A lot of people at Merck must be wondering just exactly what they're being paid back for. If you'd sat down a couple of years ago and tried to come up with a doomsday timeline for Merck, you couldn't have done much better than what's actually happened. The latest is Friday's ruling (PDF) that Merck's patent for a weekly dosing formulation of their osteoporosis drug Fosamax is invalid. That's their second-biggest selling drug - the biggest, Zocor, is coming off patent next year, don't you know.
Teva, a generic powerhouse, already has an application in to sell Fosamax (alendronate) in 2008, when the original chemical matter patent expires. But the biggest-selling form of the drug is the weekly dose, and Merck had (so they thought) wrapped up patent protection on that one until 2018. They'd won a round in the District Court in 2003, which found that Teva's application infringed on the Merck formulation patent. But Teva appealed, and the Court of Appeals for the Federal Circuit, to Merck's dismay, reversed the District Court ruling.
That doesn't leave Merck too much room, as I understand it. The Supreme Court doesn't take many patent cases - the last one, I think, was the Festo appeal, and that dealt with more fundamental questions of patent law. This, unfortunately for Merck, just looks like another patent fight, and as such I'd be surprised if the Supreme Court agrees to hear it.
One of the grounds for reversal is an obviousness argument against Merck's patent, based on a 1996 article in a trade publication on the desirability of a weekly dose of alendronate. The other reversal argument comes down to the interpretation of a single word in the original patent claims. Merck claimed a method for treating osteoporosis by administering "about 70 mg" of the compound once weekly, and a method for preventing it by administering "about 35 mg" of the compound weekly. Based on other language in the patent, the District Court believed that this "about" language was an attempt to take into account the different salt forms and formulations of alendronic acid, in order to deliver the exact 35 or 70 mg of sodium alendronate. Teva's application was for 35 and 70 mg dosages, and they were held to infringe.
The CAFC, noting that Merck had acted "as its own lexicographer", pointed out that this would mean that "about 35 mg" now was being held to mean the same thing as "exactly 35 mg.", Noting the weirdness of this, they sharply yanked the definition back to the more commonly accepted one. Teva is now in the clear, and Merck (who probably hoped to throw the largest shadow they could with that adjective) finds themselves in trouble.
There's a testy dissent to the ruling (also in that PDF file above), which the majority opinion describes as ". . .pursuing a philosophical argument as to the deference which should be given to the trial court. Claim construction being a legal matter it is reviewed de novo and this is still the law notwithstanding the desire of some members of this court to consider creating an exception to that rule." Perhaps Howard Bashman has some background on this intra-judicial elbow-throwing. The Patent Law Blog has some comments, too, along with a more technical discussion of the case than I've given here.