Slynd® (drospirenone)
Case Name: Exeltis USA, Inc. v. Lupin Ltd., Civ. No. 22-434-RGA, 2024 WL 4040470 (D. Del. Sept. 4, 2024) (Andrews, J.)
Drug Product and Patent(s)-in-Suit: Slynd® (drospirenone); U.S. Patent Nos. 11,123,299 (“the ’299 patent”), 11,291,632 (“the ’632 patent”), 11,351,122 (“the ’122 patent”), 11,412,249 (“the ’249 patent”), and 11,478,487 (“the ’487 patent”)
Nature of the Case and Issue(s) Presented: Slynd is indicated to prevent pregnancy. Prior to trial the parties narrowed the issues to infringement of the patents-in-suit, obviousness, written description, and indefiniteness.
Why Plaintiffs Prevailed: Indefiniteness. Lupin argued that two claim limitations were indefinite. The first recited that no more than 50% of the drospirenone present in the pharmaceutical composition needed to dissolve within thirty minutes when subjected to an in vitro dissolution test in accordance with the USP XXIII Paddle Method. While the file history disclosed multiple ways to use the Paddle Method, the court concluded that a POSA would know which approach to select when practicing the patents-in-suit. In particular, Example 2 and Example 5 of the patents-in-suit described dissolution tests performed according to the recited Paddle Method. Further, during prosecution, Exeltis submitted an inventor declaration outlining the same Paddle Method.
Lupin next argued that certain claims were indefinite because they did not require a specific method for measuring particle size, and, according to Lupin, different methods lead to different results that may or may not be within the scope of the claims. The court found that there were different methods for measuring particle size, but it rejected Lupin’s argument because it found that when properly performed, each method lead to the same particle size measurement.
Infringement. Lupin argued that it did not meet the dissolution and particle limitations of the patents-in-suit. With regard to the dissolution limitation, Lupin argued that a POSA would not have tested its product with the parameters used by Plaintiffs. The court disagreed for the same reasons explained in its indefiniteness analysis, and concluded that a POSA would have used the method outlined in the Examples of the patents-in-suit. For the particle limitations, Lupin argued that Plaintiffs’ expert never showed he was only measuring drospirenone, rather than drospirenone co-located with Eudagit. Plaintiff’s expert, though, stated that he did not include any drospirenone with Eudagit, and Lupin’s expert did not test Lupin’s drug product. For these reasons, Lupin was found to infringe the particle limitation.
Adequate written description. Lupin argued that the claims were directed to a broad, functionally claimed genus: any 4 mg formulation that meets the claimed dissolution and PK limitations. In particular, Lupin argued that the specification did not show that the inventors had possession of the full scope of the genus. But the court agreed with Exeltis’s argument that the specification did not need to identify representative species or common structural features of the claimed formulations because they were well known in the art. By way of example, the court concluded that the specification did not need to describe Eudragit, which Lupin’s ANDA product used, because Eudragit was well known in the art.
Obviousness. Lupin argued that the combination of prior-art references Huempel and Davila rendered the patents-in-suit obvious. In response, Exeltis argued that Huempel did not teach the claimed Tmax range of 2.2 to 6 hours. Next, Exeltis provided that the prior art did not teach a 24/4 dosing schedule for a progestin-only pill (“POP”). The court agreed, finding that the prior art did not teach a drospirenone POP with a non-continuous dosing schedule, nor did it teach a drospirenone POP with the claimed PK parameters. The Court concluded that while a POSA would have been motivated to: (i) make drospirenone formulations in the claimed dosage ranges; and (ii) use the claimed particle sizes to achieve the claimed PK and dissolution profiles, it would not have been motivated to make slow-release drospirenone POPs, to make a product with the claimed PK profile, or to use 24/4 dosing.
As to secondary indicia of non-obviousness, the court concluded that Slynd had a superior bleeding profile by comparison to the prior art. Further, the court adopted Exeltis’s argument that many patients, especially ones with cardiovascular risk factors, did not have a suitable option for oral contraceptives as of the effective filing date of the patents-in-suit. As a result, the court found a long-felt, but unmet need. As to praise, the court found that several journal articles discussed the “valuable addition” that Slynd made to the oral contraceptive market. Finally, the court concluded that Exeltis has shown significant evidence of commercial success based on a combination of market share and sales.
