***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: BACKGROUND Interferon-based hepatitis C virus ( HCV ) therapy is safe and effective among people receiving opioid substitution therapy ( OST ) , but treatment uptake remains low . Our aim was to evaluate the impact of OST and drug use during therapy on completion , adherence , sustained virologic response ( SVR12 ) , and safety of ledipasvir/sofosbuvir ± ribavirin . METHODS The phase 3 ION studies evaluated a fixed-dose combination of ledipasvir/sofosbuvir ± ribavirin administered for 8 , 12 , or 24 weeks in patients with chronic HCV genotype 1 . People with clinical ly significant drug use ( prior 12 months ) or noncannabinoids detected at screening by urine drug tests ( not explained by prescriptions ) were ineligible . Stored sample s were available from ION-1 for retrospective testing for illicit drugs by enzyme-linked immunosorbent assay . RESULTS Among 1952 patients enrolled in the ION studies , 4 % ( n = 70 ) were receiving OST . Among those receiving ( n = 70 ) and not receiving OST ( n = 1882 ) , there was no difference in treatment completion ( 97 % vs 98 % ; P = .40 ) , ≥80 % adherence ( 93 % vs 92 % ; P = 1.00 ) , SVR12 ( 94 % vs 97 % ; P = .28 ) , and serious adverse events ( 4 % vs 3 % ; P = .43 ) , respectively . Among participants in the ION-1 trial , 23 % ( n = 196 ) used illicit drugs during therapy ( 15 % cannabinoids alone ; 8 % other illicit drugs ± cannabinoids ) . There was no difference in treatment completion , ≥80 % adherence , SVR12 , or serious AEs in those with no drug use during treatment compared with those who used cannabinoids and /or other illicit drugs . No cases of HCV reinfection were observed in the 24 weeks following treatment . CONCLUSIONS OST and drug use during HCV therapy did not impact treatment completion , adherence , SVR12 , or safety . CLINICAL TRIALS REGISTRATION ION-1 ( NCT01701401 ) ; ION-2 ( NCT01768286 ) ; and ION-3 ( NCT01851330 ) In this analysis of the ASTRAL trials ( non-opioid substitution therapy [ OST ] , n = 984 ; OST , n = 51 ) evaluating the once-daily , pan-genotypic regimen of sofosbuvir/velpatasvir for hepatitis C virus infection , OST did not impact completion , adherence , sustained virologic response ( SVR12 ) , or safety . SVR12 was 96 % ( 95 % confidence interval , 87 % , > 99 % ) in those receiving OST BACKGROUND A barrier to hepatitis C virus ( HCV )  treatment among people who inject drugs ( PWID ) has been a concern that interferon-based HCV treatment may increase injecting risk behaviours . This study evaluated recent ( past month ) injecting risk behaviours during follow-up among PWID that did and did not receive HCV treatment .  METHODS The Australian Trial in Acute Hepatitis C ( ATAHC ) was a prospect i ve study of natural history and treatment of recent HCV infection . Analyses were performed using generalized estimating equations . RESULTS Among 124 participants with a history of injecting drug use ( median age 32 years ) , 69 % were male , and 68 % were treated for HCV infection .  HCV treatment was not associated with an increase in recent injecting drug use ( adjusted odds ratio ( aOR ) 1.06 , 95 % CI 0.93 , 1.21 ) or recent used needle and syringe borrowing during follow-up ( aOR 0.99 , 95 % CI 0.89 , 1.08 ) . HCV treatment was associated with a decrease in recent ancillary injecting equipment sharing during follow-up ( aOR 0.85 , 95 % CI 0.74 , 0.99 ) . Further , among treated participants who remained in follow-up ( n=24 ) , ancillary injecting equipment sharing significantly decreased from 54 % at enrolment to 17 % during follow-up ( P=0.012 ) . CONCLUSIONS HCV treatment was not associated with drug use or used needle and syringe borrowing during follow-up , but was associated with decreased ancillary injecting equipment sharing during follow-up . Programs to enhance HCV assessment and treatment among PWID should be exp and ed , given that HCV treatment does not lead to increases in injecting risk behaviours and has previously been demonstrated to be safe and effective among PWID Background Hepatitis C virus ( HCV ) infection is common in persons who inject drugs ( PWID ) . Objective To evaluate elbasvir-grazoprevir in treating HCV infection in PWID . Design R and omized , placebo-controlled , double-blind trial . ( Clinical Trials.gov : NCT02105688 ) . Setting Australia , Canada , France , Germany , Israel , the Netherl and s , New Zeal and , Norway , Spain , Taiwan , the United Kingdom , and the United States . Patients 301 treatment-naive patients with chronic HCV genotype 1 , 4 , or 6 infection who were at least 80 % adherent to visits for opioid agonist therapy ( OAT ) . Intervention The immediate-treatment group ( ITG ) received elbasvir-grazoprevir for 12 weeks ; the deferred-treatment group ( DTG ) received placebo for 12 weeks , no treatment for 4 weeks , then open-label elbasvir-grazoprevir for 12 weeks . Measurements The primary outcome was sustained virologic response at 12 weeks ( SVR12 ) , evaluated separately in the ITG and DTG . Other outcomes included SVR24 , viral recurrence or reinfection , and adverse events . Results The SVR12 was 91.5 % ( 95 % CI , 86.8 % to 95.0 % ) in the ITG and 89.5 % ( 95 % CI , 81.5 % to 94.8 % ) in the active phase of the DTG . Drug use at baseline and during treatment did not affect SVR12 or adherence to HCV therapy . Among 18 patients with posttreatment viral recurrence through 24-week follow-up , 6 had probable reinfection . If the probable reinfections were assumed to be responses , SVR12 was 94.0 % ( CI , 89.8 % to 96.9 % ) in the ITG . One patient in the ITG ( 1 of 201 ) and 1 in the placebo-phase DTG ( 1 of 100 ) discontinued treatment because of an adverse event . Limitation These findings may not be generalizable to PWID who are not receiving OAT , nor do they apply to persons with genotype 3 infection , a common strain in PWID . Conclusion Patients with HCV infection who were receiving OAT and treated with elbasvir-grazoprevir had high rates of SVR12 , regardless of ongoing drug use . These results support the removal of drug use as a barrier to interferon-free HCV treatment for patients receiving OAT . Primary Funding Source Merck & 
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However , theoretical model projections suggest that substantial reductions in HCV transmission among PWID will require both traditional harm reduction/ primary prevention and HCV treatment scale-up [ 13,14 ] .