Can Gilead dismiss ViiV’s patent lawsuit for Biktarvy?
Zachary Silbersher
We previously blogged about ViiV Healthcare’s ($GSK) patent lawsuit against Gilead ($GILD) when the case commenced in February 2018. In the case, ViiV alleges that Gilead’s Biktarvy® infringes ViiV’s ‘385 patent. The case is heading for trial in late 2020. Before that, however, Gilead has moved to dismiss the case outright before trial. Will Gilead succeed? Whether or not Gilead’s motion is granted, the issues outlined below will likely form the crux of the dispositive issues in dispute as the case proceeds.
The principle allegations in the lawsuit are summarized in our prior blog post. Briefly, ViiV alleges that its ‘385 patent covers dolutegravir. ViiV alleges that Gilead essentially copied dolutegravir, made minor changes, and then started selling it to the public as bictegravir (brand name Biktarvy®). Since the case commenced, the Court has held a Markman hearing and construed the claims.
In light of those constructions, ViiV has abandoned its allegation that bictegravir literally infringes the asserted claims. That is another way of admitting that Gilead’s compound does not literally meet every limitation of the asserted claims of the ‘385 patent. Instead, ViiV is now relying upon the doctrine of equivalents to show infringement.
Where a defendant does not literally meet every limitation of an asserted patent claim, the plaintiff can nonetheless show infringement under the doctrine of equivalents. Under that doctrine, Gilead’s compound will be deemed infringing if the differences between bictegravir and dolutegravir are essentially insubstantial. The caselaw has delineated numerous different ways for assessing whether an accused product is insubstantially different from a patent. Yet, the bottom line is that there are few bright-line rules, and it is often a highly-factual question that, more often than not, depends upon expert opinion.
When ViiV took the position that it would be relying upon the doctrine of equivalents rather than literal infringement, Gilead moved to dismiss the case. Gilead filed its motion in July 2019, and the motion is styled as one for judgment on the pleadings. A motion for judgment on the pleadings is similar in nature to a motion to dismiss. The gravamen of Gilead’s argument is that there are no facts in dispute and there is no need to hear expert testimony because, given the Court’s claim constructions, there is no way that ViiV can legally show infringement under the doctrine of equivalents.
ViiV asserts two claims from the ’385 patent, namely, claim 2 and claim 6. Gilead’s motion addresses each claim separately and argues each should be dismissed for different reasons. We will therefore address each claim in turn, starting with claim 6, which is how Gilead’s motion proceeds.
Claim 6 from the ‘385 patent
Claim 6 is a composition-of-matter patent claim directed to dolutegravir. The structural formulas for both dolutegravir and bictegravir are depicted below.
(These images are taken from ViiV’s opposition brief to Gilead’s motion. See ViiV Healthcare Co. v. Gilead Sciences, Inc., Case No. 1:18-cv-00224-CFC-CJG (D. Del.) (Dkt. 122)).
As can be seen from the structural formulas above, dolutegravir has two fluorines attached to the molecule called a “benzyl ring” in the patent, whereas bictegravir has three fluorines attached to the benzyl ring.
ViiV is arguing that bictegravir is “equivalent” to dolutegravir despite the difference in the number of fluorines attached to the benzyl ring. In response, Gilead argues that this argument is barred by the “disclosure-dedication doctrine.” That doctrine is essentially an exception to the doctrine of equivalents. Under the disclosure-dedication doctrine, if a patent discloses a specific structural feature, but did not claim that feature as part of its patent, then the patentee cannot recapture that unclaimed feature under the doctrine of equivalents. Using the example used by Gilead, if a patent describes a table with three, four or five legs, but only claims a table with four legs, the patentee cannot subsequently claim, in litigation, under the doctrine of equivalents, that an accused three-legged table is “equivalent” to the claimed four-legged table.
The policy behind the doctrine of equivalents is relatively straight-forward. The Supreme Court has recognized that infringers should not be permitted to avoid liability by copying an invention but making only minor, insubstantial tweaks that are of no consequence. Otherwise, the teeth behind patent-protection would purportedly be mitigated. On the other hand, competitors must be in a position to reasonably ascertain the scope of a patent’s coverage so that design-arounds are feasible. Accordingly, under the disclosure-dedication doctrine, if a patent describes a unique feature, but fails to claim it as part of the protectable invention, then a competitor should be permitted to presume that that feature is not covered by the patent, but has instead been “dedicated” to the public.
Here, Gilead argues that ViiV essentially dedicated to the public an embodiment of dolutegravir by describing it with three flurorines attached to the benzyl ring, but only claiming it with two fluorines. ViiV disputes this conclusion, primarily on legal grounds. ViiV argues that Gilead is focusing on a feature of the patent claim that is too granular. Specifically, ViiV contends that, legally, the disclosure-dedication must focus on an entire “claim limitation.” In this case, the relevant claim limitation according to ViiV is the entire formula for dolutegravir. It is not simply a feature of that entire formula, namely, whether or not there are two or three fluorines attached to the benzyl ring.
Looking at the relevant claim limitation, namely, the entire formula for dolutegravir as recited in the patent claim, ViiV argues that Gilead’s argument falls apart. ViiV acknowledges that the ‘385 patent does not anywhere disclose an embodiment that literally resembles bictegravir. (This, in itself, is a potentially risky admission because it may open the door to another defense for Gilead, namely, lack of written description. This admission also carries the risk that it may not play well in front of a jury, if the case makes it that far.) Thus, according to ViiV, because the ‘385 patent does not expressly disclose the formula for bictegravir, then ViiV cannot have otherwise dedicated that embodiment of its patents to the public, and therefore, Gilead’s “dedication-disclosure” argument must fail.
The problem for ViiV is that its argument does not appear to be necessarily firmly grounded in precedent. The phrase “claim limitation” is used frequently in patent law, but exactly where claim limitations begin and end is not an issue that has been frequently litigated. ViiV does not point to any strong precedent holding that, for the purposes of assessing a chemical compound claim limitation under the doctrine of equivalents, the analysis must begin and end with the entire formula. Indeed, persons of skill in the art—namely chemists—may read chemical formulas as having multiple constituent parts that can be independently substituted. That would be distinct from a claim limitation directed, for example, to a precise measurement, such as 0.5 mg, which cannot necessarily be further broken down into more granular limitations on the invention.
ViiV makes another argument. ViiV argues that the dedication-disclosure doctrine cannot apply to features that were otherwise claimed in another patent claim within the same patent. Here, a different claim in the same patent requires that three fluorines are attached to the benzyl ring. Because of this, ViiV argues that Gilead’s dedication-disclosure argument must fail.
Again, the problem for ViiV is that it has not marshaled any real precedent to support this purported rule. In fact, Gilead points out that none of the cases cited by ViiV ruled on this particular scenario. Worse, Gilead points out that ViiV previously lost when it made the same argument in a different case. (See ViiV Healthcare UK Ltd. v. Lupin Ltd., 6 F. Supp. 3d 461 (D. Del. 2013). According to Gilead, ViiV is reading language from prior cases precluding use of the dedication-disclosure doctrine to instances when the subject matter is “unclaimed” to suggest that it must be unclaimed in the entire patent, rather than unclaimed in the claim at issue.
These arguments can be admittedly difficult to follow because they are based upon legal constructs that are themselves exceptions of exceptions. The dedication-disclosure doctrine is itself an exception to the doctrine of equivalents, which is itself an exception to literal infringement.
Overall, the weight of the law appears to be on Gilead’s side. Nevertheless, there is the possibility that the Court denies Gilead’s motion. Not because it necessarily disagrees with Gilead’s position on the law, but rather because the Court may be wary of dismissing the case where expert opinion is warranted. For instance, on the question of whether a person of skill understands that chemical formulas effectively comprise multiple claim “limitations,” that may be an issue of fact on which the Court would prefer to supplement the record before dismissing the case.
Claim 2 from the ‘385 patent
For claim 2, Gilead argues that ViiV is barred from proving infringement pursuant to the doctrine of equivalents under a different exception to that doctrine, namely, the doctrine of specific exclusion.
The claim itself depicts a structural chemical formula (shown below).
After that, the claim recites the following language:
R20, R21, R22, R23, R24 and R25 are independently hydrogen, C1-C8alkyl, C6-C14arylC1-C8alkyl, C6-C14aryl, or alkoxy;
During Markman hearing, the Court interpreted this language to require that the substitutions at each R-position to be “distinct” from the substitution at each other R-position. The parties are now disputing what the essentially means.
One of the ways that Gilead’s bictegravir differs from ViiV’s dolutegravir is that, for the substitutions at two R-positions, Gilead added a “bridge” (an extra chemical bond) between two carbon atoms. This is shown below. Figure 1 shows the literal version of the dolutegravir compound recited in claim 2 of the ‘385 patent. Figure 2 shows Gilead’s bictegravir compound, which ViiV argues is infringed under the doctrine of equivalents.
Gilead argues that, in its bictegravir compound, the green and purple grouping of atoms in Fig. 2 are not distinct. This is because of the carbon bridge in blue depicted in Fig. 2 makes it a single group of atoms, and thus the R-positions for the green CH2 and the purple CH2 do not have “distinct” substitutions.
Under the doctrine of specific exclusion, a patent holder cannot argue that an accused product is “equivalent” to a patented invention where the accused product is literally inconsistent with or the opposite of the claimed invention. Prior caselaw illustrates this doctrine best. For instance, one earlier case held that a patent for an “unmounted” computer cannot be equivalent to a “mounted” computer. Another case held that a patent requiring a “majority” of a specific feature cannot be equivalent to a product having only a “minority” of that specific feature.
Here, the thrust of Gilead’s argument is that two of the R-positions for bictegravir share a group of atoms. According to Gilead, the group of atoms for those two R-positions are not distinct. Yet, under the Court’s claim construction for claim 2, each R-position must have substitutions that are distinct. Accordingly, Gilead claims that an embodiment where two R-positions share a group of atoms was specifically excluded. Thus, Gilead argues that bictegravir cannot, as a matter of law, infringe claim 2 of the ‘385 patent under the Court’s current claim construction.
ViiV obviously disputes Gilead’s argument. ViiV argues that the substitutions at the two relevant R-positions are, in fact, distinct. One R-position has the green CH2 and the other R-position has the purple CH2. The fact that they are joined by the blue bridge does not make them indistinct. Rather, it just means that two distinct things are otherwise connected. ViiV draws upon that the intuitive counterexample that two different and distinct people do not suddenly become indistinct once they are connected by holding hands. ViiV claims that Gilead specifically advocated for an interpretation of the claim that would have required that the substitutions at the respective R-positions are “not connected.” But the Court rejected that proposed construction of the claim.
The parties are essentially disputing the scope of the Court’s prior claim construction. That is all the more peculiar given that the parties both agreed to the claim construction that was adopted by the Court. Moreover, in doing so, Gilead staked out its position that the construction that the Court eventually adopted would exclude a chemical structure like that in Figure 2 above, and yet, ViiV does not appear to have objected to this interpretation at the time.
The Court heard oral argument on Gilead’s motion in November 2019. For claim 2, like claim 6 above, there is the possibility that the Court does not rule on the merits of Gilead’s motion because, once again, it deems an issue of fact precludes it from doing so. For instance, whether or not a person of skill would understand that two groups of atom joined by a bridge are “distinct” may not be something the Court wishes to weigh in on without expert opinion. On the other hand, because Gilead’s argument on claim 2 is really one of claim construction—namely, whether or not bictegravir is literally excluded from the Court’s construction of claim 2— then that would warrant a decision on this motion.
Even if Gilead’s motion is not granted, the issues outlined in Gilead’s motion will likely form the crux of the dispute between the parties as the case heads towards trial in 2020. If so, Gilead would likely renew its motion as one for summary judgment before trial.