Merck & Co has submitted its single-tablet combination therapy for hepatitis C virus (HCV) to the US FDA as it tries to catch up with the leading players in the all-oral therapy sector.
Merck – known as MSD outside the US – is seeking marketing approval for a once-daily fixed-dose combination of its NS3/4A protease inhibitor grazoprevir and elbasvir, an NS5A replication complex inhibitor, which has been awarded breakthrough status by the FDA.
If approved, the one-tablet, once-daily formulation will be a direct competitor to Gilead Science’s Harvoni (sofosbuvir/ledipasvir), which is growing at a phenomenal rate since its launch towards the end of last year with first-quarter sales topping $3.5bn.
Merck has filed grazoprevir/elbasvir initially for the treatment of adult patients with chronic infections with HCV genotypes 1, 4 or 6, and says it will submit additional license applications in the EU and other markets by the end of the year.
While Merck is playing catch-up in the market with Harvoni and other rivals such as AbbVie’s Viekira Pak (ombitasvir/paritaprevir/ritonavir and dasabuvir) – which achieved first-quarter sales of $231m – analysts have suggested its combination could eventually achieve sales in the region of $2bn a year.
A key factor in those predictions rests in the combination’s benign profile in patients with HCV and concomitant kidney disease – in fact, the FDA’s breakthrough designation was awarded specifically for the drug’s use in patients with end stage renal disease who need haemodialysis as well as for those with genotype 4 HCV.
An earlier, more general breakthrough status in HCV was rescinded by the FDA after other all-oral HCV regimens reached the market.
In addition to kidney disease, Merck is also exploring the use of its drug in other hard-to-treat HCV setting – including co-infection with HIV, inherited blood disorders, liver cirrhosis and in patients receiving opiate substitution therapy to tackle addiction – that could help differentiate it from its rivals.
Meanwhile, Merck is also developing an HCV polymerase inhibitor – called MK-3682 – that it is testing alongside grazoprevir/elbasvir and other dual HCV therapies and is due to start phase III later this year.