Senju Pharmaceutical Co. v. Apotex Inc.
836 F. Supp. 2d 196
D. Del.2011Background
- Senju and Kyorin co-own U.S. Patent No. 6,333,045 on aqueous gatifloxacin compositions with disodium edetate (EDTA) and related methods.
- Allergan’s NDA covers a 0.3% gatifloxacin ophthalmic solution (ZYMAR) that relates to the patent claims and is listed in the Orange Book.
- Apotex filed an ANDA seeking to manufacture a generic version prior to patent expiry, asserting noninfringement and challenging validity.
- Defendants asserted that the accused product would not infringe or that the claims were invalid; plaintiffs alleged infringement of claims 1-3, 6-9.
- The court initially held that claims 1-3, 6-9 would be infringed and that several claims were rendered obvious by prior art; claim 7’s invalidity was contested and later reopened for additional evidence on solubility–precipitation.
- After a reopened record and supplemental hearings, the court concluded by clear and convincing evidence that claim 7 is obvious.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Obviousness of claim 7 under 35 U.S.C. §103 | Plaintiffs argue no clear link between EDTA and precipitation control in this context | Defendants rely on Riley and scholarly/experimental evidence showing inverse solubility–precipitation relationship | Claim 7 is obvious by clear and convincing evidence |
| Validity evidence adequacy based on norfloxacin tests | Norfloxacin tests demonstrate EDTA increases precipitation and challenges validity | Tests are misaligned with prior art and lack solubility data; scholarly evidence supports invalidity | Evidence insufficient to counter the obviousness finding; tests not persuasive |
| Role of pretrial discovery and new evidence on record reopening | Discovery failed to cover EDTA/precipitation interplay; new evidence unfairly used | Record expansion necessary to resolve critical questions about solubility–precipitation | Record reopened; new evidence considered in supplemental hearings but did not negate obviousness finding |
| Relevance of freeze-thaw testing to claim 7 scope | Freeze-thaw data applicable to aqueous preparations; supports nonobviousness | Freeze-thaw is appropriate testing context but not sole basis for obviousness | Even discounting nonfreeze data, the overall record supports obviousness under §103 |
Key Cases Cited
- KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398 (U.S. 2007) (obviousness requires common sense and a motivation to combine elements)
- Graham v. John Deere Co., 383 U.S. 1 (U.S. 1966) (establishes framework for assessing obviousness with factual inquiries)
- PowerOasis, Inc. v. T-Mobile USA, Inc., 522 F.3d 1299 (Fed. Cir. 2008) (preserves deference to PTO findings and addresses obviousness burden)
- Duramed Pharm., Inc. v. Watson Labs., Inc., 413 F. App’x 289 (Fed. Cir. 2011) (illustrates how claims broad enough to cover obvious matter can be unpatentable)
- Kao Corp. v. Unilever U.S., Inc., 441 F.3d 963 (Fed. Cir. 2006) (patent invalidity burden when asserting obviousness)