Merck & Co’s new anaesthesia drug sugammadex has been delayed en route to the US market as the FDA says it needs more time to complete its review of the marketing application.
The FDA said it will take another three months to complete its assessment of the neuromuscular blocking agent, which is already sold outside the US under the Bridion brand name.
Sugammadex is used to reverse the effects of muscle relaxants given during surgery, such as rocuronium or vecuronium, and is claimed to help patients come out of anaesthesia more quickly and with fewer side effects than competing agents.
Merck said earlier this year that it hoped to launch the drug in the US in the second half of 2013 as one of four major new growth products, alongside novel insomnia drug suvorexant, ovarian cancer treatment vintafolide, and its combination of Zetia (ezetimibe) and atorvastatin for high cholesterol.
Sugammadex has had a tricky regulatory route in the US, however, with the FDA turning down a New Drug Application (NDA) in August 2008, asking for more data on allergic reactions and bleeding events observed in clinical trials of the drug.
Merck carried out additional clinical trials in support of the NDA and re-filed the dossier towards the end of 2012.
Sales of Bridion outside the US were around $260m in 2012, and have been growing at a fairly brisk pace from $40m in 2009 – its first year on the market – to $100m in 2010 and $201m in 2011.
Analysts have suggested Bridion could achieve sales of $400m-$700m a year with US approval, depending on pricing and how successful Merck is in positioning it against established generic reversal agents such as suxamethonium, neostigmine and pyridostigmine.
There are around 30 million surgeries carried out per year in the US. Muscle relaxants are used in around half of that total, and in the majority of cases pharmacological reversal agents are also employed, according to Merck.