GSK/Pozen Win Long-awaited Approval For Combo Migraine Drug

Treximet will hit the U.S. market in mid-May, GSK says.

Concluding a nearly three-year FDA review process, GlaxoSmithKline and developmental partner Pozen announced they received marketing approval April 15 for Treximet (sumatriptan/naproxen sodium), a combination drug for acute treatment of migraine attacks with or without aura in adults.

GSK says the drug, formerly called Trexima , is likely to be available by mid-May. The U.K. pharma told "The Pink Sheet" DAILY it has no plans to seek approval of Treximet in other countries, and the company was mum on its marketing strategy in the U.S.

"Obviously, we'll be trying to get the information out to as many appropriate people as we can," GSK said. "Certainly, doctors who treat migraine patients, some of those are primary-care physicians."

GSK and Pozen, based in Chapel Hill, N.C., signed a licensing agreement for Treximet in June 2003 and filed an NDA in August 2005. Final regulatory clearance was delayed by two FDA "approvable" letters, the first of which cited concerns with cardiotoxicity (¹ (Also see "Trexima Approvable Letter Another Headache For Pozen" - Pink Sheet, 9 Jun, 2006.)).

The second letter, received in August 2007, raised concerns about potential implications of a preclinical in vitro chromosomal aberration study (² (Also see "Pozen/GlaxoSmithKline’s Trexima Gets Second FDA Approvable Letter" - Pink Sheet, 2 Aug, 2007.)).

The agency requested an alternative genotoxicity test and/or a test in human subjects at plasma concentrations that would mimic those seen in people taking the indicated dose of Treximet.

Pozen responded to the second FDA letter Oct. 15; the agency deemed it a "complete response" several weeks later. At the time, the firms requested a two-month review, but FDA decided on a six-month review schedule instead, setting up an April 15 PDUFA date.

Getting the product to market quickly is a key priority for GSK's migraine franchise - the company's Imitrex (sumatriptan) is slated to lose exclusivity this year (³ (Also see "Imitrex Patent Settlement Allows For Entry During Pediatric Exclusivity Period" - Pink Sheet, 13 Nov, 2006.)).

On Jan. 15, Pozen said it had submitted findings from a short-term genotoxicity study to FDA, which showed no chromosomal aberrations were induced in peripheral blood lymphocytes when Treximet was administered for seven days.

In addition, Pozen said, FDA accepted the brand name Treximet for the candidate. GSK told the DAILY the company changed the drug name from Trexima because the agency concluded it might be confused with other marketed products.

GSK claims Treximet is the only migraine product designed to target multiple mechanisms of migraine by combining a triptan and an anti-inflammatory in a single tablet. The tablet comprises 85 mg of sumatriptan and 500 mg of naproxen sodium.

In clinical testing, the combination provided migraine pain relief to a significantly greater percentage of patients at two hours than either of the components given alone, GSK says. More patients also reported sustained pain relief between two and 24 hours with the combination than with either individual component.

-Joseph Haas ([email protected])