IP Law Daily, PATENT—Fed. Cir.: Federal Circuit affirms invalidity of Hetlioz sleep medicine patents, (May 10, 2023)

By George Basharis, J.D.

The Federal Circuit upheld a district court’s decision invalidating four patents related to Vanda Pharmaceutical’s sleep disorder treatment drug, Hetlioz.

The U.S. Court of Appeals for the Federal Circuit has affirmed a district court’s decision finding that Vanda Pharmaceutical’s patents for Hetlioz, a drug used to treat sleep disorders, are invalid because the dosage and method of administering the drug were obvious before the patents were issued. Vanda had sued Apotex Corp. and Teva Pharmaceuticals USA, Inc. for alleged infringement of Vanda’s Hetlioz patents. However, the lower court ruled that multiple combinations of prior art references rendered each of the asserted claims of the Vanda patents obvious (Vanda Pharmaceuticals Inc. v. Teva Pharmaceuticals USA, Inc., May 10, 2023, Dyk, T.).

Vanda Pharmaceutical’s Hetlioz, a drug that uses tasimelteon, has been approved by the Federal Food and Drug Administration (FDA) for treating Non-24, a circadian rhythm disorder that disrupts nighttime and daytime sleep. Tasimelteon works by synchronizing, or entraining, a person’s circadian rhythm to the 24-hour day. Vanda owns four patents related to using tasimelteon to treat Non-24: U.S. Patents Nos. RE46,604 (the RE’604 patent), 10,149,829 (the ’829 patent), 9,730,910 (the ’910 patent), and 10,376,487 (the ’487 patent).

Teva and Apotex submitted abbreviated new drug applications (ANDAs) with the FDA seeking approval for manufacturing and selling generic tasimelteon, the active ingredient in Hetlioz. Vanda sued the two companies, alleging their ANDA submissions for generic tasimelteon infringed on various claims of the Hetlioz patents. However, the district court ruled against Vanda, invalidating the claims in question on the grounds of obviousness. The court stated that the timing and dosage instructions described in the claims would have been clearly advisable or necessary to a person of ordinary skill in the art. Based on numerous prior publications, such a person would have had a reasonable expectation of success in using tasimelteon as described in the ANDAs. Vanda appealed the decision.

The RE’604 patent. Vanda alleged that Teva and Apotex infringed the RE’604 patent, which claimed a method of entraining a patient with Non-24 by administering 20 mg of tasimelteon. However, the district court found that prior art references in clinical trials to a drug similar to tasimelteon, administered in similar doses, would have given a skilled artisan a reasonable expectation of success using 20 mg of tasimelteon to treat Non-24. In addition, the lower court relied on expert testimony and a publication by Vanda to conclude that the claimed method of the RE’604 patent would have been obvious to a skilled artisan.

The Federal Circuit agreed with the lower court’s findings and rejected Vanda’s argument that the district court disregarded contrary evidence. Specifically, Vanda contended that the district court should have taken into account secondary considerations of obviousness, such as the “long-felt need,” praise of the patent specifically directed to the treatment method claimed by the RE’604 patent, and evidence from Non-24 sufferers that “until tasimelteon nothing worked for them.” However, there was no indication in the record that the district court had disregarded this evidence.

The ’487 patent. The ’487 patent claimed a method of administering tasimelteon “without food.” The district court determined that it would have been obvious to try administering tasimelteon without food, as the FDA had recognized at the time Vanda’s tasimelteon product was being developed that food could alter a drug’s bioavailability with clinically significant consequences. Therefore, the court’s finding that it would have been obvious to a skilled artisan to try administering tasimelteon without food was not clearly erroneous.

The ’910 patent. In addition, the district court did not err in finding the claims of the ’910 patent obvious. This patent claimed a method of treating Non-24 with tasimelteon while avoiding the coadministration of the antibiotic drug rifampicin. The court noted that as of the priority date of the ’910 patent, it was known that a drug similar to tasimelteon, ramelteon, was less effective when administered with rifampicin. Therefore, the court determined that given the many known similarities between ramelteon and tasimelteon, it would have been obvious to a skilled artisan to look to ramelteon to predict the interaction between tasimelteon and rifampicin.

The ’829 patent. The ’829 patent claimed a method of treating Non-24 with tasimelteon by discontinuing the use of a certain enzyme known to adversely affect the metabolization of drugs. Vanda argued that the district court erred in finding the claim obvious because the testing showing that coadministration of tasimelteon and the enzyme in question rendered tasimelteon ineffective was not conducted until after the priority date of the ’829 patent. The Federal Circuit rejected this argument, explaining that obviousness did not require certainty, only a reasonable expectation of success. Teva and Apotex established that it was reasonable for a skilled artisan to anticipate that taking tasimelteon with the enzyme inhibitor could impact the efficacy of tasimelteon. They were not required to demonstrate that coadministration would, in fact, affect the efficacy of tasimelteon.

The Case is No. 23-1247.

Attorneys: Nicholas P. Groombridge (Groombridge, Wu, Baughman & Stone LLP) for Vanda Pharmaceuticals Inc. John Christopher Rozendaal (Sterne Kessler Goldstein & Fox, PLLC) for Teva Pharmaceuticals USA, Inc. Aaron S. Lukas (Cozen O'Connor PC) for Apotex Inc. and Apotex Corp.

Companies: Vanda Pharmaceuticals Inc.; Teva Pharmaceuticals USA, Inc.; Apotex Inc.; Apotex Corp.

Cases: Patent FedCirNews DelawareNews GCNNews