Yesterday, Judge Hall granted a post-trial JMOL motion in Taiho Pharmaceutical Co., Ltd. v. MSN Laboratories Private Ltd., C.A. No. 19-2342-JLH (D. Del.), finding no infringement as a matter of law.
The motion resolved a relatively straightforward claim construction issue: what the word "purity" means in the claims.
The patentee said it meant chemical purity, while the accused infringer argued it meant "polymorphic" purity. The patent as a whole is directed towards crystal forms of a drug, and discussed purity of the crystal form—"polymorphic" purity—but also mentions chemical purity. The patenteee agreed that, if "purity" means polymorphic purity, then there is no infringement.
The Court found that the term meant polymorphic purity, essentially finding that that is what the patent is about:
Taiho contends that the term “purity” is ordinarily understood by those of skill in the art to mean chemical purity. But the question here is whether a skilled artisan would ascribe that meaning in the context of claim 3 of the ʼ666 patent. Having carefully considered all the intrinsic and extrinsic evidence of record, I agree with MSN that the term refers to polymorphic purity.
Starting with the words of claim 3, they don’t shed much light on the proper resolution of this dispute. The other claims in the patent aren’t much help either.
The remainder of the specification strongly supports MSN’s contention that a skilled artisan would understand that “purity,” as used in the context of claim 3 of the ʼ666 patent, refers to polymorphic purity. The specification acknowledges that methods for producing tipiracil hydrochloride were known in the art, but it explains that prior art methods resulted in mixtures of different crystal forms. . . . Then, under the heading “Technical Problem,” the specification provides that “[a]n objective of the present invention is to provide a stable crystal form of tipiracil hydrochloride useful as an active ingredient of medicaments.” . . . Under the heading, “Solution to Problem,” the specification states that the inventors had, “through trial and error, found a production method for advantageously obtaining a highly-pure Crystal I under specific conditions.” . . . The specification goes on to describe how to make “Crystal I of high purity.” . . . And it expressly defines “high purity” as polymorphic purity: “‘[h]igh purity’ used in the present invention means that at least 90% by mass, preferably 95% by mass, and more preferably 99% by mass of the crystals of [tipiracil hydrochloride] are the crystals of the present invention.” . . . When the disclosure is considered as a whole, it strongly supports MSN’s position that a person of skill in the art would understand that claim 3 is referring to polymorphic purity.
It sounds like home run for the defendant, but the patentee did have a few points in their favor. Plaintiff argued (and defendant didn't seem to disagree) that the default meaning was chemical impurity, and parts of the specification relate to chemical purity. The examiner also took both positions, and in a related patent the patentee had specifically limited the claims to polymorphic purity (suggested that the word "purity" alone is broader).
The Court had little trouble with those arguments given how strongly the specification supported a view that they meant polymorphic purity. And given that the parties agreed that the patentee could not show infringement of the polymorphic purity limitation, Judge Hall granted JMOL of no infringement.
How Did This Case Make It All the Way Through Trial?
You may be wondering: how did this case make it so far? Didn't the parties raise this at claim construction? If a simple black-and-white one-word construction of a term would resolve infringement, wouldn't somebody have raised it?
Turns out, at the original time for claim construction, the parties stipulated to an agreed-upon construction of another term, and stipulated that there were no terms needing construction by the Court. They also cancelled the Markman dates. That was back in 2020, over four years ago.
About a year later—three years ago—the parties realized they had a problem. The patentee's expert reports relied on the chemical purity of the accused product. The accused infringers moved to strike those reports but (according to a letter on the docket) the Court denied the motion, finding the prejudice could be cured.
The accused infringers then asked the Court to construe the term. Plaintiff opposed, arguing that it would be more efficient to resolve it at or after trial:
Taiho respectfully submits that the most practical and efficient approach for addressing the claim construction issue of this single term is for the experts to opine on the alternate meanings in their expert reports, with the Court resolving any differences after having an opportunity to hear from the experts at trial and following post-trial briefing. This would avoid any near-term imposition on Your Honor’s time and would avoid any adverse impact on the case schedule.
Id., D.I. 79 at 4. The Court agreed, and deferred claim construction of that term to during or after trial:
ORAL ORDER: Having read the parties' letter dated September 3, 2021, the Court agrees with Taiho that the parties' experts should opine on the competing definitions of the disputed claim term and the Court can resolve the claim construction issue during or after trial.
The case ultimately went to trial on this patent in April, 2024, two and a half years later (there was an intervening bench trial on another patent first). And the issue was finally resolved yesterday, three years and four months after it was initially raised, and four years after the original deadlines for claim construction.
The best time for the accused infringer to resolve this issue was during the original Markman hearing. That could have saved years of litigation on this patent.
But could the accused infringer have raised this construction dispute earlier? It's hard to say. It may be that they had an inkling of an idea that this is where the patentee was going, but held off to try for preclusion instead.
Or it may be that both sides thought this would be a factual dispute about the polymorphic purity of the accused product, and only later did plaintiff realize that the accused product didn't meet the polymorphic purity limitation, and pivoted to chemical purity. That seems a bit more likely, given that they didn't disclosure the argument in their contentions.
Either way, it's a good reminder for us all to think long and hard about what terms may need construction, and early in the case. I don't think any defendant wants to pursue four extra years of litigation.
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