Ethinylestradiol & Etonogestrel - USA

On Oct 19, 2017, in a nonprecedential opinion Federal circuit reversed District court of Delaware’s decision on obviousness in NuvaRing® (Ethinylestradiol/etonogestrel) on improper hindsight (Merck Sharp & Dohme B.V., v. Warner Chilcott Co. LLC.). Previously district court held that claims 4 and 11 of U.S. Patent No. 5,989,581 are invalid as obvious. Merck appealed.

The ’581 patent relates to a vaginal ring used for contraception, and its commercial embodiment is sold under the brand name NuvaRing®. Warner Chilcott is seeking to introduce a generic version of NuvaRing®, and concedes that its generic product would infringe the ’581 patent if the claims are found valid. Importantly, claims 4 and 11 both require at least a single-compartment that includes a progestogenic steroidal compound and an estrogenic steroidal compound. Warner Chilcott argued that the asserted claims are anticipated or rendered obvious by International Patent Application WO 97/02015.

Like the ’581 patent, PCT ’015 also discloses a vaginal ring that prevents contraception by releasing ETO and EE. PCT ’015, however, relies on a two compartment design, in which a first compartment includes ETO only, and a second compartment includes ETO and EE. PCT ’015 criticizes one-compartment vaginal rings, stating that:

“These above-mentioned one-compartment rings have the disadvantage that, when loaded with more than one active substance, release patterns of these substances cannot be adjusted independently. Such devices usually show suboptimum release patterns for the different substances, whereas it is generally preferred that all substances are released in a controlled rate and during a similar duration of time. As a consequence the release ratio of the active substances undergoes a change after a period of time”.

After a four-day bench trial, the district court found that PCT ’015 renders obvious the ’581 patent claims. Specifically, the court reasoned that “a person of ordinary skill would have been motivated to optimize PCT ’015 such that the second compartment released physiologically required amounts of ETO and EE.”

Federal circuit however disagreed with district court & said that PCT ’015 does not actually disclose a ring with a second compartment that comprises 97% of the ring, and includes a higher concentration of ETO than EE in the second compartment. Instead, PCT ’015 provides a broad range of values for the relative size of each compartment as well as concentrations of each compound.  To arrive at the hypothetical ring that the district court relied on for obviousness, the person of ordinary skill must make the second compartment 97% of the total ring, which is outside of the usual or preferred range disclosed in PCT ’015. Also prior art was silent on possible combinations of ETO (high end) & EE (low end) concentrations.

Instead, the only way to arrive at the hypothetical ring is by using the ’581 patent as a roadmap to piece together various elements of PCT ’015. That represents an improper reliance on hindsight. The district court’s reliance on hindsight is further underscored by the prior art’s criticism of the one compartment solution. PCT ’015 expressly states that one compartment rings are undesirable because it is difficult to control the release rates for both compounds. Therefore the person of ordinary skill would not be motivated to modify PCT ’015 to make a one-compartment ring.

Because it was not obvious to load the claimed concentrations of progestogenic compounds and estrogenic compounds in one compartment, Federal circuit thus reversed the district court’s finding of invalidity.