Don’t Put All Your Eggs in One Basket: Patent Claim Strategies for Medical Device and Consumer Health Companies

Introduction: Key Lessons from IPR2024-01487 (First Quality v. Essity)

In a recent Patent Trial and Appeal Board (PTAB) decision, all 14 challenged claims of U.S. Patent No. 9,308,138 — covering an absorbent article (incontinence pad) with a specialized layered structure — were found unpatentable. This outcome in IPR2024-01487 (First Quality v. Essity) highlights critical lessons for medical device and consumer health companies regarding patent claim drafting and portfolio building strategy. An examination of the ’138 patent claims and the arguments involved in this case suggest several practical takeaways for strengthening patent protection and avoiding common pitfalls in patent practice, particularly for medical device and consumer health companies.

Background on the Dispute

In March 2024, Essity Hygiene and Health AB and its North American licensee Essity HMS North America Inc. filed suit in the District of Delaware against First Quality Products, Inc. and several affiliated First Quality entities, alleging infringement of U.S. Patent No. 9,308,138 — a patent covering an absorbent article with a specialized fluid intake structure designed to improve absorption speed and reduce leakage in incontinence pads. Essity alleged that First Quality’s Prevail Plus line of products featuring its “MaxSorb+ Zone” technology copied the layered fluid flow control structure claimed in the ’138 patent, and sought a permanent injunction, treble damages for willful infringement, and attorneys’ fees.

First Quality responded aggressively, filing a petition for inter partes review at the PTAB in October 2024, challenging all of the asserted claims. The district court case was eventually stayed pending resolution of that IPR proceeding — a common outcome in patent litigation where a parallel validity challenge is mounted at the PTAB, and one that effectively put the Delaware litigation on hold while the Board assessed the validity of the ’138 patent claims.

Recently, on May 12, 2026, the PTAB issued its Final Written Decision in the IPR, and the result was a loss for Essity. The Board found all 14 challenged claims — claims 1–5, 7, 8, and 20–22, 24, and 25 — unpatentable, determining that the claims were either anticipated by or obvious in view of prior art references including a PCT publication by Bergstrom and a combination of Japanese and U.S. patents by Nakazawa, Glaug, and others. The ’138 patent is the only asserted patent in the Delaware action.

Practice Pointers and Takeaways for Medical Device and Consumer Health Companies

1. Don’t Rely on Functional Limitations Being Read into Structural Claim Terms

The central dispute here was whether “perforated polymeric layer” required fluid flow functionality (patent owner Essity’s position) or simply meant a layer pierced with holes or apertures (petitioner First Quality’s position, which the Board adopted). Essity lost this fight, and it cascaded through every ground.

Takeaway: Don’t rely on functional limitations being read into structural claim terms. If fluid flow capability is essential to the invention, draft it expressly into the independent claim — e.g., “a perforated polymeric layer configured to permit passage of fluid therethrough.” Attempting to reply on the specification to narrow the plain meaning of claim terms is a consistently losing strategy at the PTAB.

2. Use Dependent Claims Strategically for Claim Differentiation

The Board noted that dependent claims 2, 3, 4, 7, and 8 each added specific structural properties (basis weight, aperture size, open area, three-dimensional formation). The existence of those dependent claims actually cut against Essity on claim construction — the Board reasoned that if “perforated” in claim 1 already required all those properties, the dependent claims would be superfluous.

Takeaway: This is a classic claim drafting trap. When dependent claims add structural specificity, they can unintentionally signal that the independent claim is broader than the patentee wants it to be. Consider whether some of the dependent claim limitations should be folded into the independent claim, or whether the independent claim should include at least a minimum structural qualifier so the dependent claims read as enhancements rather than as definitions of the base case.

3. “Teaching Away” Arguments Require Clear Discouragement in the Reference

Essity repeatedly argued that combining references (Nakazawa with Glaug, and Nakazawa with Ponomarenko) would be antithetical to each reference’s purpose. The Board applied the Federal Circuit’s standard from In re Gurley 27 F.3d 551 (Fed. Cir. 1994) — teaching away requires that a skilled artisan would be discouraged from the path, not merely that the reference has a different preferred embodiment. Nakazawa’s Figure 15 showed one embodiment that might impede fluid flow, but the reference disclosed other embodiments and the Board found no clear discouragement.

Takeaway: Teaching away is a high bar. For patent owners a better argument is often that a combination would not achieve the claimed result (e.g., changed principle of operation, no reasonable expectation of success, etc.), rather than to argue the prior art actually teaches away. More practically for applicants: draft claims with structural or functional language that clearly differentiates from the prior art, rather than relying on the prior art’s teaching away to do the work.

4. Continuation Practice and Portfolio Architecture Are Critical to Success

Essity’s ’138 patent resulted from U.S. national phase entry of an earlier PCT filing. While Essity obtained counterpart patents in a surprising 14 other jurisdictions, they never obtained more than one patent in any country, including in the US. A single US patent with only one independent claim put all of Essity’s eggs in one basket, which undoubtedly made it a ripe target for a PTAB invalidity challenge, once Essity asserted it against First Quality in a related district court action. Had Essity pursued additional claim sets in continuation applications with varying structural scopes or alternative claim approaches (e.g., method claims, claims directed to different structural configurations), they may have retained some protection even after this IPR loss. As things stand, their currently stayed district court case against First Quality involving only this patent may be in trouble.

Takeaway: For medical device and consumer health companies with core technology, robust continuation practice — including method of manufacture claims, method of use claims, and claims directed to different levels of structural specificity — provides resilience against IPR invalidity findings. No single patent should be the only line of defense for a core commercial product. Instead, aim to build an effective patent thicket.

Conclusion

The PTAB’s decision in First Quality v. Essity is a stark reminder that patent protection is only as strong as the strategic choices behind it. Even for commercially valuable and widely protected technologies, a narrow claim construction loss or an overreliance on a single patent can unravel an entire enforcement effort. For medical device and consumer health companies in particular—where incremental structural features often carry significant commercial weight—precision in claim drafting and foresight in portfolio development are essential.

The lessons here reinforce a broader principle: patent strategy must be proactive, not reactive. Clear functional language should be expressly captured where it matters, and dependent claims should be crafted to strengthen rather than undermine the independent claim. Most importantly, companies should invest in building layered protection through continuation practice and diversified claim sets in key jurisdictions.

Even in today’s rapidly changing USPTO environment, PTAB and Central Reexamination Unit challenges can still be effective; a single patent is rarely sufficient to base an infringement action on to safeguard a core product. A resilient patent portfolio—thoughtfully constructed and strategically maintained—remains the best defense against invalidity risks and the strongest foundation for long-term competitive advantage.