Obviousness: Suture Storage Package
Conventional packaging of polyglycolic acid sutures is unsatisfactory because
if stored the sutures disintegrate too quickly when subsequently used in the
human body. Research by the applicant disclosed the cause of the problem.
The sutures must be thoroughly dried and kept in a dessicated state in hermit-
ically sealed containers which have themselves been dessicated before use and
which are completely impermeable to moisture.
Final Action: Modified.
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This decision deals with a request for review by the Commissioner of
Patents of the Examiner's Final Action dated December 8, 1975, on applica-
tion 086,315 (Class 217-36). The application was filed on June 23,
1970, in the name of Arthur Glick, and as entitled "Storage Stable Package
For Absorbable Polyglycolic Acid Sutures, And Process For Preparing Same."
The Patent Appeal Board conducted a Hearing on November 23, 1977, at which
Messrs. D. Sim, Q.C. and I Brameld represented the applicant. Also present were
Dr. J. Richards and Mr. J. McPherson, representatives of American Cyanamide.
This application relates to the packaging of polyglycolic acid sutures
so that the sutures are stable during storage. This is accomplished by desicc-
ating sutures and container prior to sealing. Figure 1 of the application
which illustrates the invention is shown below:
(See formula 1)
In the Final Action the examiner rejected claims 1, 2, 4, 5, 6, 7 and 8 for
failing to define any patentable subject matter because of common knowledge
and the following reference:
U.S. Patent 3,297,033 Jan. 10, 1967 Schmitt
The Schmitt patent, which is owned by the applicant company, describes
a synthetic absorbable surgical suture of polyhydroxyacetic acid esters and
absorbable surgical sponges or gauze of the same material. Monofilaments of
the fiber are attached to surgical needles, sealed in transparent polyester-
polyethylene packets, and dry sterilized by permeating the seal line pith
ethylene oxide. These sutures may be stored in a conditioning liquid such
as alcohol-water mixtures.
In the Final Action the examiner stated (in part):
The applicant, in the rejected claims, is predicating patentability
on the broad idea of packaging polyglycolic acid sutures in a
moisture free atmosphere. Accordingly claims 1 and 2 are directed
to a method of packaging as is claim 4. Claims 5 to 8 are directed
to a package. The claims under rejection are very broad and in
reality merely define an idea that may have floated through some-
one's mind. Applicant, in fact, contends that his invention lies
in the discovery or realization that even traces of water will
seriously affect the suture.
It is the Examiner's contention that this is merely expected skill
to one skilled in this art. The sutures per se are known, the
fact that moisture adversely affects the sutures is well known and
conceded by the applicant. (see page 5, lines 23 to 26 of this
disclosure). It is considered to be entirely obvious that if it
is known that large amounts of water deteriorates the sutures that
smaller amounts wall also have a similar affect but perhaps to a
lesser degree. The examiner contends that the skilled artisan
would be unerringly led to this conclusion by the facts set forth
above and therefore no invention was necessary.
That being the case, and the applicant has not persuaded the exam-
iner to the contrary by his arguments, the applicant's invention
must be in a specific method of producing the moisture free package
and a specific package per se. The examiner will not allow claims
that merely set forth a package that maintains a suture in a moisture
free manner as present claim 5 now does.
The examiner, further, will not allow claims such as claims 6 to 8
herein. The gaseous contents of sealed containers have been
evacuated for years and also non-reactive gases have been used
widely. Aluminum foil packages have been in use for years and
it is further submitted that this alone is not sufficient to give
the applicant what he desires. Claims 6 to 8 are rendered obvious
by almost all of the vacuum packs available today.
In response to the Final Action the applicant amended claims 1 and 5 to 7 by
replacing them with new claims 1 to 5 and stated (in part):
The Examiner has construed the claimed invention as being
based "on the broad idea of packaging polyglycolic acid sutures
in a moisture-free atmosphere" adding that "the claims under
rejection are very broad and in reality merely define an idea
that may have floated through someone's mind". The Examiner
appears to have appreciated the point made in applicant's previous
amendment that the invention lies in the discovery or realization
that even traces of water will seriously affect the suture. How-
ever, the Examiner comes to the conclusion that this is merely
expected skill to one skilled in the art. He states that "it is
considered to be entirely obvious that if it is known that low
amounts of water deteriorates the sutures that smaller amounts
will also have a similar affect but perhaps to a lesser degree".
At this point, applicant wishes to refer to method claim 1 which
calls for the packaging of the suture in a water-vapor impervious
container and requires that "substantially all of the water is removed
from said suture and container". By contrast, former claim 5, although
referring to a water-vapor impervious container, used slightly
different language, possibly ambiguous, in regard to the freedom
from water, i.e. "water-vapor impervious container having enclosed
therein a sterile polyglycolic acid suture which is substantially
free from water". In particular, it could be alleged that "sub-
stantially free from water" is more permissive regarding the quantity
of water present than the method claim which calls for "substantially
all of the water is removed". Moreover, the method claim makes it
clear that this water is removed "from said suture and container"
whereas former claim 5 did not make it perfectly clear that both the
container and the suture are free from water. Proposed new claim 5, to
take the place of former claims 5-7, is more specific in making it
clear that absorbed moisture has been removed from the suture and from
the (interior of) the container. Furthermore, proposed new claim 1
has been restricted in the interests of defining the invention more
explicitly so that it now covers only the subject matters of claims
2 and 3. In other words, it still constitutes the necessary broad
claim 1 to satisfy Rule 60 but it does not go beyond what is claimed
separately in claims 2 and 3.
The point which applicant wishes to emphasize is that conventional
dry packaging techniques for sutures are not sufficient in the case
of polyglycolic acid sutures to prevent deterioration leading ultimate-
ly to unsatisfactory in vivo strengths. The whole argument has been
set out clearly by applicant's expert, Dr. James Beverley McPherson,
in affidavits filed in connection with the opposition by Ethicon Inc. to
the grant of letters patent on applicant's corresponding U.K.
specification Serial No. 1,263,217. Since portions of Dr. McPherson's
affidavit evidence related to specific allegations in declarations
filed by the U.K. opponent, there are quoted hereinafter only the
portions of Dr. McPherson's affidavit which seem to be relevant to
the present proceedings. If the Commissioner finds it necessary or
desirable, a further affidavit could be obtained from Dr. McPherson
specifically for the purposes of the present Canadian application.
A further response submitted October 21, 1977, was accompanied by an affidavit
made by Dr. J. E. McPherson. Of the newly submitted claims 1 to 10, we in-
formed the applicant prior to the Hearing that claims 1 to 4 and 7 to 10 were
acceptable. They cover a particular process for preparing the packages
and certain specific packages which we are satisfied embody patentable
features. At the Hearing, consequently, Mr. Sim limited his remarks
to new claims 5 and 6. These claims are as follows:
5. A storage stable packaged polyglycolic acid suture
comprising an air-tight sealed water-vapour impervious
container, and within the container a dry, sterile poly-
glycolic acid suture, the gaseous contents of the
container having been evacuated or replaced by a dry
gaseous atmosphere non-reactive with polyglycolic acid,
and the suture and interior of the container being
substantially free of all absorbed moisture.
6. A storage stable, packaged polyglycolic acid suture
according to claim 5 wherein said container is rendered
moisture vapor impervious through the use of aluminum
foil.
The issue to be determined is whether these claims represent a patentable
advance in the art.
Claims of similar scope were rejected in the Final Action, in which the
examiner stated that they "...are very broad and in reality merely define
an idea that may have floated through someone's mind. Applicant,, in fact,
contends that his invention lies in the discovery or realization that
even traces of water will seriously affect the suture...." To support
his position the examiner argues that "sutures per se are known" and "the fact
that the moisture adversely affects the sutures is well known and con-
ceded by the applicant (see page 5, lines 23 to 26 of the disclosure)."
He adds that "it is considered to be entirely obvious that if it is known
that large amounts of water deteriorates the sutures that smaller amounts
will also have a similar effect but perhaps to a lesser degree."
Dealing with these statements at the Hearing Mr. Sim agreed that "sutures
per se are known." He disagreed with the allegation that the applicant con-
cedes it was known that moisture adversely affects sutures. Page 5 of the
disclosure (at lines 23 to 26) reads "it is known that when polyglycolic acid
is contacted with water and particularly at high temperatures, that degradation
of polymer will occur quite rapidly." According to the applicant this only
acknowledges that degradation will occur in contact with water, particularly
at higher temperatures but gives no indication as to what would be the effect
of "moisture" at normal temperatures. Using gelatine as an example, Mr. Sim
pointed out that it would deteriorate in boiling water, but it is stable to
ambient moisture at normal temperatures.
Another issue raised by the examiner was that since it is known that large
amounts of water affects these sutures, it would be obvious that smaller
amounts will have a similar effect to a lesser degree. He contends all the
applicant has done is to store the suture in a moisture free atmosphere.
Responding to this objection, Mr. Sim stressed that conventional dry packaging
techniques were not satisfactory for polyglycolic acid sutures, since con-
ventional dry storage results in unsatisfactory in-vivo strength of the sutures
if used after a relatively short storage period on the shelf. To support
his position he referred to the affidavit of Dr. McPherson, which accompanied
one of the responses to the Final Action. This affidavit sets out the circum-
stances in which the cause of poor in-vivo strengths were determined, and the
subsequent steps taken to overcome the problem.
Upon reviewing suture development as outlined in Dr. McPherson's affidavit,
we note that applicant's U.S. patent, 3,297,033 (Schmitt) represents the first
synthetic surgically acceptable absorbable suture. This suture possesses
superior properties to conventional catgut. Initially it was stored in the
conventional dry packaging system used for other non-absorbable sutures of
cotton, linen, silk, etc. It was found that polyglycolic sutures stored
for long periods of time had not suffered any significant loss in initial
strength and had the appearance of being storage stable on tensile testing.
However, animal implants revealed that the in-vivo strength deteriorated
rapidly after prolonged storage before use. About this problem the affidavit
states at page 5:
At first we were puzzled by these facts and we considered whether
the cause of the trouble might lie in oxidative degradation of the
polymer or from progressive depolymerization resulting from the
presence of small quantities of catalyst, or from the presence of
excessive quantities of unreacted glycolide, or from the presence of
glycolic acid residues or its dimer entering into transesterification
reaction with the PGA polymer chain, or autocatalytic degradation
from unidentified sources.
9. Intensive efforts in our laboratories eventually showed
that although the sutures had been packaged "dry", nevertheless
residual moisture present in the suture coupled with the moisture
vapor present in the package were the culprits.
and on page 9:
15. To secure the advantages of the present invention three
things must be achieved. One must vigorously remove absorbed mois-
ture vapor from the suture material and container interior. One must
keep the container interior and its contents in a desiccated state
before sealing the container. Finally, one must hermetically seal
the moisture vapor impermeable container.
The corresponding U.K. application was involved in opposition proceedings,
during which it was attacked for obviousness. We were provided a copy of the
Interim Decision of the U.K. Office following those proceedings, and quote
the following from page 6 of that decision:
Having considered all the evidence in this case it is my view that,
while it was generally known that PGA was liable to undergo some
degree of hydrolysis if immersed in water for a prolonged period,
it was not generally understood that this material was so sensitive
to minute amounts of water vapour absorbed from the atmosphere,
as to make it unsuitable for use in surgical sutures after storage
in conventional dry conditions. Whereas I accept the opponents'
argument that in the case of a material for use in surgery it would
be necessary to be particularly careful, I am not persuaded that it would
be obvious to one skilled in the art that PGA sutures, already described
as "dry" should be subjected to a further drying operation in order
to preserve their tensile strength. (emphasis added)
It is clear that a stored polyglycolic suture using the conventional "dry"
packaging method resulted in an unsatisfactory product. Consequently further
research was necessary to discover the cause of the problem and its solution.
This discovery appears to constitute the basis for an inventive step which pro-
duces a new and useful result. On this point we refer to the comments
of Lord Simmons in Raleigh Cycle vs H. Miller (1948) R.P.C. vol. LXV 141
@ 148:
The patentee, having made this discovery, proceeded to make an
article which gave effect to it. It achieved under the name of a
"Dynohub" an immediate commercial success, and though, I think,
no great ingenuity was needed for the construction of the article,
I am not prepared to dissent from the view taken by the Court of
Appeal that here there was subject-matter to support a patent.
The discovery was the inventive step which gave to the invention
the necessary merit. [underlining added]
Similarly in Continental Soya vs Short Milling 1942 S.C.R. 187 @190 the
Supreme Court said:
The distinction between discovery and invention must, of course,
be borne in mind. The relevant principle, in my opinion, is
stated in the treatise on Patents and Inventions by Lord Justice
Luxmoore, H. Fletcher Moulton and A.W. Bowyer in the 2nd edition
of Halsbury, at p. 591:
The difference between discovery and invention has been fre-
quently emphasized, and it has been laid down that a patent
cannot be obtained for a discovery in the strict sense. If,
however, the patented article or process has not actually
been anticipated, so that the effect of the claims is not to
prevent anything being done which has been done or proposed
previously, the discovery which led to the patentee devising
a process of apparatus may well supply the necessary element
of invention required to support a patent. This is certainly
the case if it can be shown that, apart from the discovery,
there would have been no apparent reason for making any variation
in the former practice.
We will now summarize the factors which can be considered as known with
respect to polyglycolic acid sutures prior to the applicant's research:
It is absorbable in body fluids over a period of time.
It degrades when exposed to water, particularly water at high
temperatures.
It loses in-vivo strength if used after storage in conventional dry
packages.
Applicants cited U.S. Patent 3,297,033 recommended storage in an
alcohol-water mixture.
As for catgut sutures, the following properties are known:
They are absorbed in body fluids over a period of time.
They degrade more rapidly when exposed to water, particularly at
high temperatures.
When packaged in an alcohol solution containing water it is stable.
The applicant discovered that removal of minute traces of moisture normally
present in the suture, and from the atmosphere inside the package, is necessary
to obtain a product which is stable when stored. In our view this is not
obvious, and represents an inventive step.
At the Hearing there was considerable discussion about the terminology used in
claim 5. The word "dry" in line three of this claim is meant to describe a
"moisture-free" condition and the applicant suggested it might be more accurate
to use the word "desiccated". We believe that such phrasing more accurately
reflects the applicant's invention, and should be used here, and also in claim 1.
There was also some discussion about the term "dry" used in line 4 of claim 5
to describe the gaseous atmosphere present in the section. We think that a
"dry gaseous atmosphere" could include traces of moisture, and the word
"desiccated" should be employed here as well. Another term considered was
"substantially", which is found in the last line of the claim. We believe that
the word "essentially" would reflect the true nature of the invention more
accurately.
At the Hearing Mr. Brameld agreed to a further amendment to claim 5. Since the
claim is for a product, but embodies certain process steps, it would be desir-
able to replace the process limitation by product limitations. We think such
an amendment should be made.
To summarize, we recommend that claims 2 to 4 and 7 to 10 as proposed be
accepted and that claims 1 and 5 would be accepted if amended as above. Depend-
ent claim 6 would then be acceptable, also.
Gordon Asher
Chairman
Patent Appeal Board, Canada
Having considered the prosecution of this application, the recommendations of
the Patent Appeal Board made subsequent to the Hearing, and the claims proposed
subsequent to the Final Rejection, I confirm the rejection of existing claims
1, 2, 4, 5, 6, 7 and 8 for failure to describe the invention properly. I
further direct that proposed claims 2 - 4 and 7 - 10 received on June 8,
1976, be accepted, and that claims 1, 5 and 6 be accepted if amended in
the manner called for by the Board. The applicant has six months to make
such amendment, or to appeal to the Federal Court under Section 44 of
the Patent Act.
J.H.A. Gariepy
Commissioner of Patents
Dated at Hull, Quebec
this 30th. day of December, 1977
Agent for Applicant
Smart & Biggar
70 Gloucester St.
Ottawa, 4, Ontario