Novartis Pharms. Corp. v. Torrent Pharma Inc. (In re Entresto (Sacubitril_Valsartan))

Authored by: Jeremy J. Gustrowsky

A recent Federal Circuit decision has important implications for pharmaceutical patents covering drug combinations, especially when new forms of those combinations are discovered after the original patent is filed. The case centered on U.S. Patent No. 8,101,659, which protects Novartis’s blockbuster heart failure drug Entresto®, a combination of valsartan and sacubitril. Novartis sued several generic drug makers after they sought approval to market generic versions of Entresto, leading to a legal dispute over whether the patent was valid.

The core issue was whether the ‘659 patent provided an adequate written description for the claimed invention—a pharmaceutical composition combining valsartan and sacubitril—when the specific complexed form of the two drugs (as found in Entresto) was not discovered until years after the patent’s filing date. The district court initially ruled that the patent was invalid for lack of written description, reasoning that the patent did not describe these later-discovered complexes. However, the Federal Circuit reversed this finding, clarifying that a patent only needs to describe what is actually claimed, not every possible later-developed form. Since the ‘659 patent claimed the combination of valsartan and sacubitril, and the specification described this combination, the written description requirement was satisfied.

The court also addressed arguments about enablement and obviousness. It held that the patent did not need to enable or describe the later-discovered complex form, because enablement is judged based on what was known at the time of filing. Additionally, the court agreed with the lower court that the combination of valsartan and sacubitril was not obvious in 2002, as there was no clear motivation in the prior art to combine these specific drugs, and sacubitril had not even been tested in humans or animals for heart failure at that time.

This decision provides reassurance to innovators that their patents will not be undermined by later scientific advances, as long as the original invention is adequately described and enabled based on what was known at the time. It also underscores the importance of clear claim drafting and specification support in general, and particularly for pharmaceutical combinations.