CAFC Affirms ITC in Finding Brita ‘Gravity Flow’ Patent Invalid for Lacking Written Description, Enablement

The U.S. Court of Appeals for the Federal Circuit (CAFC) on Wednesday issued a precedential decision in Brita LP v. International Trade Commission, affirming the International Trade Commission’s (ITC’s) finding that claims of a Brita patent for a water filtration system are invalid for lacking adequate written description and lack of enablement. The opinion was authored by Circuit Judge Prost and joined by Judges Reyna and Chen.

The case originated from a complaint Brita LP filed at the ITCunder Section 337 of the Tariff Act, alleging that Vestergaard Frandsen Inc., Kaz USA, Inc., and Helen of Troy Limited infringed its U.S. Patent No. 8,167,141. While an Administrative Law Judge (ALJ) initially found a violation, the Commission reversed the decision, finding the claims invalid, which prompted Brita’s appeal.

The ‘141 patent, titled “Gravity Flow Filter,” covers filtration systems using gravity to pass water through filter media. The dispute centered on claim 1, which recites a “filter media including at least activated carbon and a lead scavenger” that achieves a “Filter Rate and Performance (FRAP) factor of about 350 or less.” Although the patent identified several types of filter media, such as carbon blocks and mixed media, and stated the performance criteria were “applicable to” these formats, the specification’s disclosure was more limited.

On the issue of written description, the Federal Circuit agreed with the Commission that the patent’s disclosure did not reasonably convey to a person of ordinary skill in the art that the inventors possessed the full scope of the claimed invention. The court reviewed this question of fact for substantial evidence and found it strongly supported the Commission’s conclusion.

The opinion highlighted that while the claims broadly covered any “filter media” meeting the functional FRAP limitation, the specification only described carbon block as the one type of filter capable of achieving it. All of the patent’s examples and figures depicted carbon-block filters. In contrast, the specification explicitly stated that “No mixed media filters tested met the claimed FRAP factor range due to their inability to remove particulate lead.” The patent further asserted that “[t]he formulations of gravity fed carbon blocks disclosed are unique in [their] ability to meet the required FRAP factor.”

The court found the inventors’ acknowledgment that their technology was limited to carbon blocks compelling and noted that their own testimony reinforced this conclusion. One inventor, Dr. Elizabeth Knipmeyer, testified that her group “changed technology from a granular media to a carbon block.” The panel agreed with the Commission’s finding that the inventors, by their own admission in the patent, were only in possession of a filter that used carbon blocks.

Brita argued that because other filter media types were known in the art, the detailed description of carbon-block embodiments was sufficient to show possession of an invention applicable to all known filter types. The court rejected this, stating that the ultimate effect of adjusting known variables to meet the previously unknown FRAP equation was unpredictable. “Brita cannot use the knowledge of a skilled artisan to make up for the specification’s lack of disclosure as to non-carbon-block filters that can meet the claimed FRAP factor,” the court wrote.

Separately, the Federal Circuit affirmed the Commission’s determination that the claims were invalid for lack of enablement. Applying the standard from Amgen Inc. v. Sanofi, the court agreed that the specification failed to enable a person skilled in the art to make and use the entire class of the invention without undue experimentation. The court reviewed the Commission’s analysis of the In re Wands factors and found no reversible error.

The evidence showed that making and using non-carbon-block filters that met the claim requirements would require undue experimentation. The ‘141 patent provided no “road map” for how other filter types could achieve the required FRAP value. Instead, it described specific problems with other media and characterized its own carbon-block formulations as “unique.”

Brita contended that the art was highly predictable, but the court disagreed, citing both testimony and the patent itself, which acknowledged the complex and interrelated nature of the variables in the FRAP equation. Changing one variable could unpredictably alter the others and the final FRAP value, according to the Commission. Dr. Knipmeyer’s testimony that creating non-carbon-block embodiments would involve “new technology” further undercut Brita’s position.

Citing the decision in Genentech, Inc. v. Novo Nordisk A/S, “it is the specification, not the knowledge of one skilled in the art, that must supply the novel aspects of an invention in order to constitute adequate enablement,” the court stated. The court concluded that substantial evidence supported the finding of non-enablement, as the patent failed to teach how to practice the full scope of the claims.

The Federal Circuit declined to address the Commission’s alternative finding of indefiniteness, ultimately affirming the final determination of no violation of section 337 for lack of written description and lack of enablement.