biostudies-literatureUnknown6(7)Dietz J<h4>Background and aims</h4>Data on the prevalence and characteristics of so-called rare HCV genotypes (GTs) in larger cohorts is limited. This study investigates the frequency of rare GT and resistance-associated substitutions and the efficacy of retreatment in a European cohort.<h4>Methods</h4>A total of 129 patients with rare GT1-6 were included from the European resistance database. NS3, NS5A, and NS5B were sequenced and clinical parameters and retreatment efficacies were collected retrospectively.<h4>Results</h4>Overall 1.5% (69/4,656) of direct-acting antiviral (DAA)-naive and 4.4% (60/1,376) of DAA-failure patients were infected with rare GT. Although rare GTs were almost equally distributed throughout GT1-6 in DAA-naive patients, we detected mainly rare GT4 (47%, 28/60 GT4; of thesJHEP reports : innovation in hepatology101072https://www.ebi.ac.uk/biostudies/studies/S-EPMC11246049biostudies-literatureRare HCV subtypes and retreatment outcomes in a cohort of European DAA-experienced patients.PMC11246049Dietel PEhrle UOlejnik HDurmashkina EFriese GRissland JTeubner KKanzler SSchewe CFrank MZizer ESeidel TMoradpour DBruch HRJohn CBerzow DBorner NMroß MMahle IGschwantler MHerrmann AKnevels UBoettler TBerger FNiehaus-Hahn SDeterding KLutz USchulze PLutz TBusch NSteckstor WBeretta-Piccoli BTEmke FMauss SEbert MMerle UDrude LPhilipp AMoreno CAngeli WBohr UHurst ARieke ASeufferlein TThimme RSchott EHerder MGlaunsinger TKStein KWinzer TWeinberger FMagenta LSchattenberg JMGeyer PLittman MHorster HBucholz DPort KWedemeyer HKerzel WKodal AMuehlenberg KLink RBerg TMuller-Schilling MKoster AStrey BGress MSchleehauf DFrick BCanbay AEllenrieder VMaurer PEuropean HCV Resistance Study GroupSemela DDelker RGundling FDreher FRiecken BTeuber GKordecki NHarter GDiehl MZeuzem SSchmiegel WMundlos MMuller TBehrends JRietzler SKluppelberg UNehls OEpple HJMuche MBackhus JMullhaupt BSarrazin CAdler MRambach WGiostra EGalle PGunther RUschner FKuhn MZehnter EBerning MPetrides AGadow KSteinmuller MWietzke-Braun PGobel UHametner STal AOKlugewitz KBruns TLange CMBlaukat ODischer TCornberg MNiederau CTeufel AKrawczyk MPetersen JKlarhof MGustot TRockstroh JTrebicka JMohr LMichl PDiedrich JKnapp BHeyne RGotze TStickel FJordan SRossle MHeuchel TSchwenzer JThieringer JNaumann UBeckebaum SHirschi CSchlee PKeitel-Anselmino VHartmann CWeber AChave JPBokemeyer BRaddant RFelten GSvensson KKallinowski BKnecht GScholz DReiter FPWeber TKhaykin PHuppe DBurkhard OWolfratshausenBodtlander AHofmann WPTrautwein CSpengler USchwind HRBaermann CGoebel FHoffmann CHoffmann DGraf CMatschenz KGeier AHaag SSchober ANeumann-Haefelin CSchulze Zur Wiesch JStauber Rvon Felden JPiecha FFischer UBalavoine JHeuer SGlas MWalter EWilluweit KHampe JLohr HPinkernell MLohse AVogelmann RAbels WDikopoulos NTacke WBohm GKapzan BSemmo NFischer JHoffl KHGenne DGraf RSeitel GStrassburg CPSchmidt-Heinevetter GWege HRoth JUngemach JBarth REnde KVermehren JUrban GSchneider AGruber HKunzig BJagel-Guedes EStallmach ALobermann MSternfeld TTomesch ABastlein EBarthel KGorlitz BMainz DTrauth JErhardt ARufle WWerner PRoeb EKorfer ASchneider MMenges MSchneider LHeyer TReiser MBrockmeyer NHRump AAudebert FChirca CHinrichsen HNingel RJung MSteffens HFrederking DDultz GZachoval RKremer AEPascher ESimon KDietz JOelmann AKraus MReinhardt LUllrich JWerheid-Dobers MSchmidt HSeegers BJussios AGarrido-Luneburg ASchmidt WStenschke FDienethal ASick CSchelling MBeyer TStahler DMoritzen DUsadel SMayerle JLangekamp ABerg CPWollschlager SPeiffer KHProtzer UGute PSchofl RBenninger Jvon Lucadou ADe Gottardi APiso RRauch ASchulten-Baumer UAl-Taie OMoller HHolst FTacke FKullig UGlosemeyer RStich AGattringer HGantke BBecker WSeelhoff AMaieron AMayer CKlag CRiedel MHilgard GKochsiek TFabris JSDreck MWinter TSonne JUKocheise FPolzien FPichler MManns MHeinzow HSiebler JSchuchmann MBaumgartl KBuggisch PHunstiger MZipf ASprinzl MTrappe UAntoni CBierbaum MPaulweber BfalseRare HCV subtypes and retreatment outcomes in a cohort of European DAA-experienced patients.<h4>Background and aims</h4>Data on the prevalence and characteristics of so-called rare HCV genotypes (GTs) in larger cohorts is limited. This study investigates the frequency of rare GT and resistance-associated substitutions and the efficacy of retreatment in a European cohort.<h4>Methods</h4>A total of 129 patients with rare GT1-6 were included from the European resistance database. NS3, NS5A, and NS5B were sequenced and clinical parameters and retreatment efficacies were collected retrospectively.<h4>Results</h4>Overall 1.5% (69/4,656) of direct-acting antiviral (DAA)-naive and 4.4% (60/1,376) of DAA-failure patients were infected with rare GT. Although rare GTs were almost equally distributed throughout GT1-6 in DAA-naive patients, we detected mainly rare GT4 (47%, 28/60 GT4; of thes2024-01-01T00:00:00Z2024 Jul2025-04-18T21:45:01.821Z2025-02-19T02:34:26.601ZS-EPMC112460493900650310.1016/j.jhepr.2024.101072