In Exela Pharma Scis., LLC v. Eton Pharms., Inc., No. 20-cv-365 (D. Del. Feb. 8, 2022), the District Court for the District of Delaware granted Exela's motion to exclude under Rule 702 Eton's expert non-infringement opinions that were based on an erroneous legal theory.


Exela owns several patents covering its ELCYS® product which is a L-cysteine hydrochloride injection. Id. at 1. ELCYS® “is indicated for use as an additive to amino acid solutions to meet the nutritional requirements of newborn infants . . . and of adult and pediatric patients with severe liver disease . . . .” Id. Eton filed an Abbreviated New Drug Application (“ANDA”) to market a generic version of ELCYS®. Id. Exela then filed suit alleging infringement of six patents. Id.

Eton's expert, Dr. Baertschi, filed an expert report based on the theory that the product that will ultimately be brought to market—and not what product the ANDA specification allows the applicant to market—determines infringement. Id. at 2. Ignoring the ANDA specification, Dr. Baertschi relied on biobatch data to conclude Eton's product will not infringe the patents-in-suit. Id. Exela argued that Dr. Baertschi's expert report was unreliable and unhelpful because a judgment of infringement must follow when the product described in an ANDA falls within the scope of a patent claims. Id.

District Court Decision

The District Court relied on Sunovian Pharm., Inc. v. Teva Pharm., Inc. to conclude that the ANDA specification controls the infringement analysis when it speaks to a claim limitation and, if the ANDA specification is silent on a claim limitation, then other materials may be examined to look at the product that the generic company is likely to sell. 731 F.3d 1271 (Fed. Cir. 2013). In Sunovian, the Federal Circuit made clear that “[w]hat [the generic] has asked the FDA to approve as a regulatory matter is the subject matter that determines whether infringement will occur[.]” Id. at 1278. The Federal Circuit reasoned that, if generics do not intend to infringe, they should not request, or accept, approval to market a product within the scope of patented claims. Id. at 1279.

The District Court rejected Eton's reliance on two cases decided before Sunovian where each court examined ANDA materials other than the ANDA specification. Exela, No. 20-cv-365, at 4–5. The court in each case only did so because the ANDA specification did not speak to the claim limitation at issue. Id. at 5. Similarly, in Ferring B.V. v. Watson Labs., Inc., where the ANDA specification itself did not resolve the infringement question, the Federal Circuit endorsed an infringement analysis based on all evidence relevant to what the generic application was likely to bring to the market. 764 F.3d 1401 (Fed. Cir. 2014). On the other hand, in Par Pharma, Inc. v. Hospira, Inc., the Federal Circuit looked no further than the ANDA specification because it was not silent as to whether the generic's product fell within the scope of the patent claims at issue. 835 F. App'x 578, 586 (Fed. Cir. 2020).

The District Court held that Dr. Baertschi's non-infringement opinions were based on a legally erroneous premise and excluded them. Exela, No. 20-cv-365, at 6.


Exela reinforces the Federal Circuit's decision in Sunovian that ANDA product infringement is determined by comparing the ANDA specification to the asserted claims and that the ANDA specification, and not other materials such as biobatch data, controls when it speaks to the claim limitations. Experts and parties should therefore be careful when preparing expert testimony opining on non-infringement positions relating to ANDAs. If the ANDA specification speaks to a claim limitation, then the ANDA specification controls the infringement analysis and experts may base their opinions on the ANDA specification. If the ANDA specification is silent to the claim limitation, then the expert may base their opinion on other materials.

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