Therefore, physicians treating AHC have investigated the use of viral kinetics in determining treatment duration. The European multicentre cohort study in HCV/HIV-infected patients showed that in those who achieved an RVR, 93% achieved an SVR [125]. Sub-analysis demonstrated that after a first undetectable HCV RNA, those who received at least 20 weeks of treatment achieved SVR of 96% compared with only 20%

in those who Selleckchem Antiinfection Compound Library received less than 20 weeks of therapy. Together, these findings suggest that 24 weeks of therapy may be sufficient in HIV-infected individuals with AHC who achieve an RVR. This has been supported by a number of other studies. In the Australian Trial in Acute Hepatitis C, where 24 weeks of combination therapy was used, RVR yielded a positive predictive value (PPV) for SVR of 75% and negative Buparlisib chemical structure predictive value (NPV) of 13% [116,126]. The high PPV supports 24 week treatment duration for those who achieve an RVR, while the low NPV suggests that 24 weeks of therapy may also be sufficient in those who do not achieve an RVR. However, not all studies demonstrate similarly low levels of relapse in non-RVR subjects treated for only 24 weeks. A recent Spanish study investigated 24 weeks of combination

therapy with a low overall SVR of 47%. While 92% of those who achieved an RVR also achieved an SVR, only 20% of non-RVR individuals did, suggesting that 24 weeks of therapy may have been insufficient [133]. Few studies have compared short and long treatment durations. Observational cohort data are difficult to interpret as it is unclear how to deal with ‘null responders’ whose therapy is discontinued early [134]. Results exist from a prospective study where individuals were treated for either 24 or 48 weeks with combination therapy: SVRs were achieved in 71% and 79%, respectively, with PPV of RVR for SVR also similar (81% and 89%). However, those without RVR in the 24-week group only achieved a 40% (2/5) SVR, compared to a 64% (7/11) SVR Lck in the 48-week group [117]. A 48-week therapy duration may thus be necessary

to achieve acceptable SVR rates in those who do not achieve an RVR. Due to these results, a treatment strategy where RVR is used to determine duration of therapy (24 weeks if RVR is achieved and 48 weeks if it is not) has been suggested. Data from a London cohort have demonstrated that this strategy can lead to an SVR of 91%, similar to that observed in the HCV-monoinfected population [135]. In chronic HCV, week-12 HCV RNA levels are routinely used to determine the likely futility of therapy and thus the need to discontinue treatment. Interpreting week-12 data within the available AHC cohort studies is difficult as it is not always transparent whether failure to achieve an EVR has been used as a stopping rule, thus heavily biasing its NPV.