Hepatitis C virus therapy with peg-interferon and ribavirin in Myanmar: A resource-constrained country

Guanosine inhibits hepatitis C virus replication and increases indel frequencies, associated with altered intracellular nucleotide pools

In the course of experiments aimed at deciphering the inhibition mechanism of mycophenolic acid and ribavirin in hepatitis C virus (HCV) infection, we observed an inhibitory effect of the nucleoside guanosine (Gua). Here, we report that Gua, and not the other standard nucleosides, inhibits HCV replication in human hepatoma cells. Gua did not directly inhibit the in vitro polymerase activity of NS5B, but it modified the intracellular levels of nucleoside di- and tri-phosphates (NDPs and NTPs), leading to deficient HCV RNA replication and reduction of infectious progeny virus production. Changes in the concentrations of NTPs or NDPs modified NS5B RNA polymerase activity in vitro, in particular de novo RNA synthesis and template switching. Furthermore, the Gua-mediated changes were associated with a significant increase in the number of indels in viral RNA, which may account for the reduction of the specific infectivity of the viral progeny, suggesting the presence of defective genomes. Thus, a proper NTP:NDP balance appears to be critical to ensure HCV polymerase fidelity and minimal production of defective genomes.

Pegylated interferon and ribavirin gone but not forgotten in the era of direct-acting antivirals

BACKGROUND

Therapy with pegylated interferon and ribavirin (PEG-IFN+RBV) for chronic hepatitis C (CHC) remains the only option available for children in many Eurasian and European countries. Our aim was to evaluate the influence of host and viral factors on response to IFN-based therapy to optimize it for those in whom directly acting antivirals (DAA) are currently unavailable.

METHODS

Seventeen vertically infected, treatment naive children (10 male and 7 female) aged 5-16 years with CHC underwent a course of PEG-IFN+RBV. The end point was sustained virologic response (SVR). Host and virus factors were divided into pre- and on-treatment predictors of response to therapy.

RESULTS

Eleven patients obtained SVR (64%), 4 were non-responders (23%), and 2 were relapsers (12%). Significant relationship was found between HCV RNA elimination and following variables: virus genotype and early virologic response (EVR) (P<0.037, P<0.029 respectively). Higher eradication rate was observed in patients infected with genotype 3 HCV (100% vs. 65% with genotype 1 or 4), and in those with undetectable HCV RNA by week 12 (88% vs. 66% with viremia). EVR was associated with SVR (83% vs. 0% in nonresponders; P<0.004). C allele of IL28B rs12979860 was a predictor of EVR (P<0.043). The SVR rates among CC, CT, and TT carriers were as follows: 75%, 67%, and 33%.

CONCLUSIONS

Detection of favorable HCV and IL28B genotype prior to commencement of PEG-IFN+RBV and continuing it in patients with EVR is of major importance for those in whom DAA are still unavailable.

High sustained virologic response in genotypes 3 and 6 with generic NS5A inhibitor and sofosbuvir regimens in chronic HCV in myanmar

Exclusive HCV therapy clinical trials with genotype 6 patients in high prevalence areas have been sparse. We analysed the safety and efficacy of two generic, pangenotypic NS5A/NS5B combination oral DAA regimens, primarily in genotypes 3 and 6, in a real-world setting: (a) daclatasvir/sofosbuvir (DCV/SOF) ± ribavirin (RBV) and (b) Velpatasvir/sofosbuvir (VEL/SOF ± RBV). Between December 2015 and November 2017, data from 522 patients were analysed, 311 of whom were treated with DCV/SOF ± RBV for 12/24 weeks (genotype 3: n = 193, genotype 6: n = 89) and 211 were treated with VEL/SOF ± RBV for 12/24 weeks (genotype 3: n = 83, genotype 6: n = 77). Overall SVR rates were high for both DCV/SOF ± RBV (96.1%, n = 299/311) and VEL/SOF ± RBV (95.3%, n = 201/211), and there was a good adverse event profile. Treatment naïve status and inclusion of RBV (in advanced fibrosis/cirrhosis) were significant independent predictors of achieving SVR12, while type of DAA regimen was not predictive. In this large cohort of genotypes 3 (n = 276) and 6 (n = 166; n = 127 unique subtype of 6c-l), high SVR rates of 94.9% (n = 262/276) and 95.2% (n = 158/166), respectively, were noted. In conclusion, generic and pangenotypic DCV/SOF and VEL/SOF ± RBV regimens were highly effective and safe, in genotypes 3 and 6 chronic HCV in Myanmar. These efficacious pangenotypic regimens suggest that baseline genotype testing can be eliminated moving forward. While RBV may still be needed for those with advanced fibrosis/cirrhosis, in a global elimination strategy it would not be practical even if it does compromise SVR in a minority with difficult to treat characteristics.

Fib-4 Predicts Early Hematological Adverse Events Induced by Interferon-Based Triple Therapy in Chronic Hepatitis C Virus Patients

Interferon-alpha (IFN-α)-based therapy is associated with several hematological adverse events in hepatitis C virus (HCV)-infected patients with advanced fibrosis. We performed this study to evaluate the association between Fibrosis-4 (Fib-4) index and hematological adverse events in patients with chronic HCV infection, undergoing IFN-α-based triple therapy. We included 120 HCV-infected patients, receiving triple therapy: weekly PegIFN-α, daily ribavirin (1,000-1,200 mg), and daily sofosbuvir (400 mg) for 12 weeks. We compared Fib-4 scores for patients who developed hematological adverse events at weeks 4 (w4) and w12 of treatment and w12 post-treatment versus those who did not. Treatment with the aforementioned triple regimen was associated with a sustained virological response (SVR)-12 rate of 93.9%. We found no significant associations (P > 0.05) between SVR12 rate and the degree of fibrosis or the risk of hematological adverse events. The Fib-4 score could predict patients who developed hematological adverse events (anemia, leukopenia, and neutropenia) in the first month of treatment, but not in later stages. A Fib-4 cutoff value of 3.59 had high specificity for anemia, leukopenia, and neutropenia (85.1%, 87.2%, and 88.2%, respectively), but had low sensitivity for detecting the 3 events. In conclusion, the Fib-4 score may predict early hematological adverse effects in HCV-infected patients on IFN-based triple therapy.

Strategy and Efficacy of Generic and Pan-genotypic Sofosbuvir/Velpatasvir in Chronic Hepatitis C Virus: A Myanmar Experience

BACKGROUND

In resource-constrained areas, generic direct-acting antivirals (DAAs) have considerably reduced the cost of hepatitis C virus (HCV) therapy while there remain significant costs related to the baseline and follow-up virologic assays.

AIM

The aim was to assess the efficacy and safety of HCV therapy in Myanmar with pan-genotypic generic DAA sofosbuvir/velpatasvir (SOF/VEL) and with and without the baseline genotype testing, while the duration of treatment and use of ribavirin (RBV) was dictated by cirrhosis and prior treatment failure.

METHODS

Between September 2016 and June 2017, data from the 359 participants who completed treatment with SOF/VEL (± RBV) for 12-24 weeks were analyzed. Two hundred one patients did not have the baseline HCV genotype tested.

RESULTS

Regimens included SOF/VEL for 12 weeks (n = 43), SOF/VEL/RBV for 12 weeks (n = 275), or SOF/VEL/RBV for 24 weeks (n = 41). The mean age was 52 years, 44% were men (n = 159), 41 (11.4%) had a history of previous DAA therapy, 7 (1.9%) had a history of hepatocellular carcinoma, and 55 (15.3%) had cirrhosis. Overall, the sustained viral response (SVR)12 rate was 98.6% (354/359) and with a good adverse event profile. SVR rates were similar to those with and without baseline genotype testing and also across all genotypes in those who had genotype tested.

CONCLUSIONS

In Myanmar, generic and pan-genotypic SOF/VEL ± RBV is a highly effective and safe treatment for HCV, regardless of the HCV genotype, and therefore, the requirement for the baseline genotype can be eliminated. Future strategies should include elimination of treatment and end of treatment HCV RNA testing to enhance treatment uptake and further reduce cost.

Safety and efficacy of sofosbuvir-based direct-acting antiviral regimens for hepatitis C virus genotypes 1-4 and 6 in Myanmar: Real-world experience

This open-label, clinical experience investigated the safety and efficacy of direct-acting antiviral (DAA) hepatitis C virus (HCV) therapy in Myanmar; 344 patients completed treatment between June 2015 and May 2016. Patients with HCV genotypes 1-4 and 6 received one of four treatments: (i) Peg-interferon (PEG-IFN)+sofosbuvir (SOF)+ribavirin (RBV) for 12 weeks, (ii) SOF+RBV for 24 weeks, (iii) ledipasvir (LDV)+SOF for 12 weeks or (iv) daclatasvir (DCV)+SOF+RBV for 12 or 24 weeks. Genotype 3 was most common (n=133, 38.7%), followed by genotype 6 (n=122, 35.5%) and genotype 1 (n=86, 25%). Overall, 91% of patients achieved sustained virologic response (SVR); 99% in group 1, (n=148/149), 90% in group 2 (n=95/106), 78% in group 3 (n=65/83) and 100% in group 4 (n=6/6). In group 3, SVR rates were 96.8% in genotype 1 (n=30/31) and 64.1% in genotype 6 (n=25/39). Multivariable regression analysis identified advanced fibrosis (F3-4) (OR=.16 CI: 0.05-0.57, P=.005), genotype 6 (OR=.35, CI: 0.16-0.79, P=.012) and diabetes (OR=.29, CI: 0.12-0.71, P=.007) as negative independent predictors of response. Adverse events were mild with all-oral therapy.

CONCLUSION

DAA therapy ±PEG-IFN achieved high SVR rates. Genotype 6 patients had a low SVR to 12 weeks of LDV and SOF raising the need for other regimens, RBV or longer treatment duration in this population.