US Supreme Court refuses to hear Tamiflu ‘double patenting’ case

The US Supreme Court yesterday (March 9) refused to hear a case between Californian pharmaceutical company Gilead and India-based Natco that concerns ‘double patenting’.

Gilead asked the Supreme Court in November whether the double patenting doctrine allows a party to invalidate another’s patent by using as a reference one that was issued after the disputed patent.

The double patenting doctrine seeks to prevent the unjustified extension of patent exclusivity beyond the patent term. The US Patent and Trademark Office says people should be able to assume that after a patent term ended, they may use the invention claimed by the patent.

Gilead owns two US patents that cover flu medicine Tamiflu (oseltamivir phosphate)—5,952,375 and 5,763,483. The patents are both directed to antiviral compounds and methods for their use, and have respective expiry dates of February 27, 2015 and December 27, 2016.

In 2011, Gilead sued Natco at the US District Court for the District of New Jersey for allegedly infringing the ‘483 patent, after the Indian company asked the US Food and Drug Administration for approval to make and sell a generic version of Tamiflu.

Natco argued that the ‘375 patent qualified as an obviousness-type double patenting reference for the ‘483 patent.

Gilead said that the ‘375 patent could not serve as a reference for double patenting of the ‘483 patent, as the ‘375 patent was issued after the ‘483 patent (even though the earlier-issued patent is due to expire 22 months after the later-issued one). Even though the ’375 patent was issued second, Gilead filed it first, which means it expires before the ’483 patent.

The district court agreed with Gilead, finding that Natco had infringed the ‘483 patent.

In its appeal against the decision at the US Court of Appeals for the Federal Circuit, Natco argued that the ‘375 patent does qualify as an obviousness-type double patenting reference for the ‘483 patent because the ‘375 patent expires before the ‘483 patent.

In its opposition to Gilead’s Supreme Court petition, Natco said that the 22-month period between the expiry of the two patents amounts to an “unjustified extension” of the ‘375 patent’s term.

The Federal Circuit had agreed, overturning the Jersey court’s decision.

It said: “Because the obviousness-type double patenting doctrine prohibits an inventor from extending his right to exclude through claims in a later-expiring patent that are not patentably distinct from the claims of the inventor’s earlier-expiring patent, we agree with Natco that the ‘375 patent qualifies as an obviousness-type double patenting reference for the ‘483 patent.”

In its petition, Gilead argued that the US Court of Appeals for the Federal Circuit had “inverted” the double patenting doctrine when it found that the first-issued patent (‘483) was invalid based on the second-issued patent (‘375).

Trade group the Pharmaceutical Research and Manufacturers of America filed an amicus brief in support of Gilead in December, arguing that the Supreme Court’s review “is necessary to define the scope of the double patenting doctrine and to restore critical patent law incentives for future biopharmaceutical innovation”.

After the Supreme Court refused to hear the case, a spokesperson for Gilead said: “We are disappointed that the Supreme Court declined to address the legal standards for double patenting. As a result of the Supreme Court’s decision, a trial on the merits of Natco’s challenge will proceed. We will continue to defend our Tamiflu patents against Natco’s challenge.”

Natco did not respond to a request for comment.