Ertapenem sodium - USA

On October 7, 2016, Judge Richard Andrews of the U.S. District Court for the District of Delaware issued a decision in Merck’s patent infringement lawsuit against Hospira (a subsidiary of Pfizer) involving Hospira’s ANDA for a generic version of Invanz (ertapenem sodium).

Invanz (ertapenem sodium) is a penem antibacterial indicated for the treatment of certain infections. Invanz is approved in the form of a sterile lyophilized powder for reconstitution with an appropriate diluent for intravenous or intramuscular use. Each vial of Invanz contains ertapenem sodium equivalent to 1 g ertapenem. Each vial also contains sodium bicarbonate and sodium hydroxide as inactive ingredients.

There is one unexpired patent remaining in the Orange Book for Invanz: U.S. Patent No. 5,952,323 (set to expire on May 15, 2017, with pediatric exclusivity until November 15, 2017). The ’323 patent states that ertapenem, when powder-blended with sodium bicarbonate, will produce a stabilized carbamate form of ertapenem upon reconstitution. The stabilized form of ertapenem will convert back into ertapenem over time. The ’323 patent covers the stabilized carbamate form of ertapenem.

Merck also owns U.S. Patent No. 6,486,150 (set to expire on October 27, 2020), which is not listed in the Orange Book. The ’150 patent covers certain processes for manufacturing ertapenem.

Judge Andrews issued his decision in the lawsuit. Judge Andrews issued a decision in favor of Merck with respect to the ’323 patent and rejected Hospira’s challenges to the validity of that patent. Although Judge Andrews agreed with Merck that the ’150 patent covers Hospira’s proposed manufacturing process, he concluded that the ’150 patent is invalid due to obviousness in view of the ’323 patent.

Infliximab - USA

U.S. District Court for the District of Massachusetts granted Celltrion’s “Gilead Motion” for summary judgment of invalidity of U.S. Patent 6,284,471. Celltrion got FDA approval for biosimilar version (Inflectra) of Janssen’s Remicade® (infliximab) product–in April 2016.

The Gilead Motion
As summarized in the court’s September 28, 2016 Memorandum and Order, Celltrion filed a motion for summary judgment of invalidity of the ‘471 patent based on obviousness-type double patenting in view of U.S. Patent 6,790,444. Since the ‘471 patent was granted before the ‘444 patent, the theory of obviousness-type double patenting was based on the Federal Circuit decision n Gilead. In that case, the court held that a patent that issues after but expires before another patent can qualify as a double patenting reference for that other patent.

But the issue was slightly different from Gilead case where both the patents were post-GATT. In this case '471 is pre-GATT (17 or 20 rule) and '444 is post GATT (20 year rule). The court then emphasized the policy concerns behind the doctrine, and found that they would be violated if the ‘471 patent was permitted to extend beyond the term of the ‘444 patent:

Thus, the court determined that the ‘444 patent is citable as an obviousness-type double patenting reference against the ‘471 patent. In view of Celltrion’s concession that the claims were not patentably distinct, the court held that the challenged claims of the ‘471 patent are invalid for obviousness-type double patenting.