UPDATED: Corks are a-popping at Teva with FDA nod for its new Copaxone formula

Teva Pharmaceutical Industries hit the finish line in its long race to develop a longer-acting formulation of its multiple sclerosis treatment Copaxone. Tuesday evening, Teva ($TEVA) said the FDA had approved the three-times-weekly formula, and not a moment too soon. The Israel-based drugmaker now has till mid-May to convert as many patients as possible to the latest and greatest version, before the original drug's patent expires.

Teva executives predict that 45% of current Copaxone patients will convert to the long-acting formulation. It needs as many conversions as it can get; the original is Teva's biggest seller, with about 20% of its revenue and 50% of its profits. In 2012, the drug brought in $3 billion in the U.S. alone.

There's no word yet on pricing for the longer-acting dose, and Teva's full-year 2013 figures aren't yet out, so there's no way to guesstimate how much a 45% conversion would be worth, dollar-wise. We'll leave that number crunching to the analysts; their consensus estimates are for $4.2 billion in global Copaxone sales for 2013.

Suffice it to say that Teva should be thrilled if its conversions keep ahead of generic erosion once copycat rivals hit the market. With patent protection till 2030 on this model, it could pay off for many years to come. But that's not a given; new formula or old, Copaxone does face competition from other brands, including the Novartis ($NVS) pill Gilenya, Sanofi's ($SNY) Aubagio, and Biogen Idec's ($BIIB) new-and-hot Tecfidera.

The new formula is shipping immediately and will be available to patients "within days," the company said in a statement. Teva has staffed up at its patient support center--Shared Solutions--to help current patients move to the thrice-weekly formulation. That means help navigating insurance coverage, finding the right pharmacy, and for some, financial assistance. Patients can even call the hotline directly to ask to switch. Of course they can also call their doctors, and DTC ads will no doubt soon urge them to do so. And Teva reps have been gearing up for some time to spread the word to physicians.

The company thought it would have 18 more months to persuade patients to make the Copaxone switch, but a U.S. appeals court last year invalidated a patent that expired next November. Now, the fuse runs out in May. Teva hasn't given up on the original formula, though. Last week, the company asked the U.S. Supreme Court to take up its patent case. And it's still arguing for stepped-up FDA scrutiny for any would-be Copaxone copycats. Meanwhile, Teva continues to cut costs and lay off workers in a worldwide restructuring designed to save $2 billion.

- see the Teva release

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