Expecting The "Unexpected": Asserted Claims Found Invalid After Allegedly "Unexpected Results" Suggested In Prior Art References

Published date31 January 2023
Subject MatterIntellectual Property, Food, Drugs, Healthcare, Life Sciences, Patent, Food and Drugs Law
Law FirmFinnegan, Henderson, Farabow, Garrett & Dunner, LLP
AuthorMr Jameson Gardner, Thomas Irving and Stacy Lewis


In Vanda Pharmaceuticals, Inc. v. Teva Pharmaceuticals USA, Inc., 2022 WL 17593282 (D. Del. Dec. 13, 2022) the district court held that all patent claims asserted against defendants Teva and Apotex were invalid for obviousness.


Vanda Pharmaceuticals, Inc. ("Vanda") is the holder of several patents related to its Hetlioz' drug product, which is the only FDA-approved drug indicated for the treatment of Non-24-Hour Sleep-Wake Disorder. Teva Pharmaceuticals USA ("Teva") and Apotex Inc. ("Apotex") each submitted an ANDA seeking approval to market a generic version of Hetlioz'. In response, Vanda asserted four patents, U.S. Patent No. RE46,604 ("RE604"), U.S. Patent No. 10,149,829 ("the '829 patent"), U.S. Patent No. 9,730,910 ("the '910 patent"), and U.S. Patent No. 10,376,487 ("the '487 patent"), that the ANDA filings allegedly infringe.


The district court held in favor of Teva and Apotex (collectively, "Defendants"), finding all asserted patent claims invalid for obviousness.

Defendants alleged that the asserted patent claims were invalid in view of various combinations of Hack, Lankford, Hardeland, Pandi-Perumal, and the '244 publication. Notably, Vanda argued in its post-trial brief that Lankford "'is not even prior art' 'because it represents Vanda's own work and was published in May of 2011, less than a year before the priority date of the RE604 patent.'" Id. at 30. The court noted that this was the first time that Vanda presented this argument. Vanda had not objected to the introduction of and reliance on Lankford before and during the trial, and therefore forfeited the right to argue that Lankford is not prior art. Id.


Defendants first alleged that claim 3 of the RE604 patent was invalid. Claim 3 of the RE604 patent depends from claims 1 and 2.

Claims 1-3 recite:

1. A method of entraining a patient suffering from Non-24 to a 24-hour sleep-wake cycle in which the patient awakens at or near a target wake time following a daily sleep period of approximately 7 to 9 hours, and maintaining said 24 hour sleep-wake cycle said method comprising: treating the patient by orally administering to the patient 20 mg of tasimelteon once daily before a target bedtime.

2. The method of claim 1, wherein the patient is totally blind.

3. The method of claim 2, wherein the tasimelteon is administered 0.5 to 1.5 hours before the target bedtime.

Vanda argued that claim 3 of the RE604 was not obvious due to unexpected results relating to (1) the relatively long half-life of tasimelteon in view of the relatively short half-life of melatonin, (2) the efficacy of the 20 mg dose of tasimelteon, (3) the timing of tasimelteon administration, and (4) the phase-response curve. The court noted that although Lankford disclosed that there were differences in the half-life of melatonin and tasimelteon, Lankford concluded that "[t]he longer half-life could make tasimelteon more suitable for treating insomnias other than just the sleep onset type." Based on this disclosure, the court found that a skilled artisan would have "understood Lankford as teaching or suggesting that tasimelteon could likely entrain blind patients with Non-24." Id. at 49. The court also noted that the references cited by the defendant additionally disclose the 20 mg dosage of tasimelteon, which would suggest that the dosage was not unexpected, and that tasimelteon could be administered approximately a half-hour...

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