What is patent
claim construction
essentially about?
Claim 1 of the patent in issue
recited, in part, “A pharmaceutical
composition comprising… (a) at
least one water-soluble therapeutic
agent…in a therapeutically effective
total amount constituting about 30%
to about 90% by weight…”. Further,
claim 11 recited a composition “that
consists essentially of the therapeutic
agent and the buffering agent”.

In his reasons Justice Burley made
light work of the construction of
“essentially”. Whilst essentially
is a relative term, it was given its
ordinary meaning of “mostly”,
but not exclusively, which was
consistent with its use in the claims
and the specification. The terms
“therapeutic agent” and “about”
required a little more consideration.

The claims encompassed a
pharmaceutically active parent
compound (in the form of a prodrug)
or a sodium salt of the parent
compound. Because the sodium
salt of the parent compound is
heavier than the parent compound
alone, it needed to be determined
if the claimed weight range of the
“therapeutic agent” related to the
parent compound only or could also
relate to the salt. With reference
to the specification, Justice Burley
determined that either the sodium
salt or the parent compound alone
can be regarded as therapeutic
agents even though only the parent
compound exerts a therapeutic
effect. Hence a composition having
31% of the sodium salt would fall
within the claimed range of 30%
to 90% for the “therapeutic agent”
even though the percentage (by
weight) of the pharmaceutically
active component (i.e. the parent
compound) was less than 30%
when the weight of the sodium is
disregarded. The term “about”, like “essentially”,
is a relative term. In the context
of the patent claims it was used
to define the weight ranges of
the various components of the
composition. Justice Burley was
asked to determine if “about”
should allow a 5% margin of error
(i.e. “to 90%” would become “to
94.5%”) or should only allow for
rounding to the nearest number (i.e.

“to 90%” becomes “to 90.49%”).

It was agreed by both sides that
the term “about” was not a term in
the precise field of pharmaceutical
sciences and therefore was “mostly
avoided”. Consequently, the experts
assisting the court struggled to
give relevant meaning to the term.

Justice Burley turned to the ordinary
English meaning of the term
(“near; close to”) and the use of the
term in the patent specification.

Notably, the term was not defined
in the specification. Therefore, the
applicants asserted that specific
examples and disclosures in the
specification supported the broader
5% margin of error. However,
Justice Burley did not agree that the
passages cited by the applicants
clearly supported the broader range.

He further stated that it could not be
the intention of the inventors for the
meaning of the word “about” to be
mined from obscure passages in the
specification, nor could
such obscurity provide
sound basis for construing a
claim. Ultimately, the term “about”
was narrowly construed to allow for
rounding errors only (i.e. “to 90%”
was considered as “to 90.49%”)
In comparison the term “about”
was briefly considered in Meat &
Livestock Australia Limited v Cargill,
Inc [2018] FCA 51, also in relation
to a claimed numerical range. Here
Justice Beach construed “about”
as providing a 10% margin of error.

Importantly, unlike the present case,
the specification clearly defined
“about” as meaning ±10%.

While it is common to use relative
or imprecise terminology in claims,
this should be done with caution.

Typically, these terms are used as
a fallback allowing extension of the
claimed boundaries, which may
provide utility if a potential infringing
act or product arises. However, as
exemplified with the term “about”
this extension of the boundaries
may be limited and may vary
depending on the technical field
of the invention.

3 Dr Leigh Guerin | Senior Associate
BMedPharmBiotech(1st Class Hons) PhD MIPLaw
1 Pharmacia LLC v Juno Pharmaceuticals Pty Ltd [2022] FCA 92
Inspire March 2022
Anyone familiar with patents in the life sciences space
will be familiar with patent claims that use terminology
such as “essentially”, “therapeutic agent” and “about”.

The familiarity of such terms means that they are
often recited without much consideration. However,
their meaning was in issue in the recent decision in
Pharmacia LLC v Juno Pharmaceuticals Pty Ltd. 1
leigh.guerin@pof.com.au