Knoa Pharma v. Accord Healthcare — Federal Circuit Affirms OxyContin Abuse-Deterrent Patent Invalid as Obvious

Background

OxyContin, the extended-release oxycodone tablet that became central to the opioid crisis, has a successor product — an abuse-deterrent formulation designed so that the pills cannot easily be crushed and snorted or dissolved and injected. Purdue Pharma developed that formulation, obtained FDA approval in 2010, and patented the process in U.S. Patent No. 11,304,908 (the “‘908 patent”). After Purdue’s bankruptcy, those rights passed to Knoa Pharma LLC.

The core innovation claimed: mix oxycodone with polyethylene oxide (PEO), press into a tablet, then cure the tablet in a coating pan at at least 60°C for at least five minutes. Coating pans are drum-shaped manufacturing devices ordinarily used to spray and dry coatings on tablets. Purdue argued that repurposing coating pans for curing tablets was a non-obvious insight deserving patent protection.

Generic drugmaker Accord Healthcare filed an ANDA to market a generic version of the abuse-deterrent OxyContin. It stipulated to infringement but challenged validity. After a bench trial in the District of Delaware, Judge William Bryson (by designation) found all asserted claims invalid as obvious based on the “Bartholomäus” reference — a 2005 German patent application by Grunenthal GmbH that had already taught the core PEO abuse-deterrent concept. Purdue appealed as to claim 18 only — the claim specifically requiring a coating pan.

The Court’s Holding

The Federal Circuit affirmed invalidity under 35 U.S.C. § 103. Writing for the panel, Chief District Judge Seeborg (sitting by designation) rejected all three of Purdue’s arguments.

Motivation to combine. Accord’s expert testified that a person of ordinary skill in pharmaceutical manufacturing would have been strongly motivated to substitute a coating pan for the tablet press described in Bartholomäus, because coating pans could process commercial-scale batches and were standard equipment in drug manufacturing. The trial court credited that testimony, and the Federal Circuit found no clear error.

Reasonable expectation of success. Purdue argued the trial court was too conclusory. The appellate court applied the deferential “clear error” standard to post-bench-trial factual findings and, because the trial court had credited expert testimony, affirmed.

Long-felt unmet need. Purdue argued its product met a decades-long need for abuse-deterrent opioids. The court rejected this on two grounds: (1) Bartholomäus itself had already addressed that need, so it was not “unmet”; and (2) Purdue’s reframed argument — that the need was for a scalable commercial process — was forfeited for not having been raised below, and in any event claim 18 does not recite scalability.

Key Takeaways

• Adapting standard manufacturing equipment (coating pans) to a new temperature or curing purpose does not automatically create non-obvious patent claims when such equipment was already well-known in the art.
• A “long-felt unmet need” argument fails when the prior art already addressed the core need before the patent’s priority date.
• New non-obviousness theories (here, a “scalable process” long-felt need) raised for the first time on appeal are treated as forfeited.
• This decision follows the Federal Circuit’s December 2024 affirmance of invalidity in a related Purdue/Accord case (No. 2023-1953) involving a different patent from the same OxyContin family.

Why It Matters

This ruling closes another chapter of the sprawling OxyContin patent litigation as Purdue’s successors attempt to protect the reformulated product from generic competition. For the pharmaceutical industry, it reinforces that commercializing a lab-scale process using conventional manufacturing equipment at scale is not patentable, even when commercially successful. The “motivation to combine” inquiry focuses on what a skilled practitioner would have done, not on the patentee’s own innovative journey.

For generic manufacturers filing ANDAs, the ruling affirms that scalability and manufacturing efficiency are effective invalidity arguments when an innovator has merely applied standard industrial equipment to a previously-taught formulation concept.