GlaxoSmithKline wins an FDA nod for its GLP-1 diabetes drug albiglutide

After a three-month delay pushed pause on its commercial plans, GlaxoSmithKline ($GSK) has secured FDA approval for albiglutide, a new diabetes treatment that will contend for market share in a fast-crowding space.

The drug, which will be marketed as Tanzeum, is a once-weekly GLP-1 agonist that helps spur the body's natural insulin production in patients with Type 2 diabetes. Across its 5,000-patient clinical program, GSK found the drug could improve patients' hemoglobin A1c levels both when used as a monotherapy and in tandem with other diabetes drugs. On the safety side, Tanzeum will carry a black-box warning advising doctors that thyroid tumors have popped up in animal studies of drugs in the GLP-1 class.

GSK initially expected to win approval for Tanzeum in January, but the FDA requested more time to review its application, stalling the drugmaker's access to a GLP-1 market analysts figure could top out at $5 billion a year.

But few expect Tanzeum to take the lion's share of that total. Leading the market are Novo Nordisk's ($NVO) daily Victoza and AstraZeneca's ($AZN) weekly Bydureon, and coming down the pike is Eli Lilly's ($LLY) much-hyped dulaglutide, a once-a-week treatment that, unlike Tanzeum, proved noninferior to Novo's drug in a head-to-head trial.

And the market is only getting more crowded. Sanofi ($SNY) is planning an FDA submission for its GLP-1-targeting lixisenatide next year, and Boehringer Ingelheim recently rebooted its collaboration with Zealand Pharma by handing back a daily GLP-1 treatment in order to pick another candidate from a crop of compounds that includes some weekly formulations.

GSK's drug has already won approval in Europe, where it is marketed as Eperzan.

- here's the FDA's announcement