GlaxoSmithKline's best-selling asthma drug Advair is proving tough to copy by generic rivals, the Wall Street Journal reports.
That challenge could allow GSK, the British drug maker with its North American headquarters in Research Triangle Park, to protect Advair even after its loses patent protection next year.
Typically, losing such protection opens the door for cheaper copycat versions and hurts sales. But Advair combines two drugs in a fine powder that's inhaled through an intricate device called a Diskus.
Generic-drug makers Teva Pharmececeutical and Sandoz, a subsidiary of Novartis, have each recruited GSK researchers to help develop a generic rival, the newspaper reports. The difficulty represents a challenge generics companies face, trying to replicate increasingly complex drugs.
"We have seen all sorts of people stub their toe on what everybody thought was a very easy proposition," GSK CEO Andrew Witty said during a conference call with analysts last month. "I remain of the view that we are likely to have Advair as a very major product for GSK for a very long time."
Advair, which GSK packages at its factory in Zebulon, has about $8.1 billion in global sales. That accounts for about 18 percent of GSK's total sales, and a quarter of its earnings, the newspaper reports. Meanwhile, GSK is developing a new version called Relovair.
Read the full Wall Street Journal report here.