***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective Due to a high efficacy in clinical trials , sofosbuvir ( SOF ) and ribavirin ( RBV ) for 12 or 16 weeks is recommended for treatment of patients with HCV genotype ( GT ) 2 infection . We investigated safety and effectiveness of these regimens for GT2 in HCV-TARGET participants . Design HCV-TARGET , an international , prospect i ve observational study evaluates clinical practice data on novel antiviral therapies at 44 academic and 17 community medical centres in North America and Europe . Clinical data were central ly abstract ed from medical records . Selection of treatment regimen and duration was the investigator 's choice . The primary efficacy outcome was sustained virological response 12 weeks after therapy ( SVR12 ) . Results Between December 2013 and April 2015 , 321 patients completed 12 weeks ( n=283 ) or 16 weeks ( n=38 ) of treatment with SOF and RBV . Prior treatment experience and cirrhosis was more frequent among patients in the 16-week regimen compared with 12 weeks ( 52.6 % vs 27.6 % and 63.2 % vs 21.9 % , respectively ) . Overall , SVR12 was 88.2 % . The SVR12 in patients without cirrhosis was 91.0 % and 92.9 % for 12 or 16 weeks of therapy , respectively . In patients with cirrhosis treated for 12 or 16 weeks , SVR12 was 79.0 % and 83 % . In the multivariate analysis , liver cirrhosis , lower serum albumin and RBV dose at baseline were significantly associated with SVR12 . Common adverse events ( AEs ) included fatigue , anaemia , nausea , headache , insomnia , rash and flu-like symptoms . Discontinuation due to AEs occurred in 2.8 % . Conclusions In this clinical practice setting , SOF and RBV was safe and effective for treatment of patients with HCV GT2 infection . Trial registration number NCT01474811 BACKGROUND & AIMS Hepatitis C virus ( HCV ) therapy that is highly efficacious , pangenotypic , with a high barrier to resistance and short treatment duration is desirable . The efficacy and safety of 8- and 12-week treatments with glecaprevir ( ABT-493 ; NS3/4A protease inhibitor ) and pibrentasvir ( ABT-530 ; NS5A inhibitor ) were evaluated in non-cirrhotic patients with chronic HCV genotype 1 - 6 infection . METHODS SURVEYOR-I and SURVEYOR-II were phase II , open-label , multicenter , dose-ranging trials including patients with chronic HCV genotype 1 - 6 infection who were either previously untreated or treated with pegylated interferon plus ribavirin . Patients received once-daily glecaprevir plus pibrentasvir at varying doses with or without ribavirin for 8 or 12weeks . The primary efficacy endpoint was the percentage of patients with a sustained virologic response  at post-treatment week 12 ( SVR12 ) . RESULTS Of the 449 patients who received varying doses of glecaprevir plus pibrentasvir  , 25 % , 29 % , 39 % , and 8 % had HCV genotype 1 , 2 , 3 , and 4 - 6 infection , respectively . Twelve-week treatment achieved SVR12 in 97 - 100 % , 96 - 100 % , 83 - 94 % , and 100 % in genotypes 1 , 2 , 3 , and 4 - 6 , respectively . Eight-week treatment with 300 mg glecaprevir plus 120 mg pibrentasvir in genotype 1- , 2- , or 3-infected patients yielded 97 - 98 % SVR12 with no virologic failures . Three ( 0.7 % ) patients discontinued treatment due to adverse events ; most events were mild ( grade 1 ) in severity . No post-nadir alanine aminotransferase elevations were observed . CONCLUSIONS Glecaprevir plus pibrentasvir was well tolerated and achieved high sustained virologic response rates in HCV genotypes 1 - 6-infected patients without cirrhosis following 8- or 12-week treatment duration s. LAY SUMMARY The combination of direct-acting antivirals glecaprevir and pibrentasvir comprise a once-daily , all-oral , pangenotypic treatment for HCV genotype 1 - 6 infection . This article describes results from two phase II trials investigating a range of doses at treatment duration s of 8 or 12weeks in 449 patients without cirrhosis . Efficacy of the optimal dose , as determined by rates of sustained virologic response at post-treatment week 12 , ranged from 92%-100 % ; treatment was well tolerated and significant laboratory abnormalities were rare . CLINICAL TRIAL REGISTRATION clinical trials.gov Identifiers : NCT02243280 and NCT02243293 . http://www . clinical trials.gov/show/NCT02243280 , http://www . clinical trials.gov/show/NCT01939197 Abstract Background & Aims In Taiwan , patients with chronic hepatitis C virus ( HCV ) infection are currently treated with pegylated interferon‐alpha plus ribavirin , but interferon‐based regimens can be poorly tolerated , especially by those with advanced liver disease and the elderly . Sofosbuvir , an oral nucleotide analogue inhibitor of HCV NS5B polymerase , is approved in Europe , the USA and Japan for treating chronic HCV infection . This phase 3b study examined the efficacy and safety of sofosbuvir plus ribavirin in Taiwanese patients with chronic genotype 2 HCV infection ± compensated cirrhosis . Methods In this multicentre , open‐label , phase 3b ( NCT02021643 ) study , 87 patients ( n = 43 , treatment‐naive ; n = 44 , treatment‐experienced ) received 12 weeks of treatment with sofosbuvir plus weight‐based ribavirin . The primary efficacy endpoint was the proportion of patients with sustained virological response 12 weeks after treatment discontinuation ( SVR12 ) . Safety and pharmacokinetic data were also collected . Results All 87 patients ( 100 % ; 95 % confidence interval , 92–100 % ) achieved SVR12 , including the 13 patients with compensated cirrhosis . The most common treatment‐emergent adverse events ( AEs ) were insomnia ( 16 % , 14/87 ) and upper respiratory tract infection ( 16 % , 14/87 ) . No grade 3 or grade 4 AE was reported . There was one serious AE ( biliary colic ) , which was deemed unrelated to study treatment . Laboratory abnormalities other than ribavirin‐related reductions in haemoglobin were uncommon . Conclusions The results from this phase 3b study demonstrate that 12 weeks of treatment with the interferon‐free regimen sofosbuvir plus ribavirin is effective and well tolerated in both treatment‐naive and treatment‐experienced Taiwanese patients with chronic genotype 2 HCV infection In Korea , patients with chronic hepatitis C virus ( HCV ) infection are typically treated with pegylated interferon-alpha plus ribavirin , but interferons are contraindicated in many patients and are often poorly tolerated , particularly by the elderly and those with advanced liver disease . No interferon-free treatment regimens are approved in Korea . Sofosbuvir is an oral nucleotide analog inhibitor of the HCV nonstructural 5B RNA polymerase . It is approved in the USA , European Union and Japan for treating a number of HCV genotypes , including genotype 2 . Genotype 2 has a seroprevalence of 38 - 46 % in Korea . This single-arm , phase 3b study ( NCT02021643 ) examined the efficacy and safety of sofosbuvir plus ribavirin ( 12-week duration ) in chronic genotype 2 HCV-infected treatment-naive and treatment-experienced Korean patients with and without cirrhosis . The proportion of patients with sustained virologic response 12 weeks after treatment discontinuation ( SVR12 ) was 97 % ( 125/129 ) , with 96 % ( 101/105 ) of treatment-naive and 100 % ( 24/24 ) of treatment-experienced patients achieving SVR12 . Two patients experienced virologic failure ( n = 1 , on-treatment failure ; n = 1 , relapse ) . No patient discontinued study treatment due to an adverse event ( AE ) . The most common treatment-emergent AEs were headache ( 18 % , 23/129 ) and pruritus ( 15 % , 19/129 ) . Few patients had grade 3 AEs ( 5 % , 6/129 ) or grade 3 laboratory abnormalities ( 12 % , 15/129 ) . No grade 4 AE was reported . These data suggest that 12 weeks of treatment with the all-oral , interferon-free regimen of sofosbuvir plus ribavirin is effective and well tolerated in Korean patients with chronic genotype 2 HCV infection Background High sustained virological response at 12 weeks after end of treatment ( SVR12 ) with 12 weeks of simeprevir and sofosbuvir±ribavirin ( SMV+SOF±RBV ) has been demonstrated in hepatitis C virus genotype 1 ( HCV-1 ) but is based on limited data . Therefore , we performed a meta- analysis of available data evaluating the effectiveness of SMV+SOF±RBV in HCV-1 . Methods We performed a comprehensive literature search in June 2015 to identify r and omised controlled trials ( RCTs ) and observational studies of HCV-1 patients treated with 12 weeks of SMV+SOF±RBV . Original studies with SVR12 data in ≥5 HCV-1 patients were included . We excluded studies on liver transplant recipients and /or patients co-infected with HIV or hepatitis B/D. We estimated pooled effect sizes using a r and om-effects model and evaluated heterogeneity with Cochrane Q-test , p≤0.10 and I2 statistic ≥50 % . Results Pooled SVR12 was 85.6 % ( CI 81.3 % to 89.0 % ) in 1389 HCV-1 patients from 15 studies . On subgroup analysis , SVR12 was 83.9 % ( CI 79.4 % to 87.5 % ) in observational studies , which was lower than 93.5 % ( CI 85.7 % to 97.2 % ) in RCTs . A trend showed SVR12 was higher in mild fibrosis , 93.0 % ( CI 86.2 % to 96.6 % ) compared with advanced fibrosis , 81.5 % ( CI 75.7 % to 86.1 % ) , OR 2.22 ( CI 0.79 to 6.25 , p=0.131 ) . There was no significant difference in SVR12 rates between HCV-1a , 89.9 % ( CI 81.9 % to 94.6 % ) and HCV-1b , 89.0 % ( CI 78.9 % to 94.6 % ) with OR 1.35 ( CI 0.75 to 2.42 , p=0.322 ) . The most common pooled side effects were : headache 15.2 % ( n=55/361 ) , fatigue 12.1 % ( n=78/646 ) , nausea 9.5 % ( n=50/527 ) and rash 9.3 % ( n=68/728 ) . Conclusions SMV+SOF±RBV is an effective regimen in HCV-1 patients . The SVR12 rate in observational studies was lower than that in RCTs , which may reflect the more diverse patient population in real-world setting BACKGROUND In clinical trials , treatment with a combination of the nucleotide polymerase inhibitor sofosbuvir and the antiviral drug ribavirin was associated with high response rates among patients with hepatitis C virus ( HCV ) genotype 2 infection , with lower response rates among patients with HCV genotype 3 infection . METHODS We conducted a study involving patients with HCV genotype 2 or 3 infection , some of whom had undergone previous treatment with an interferon-based regimen . We r and omly assigned 91 patients with HCV genotype 2 infection and 328 with HCV genotype 3 infection , in a 4:1 ratio , to receive sofosbuvir-ribavirin or placebo for 12 weeks . On the basis of emerging data from phase 3 trials indicating that patients with HCV genotype 3 infection had higher response rates when they were treated for 16 weeks , as compared with 12 weeks , the study was unblinded , treatment for all patients with genotype 3 infection was extended to 24 weeks , the placebo group was terminated , and the goals of the study were redefined to be descriptive and not include hypothesis testing . The primary end point was a sustained v 
    Output:
    
Conclusions SOF+RBV for 12 weeks was safe and effective for patients with CHC GT2 in Asia , although those with cirrhosis and prior treatment failure had a lower pooled SVR12 rate .