Impax Laboratories Inc. v. Lannett Holdings Inc.
893 F.3d 1372
| Fed. Cir. | 2018Background
- AstraZeneca (owner) and Impax (exclusive licensee) hold U.S. Patents 6,760,237 and 7,220,767 covering intranasal formulations of zolmitriptan (Zomig® Nasal Spray).
- Lannett filed an ANDA with a Paragraph IV certification seeking approval of a generic Zomig nasal spray; Impax/AstraZeneca sued for infringement under 35 U.S.C. § 271(e)(2).
- District court construed key claim terms (preamble limiting; "zolmitriptan" as chemical structure; "buffer" functionally) and held a bench trial on infringement and validity.
- Parties stipulated that Lannett’s proposed product (target pH 5) would infringe if approved; trial focused on invalidity (anticipation and obviousness).
- The district court found the asserted claims not invalid, principally because the prior art taught away from intranasal zolmitriptan given its active, more-potent metabolite (183C91), and Appellees’ expert testimony and objective indicia (including a $130M license) supported nonobviousness.
- Lannett appealed only the obviousness ruling; the Federal Circuit affirmed, deferring to the district court’s factual findings and credibility determinations.
Issues
| Issue | Plaintiff's Argument (Lannett) | Defendant's Argument (Impax/AstraZeneca) | Held |
|---|---|---|---|
| Obviousness of asserted claims (would a POSA be motivated to make intranasal zolmitriptan with reasonable expectation of success?) | Prior art (e.g., Chauveau, Tepper & Rapoport) discloses or suggests intranasal zolmitriptan and other triptan nasal forms; thus making nasal zolmitriptan would have been obvious. | Prior art taught away because zolmitriptan’s efficacy was believed to depend on its active metabolite produced by first‑pass metabolism; a POSA would have chosen other triptans and lacked reasonable expectation of success. | Affirmed nonobvious: district court’s finding that prior art taught away and lack of reasonable expectation of success was not clearly erroneous. |
| Weight of Chauveau’s disclosure of zolmitriptan | Chauveau expressly lists zolmitriptan as an example for nasal/oromucosal formulations, supporting obviousness. | Chauveau is a broad formulation reference (Labrasol® excipient) and only fleetingly mentions zolmitriptan; considered in context it does not teach successful intranasal zolmitriptan. | Affirmed: court properly viewed Chauveau in full and did not clearly err in treating its zolmitriptan mention as insufficient to render claims obvious. |
| Objective indicia / nexus (2012 $130M license) | The license covers the whole Zomig franchise; payment cannot be reliably attributed to the intranasal patents. | Timing, portfolio structure, sales statements, and press releases show at least part of the payment was for expected profits tied to intranasal patents, supporting nexus. | Affirmed: district court did not clearly err in finding a sufficient nexus for the license payment to weigh as a secondary consideration favoring nonobviousness. |
| Standard of review / evidentiary weight | Lannett stresses prior art disclosures and urges de novo reconsideration. | Appellees rely on district court’s credibility findings and the high clear‑and‑convincing standard for invalidity. | Affirmed: appellate court defers to district court factual findings and credibility determinations; Lannett failed to meet clear‑and‑convincing burden. |
Key Cases Cited
- Golden Blount, Inc. v. Robert H. Peterson Co., 365 F.3d 1054 (Fed. Cir.) (standard of review for bench trial: facts for clear error; law de novo)
- Microsoft Corp. v. i4i Ltd. P’ship, 564 U.S. 91 (clear and convincing evidence required to establish patent invalidity)
- Graham v. John Deere Co., 383 U.S. 1 (Graham factors for obviousness analysis)
- KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398 (teaching, motivation, and reasonable expectation in obviousness)
- Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831 (deference to district court factfinding, especially credibility)
- Par Pharm., Inc. v. TWi Pharm., Inc., 773 F.3d 1186 (presence/absence of motivation to combine is a factual question)