day ribavirin,
for 48 weeks. Results were reported in the August 2007 issue of Gut.
Results
•
The HCV
RNA decrease at week 2 was significantly greater in sustained responders compared
with non-responders.
•
The best positive predictive
value for SVR (97%) was obtained with RVR, defined as undetectable HCV RNA at
week 4.
•
The best negative predictive
value for SVR (99%) was obtained with EVR, defined as at least a 2 log decrease
in HCV RNA by week 12.
•
Prediction
of lack of SVR was obtained for all patients using HCV RNA cut-off levels above
460,000 IU/mL at week 4 and above 39,000 UI/mL at week 12.
•
These cut-offs remained valid
regardless of HCV genotype or treatment arm (pegylated or conventional interferon).
Conclusion
In
conclusion, the investigators wrote, "We propose a new algorithm based on
RVR thresholds using HCV RNA that allows for excellent prediction of non-SVR as
early as Week 4."
The earlier measure may be more useful because many
eventual relapsers will still have detectable HCV RNA after 4 weeks of treatment,
but most will have low or undetectable HCV viral load after 12 weeks.
Some
studies have suggested that HIV-HCV coinfected patients may be slower to respond
initially and may benefit from longer therapy than HIV negative individuals with
HCV, but data have been inconsistent.
10/12/07
Reference C
Payan, A Pivert, P Morand, and others. Rapid and early virological response to
chronic hepatitis C treatment with IFN alpha2b or PEG-IFN alpha2b plus ribavirin
in HIV/HCV co-infected patients. Gut 56(8): 1111-1116. August 2007.
