Dual daclatasvir and sofosbuvir for treatment of genotype 3 chronic hepatitis C virus infection

Chronic hepatitis C virus (HCV) infection is one of the most common etiologies of liver-related mortality throughout the world. Traditionally, therapy has been focused on pegylated interferon in combination with ribavirin, with clinical trials demonstrating that HCV genotype 1 had the lowest response rate (40-50%), while genotype 3 had an intermediate response rate (60-70%). Recently, significant advances have been made with all-oral direct-acting antiviral (DAA) therapy, which have significantly improved cure rates for HCV genotype 1. Accordingly, HCV genotype 3 is now potentially the most difficult to treat. One of the most potent DAA medications is sofosbuvir, a pan-genotypic nucleotide analogue that inhibits the NS5B polymerase of HCV. Daclatasvir, a pan-genotypic inhibitor of the HCV NS5A replication complex, was recently approved in the United States for treatment of HCV genotype 3 in conjunction with sofosbuvir. This combination may provide a powerful tool in the treatment of HCV genotype 3.

A highly specific and sensitive hepatitis C virus antigen enzyme immunoassay for One-step diagnosis of viremic hepatitis C virus infection

The current standard in diagnosing hepatitis C virus (HCV) infection requires two sequential steps: anti-HCV test to screen, followed by HCV RNA reverse-transcription polymerase chain reaction to confirm viremic HCV (V-HCV) infection. HCV core antigen tests provided potential for possible one-step diagnosis. However, low sensitivity and specificity limit their clinical utility. The present study developed a novel HCV antigens enzyme immunoassay (HCV-Ags EIA) and assessed its sensitivity, specificity, and utility for one-step diagnosis of V-HCV infection using 365 serum specimens, including 176 without and 189 with V-HCV infection. First, we confirmed the presence of HCV nonstructural proteins 3, 4b, and 5a besides HCV core antigen during HCV infection and developed a novel HCV-Ags EIA through simultaneous detection of all four HCV proteins. For the first time, the present study demonstrated that serum sample denaturation decreases the test specificity due to release of HCV-Ags sequestered in HCV immune complexes and should not be used in any HCV-Ags, including all the current HCV core antigen assays. On the other hand, using sample nondenaturation, the HCV-Ags EIA results showed 98.9% specificity and 100% sensitivity compared to serum anti-HCV and HCV RNA reverse-transcription polymerase chain reaction results. Using serum sample dilution, and nondenaturation, the lowest limits of detection of the HCV-Ags EIA were equivalent to serum HCV RNA levels of approximate 150-250 IU/mL.

CONCLUSIONS

The highly specific and sensitive HCV-Ags EIA developed in the present study has the lowest limit of detection equivalent to serum HCV RNA levels of 150-250 IU/mL; using nondenaturation of serum samples, our HCV-Ags EIA reliably differentiated V-HCV infection from resolved HCV infection, accomplishing screening and diagnosis of V-HCV infection in one step. (Hepatology 2016;64:415-424).

Faldaprevir for the treatment of genotype-1 hepatitis C virus

Historically, pegylated interferon in combination with ribavirin was the standard of care in hepatitis C virus; however, this combination is often poorly tolerated, has a significant side-effect profile and is of limited efficacy in hepatitis C virus genotype-1. More recently, pegylated interferon/ribavirin has been combined with direct acting antiviral agents such as the first generation NS3/4A protease inhibitors. Faldaprevir, a first generation, second-wave protease inhibitor, when used with a pegylated interferon/ribavirin regimen, has also been shown to increase treatmentsuccess while shortening treatment duration; however, second generation direct acting antiviral agents offer even betterefficacy and tolerability. Various direct acting antiviral agent combinations in interferon-free regimens have been effective in over 95% of patients and are now in licensed use. While faldaprevir was a pioneering drug, by the time it reached late phase development it was superseded by newer agents.