Despite scoring an FDA nod, Merck's biosim Lusduna must wait to challenge Lantus

Sanofi’s top-selling Lantus is already contending with one copycat rival, and Merck & Co. just won FDA approval for another. Luckily for the $5 billion basal insulin, Merck’s new Lusduna Nexvue has to sit on the sidelines for now—and maybe for more than a year.

Sanofi sued Merck for patent infringement last September, triggering an automatic 30-month stay under the Hatch-Waxman Act, which governs generic drugs’ path to market. The two companies will be squaring off in patent court in the meantime, though, and if Merck prevails, the launch can proceed.

Eli Lilly and Boehringer Ingelheim’s Lantus biosim, Basaglar, rolled out in December under a settlement with Sanofi.

For now, the Lantus competition remains a contest between those two (and other basal insulin brands, but that’s a different story). That means there’s also less discounting pressure for now. When Merck’s rival comes to market, however, the pricing contest could heat up considerably.

Lusduna won approval after a couple of late-stage clinical trials, one in type 1 and one in type 2 diabetes. Formerly known as MK-1293, the drug "showed a very nice reduction in A1C at similar doses and with a similar safety profile" to the originator med, a Merck executive said in an interview when the data were released. "In both studies, we saw very nice results comparing MK-1293 to Lantus."

Technically, like Basaglar, Lusduna isn’t a biosimilar, but a "follow-on biologic," though the general effect is the same. Also like Basaglar, it can be substituted for Lantus—not at the pharmacy, but on a doctor’s prescription pad—and at least two major payers did just that on their national formularies for 2017.

There’s no way to know for sure yet how multiple biologic copycats will affect brand pricing and sales in the U.S. Biosimilars are new to the country, with the first launch in late 2015. All-out competition hasn’t yet hit any copied brand.

And as branded drugmakers are fond of noting, biosimilars are a different breed from traditional generics. Biosims must pass clinical trials to win FDA approval, a task much more expensive than the testing required for small-molecule copies. There’s less room for discounting, in other words, because biosim makers need prices to be high enough to recoup their development costs and make a profit, too.

So, the old adage of a brand’s sales plummeting by two-thirds or more as soon as multiple generics hit the market doesn’t necessarily apply. But in Europe, Remicade biosimilars have hit Merck hard, with some of those copies priced at discounts in the 40% range rather than the 15% or so that drugmakers have predicted in the U.S.

For the first quarter of this year, its first on the market, Lilly and Boehringer’s Basaglar pulled in $22 million in U.S. sales, $46 million total.

Lantus, meanwhile, dropped by 21% in the U.S. during that period, to €690 million, but its newer insulin Toujeo—which also competed with the copycat form—grew to €115 million, an increase of 42%.

It’ll take time to see how the basal insulin market, one of the toughest in pharma these days, shakes out as newer insulins battle for share and Lantus tries to hold its own against Basaglar and, eventually, Lusduna. The 2018 formularies, due out early next month, could give us some clues, though. Stay tuned.