Fargion 2004.

Methods	Randomised clinical trial with two parallel‐group design. Samlpe size calculation: not described.
Participants	Country: Italy. Number of participants randomly assigned: 185. All participants were non‐responders to previous interferon plus ribavirin treatment. Inclusion and exclusion criteria: none stated.
Interventions	Participants were randomly assigned to two groups. Group 1: peginterferon alpha‐2a 180 µg plus ribavirin 800 mg to 1000 mg plus amantadine hydrochloride 200 mg for 48 weeks. Group 2: interferon alpha 2a 6 MU daily for four weeks, then 3 MU daily for additional 20 weeks, and then 3 MU thrice weekly for additional 24 weeks plus ribavirin 800 mg to 1000 mg plus amantadine hydrochloride 200 mg for 48 weeks. Participants with detectable HCV RNA after 24 weeks of treatment were considered non‐responders and therapy discontinued. Participants were followed‐up for 24 weeks after the end of treatment.
Outcomes	Primary outcome was sustained virological response, defined as undetectable HCV RNA 24 weeks after the end of treatment. Other outcome reported was end of treatment virological response.
Notes	The report is abstract; because the study has not been published yet, no data about inclusion and exclusion criteria are provided. Data were extracted from the primary reference and the previous abstract: Fargion S et al. End of treatment and sustained response to peginterferon alfa‐2a (40 kD) (Pegasys) plus ribavirin (RBV) (Copegus) and amantadine (AMA), and to induction therapy with interferon (IFN) alfa‐2A (Roferon‐A) plus RBV and AMA in INF/RBV non‐responders with chronic hepatitis C (CHC) [AASLD abstract]. Hepatology 2003;38(4, Suppl 1):733A. Number of participants in each group is not reported, so we provisionally divided the total number of participants by two. Study author contacted for additional information, but no data were obtained.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comments: Method of sequence generation is not mentioned.
Allocation concealment (selection bias)	Unclear risk	Comments: Allocation concealment is not mentioned.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Comments: Blinding to outcome assessors is not mentioned.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comments: No post randomisation dropouts were reported.
Selective reporting (reporting bias)	Unclear risk	Comment: All clinically relevant and reasonably expected outcomes were reported.
Other bias	Low risk	Comments: The trial seem to be free of other sources of bias.