Impact of hepatitis C virus recombinant form RF1_2k/1b on treatment outcomes within the Georgian national hepatitis C elimination program.

AIM: Hepatitis C virus (HCV) recombinant form RF1_2k/1b is common in ethnic Georgians. This chimera virus contains genomic fragments of genotype 2 and genotype 1 and is misclassified as genotype 2 by standard genotyping. We aimed to identify RF1_2k/1b strains among genotype 2 patients and assess its impact on treatment outcomes.

METHODS: The study included 148 patients with HCV genotype 2 as determined by 5-untranslated region/core genotyping assay. RF1_2k/1b was identified by sequencing the non-structural protein 5B region. Patients were treated within the national hepatitis C elimination program with sofosbuvir/ribavirin (SOF/RBV), interferon (IFN)/SOF/RBV, or ledipasvir (LDV)/SOF/RBV.

RESULTS: Of 148 patients, 103 (69.5%) had RF1_ 2k/1b. Sustained virologic response (SVR) data was available for 136 patients (RF1_ 2k/1b, n = 103; genotype 2, n = 33). Sustained virologic response was achieved in more genotype 2 patient than in RF1_2k/1b patients (97.0% vs. 76.7%, P = 0.009). Twelve weeks of LDV/SOF/RBV treatment was highly effective (100% SVR) in both genotypes. Among RF1_2k/1b patients, LDV/SOF/RBV for 12 weeks was superior (100% SVR) to SOF/RBV for 12 weeks (56.4%, P < 0.0001) or 20 weeks (79.2%, P = 0.05). Twelve weeks of IFN/SOF/RBV also showed better response than SOF/RBV for 12 weeks (88.9% vs. 56.4%, P = 0.02) in these patients.

CONCLUSIONS: High prevalence of the RF1_2k/1b strain can significantly affect treatment outcomes. Treatment with IFN/SOF/RBV and especially LDV/SOF/RBV ensured significantly higher SVR in patients infected with RF1_2k/1b strain compared to standard HCV genotype 2 treatment with SOF/RBV. There is a need to reassess existing methods for the management of HCV genotype 2 infections, especially in areas with high prevalence of the RF1_2k/1b strain.