Pearlman 2007.

Methods	Randomised clinical trial. Study design: Chronic HCV G1 patients were defined as slow responders if they had at least 2‐lo decrement in baseline serum HCV RNA, albeit detectable viraemia at 12 weeks and undetectable serum HCV RNA at 24 weeks. After 24 weeks they were randomised to continue therapy for an additional 24 weeks or 48 weeks. Duration of follow‐up: 24 weeks after the end of treatment.
Participants	Location: Atlanta Medical Center for Hepatitis C and Sheffield Health Center ‐ ambulatory clinics in downtown Atlanta, GA, USA. Time of participant selection: 6/2003 ‐ 9/2005 Included participants in our meta‐analysis: chronic hepatitis C genotype 1 naive patients with detectable HCV RNA and ≥ 2 log viral reduction at week 12 and undetectable HCV RNA at week 24. No. participants: 49 in the 48‐week treatment group and 52 in the 72‐week treatment group. Mean age: 56 years in the 48‐week treatment group and 54 years in the 72‐week treatment group. Males: 33/49 in the 48‐week treatment group and 34/52 in the 72‐week treatment group. Mean BMI: 28.9 in the 48‐week treatment group and 28.8 in the 72‐week treatment group. Liver biopsy: preformed within the past two years, consistent with chronic hepatitis.
Interventions	Experimental: s.c. peginterferon alfa‐2b 1.5 µg/kg/week and p.o. ribavirin 800 to 1400 (weight depended) mg*1/d for 72 weeks. Control: s.c. peginterferon alfa‐2b 1.5 µg/kg/week and p.o. ribavirin 800 to 1400 (weight depended) mg*1/d for 48 weeks.
Outcomes	Outcomes and time points considered in the review Primary outcome: SVR. Secondary outcomes: relapse rate. Additional data that were extracted: dose reduction or therapy discontinuation due to adverse events; serious adverse events; adherence. Outcomes and time points not considered in the review: none.
Notes	A total of 361 naive participants with chronic HCV genotype 1 were treated, 112 of them matched the definition of slow responders and were included in this trial. 'Eleven slow responders either declined to participate in the study or were ineligible'.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Participants were randomly allocated, but there is Insufficient information about the sequence generation process.
Allocation concealment (selection bias)	Low risk	"Patients were randomised to 1 of 2 study treatment durations at a ratio of 1:1 without stratification, and randomisation groups were concealed until after patients consented to participate and interventions were assigned."
Blinding (performance bias and detection bias) All outcomes	High risk	There was no blinding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups: Seven participants in the standard duration arm (14%) and eight participants in the extended duration arm (15%) discontinued treatment, but all the discontinuations occurred before week 48 in both groups. Data about major adverse events were given.
Selective reporting (reporting bias)	High risk	No clinical data on mortality were reported.
Other bias	Low risk	The trial appears to be free of other sources of bias.