Weight-based dosing: which impact on efficacy and safety of therapy?

Pegylated interferons (PEG-IFNs) in combination with ribavirin represent the most recent advance in the treatment of patients with chronic hepatitis C (CHC): two large clinical trials have shown a superior efficacy in clearing HCV in almost 60% of treated naïve patients. Responses to antiviral treatment of CHC vary according to both viral and host factors. Managing patients with CHC infection requires individualised treatment strategies to optimise outcomes. Several landmark publications on PEG-IFNs have reported that weight is a significant predictive factor for SVR in the treatment of CHC with fixed-dose drug administration. With fixed-dose treatment, there is a direct correlation between increasing body weight and decreasing rate of SVR. As patient's weight increases, fixed-dose therapy provides proportionately lower amounts of drug. Therefore, under this dosing scheme, heavier patients do not have an equal chance at achieving SVR as do lighter patients. Unfortunately though, lighter patients may also suffer, as fixed dosing can provide these patients with an excessive amount of drug, increasing their risk for adverse events. Individualised weight-adjusted dosing of both PEG-IFN and ribavirin might represents the best treatment strategy to assure that all patients have the same opportunity to achieve SVR.