Those who have filed patent applications in the US will no doubt
be familiar with the onerous duty of disclosure requirements. The
USPTO is currently proposing rule changes which could simplify the
task of determining what should and should not be disclosed, and
reduce paranoia surrounding the duty.
The Importance of Duty to Disclose
Under US patent law, applicants and other individuals associated
with the filing and prosecution of a patent application, have a
duty to disclose to the USPTO all information known to that
individual to be "material to patentability". There has
historically been a great deal of paranoia surrounding this
requirement; and with good cause. Failing to satisfy the duty of
disclosure requirements can (and on many occasions does) invalidate
The paranoia has been fed by a strong preference on the part of
US litigators to explore duty of disclosure in an attack on patent
validity. This is entirely understandable: this avenue provides an
opportunity to have a patent quashed in its entirety without having
to explore complex technical issues such as obviousness.
As a result of the paranoia, there has been a tendency to act on
the side of caution, and disclose anything and everything that
comes to light. Often, due to the times at which material is found,
this cases significant hurdles in the patent process, sometimes
requiring surrendering a granted patent just so that a document of
questionable relevance can be officially marked as
The Proposed Changes
In general terms, the USPTO is proposing a
"but-for-plus" standard in relation to determining
materiality. This follows a US Federal Circuit decision in
Therasense, Inc. v. Becton, Dickinson and Co. (Fed. Cir.
2011). In that decision, the court held that "[w]hen an
applicant fails to disclose prior art to the PTO, that prior art is
but-for material if the PTO would not have allowed a claim had it
been aware of the undisclosed prior art". In this manner, it
was held that the Court must determine, for an undisclosed piece of
prior art, whether the USPTO would have allowed a particular claim
of a patent if that piece of prior art had been disclosed.
With Therasense in mind, the USPTO has proposed the
Information is material to patentability under Therasense
(1) The Office would not allow a claim if
it were aware of the information, applying the preponderance of the
evidence standard and giving the claim its broadest reasonable
(2) The applicant engages in affirmative
egregious misconduct before the Office as to the
As a result, it would seem that the mere failure to disclose
information would not be considered material to patentability if
the claim in question is allowable even in light of that
information. That is, it would be difficult to invalidate a patent
for failure to disclose prior art that is, at a practical level, of
limited relevance to the patentability of the claims.
This, on face value, presents a fairly pragmatic approach. The
benefits are twofold: applicants are provided improved guidance as
to what need and need not be disclosed; and the USPTO should in
theory receive a reduced quantum of material from applicants (hence
improving their ability to fully consider what is indeed provided).
However, it is impossible to predict the actual effects, should the
rule change be effected.
As noted, these are proposed changes only. In the meantime,
applicants should remain diligent in informing their attorneys of
everything and anything of potential relevance to their patent
The content of this article is intended to provide a general
guide to the subject matter. Specialist advice should be sought
about your specific circumstances.
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