Endo sued several drug manufacturers that had filed Abbreviated New Drug Applications to market generic versions of the patented drug oxymorphone, which was licensed to Endo. Representative claim 1 recites: “A hydrochloride salt of oxymorphone comprising less than 0.001% of 14-hydroxymorphinone.”
The district court construed the claim term “14-hydroxymorphinone” to mean “14-hydroxymorphinone hydrochloride” when read in view of the specification and based on testimony from Actavis’s expert. This claim construction barred prior art disclosing the non-salt form of 14-hydroxymorphinone from being applied to the asserted claims. The district court also found that a person of ordinary skill in the art would not have a reasonable expectation of success in combining the prior art, despite an FDA communication mandating that opioid manufacturers reduce ABUK impurities (which include 14-hydroxymorphinone) in oxymorphone to below 0.001%. The district court subsequently ruled that the asserted claims were valid and had been infringed, which the defendant drug manufacturers appealed.
(i) Did the district court err in its claim construction?
(ii) Did the district court err in holding that the claimed composition was not obvious? (continue reading)
Summary by: Patrick Gildea
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