The US Food and Drug Administration (FDA) has accepted for review Merck's New Drug Application for grazoprevir/elbasvir (100mg/50mg), an investigational, once-daily, single-tablet combination therapy for the treatment of adult patients infected with chronic hepatitis C virus (HCV) genotypes (GT) 1, 4 or 6.1

The FDA granted Priority Review for grazoprevir/elbasvir (100mg/50mg), with a Prescription Drug User Fee Act (PDUFA) action date of January 28, 2016.

“The US FDA’s Priority Review designation for grazoprevir/elbasvir underscores how innovative treatment approaches for chronic hepatitis C are still needed for many patient populations,” said Dr. Roy Baynes, senior vice president of clinical development, Merck Research Laboratories.

“Our clinical data for grazoprevir/elbasvir in broad and diverse patient populations with chronic hepatitis C are very encouraging, and we look forward to continuing our dialogue with the FDA to bring this novel combination medicine to the appropriate patients with chronic hepatitis C.”

The New Drug Application for grazoprevir/elbasvir (100mg/50mg) is based in part upon data from the pivotal C-EDGE clinical trials programme, as well as the C-SURFER and C-SALVAGE trials. Data from these trials were previously presented at The International Liver Conference 2015. Collectively, these trials evaluated treatment regimens of grazoprevir/elbasvir (100mg/50mg), with or without ribavirin, in multiple genotypes (GT1, 4 and 6) including patient populations who were previously treated, and those with cirrhosis or certain co-morbidities (e.g., HIV/HCV co-infection, chronic kidney disease stages 4 and 5).

Grazoprevir/elbasvir is once-daily, single-tablet combination therapy consisting of grazoprevir (NS3/4A protease inhibitor) and elbasvir (NS5A replication complex inhibitor). As part of Merck’s broad clinical trials programme, grazoprevir/elbasvir is being evaluated in multiple HCV genotypes including patients with difficult-to-treat conditions such as HIV/HCV co-infection, advanced chronic kidney disease, inherited blood disorders, liver cirrhosis and those on opiate substitution therapy.

In April 2015, the FDA granted Breakthrough Therapy designation status for grazoprevir/elbasvir for the treatment of patients infected with chronic HCV GT1 with end stage renal disease on hemodialysis, and Breakthrough Therapy designation status for grazoprevir/elbasvir for the treatment of patients infected with chronic HCV GT4. Breakthrough Therapy designation is intended to expedite the development and review of a candidate that is planned for use, alone or in combination, to treat a serious or life-threatening disease or condition when preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints.