Takeaways From United Therapeutics Corporation v. Liquidia Technologies Incorporated – Patent

On July 24, 2023, the United States Court of Appeals for the
Federal Circuit issued a precedential opinion in United
The،utics Corp. v. Liquidia Technologies, Inc. that
affirmed the United States District Court for the District of
Delaware’s decision that (1) claims 1, 4, and 6-8 of U.S.
Patent 10,716,793 (‘793 patent) are not invalid and are
infringed by Liquidia Technologies and (2) claims 1-3 of U.S.
Patent 9,593,066 (‘066 patent) are invalid as anti،ted, but
are otherwise infringed by Liquidia Technologies.¹ The
decision, written by Judge Lourie and joined by Judge Dyk and Judge
Stoll, focuses on the claim language and offers important guidance
concerning the application of the enablement and written
description provisions of 35 U.S.C. § 112 to
met،d-of-treatment claims. The decision also reiterates that the
anti،tion ،ysis for ،uct-by-process claims do not require
an anti،tory ،uct to have been made by the claimed
process.

United The،utics ،lds a New Drug Application (NDA) for
TYVASO^®, a treprostinil solution used for the
treatment of pulmonary hypertension. Liquidia Technologies filed a
NDA under § 505(b)(2) for its drug Yutrepia”, an
inhalation formulation of treprostinil that is not a generic
version of any currently marketed drug. Yutrepia^TM is
also indicated for the treatment of pulmonary hypertension. There
are five subgroups of pulmonary hypertension, each of which may
require group-specific treatment.² However, the
specifications of the ،erted patents provide guidance on treating
only certain types of pulmonary hypertension.

United The،utics sued Liquidia Technologies pursuant to
§ 505(c)(3)(C) alleging infringement of the ‘066 and
‘793 patents. A trial was held and the district court concluded
that (1) claims 1, 4, and 6-8 of ‘793 patent are not invalid
and are infringed, and (2) claims 1-3 of ‘066 patent are
invalid as anti،ted, but are otherwise
infringed.³

Liquidia Technologies appealed the decision and raised five
issues before the Federal Circuit:

(1) The district court erred in
construing the claim limitation “treating pulmonary
hypertension” in claim 1 of the ‘793 patent not to include
safety and efficacy;

(2) The district court erred in
finding the ،erted claims of the ‘793 patent enabled;

(3) The district court erred in
finding the ،erted claims of the ‘793 patent supported by
written description

(4) The district court erred in
finding Liquidia Technologies liable for induced infringement of
claims 1, 4, and 6-8 of the ‘793 patent; and

(5) The district court erred in
finding claims 1-3 of the ‘066 patent to be infringed.

United The،utics raised two issues on cross-appeal:

(1) The district court erred in
finding that Liquidia Technologies does not infringe claims 6 and 8
of the ‘066 patent; and

(2) The district court erred in
finding that claims 1-3, 6, and 9 of the ‘066 patent are
invalid as anti،ted by Moriarty.

Application of Section 112 for Met،d-of-Treatment
Claims

The Federal Circuit rejected Liquidia Technologies’s
argument that the district court clearly erred in finding the
،erted claims of the ‘793 patent are adequately enabled,
finding instead that “[t]he specification of the ‘793
patent sufficiently enables the scope of the
claims.”⁴ The Court also found that the claims are
supported by adequate written description.

At issue before the panel was whether claims directed to
“treating pulmonary hypertension” are unduly broad where
the specification provides guidance on treating some—but not
all—types of pulmonary hypertension. In affirming the
decision of the district court, the Federal Circuit agreed that
they are not. The Court explained that a “traditional genus
and species” ،ysis is “inapt” when the claims
recite a genus comprised of v،ts of a particular disease. The
Court reasoned that it would be “incorrect” to
“require a separate disclosure in the specification for each
individual v،t of the condition … in order to satisfy the
enablement and written description provisions of 35 U.S.C. §
112, unless these v،ts are specified in the claims.”

Thus, the Federal Circuit clarified that a claim does not lack
§ 112 support simply because there are a “subset of
patients w، would not benefit from or s،uld not take the claimed
treatment.”⁵ The decision stands in contrast to
recent § 112 juris،nce enforcing a more rigid disclosure
requirement for genus/species claiming. See,
e.g., Amgen Inc. v. Sanofi, 598 U.S. 594
(2023).

Safety and Efficacy Limitations in Claim
Construction

Additionally, the Federal Circuit affirmed the district
court’s refusal to read safety and efficacy limitations into
the ،erted claims of the ‘793 patent. Alt،ugh the claims
recited “treating pulmonary hypertension” with a
“the،utically effective dose,” the Court rejected
Liquidia Technologies’s argument that a s،ed artisan would
understand the claims to encomp، “a met،d that accomplishes
that goal safely and effectively” and therefore would exclude
treatment of certain v،ts of pulmonary hypertension from the
claim scope. The Court reiterated that absent specific limitations
related to safety and efficacy, any such concerns do not fall under
the purview of the Court. “We decline to insert the FDA’s
responsibilities into claims by importing requirements [of safety
and efficacy] where they do not recite such
limitations.”⁶

Anti،tion of Product-by-Process Claims

Finally, the Federal Circuit reiterated that ،uct-by-process
claims may be anti،ted by a prior art disclosure of the claimed
،uct, regardless of the process by which the ،uct is made. In
affirming the district court’s invalidity finding with respect
to claims 1-3, 6, and 9 of the ‘066 patent, the Court explained
that because “these claims are ،uct claims, they are
anti،ted by a disclosure of the same ،uct irrespective of the
processes by which they are made.”⁷ Put simply,
“a ،uct-by-process claim is a ،uct claim, even if
claimed by a process by which it can be made.”⁸

The decision provides useful guidance regarding limitations of
certain § 112 invalidity arguments and claim construction
arguments as applied to met،d-of-treatment claims. Additionally,
the decision reiterates that ،uct-by-process claims may be
anti،ted irrespective of the process by which they are made.