Abraxis (AstraZeneca) v. Mayne (Fed. Cir. 2006).
Mayne attempted to around Abrxis’s anesthetic formulation patent covering DIPRIVAN. The district court, however, found that Mayne’s product still infringed, both directly and under the doctrine of equivalents, despite its replacement of EDTA (“edetate”) with DTPA.
On appeal, the CAFC reversed the direct infringement based on claim construction, but agreed that there was infringement under the DOE.
Infringement under the doctrine of equivalents is reviewed for clear error. To infringe under the DOE, the accused device must perform “substantially the same function in substantially the same way to obtain the same result” as the patented invention.
During the design-around, the defendant had attempted to identically match the characteristics and stability function of the Abraxis product. They eventually chose the DTPA replacement because it is “structurally similar to edetate, [and therefore] product stability is predicted to be unaffected.”
Even so, the defendant argued under the modern DOE exclusion principle that the patentee’s use of the “restrictive term edetate,” rather than a more generic term, precluded extension of equivalents coverage as a matter of law. The CAFC disagreed, finding that equivalents could be asserted because the inventors “did not clearly disavow” broader coverage.
There is no evidence that the patentees made a clear and unmistakable surrender of other polyaminocarboxylates, or calcium trisodium DTPA in particular, during prosecution.
Furthermore, because the use of DTPA was admittedly unforeseeable, it is proper to extend DOE.
The defendant also asserted that DOE should not be extended to cover DTPA because Mayne was able to obtain a patent to cover that modification. The CAFC did not buy that argument either. As noted above, the patent shows that the equivalent was unforeseeable at the time of the invention (weighing in favor of DOE). In addition, the district court’s fact finding of “substantial evidence of equivalence” withstood CAFC scrutiny.
“n a field like this, you can’t say for sure what the results will be of substituting agent X for Y, you can only say that some subsitutions are likely to have a better chance of working than others – you won’t know until you try it what the results will be.”
Exactly — biotech is an “unpredictable” art (or has been treated that way for some time) so typically patentees get claims which cover what they’ve actually reduced to practice.
And this case supports the proposition that prosecutors shouldn’t try to literally claim any more than that. By precluding any argument about what other chelating agents had been demonstrated as enabled, the patentee here was able to get a claim which covered (under the DOE) just about every functionally equivalent chelator under the sun.
I agree with you that the number one reason — perhaps the only VALID reason — the case came down the way it did is because of the admission the defendents made during prosecution of their own patent.
And now I’m curious — is that a new development? Has a defendent’s prosecution of its own unrelated patent been used to justify a broader claim construction of a patent asserted against them?
Malcolm
“Do you agree that the way you describe DTPA, it is simply unfathomable that one of skill in the art could not have foreseen its utilility as a substitute chelating agent for EDTA in the patentee’s formulation?”
Good grief no (have I understaood your question correctly? Too many negatives in there…). It’s very forseeable: using DPTA in place of EDTA in virtually any situation is, in the UK parlance “obviously worth a try”, which won’t necessarily equal US obvious, but may do so.
What makes this case a bit of a hash is that it was nonetheless “admittedly unforseeable” before the district court (and thus the CAFC didn’t review this) – presumably for the rational reason that if they said it was in fact forseeable, their own patent would most likely have been invalid for being obvious.
So they were stuck with the consequences of their own admission.
The only question about foreseeability here is that, given a PHOSITA would have thought it “obviously worth a try” to swap DPTA for EDTA (cf Rao’s statistics and examples), what is the level of predictability required to convert this into US-style obviousness. In a field like this, you can’t say for sure what the results will be of substituting agent X for Y, you can only say that some subsitutions are likely to have a better chance of working than others – you won’t know until you try it what the results will be.
So one can say “I forsee DPTA working” – ie. predict that it will. But what if your prediction is wrong? I don’t think there is much caselaw on exactly what is meant by “forseeability”, is there?
The patent in question, US 5,714,520: Propofol compostion containing edetate, describes edetate as follows:
“We then investigated the possible use of other agents which might have the action that we sought. We unexpectedly found that edetate, which is not regarded as a broad spectrum antimicrobial agent was the only agent that would meet our requirements. As referred to above, edetate as the sodium salt is mentioned in our UK Patent 1472793 as a possible metal ion sequestering agent. Sodium edetate is included in two of the many Cremophor-containing examples of that Patent….
By the term “edetate” we mean ethylenediaminetetraacetic acid (EDTA) and derivatives thereof, for example the disodium derivative is known as disodium edetate. In general suitable edetates of this invention are those salts having lower affinity for EDTA than calcium. Particular derivatives of use in the present invention include trisodium edetate, tetrasodium edetate and disodium calcium edetate. The nature of the edetate is not critical, provided that it fulfils the function of preventing significant growth of microorganisms for at least 24 hours in the event of adventitious extrinsic contamination (e.g. preferably no more than 10-fold increase following a low level of extrinsic contamination, such as 10-10.sup.3 colony forming units, at temperatures in the range of 20.degree.-25.degree. C.). As can be seen from the experimental section, sodium calcium edetate has some advantages over other additives but disodium edetate is exceptional. Accordingly, most preferably the edetate is disodium edetate.”
This patent application was filed March 22, 1995.
It is interesting to note that there are 3494 issued patents that mention EDTA and DTPA together, e.g., US 3,932,657, Liposome encapsulation of chelating agents, issued January 13, 1976, clearly claims their equivalency. (Claim 6. The method in accordance with claim 4 wherein said polyaminopolycarboxylic acid chelating agent is chosen from the group consisting of EDTA and DTPA.)
I am very much surprised that the patent drafters for Zeneca Limited (London, GB) didn’t consider it worthwhile to mention and claim DTPA or any other polyaminopolycarboxylic acid chelating agents such as the most studied common chelators: NTA, IDA, MIDA, TTHA, DOTA, NOTA and TETA.
Rao
http://www.biopatentlaw.com
Slonecker
“Is not the proper construction of a claim a predicate to the application of the DOE?”
What I think happened here is that the Federal Circuit “properly construed the claim”, then applied the district court’s assemblage of facts/testimony to the DOE issue and their construction of “edetate”, upholding the lower court’s finding wrt to infringement under the DOE while partially substituting their own rationale for the finding. At least, that’s what appears to have happened.
Luke
“So the infringers here hardly “designed” “around” the patent at all … it certainly hardly amounts to “innovation” in any non-obvious sense.”
Whether a design-around would be patentable over the claim at issue has never been the test for determining whether the design-around falls with the scope of equivalents to the claim.
Claiming DTPA is unrelated to EDTA just shows you are not a chemist!
Whatever, man.
I’m just trying to take the Federal Circuit’s opinion at face value.
Do you agree that the way you describe DTPA, it is simply unfathomable that one of skill in the art could not have foreseen its utilility as a substitute chelating agent for EDTA in the patentee’s formulation?
Malcolm wrote:
‘But here the patentee (with the Examiner’s help) had already carved out his/her “equivalents” with the relatively broad term “edetate”‘
Edetate is an extremely narrow term. For instance one can construct the following series from narrow to broad in terms of the patent at hand:
disodium edetate,
edetates (ie. salts of EDTA),
polyaminopolycarboxylates with ethylene linkers between the amino groups (eg. DPTA),
polyaminopolycarboxylates with straight chain alkylene linkers between the amino groups,
polyaminopolycarboxylates with straight chain aliphatic linkers between the amino groups,
polyaminopolycarboxylates with aliphatic linkers between the amino groups,
polyaminopolycarboxylates,
aminocarboxylates,
carboxylates,
chelating agents,
antimocrobial agents
As can be seen, EDTA is only the first step above unique species, the narrowest possible characterization, and DPTA just one step removed from that, of a 10 step sequence to get to the aimed-for antimicrobial agent.
And ‘[t]he lesson of the case, it seems, is that competitors seeking to design around a claim like the one at issue in this case should NOT attempt to develop or look for **unrelated** compounds with the desirable properties, but instead must stick with known compounds which were known to have the desired properties at the time the claim was drafted’.
Claiming DTPA is unrelated to EDTA just shows you are not a chemist! See the above classification scheme, and also note the careful distinction the court, correctly, draws between derivatives in the synthetic sense, and derivatives in the structural sense. DTPA is clearly structurally related to EDTA – they are both ethylenepolyaminepolycarboxylates. One has a single ethylenediamine unit, the other two; DTPA is the next highest homologue of EDTA in the series (the next in the series being triethylenetetraaminehexaacetic acid, as Nyffeler alluded to above) – but DPTA is only a “derivative” of EDTA in the structural sense, not the synthetic sense. A “blackboard” relationship, as one counsel put it. As a general statement, homologues can usually be expected to have similar properties, so finding these two homologues to be “equivalents” shouldn’t come as a surprise (of course, homologues are usually obvious from one another…)
So the infringers here hardly “designed” “around” the patent at all; they simply looked at the active ingredient and substituted it with its nearest homologue in the ethylenepolyaminepolyacetic acid series. Not a lot of thinking required there; it certainly hardly amounts to “innovation” in any non-obvious sense.
As for Michael Slonecker’s point – I agree there would appear to be an insuperable problem here. Markman rears its ugly head once more.
“In that case, isn’t the problem with obviousness, or even novelty, and not the DOE (unless we are talking about some kind of Formstein defence to the DOE).”
It’s a seamless web, to some extent. The DOE can’t capture subject matter that would not have been patentable in the first place (e.g., if the claim would have been obvious).
My difficulty with this decision boils down to the fact that the infringers in this case took a very reasonable approach: (1) read the claims and (2) find a non-edetate compound to replace EDTA in the formulation.
Finding that a non-edetate compound is “equivalent” to an edetate is, in my opinion, not terribly different than finding that 49% is “equivalent” to “a majority.” The doctrine shouldn’t work that way.
In fact, I would be more comfortable with a finding of an equivalent if the claim had recited “EDTA” and the infringer had made some minor modification to EDTA to get around the claim. That makes sense and seems fair.
But here the patentee (with the Examiner’s help) had already carved out his/her “equivalents” with the relatively broad term “edetate.”
The lesson of the case, it seems, is that competitors seeking to design around a claim like the one at issue in this case should NOT attempt to develop or look for **unrelated** compounds with the desirable properties, but instead must stick with known compounds which were known to have the desired properties at the time the claim was drafted.
So much for encouraging innovation …
I still keep coming back to the question “How can a DOE issue be decided when the actual claim has not as yet been decided?” Is not the proper construction of a claim a predicate to the application of the DOE?
Quoth Calvin:
“Let’s say a Response was filed and asserted patentability over prior art by arguing that the claimed embodiment was unique and the only operational embodiment because it used EDTA. Claim was not amended — it was limited to EDTA to begin with. Whould that scenario entitle patentee to equivalents? Arguably not. How is the situation different if the same assertions were made in the specification?”
Well, that depends on what you and/or the inventor mean by “unique”. Nobody short of omniscience can argue that their result is unique, full-stop – it can only be unique as far as they know. Which brings us back to forseeability. The inventor isn’t a PHOSITA, what they know and can forsee isn’t what the PHOSITA knows and can forsee. If “uniqueness” has been argued, it can only be in context, in which case whether equivalents may be in play is indeed arguable, depending on the facts. One factual consideration is that argument with the examiner is often a two-way process, and what may be meant by for example “unique”, after to-ing and fro-ing with an examiner, may be quite different from what is meant by “unique” as printed in the initial specification, and indeed, the final printed patent (one reason why many juristictions are keen to have specifications heavily modified to bring them into conformity with the claimed scope). This issue is particularly relevant if the specification has been translated by an often considerably-less-than-skilled-in-the-art-translator…
“The point is to ascertain exactly what was said to the public and what the public was entitled to believe was available”. One must remember that the public isn’t entitled to just believe every statement an inventor makes, on “uniqueness” or any other issue, whether in a specification, or argument, just because they said so. It is just one more piece of data to add to an already very complicated equation. One reason other jurisdictions ditch the entire file-wrapper estoppel bsiness completely.
And Malcolm:
“[I]t is remarkable that the term “edetate” was used in the claim and not “Mg2+/Ca2+ chelating agent” … remarkable, that is, unless the patentee was forced to argue that there was something special about “edetate and its derivatives (i.e., salts” … in which case it is plainly wrong and unfair to capture non-edetate compounds as equivalents”.
In that case, isn’t the problem with obviousness, or even novelty, and not the DOE (unless we are talking about some kind of Formstein defence to the DOE).
Should be “Parklane Hosiery” not “Parkland”. Doh.
I think if the attorneys for the defense had done a more thorough job in the district court of arguing that DTPA was NOT an “edetate,” the case might have turned out differently (one of the footnotes suggests there was some waiver of issues on appeal).
The fact that anybody could get a patent on an antimicrobial composition merely by adding EDTA is somewhat of a shock in the first place as EDTA has been used as an antimicrobial agent in biological solutions for a long long time. For most of that time, there has been no mystery about how it works.
So again: it is remarkable that the term “edetate” was used in the claim and not “Mg2+/Ca2+ chelating agent” … remarkable, that is, unless the patentee was forced to argue that there was something special about “edetate and its derivatives (i.e., salts” … in which case it is plainly wrong and unfair to capture non-edetate compounds as equivalents.
(Once again, with quotation marks)
Nyffeller:
“A ruling on the claim construction for a patent, as far as I understand it, would be legal precedent from then on, just like the patent and file wrapper.”
Nope. See, e.g., Parkland Hosiery, Blonder Tongue, other cases re offensive estoppel and the due process issues raised. Unless there is privity between the first and second alleged infringers, a prior claim construction is not binding on the second alleged infringer.
Courts are free to give the earlier constructions deference … but that’s it, unless there is privity.
Nyffeller
A ruling on the claim construction for a patent, as far as I understand it, would be legal precedent from then on, just like the patent and file wrapper.
Nope. See, e.g., Parkland Hosiery, Blonder Tongue, other cases re offensive estoppel and the due process issues raised. Unless there is privity between the first and second alleged infringers, a prior claim construction is not binding on the second alleged infringer.
Courts are free to give the earlier constructions deference … but that’s it, unless there is privity.
Let’s say a Response was filed and asserted patentability over prior art by arguing that the claimed embodiment was unique and the only operational embodiment because it used EDTA. Claim was not amended — it was limited to EDTA to begin with. Whould that scenario entitle patentee to equivalents? Arguably not. How is the situation different if the same assertions were made in the specification?
My prior statement absolutely did not imply that “a patent can only have equivalents if the inevntors haven’t tested and found any working examples.” That’s not the point at all. The point is to ascertain exactly what was said to the public and what the public was entitled to believe was available.
Calvin wrote:
“When a patent states that only one embodiment worked and claims that specific embodiment, public is on notice that equivalents, including obvious ones, are not within the scope of the patent”.
That’s a new statement of law to me. Would you care to back that up with some caselaw? You position would appear to imply that a patent can only have equivalents if the inevntors haven’t tested and found any working examples!
To say that “[t]he question is whether the patent gave public notice that equivalents of EDTA were outside of the scope of the patent” can’t possibly be right. If this were the case, every patent would have to define (give public notice)what equivalents are allowed (ie. not be utside the scpoe), which would mean they would no longer be equivalents, since they would have been disclosed.
As an aside, as a chemist, I am glad somebody on the CAFC other than Judge Newman has finally wriiten an opinion that, chemically speaking, makes complete sense – only a non-chemist could argue for the “derivative” definition the district court employed, and these two ligands are clearly not identical (no literal infringment) but they are very much equivalents in the vast majority of possible chemical reactions they can involve themselves in (therefore potentially equivalent under the DOE).
To me “whether DTPA is an obvious substitution for EDTA” is cetainly one of the questions that needs to be answered here. I say “potentially equivalent” one “one of the questions” because of the foreseability issue here that wasn’t very well argued it seems.
Luke Ueda-Sarson
The question is not whether DTPA is an obvious substitution for EDTA. The question is whether the patent gave public notice that equivalents of EDTA were outside of the scope of the patent. When a patent states that only one embodiment worked and claims that specific embodiment, public is on notice that equivalents, including obvious ones, are not within the scope of the patent.
As to the post by Mr. Slonecker, the reason for the different standards of review for questions of law and question of fact have to do with upon whom the decisions impact. Claim construction is a question of law because the construction determined by the judge can serve as legal precedence in certain situations involving future infringers. A ruling on the claim construction for a patent, as far as I understand it, would be legal precedent from then on, just like the patent and file wrapper. Doctrine of equivalents is a question of fact for the trier of fact to determine because it is dependent upon the facts that occurred between the two parties of the case.
The simplest explanation given for this I have seen somewhere (I can’t find the reference right now; I apologize) involves a car accident. The question of law is whether it is illegal for someone driving a car to run a red light. The question of fact would be whether the driver ran the light before he hit the other car. The question of fact involves a statute that governs everyone, whereas the question of fact only applies to the parties at suit.
If you take a look at the chemical structures of EDTA (edetate is an alternative name) and DTPA, you would see that the two are obviously related.
link to en.wikipedia.org
link to en.wikipedia.org
While it is true that the patent did use the term “edetate,” DTPA is nothing more than a not-so-subtle design-around of EDTA. If you can’t see the obvious resemblance, ask any chemist with at least a bachelor’s degree to explain it. The only way this would be foreseeable would be the first time some clever patent attorney tried to use it to get around a patent. Now that this case has been handed down, you would be wise to include EDTA, DTPA, and even perhaps triethylene tetraamine hexaacetic acid, if such a thing is known or even used.
Let me see if I have this:
Proper claim construction is a question of law subject to de novo review.
Application of the doctrine of equivalents is a question of fact subject to a clear error standard.
I am having a most difficult time reconciling the former with the latter in that it seems to me one needs to understand the proper construction of claim(s) before a court before equivalents can be thoughfully determined.
“Oy” is right. Oy Vey.
How can one ignore limiting statements in the specification which is a part of the prosecution history? I vote for an en banc re-write.
Oy.
EDTA is known in the art as a “chelating agent.” These chemicals trap certain ions (particularly Mg2+) and effectively remove them from solutions, thereby inhibiting undesirable events which require those ions from taking place (i.e., enzyme-catalzyed degradation reactions, microbrial growth, etc.) Again, this is ancient knowledge.
Before this case, I would have guessed that the relevant test for these facts is whether the patentee could have drafted a claim which covered other chelating agents with the properties of EDTA which had been determined (by the inventors) to achieve the desired results when combined with the other chemicals recited in the claims.
Could the inventors here have done that? Of course. They could have simply recited a “magnesium chelator” with “property blah blah.”
But it appears now that this test for equivalency only has teeth *if the claim was amended* during prosecution (and even then…?)
By the logic of this case, *assuming that the claim term in question has not been amended* anytime an applicant recites a specific chemical in a formulation, he will be entitled under the doctrine to claim scope which includes ANY AND ALL formulations which substitute compounds which were not recognized as functionally equivalent at the time of filing.
In other words, the applicant who seeks to draft a claim with the broadest scope (including DOE scope) may be best-served by presenting to the PTO from the very beginning (1) a narrow species claim, which recites SPECIFIC chemicals and (2) a specification which does not make too big of a deal about those specific. In this way (and only in this way) can the Applicant avoid invoking Festo and, according to this Federal Circuit case, capture “unforseeable” functionally equivalent compositions.
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