The United States Court of Appeals has held two patents owned by Ajinomoto Co. to be invalid for failing to comply with the ‘best mode’ requirement.
US patent law states that:
The specification...shall set forth the best mode contemplated by the inventor of carrying out his invention. (35 USC § 112)
This means that an applicant must disclose the optimum way of carrying out his invention, the purpose being that the applicant should not be able to gain protection for his invention whilst at the same time concealing the best mode of operation.
Ajinomoto’s patents(numbers 5,827,698 and 6,040,160) relate to methods for improved production of lysine using genetically engineered E.coli bacteria. The ‘698 patent includes mutations in the lysine decarboxylase gene and the ‘160 patent discloses the use of at least one of two mutations in the gene coding for a crucial enzyme in lysine production.
In 2006, Ajinomoto commenced proceedings before the International Trade Commission (ITC) to prevent importation into the USA of allegedly infringing products. However, the ITC found no infringement on the basis that the patents were invalid for multiple violations of the best mode requirement.
Patent ‘698 describes a process for producing a mutant host strain of E.coli, a sample of which was deposited at an international depository. However, the actual strain used had two further, undisclosed, genetic alterations. In the case of ‘160, two host strains were disclosed but supported by fictitious data; the preferred host strain was concealed. The ITC held that, to satisfy the best mode requirement, the inventor must disclose the preferred embodiment of the invention as defined by the claims. In failing to do this, Ajinomoto’s patents were invalid.
After appeal, this decision has been upheld by the United States Court of Appeals for the Federal Circuit. In their appeal Ajinomoto did not dispute their failure to disclose, but rather maintained that it was not necessary to disclose these details in order to satisfy the best mode requirement.
Ajinomoto asserted that disclosure conflicted with the ‘two-way street’ of the best mode obligation, arguing that since it cannot exclude others from cultivating lysine-producing strains without the claimed mutations, its best mode obligations extend only to those mutations and not to the host strain. The court, however, held that, just as infringement requires all claim limitations to be present (in this case including ‘cultivating a bacterium’), so too does the best mode requirement.
Ajinomoto also contended that they had satisfied the best mode requirement in ‘698 by depositing a strain of E.coli. However, as the deposited strain had never been used to practise the invention and they had concealed two additional mutations, the deposit did not enable one skilled in the art to practise the preferred embodiment and thus concealed the best mode.
It is clear from this case that the scope of ‘best mode’ must be taken to encompass the whole of the claimed invention rather than just the ‘inventive aspects’, in order that one skilled in the art is able to replicate the preferred embodiment.
3 June 2010