Jazz Pharmaceuticals v. Almaject — Prosecution Disclaimer Narrows Defibrotide Patent Claims

Background

Jazz Pharmaceuticals and Gentium asserted five related patents covering formulations of defibrotide. In the consolidated infringement actions, the parties asked the court to construe “defibrotide,” a term appearing in every asserted claim, and the closed transition “consisting of.”

Jazz proposed a broad scientific description of defibrotide. Almaject argued that the term must be limited to material containing less than 10% double-stranded DNA because the applicants relied on that distinction to overcome prior-art rejections during prosecution.

The Court’s Holding

Judge Stanley Chesler adopted Almaject’s construction. The prosecution history showed that the applicants distinguished their product from prior-art defibrotide by repeatedly emphasizing its low double-stranded-DNA content. Those statements were clear and unmistakable, so prosecution disclaimer prevented Jazz from recapturing the broader scope in litigation. The court construed “defibrotide” as “defibrotide containing less than 10% double stranded DNA.”

The court also gave “consisting of” its settled patent-law meaning: the claim is closed to unrecited elements. It rejected Almaject’s proposed examples because they would confuse rather than clarify the ordinary construction, and Jazz did not show that the shared specification or prosecution history displaced the exceptionally strong presumption attached to that phrase.

Key Takeaways

• Arguments used to overcome an obviousness rejection can narrow a claim even when the limitation is not added verbatim to the claim text.
• Clear prosecution statements across a patent family can affect later continuation patents sharing the same history.
• “Consisting of” ordinarily excludes unrecited elements unless the intrinsic record unmistakably gives it another meaning.

Why It Matters

The constructions shape the infringement comparison in these pharmaceutical cases. More broadly, the decision is a reminder that prosecution advocacy has lasting consequences: statements that win allowance can define the enforceable boundary of an entire patent family years later.