Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir

Sulfur(vi) fluoride exchange as a key reaction for synthesizing biaryl sulfate core derivatives as potent hepatitis C virus NS5A inhibitors and their structure-activity relationship studies

Extremely potent, new hepatitis C virus (HCV) nonstructural 5A (NS5A) featuring substituted biaryl sulfate core structures was designed and synthesized. Based on the previously reported novel HCV NS5A inhibitors featuring biaryl sulfate core structures which exhibit two-digit picomolar half-maximal effective concentration (EC50) values against HCV genotype 1b and 2a, the new inhibitors equipped with the sulfate core structures containing diversely substituted aryl groups were explored. In this study, highly efficient, chemoselective coupling reactions between an arylsulfonyl fluoride and an aryl silyl ether, known as the sulfur(vi) fluoride exchange (SuFEx) reaction, were utilized. Among the inhibitors prepared based on the SuFEx chemistry, compounds 14, 15 and 29 exhibited two-digit picomolar EC50 values against GT-1b and single digit or sub nanomolar activities against the HCV GT-2a strain. Nonsymmetrical inhibitors containing an imidazole and amide moieties on each side of the sulfate core structures were also synthesized. In addition, a biotinylated probe targeting NS5A protein was prepared for labeling using the same synthetic methodology.

Hepatitis C Therapy in Renal Patients: Who, How, When?

Renal patients are overexposed to hepatitis C virus (HCV) infection. Hepatitis C virus infection may induce renal disease, i.e., cryoglobulinemic membrano-proliferative glomerulopathy and non-cryoglobulinemic nephropathy. Hepatitis C virus impacts general outcomes in chronic kidney disease, dialysis or transplanted patients. Hepatitis C virus infection is now about to be only part of their medical history thanks to new direct acting antiviral drugs exhibiting as much as over 95% of sustained virological response. All HCV-infected patients potentially can receive the treatment. Control of the virus is associated with better outcomes in all cases, whatever the severity of the hepatic or renal disease. This article focuses on HCV-induced renal diseases, the reciprocal impact of HCV infection on the renal outcome and renal status in liver disease, use of new direct-acting antiviral drugs with dosage adaptations and the most recent safety data.

Review article: safety and tolerability of direct-acting anti-viral agents in the new era of hepatitis C therapy

BACKGROUND

Direct-acting anti-virals (DAAs) licensed to treat chronic HCV infection have revolutionised treatment algorithms by drastically mitigating side effects while enhancing efficacy relative to interferon-based therapy.

AIM

To review adverse events (AEs) uniquely associated with DAA therapy across a broad spectrum of patient populations.

METHODS

Searches of PubMed and FDA surveillance studies were undertaken to complete an exhaustive review. Search terms included 'DAAs', 'safety', and 'tolerability'.

RESULTS

While DAAs are remarkably well tolerated, they are accompanied by unique AEs. Simeprevir, an NS3/4A protease inhibitor, has been known, albeit infrequently, to cause mild hyperbilirubinemia and photosensitivity reactions; and paritaprevir boosted with ritonavir causes bilirubin and ALT elevations. Asunaprevir, another protease inhibitor, infrequently causes elevated transaminase levels. NS5A and NS5B inhibitors are well tolerated, although sofosbuvir is contraindicated in patients with severe renal impairment. Ribavirin co-administered in certain treatment regimens has been associated with cough, rash and haemolytic anaemia.

CONCLUSIONS

With the impending reality of a more tolerable interferon-sparing regimen, the future of DAA therapy offers shorter treatment duration, simplified disease management, and a patient-centred regimen. With advantages come drawbacks, including development of resistance to therapy and accessibility to this expensive treatment. DAA therapy continues to advance at a brisk pace with a promising trend for higher tolerability, even in difficult-to-treat subgroups such as those with cirrhosis, nonresponders to prior therapy, and transplant recipients. Subgroup-specific contraindications and safety-related limitations are active areas of research. Concerted research efforts and continuing advances lend hope to the goal of rendering HCV a routinely curable disease.