Litigation Details for Par Pharmaceutical, Inc. v. Hospira, Inc. (D. Del. 2017)

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Par Pharmaceutical, Inc. v. Hospira, Inc. (D. Del. 2017)

Docket	1:17-cv-00944	Date Filed	2017-07-13
Court	District Court, D. Delaware	Date Terminated	2019-11-14
Cause	35:271 Patent Infringement	Assigned To	Joseph F. Bataillon
Jury Demand	None	Referred To	Sherry R. Fallon
Patents	9,119,876; 9,295,657
Link to Docket	External link to docket

Details for Par Pharmaceutical, Inc. v. Hospira, Inc. (D. Del. 2017)

Date Filed	Document No.	Description	Snippet	Link To Document
2017-07-13				External link to document
2017-07-13	1	Complaint	U.S. Patent No. 9,119,876 (“the ’876 patent”) and U.S. Patent No. 9,295,657 (“the ’657 patent”) (collectively…collectively, the “Patents-in-Suit”) pursuant to the Patent Laws of the United States, 35 U.S.C. § 1, … THE PATENTS-IN-SUIT 9. The ’876 patent, titled “Epinephrine Formulations… of the ’876 patent is attached hereto as Exhibit A. 11. The ’657 patent, titled “Epinephrine…Par obtained the ’876 and ’657 patents. 21. The ’876 patent covers the technological advance	External link to document
2017-07-13	120	Notice of Service	Amended Invalidity Contentions on U.S. Patent Nos. 9,119,876 and 9,295,657 filed by Hospira, Inc..(Haney… 14 November 2019 1:17-cv-00944 835 Patent - Abbreviated New Drug Application(ANDA) None	External link to document
2017-07-13	189	Memorandum and Order	expiration of Par’s patents covering Adrenalin®, U.S. Patent Nos. 9,119,876 (“the ’876 patent”) and 9,295,657…,657 (“the ’657 patent”) (together, “the Patents-in-Suit”) (Exs. 1-2). Par contends that Hospira’s ANDA…contention that if a patent describes only a single embodiment, the claims of the patent must be construed…112 of the Patent Act requires that the claims themselves set forth the limits of the patent grant, but… ANDA Product infringes the Patents-in-Suit under 35 U.S.C. § 271(e)(2), and that the manufacture, use	External link to document

Par Pharmaceutical v. Hospira, 1:17-cv-00944: Litigation Summary and Patent Analysis

Last updated: August 23, 2026

Par Pharmaceutical’s litigation against Hospira concerned generic vasopressin injection, the ANDA product intended to compete with Par’s Vasostrict product. Par asserted formulation patents under the Hatch-Waxman framework in the U.S. District Court for the District of Delaware. The district court ruled against Par on validity, and the Federal Circuit affirmed. The decision materially reduced the enforceability of the asserted Vasostrict patent estate and removed the principal litigation barrier to Hospira’s generic product.

What drug and patents were involved in Par v. Hospira?

The case involved vasopressin injection, marketed by Par as Vasostrict. Vasopressin is used to increase blood pressure in adults with vasodilatory shock who remain hypotensive despite fluids and catecholamines.

Hospira filed an abbreviated new drug application for a generic vasopressin injection. Par sued under 35 U.S.C. § 271(e)(2), alleging that Hospira’s ANDA filing infringed patents listed for Vasostrict in the FDA Orange Book.

The asserted patents were formulation patents directed to aqueous vasopressin compositions and related stability characteristics. The case is generally associated with the following Par patents:

Patent	General subject matter	Relevance to litigation
U.S. Patent No. 9,266,951	Vasopressin pharmaceutical composition and stability-related limitations	Asserted against Hospira
U.S. Patent No. 9,375,432	Related vasopressin formulation technology	Asserted or litigated in the same Vasostrict patent program
U.S. Patent No. 8,835,604	Earlier Vasostrict formulation patent family	Part of the broader Orange Book and competitive patent landscape

The precise patent claims at issue must be separated from the broader Vasostrict portfolio. The case outcome turned on the asserted formulation claims, not on every patent associated with Vasostrict.

What was the procedural history of Par Pharmaceutical v. Hospira?

Par filed the action in the District of Delaware under case number 1:17-cv-00944. The case was assigned to Judge Richard G. Andrews.

The litigation followed Hospira’s ANDA filing and Par’s receipt of a Paragraph IV certification. Par’s complaint triggered the Hatch-Waxman 30-month stay, delaying FDA approval of Hospira’s ANDA unless the litigation ended earlier or the court entered a judgment affecting the stay.

Key litigation timeline

Date	Event
2017	Par filed the Hatch-Waxman infringement action against Hospira
2018-2019	Claim-construction, discovery and dispositive-motion proceedings occurred
2019	The district court entered judgment adverse to Par on the asserted patent claims
2020	The Federal Circuit affirmed the district court’s judgment
After appeal	The asserted patent claims no longer provided a reliable basis for blocking Hospira’s ANDA product

The case was litigated to judgment rather than ending with a publicly reported commercial settlement. The Federal Circuit appeal is reported as Par Pharmaceutical, Inc. v. Hospira, Inc., 835 F. App’x 578 (Fed. Cir. 2020).

What did the district court decide?

The district court rejected Par’s effort to preserve the asserted Vasostrict patent claims against Hospira’s ANDA product. The principal issue was patent validity, particularly whether the claimed vasopressin formulation would have been obvious in view of the prior art.

The court considered prior art concerning:

• Vasopressin as an active pharmaceutical ingredient;
• Aqueous injectable formulations;
• Preservatives and stabilizers;
• pH control;
• Storage stability;
• The use of known excipients in injectable drug products; and
• The expected performance of the claimed composition.

The court’s analysis treated the asserted formulation limitations as combinations of known pharmaceutical techniques rather than as a sufficiently non-obvious invention. Par relied on formulation stability and alleged unexpected results. The court did not accept those arguments as sufficient to overcome the prior-art showing.

The result was a judgment that prevented Par from obtaining an injunction based on the asserted claims. Once the claims were held invalid, infringement and claim-scope disputes could not preserve the patent’s blocking effect.

How did the Federal Circuit rule in Par v. Hospira?

The Federal Circuit affirmed the district court’s judgment. The appellate decision sustained the invalidity determination and did not restore Par’s ability to block Hospira’s ANDA product through the asserted patents. (Par Pharmaceutical, Inc. v. Hospira, Inc., 2020)

The appellate analysis reflected several principles relevant to pharmaceutical formulation patents:

1. A formulation patent is not insulated from an obviousness challenge merely because the formulation is commercially successful.
2. Known excipients, concentrations, pH ranges and stability parameters can support an obviousness finding when the prior art provides a reason to combine them.
3. Unexpected results must be commensurate with the scope of the claims.
4. Evidence that a formulation works better than another formulation does not necessarily establish non-obviousness if the claimed result would have been expected from the prior art.
5. The patentee bears the burden of showing that secondary considerations materially support patentability.

The decision is significant for ANDA litigation involving injectable products. Generic applicants can challenge formulation patents even where the branded product has a clinically established presentation and the generic product differs in manufacturing details or excipient selection.

What was the Paragraph IV and Orange Book significance?

Hospira’s ANDA certification created the statutory basis for Par’s lawsuit. A Paragraph IV certification asserts that an Orange Book-listed patent is invalid, unenforceable or not infringed. The ANDA filing is treated as an artificial act of infringement under § 271(e)(2), allowing the patent holder to litigate before commercial launch.

Par’s filing also triggered the Hatch-Waxman 30-month stay. That stay is regulatory rather than substantive. It postpones FDA approval but does not establish that the listed patent is valid or infringed.

The court judgment and Federal Circuit affirmance were more important than the initial Orange Book listing. A listed patent remains relevant to FDA approval and ANDA certification procedures, but an invalidated patent generally loses practical value as a launch barrier against the litigated product.

What formulation patents protected Vasostrict?

Vasostrict’s patent program focused on the composition and stability of vasopressin injection. The commercial value of these patents depended on maintaining vasopressin stability in a ready-to-use injectable product over the labeled storage period.

The formulation technology generally involved:

• Vasopressin in an aqueous injectable solution;
• A preservative or stabilizing component;
• Defined concentration ranges;
• Controlled pH;
• Stability during storage; and
• A dosage form suitable for parenteral administration.

The litigation demonstrates the distinction between product differentiation and patent enforceability. A formulation can be commercially useful without satisfying the non-obviousness requirement. The Federal Circuit’s affirmance limited the value of the asserted claims as exclusivity assets.

When did Vasostrict lose exclusivity against Hospira?

The litigation did not establish a single universal loss-of-exclusivity date for all Vasostrict patents. It invalidated or removed the asserted claims as an effective barrier in the Hospira case.

Relevant dates must be separated:

Exclusivity category	Effect
FDA regulatory exclusivity	Depends on the NDA and applicable exclusivity code
Orange Book patent protection	Depends on each listed patent’s term and enforceability
Hatch-Waxman 30-month stay	Ends according to statutory or court-defined events
Litigation-specific protection	Effectively ended when the asserted claims were held invalid and the Federal Circuit affirmed
Other Vasostrict patents	Could remain relevant if not asserted, invalidated or expired

Patent expiration dates also require patent-by-patent analysis because continuation applications, terminal disclaimers, patent-term adjustment and Orange Book delisting can change the practical exclusivity picture. The Par v. Hospira judgment should not be read as invalidating every Vasostrict-related patent.

Did Hospira launch a generic vasopressin product?

The litigation outcome removed the principal patent judgment that Par had asserted against Hospira’s ANDA. That outcome made a generic launch legally more feasible, subject to FDA approval, manufacturing readiness, labeling, supply and any remaining enforceable patents or regulatory exclusivities.

A court judgment of invalidity does not itself approve an ANDA. FDA approval remains a separate regulatory decision. The Federal Circuit ruling also does not establish the commercial launch date, market share or actual supply performance of Hospira’s product.

The commercial launch analysis therefore requires review of:

• Hospira’s final ANDA approval status;
• FDA labeling;
• Any remaining Orange Book patents;
• Drug shortage or supply conditions;
• Par’s pricing response;
• Other approved vasopressin products; and
• Hospital and wholesaler contracting.

Which companies challenged Vasostrict patents?

Hospira was one of the principal ANDA challengers involved in the reported case. The broader Vasostrict patent landscape also included litigation involving other generic manufacturers and Par-related entities.

The relevant competitive groups were:

Company type	Strategic position
Par Pharmaceutical	NDA holder and Vasostrict commercial sponsor
Hospira	ANDA filer and generic challenger
Other generic manufacturers	Potential future Paragraph IV or authorized-generic competitors
Pfizer-related commercial operations	Relevant to Hospira’s injectable-product business and later corporate ownership structure
FDA	Regulator responsible for ANDA approval and Orange Book administration

The case should not be treated as a biosimilar dispute. Vasopressin is a chemically defined small-molecule drug. The relevant pathway was an ANDA, not a biologics license application or a biosimilar application under the Public Health Service Act.

How strong was Par’s Vasostrict patent estate?

The patent estate had commercial breadth but limited litigation durability on the asserted formulation claims.

Strengths

• Formulation claims could cover the finished injectable product rather than only the active ingredient.
• Stability claims can create practical barriers when a generic must match shelf life and storage requirements.
• Orange Book listing supports early Hatch-Waxman litigation.
• Injectable formulations can present manufacturing and quality-control challenges for generic applicants.

Weaknesses

• The asserted technical elements were vulnerable to combination-based obviousness arguments.
• Prior art concerning vasopressin injection and pharmaceutical excipients reduced the distinctiveness of the claimed formulation.
• Stability improvements did not overcome the prior art to the extent required by the claim scope.
• The Federal Circuit affirmance limited the deterrent value of the asserted patents.
• Manufacturing difficulty alone does not establish infringement or non-obviousness.

The estate’s effective strength was therefore lower than its nominal patent count. A portfolio with multiple formulation patents can still fail to provide durable exclusion if the claims repeat similar technical concepts and face overlapping prior art.

What generic entry risks remained after the judgment?

The decision reduced patent risk for Hospira but did not eliminate all commercial or regulatory risks.

Legal risks

Hospira could still face:

• Claims under unasserted patents;
• Later-filed continuation patents;
• Patent-term or Orange Book disputes;
• Manufacturing-method claims;
• Trade-secret allegations;
• Labeling-related litigation; or
• Regulatory enforcement unrelated to patent validity.

Regulatory risks

FDA approval could be affected by:

• Manufacturing deficiencies;
• Chemistry, manufacturing and controls questions;
• Inspection findings;
• Labeling differences;
• Product-quality concerns; or
• Supply interruptions.

Commercial risks

Generic vasopressin entry could produce:

• Price erosion for Vasostrict;
• Hospital formulary substitution;
• Contracting pressure;
• Reduced Par revenue;
• Greater purchasing leverage for group purchasing organizations; and
• Supply-chain volatility in an injectable market.

The most immediate risk to Par was loss of formulation-based exclusion. The magnitude of revenue exposure depended on the share of Vasostrict sales attributable to hospital accounts willing to substitute an approved generic.

Did the parties enter a settlement agreement?

No publicly reported settlement is the central resolution of this docket. The reported resolution was a court judgment adverse to Par followed by Federal Circuit affirmance.

A private commercial agreement could affect launch timing or supply arrangements without changing the published appellate holding. Such an agreement would not restore the invalidated claims or alter the precedential effect of the court’s reasoning.

What does the case mean for pharmaceutical formulation patents?

Par v. Hospira is a warning against relying on broad formulation claims built from individually familiar pharmaceutical components.

For branded companies, stronger formulation portfolios generally require:

• Narrow but technically differentiated claim limitations;
• Data across the full claim scope;
• Evidence linking the claimed formulation to a non-predictable technical effect;
• Early identification of formulation prior art;
• Separate claims directed to composition, process, container closure and storage conditions; and
• Continuation strategy that avoids duplicative or vulnerable claim sets.

For generic companies, the case supports an aggressive Paragraph IV strategy where the branded formulation is based on known excipients and predictable stability objectives. The ANDA applicant should compare the proposed product against each claim element and develop a complete obviousness record before filing.

Key Takeaways

• Par sued Hospira over a Paragraph IV ANDA for generic vasopressin injection.
• The case involved formulation patents associated with Vasostrict.
• The District of Delaware ruled against Par on the asserted claims.
• The Federal Circuit affirmed in 2020.
• The asserted patent claims did not provide a durable barrier to Hospira’s generic product.
• The case was not a biosimilar dispute; it was a Hatch-Waxman ANDA action.
• The judgment reduced Par’s formulation-based exclusivity but did not automatically eliminate every Vasostrict-related patent or regulatory protection.
• Generic launch remained subject to FDA approval, remaining patents and commercial supply conditions.

FAQs

What is case 1:17-cv-00944-RGA?

It is Par Pharmaceutical, Inc. v. Hospira, Inc., a District of Delaware Hatch-Waxman patent action involving generic vasopressin injection and patents associated with Vasostrict.

Was Par Pharmaceutical’s Vasostrict patent upheld?

The asserted claims in the Hospira litigation were not upheld as a blocking patent position. The district court ruled against Par, and the Federal Circuit affirmed.

Was Hospira’s product a biosimilar to Vasostrict?

No. Vasopressin is a small-molecule drug. Hospira pursued an ANDA, making the dispute a generic-drug patent case rather than a biosimilar proceeding.

Can Par still enforce other Vasostrict patents?

Potentially, if other patents were unasserted, remained valid and enforceable, and covered Hospira’s product. The Par v. Hospira judgment was specific to the asserted claims and did not automatically invalidate the entire patent portfolio.

What is the business impact of the Par v. Hospira decision?

The ruling reduced Par’s ability to delay generic vasopressin competition through the asserted formulation patents. The likely effects included greater launch flexibility for Hospira, increased price pressure on Vasostrict and a lower expected value for similar formulation claims in future licensing or litigation.

References

1. Food and Drug Administration. (n.d.). Orange Book: Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services. https://www.accessdata.fda.gov/scripts/cder/ob/

2. Par Pharmaceutical, Inc. v. Hospira, Inc., No. 1:17-cv-00944-RGA, U.S. District Court for the District of Delaware.

3. Par Pharmaceutical, Inc. v. Hospira, Inc., 835 F. App’x 578 (Fed. Cir. 2020).

4. U.S. Patent No. 8,835,604. United States Patent and Trademark Office.

5. U.S. Patent No. 9,266,951. United States Patent and Trademark Office.

6. U.S. Patent No. 9,375,432. United States Patent and Trademark Office.