elbasvir

elbasvir
IUPAC name	Dimethyl N,N'-([(6S)-6-phenylindolo[1,2-c][1,3]benzoxazine-3,10-diyl]bis{1H-imidazole-5,2-diyl-(2S)-pyrrolidine-2,1-diyl[(2S)-3-methyl-1-oxobutane-1,2-diyl]})dicarbamate
Tradename	Zepatier (in combination with grazoprevir)
Drugs.com	Monograph
MedlinePlus	a616035
Licence US	Zepatier
Pregnancy AU	B3
Routes of administration	By mouth
CAS number	1370468-36-2
PubChem	67683363
ChemSpiderID	34991520
UNII	502H56VLGN
ChEMBL	3545146
Chemical formula	C₄₉H₅₅N₉O₇
Molecular weight	882.03 g·mol⁻¹

elbasvir is a direct-acting antiviral medication used as a key component in the treatment of chronic hepatitis C virus infection. It is a highly potent inhibitor of the viral NS5A protein, a non-structural protein essential for viral replication and assembly. This pharmaceutical agent is always administered in a fixed-dose combination tablet with grazoprevir, a NS3/4A protease inhibitor, under the brand name Zepatier. The combination therapy was developed by Merck & Co. and represents a significant advancement in the management of genotype 1 and genotype 4 hepatitis C infections, offering high cure rates with a generally favorable tolerability profile.

Medical uses

The fixed-dose combination of elbasvir and grazoprevir is indicated for the treatment of adult patients with chronic hepatitis C virus genotypes 1 or 4 infection. Its approval by the U.S. Food and Drug Administration and the European Medicines Agency was based on robust clinical trial data demonstrating high sustained virological response rates. Treatment regimens and duration, which can be 12 or 16 weeks, are often guided by the presence of specific viral polymorphisms and the patient's prior treatment history, including those who have failed previous therapy with peginterferon and ribavirin. It is also used in patients with co-existing human immunodeficiency virus infection and in those with advanced chronic kidney disease, including patients on hemodialysis.

Adverse effects

The combination therapy of elbasvir and grazoprevir is generally well-tolerated, with most adverse events being mild to moderate in severity. Commonly reported side effects include fatigue, headache, and nausea. Laboratory abnormalities can include elevated levels of alanine aminotransferase, though these are typically transient. A serious but rare risk associated with this regimen is the potential for reactivation of hepatitis B virus in patients with past or current infection, necessitating screening prior to initiation of therapy. As with other direct-acting antivirals, it carries warnings regarding possible drug-drug interactions, particularly with strong inducers of the cytochrome P450 system and certain HIV medications like efavirenz.

Pharmacology

Elbasvir functions as an inhibitor of the hepatitis C virus NS5A protein, a multifunctional phosphoprotein that plays a critical role in viral RNA replication and the assembly of new virions. By binding to domain I of the NS5A protein, it disrupts its normal function, leading to a potent suppression of viral replication. Pharmacokinetically, it is rapidly absorbed after oral administration, achieves peak plasma concentrations within approximately 3 hours, and has a terminal half-life that supports once-daily dosing. Its metabolism is primarily mediated by CYP3A enzymes, and it is excreted mainly in the feces.

Chemistry

Elbasvir is a complex macrocyclic molecule with a molecular formula of C₄₉H₅₅N₉O₇ and a molecular weight of 882.03 g/mol. Its intricate structure features a central indolo-benzoxazine core symmetrically linked to imidazole and pyrrolidine groups, which are critical for its high-affinity binding to the NS5A protein. The compound is synthesized as a single enantiomer, with its stereochemistry being essential for its antiviral activity. It is formulated as a hydrochloride salt for pharmaceutical use in the combination tablet with grazoprevir.

History

The discovery and development of elbasvir were spearheaded by researchers at Merck & Co. following the successful introduction of earlier hepatitis C therapies like boceprevir. The pivotal Phase III clinical trials, known as the C-EDGE program, demonstrated its high efficacy and safety across diverse patient populations. Based on this data, the FDA granted approval for the elbasvir/grazoprevir combination in January 2016, with the EMA following suit later that year. Its development marked a continued evolution in the therapeutic landscape for hepatitis C, moving towards all-oral, interferon-free regimens.

Society and culture

Marketed under the trade name Zepatier, the combination containing elbasvir has had a significant impact on public health by contributing to the goal of eliminating hepatitis C as a major global health threat. Its introduction, however, occurred amidst ongoing debates about the high cost of direct-acting antiviral therapies and issues of access and reimbursement within healthcare systems like the National Health Service in the United Kingdom and various insurers in the United States. The medication is listed on the World Health Organization Model List of Essential Medicines, underscoring its importance in treating a disease that affects millions worldwide.

Category:Antiviral drugs Category:Hepatitis C Category:Merck & Co.