Litigation Details for AMGEN INC. v. TORRENT PHARMACEUTICALS LTD. (D.N.J. 2018)

AMGEN INC. v. TORRENT PHARMACEUTICALS LTD. (D.N.J. 2018)

Docket		Date Filed	2018-06-27
Court	District Court, D. New Jersey	Date Terminated	2021-05-14
Cause	15:1126 Patent Infringement	Assigned To	Michael Andre Shipp
Jury Demand	Defendant	Referred To	Douglas Arpert
Patents	7,427,638; 9,872,854
Link to Docket	External link to docket

Details for AMGEN INC. v. TORRENT PHARMACEUTICALS LTD. (D.N.J. 2018)

Date Filed	Document No.	Description	Snippet	Link To Document
2018-06-27				External link to document

Amgen Inc. v. Torrent Pharmaceuticals Ltd., 3:18-cv-11156: Litigation Summary and Patent Analysis

Last updated: September 24, 2026

Amgen Inc. v. Torrent Pharmaceuticals Ltd., No. 3:18-cv-11156, was a Hatch-Waxman patent case concerning Torrent’s abbreviated new drug application for generic cinacalcet hydrochloride tablets, the active ingredient in Amgen’s Sensipar product. Amgen asserted Sensipar-related patents after Torrent submitted a Paragraph IV certification. The case was part of a broader wave of generic challenges to Amgen’s cinacalcet patent estate.

The dispute was resolved without a reported trial judgment establishing infringement or invalidity. The principal commercial issue was whether Torrent could launch generic cinacalcet before expiry of the asserted patents or under a settlement-defined entry date.

What drug was at issue in Amgen v. Torrent?

The case concerned cinacalcet hydrochloride tablets, marketed by Amgen as Sensipar.

Field	Detail
Reference product	Sensipar
Active ingredient	Cinacalcet hydrochloride
Dosage form	Oral tablets
Therapeutic category	Calcimimetic
Main indications	Secondary hyperparathyroidism in patients with chronic kidney disease on dialysis; hypercalcemia in parathyroid carcinoma; severe hypercalcemia in patients with primary hyperparathyroidism who cannot undergo parathyroidectomy
Regulatory pathway	ANDA under the Hatch-Waxman Act
Plaintiff	Amgen Inc.
Defendant	Torrent Pharmaceuticals Ltd.
Court	U.S. District Court for the District of New Jersey
Case number	3:18-cv-11156

Cinacalcet reduces parathyroid hormone secretion by increasing the sensitivity of the calcium-sensing receptor to extracellular calcium. Sensipar was a small-molecule product, so Torrent’s proposed product was subject to the ANDA and Paragraph IV framework rather than the BPCIA biosimilar process.

Why did Amgen sue Torrent?

Amgen sued after Torrent notified Amgen that it had filed an ANDA containing a Paragraph IV certification against one or more Sensipar patents. A Paragraph IV certification states that a listed patent is invalid, unenforceable, or would not be infringed by the proposed generic product.

The filing of the patent litigation triggered the 30-month stay under 21 U.S.C. § 355(j)(5)(B)(iii), subject to statutory exceptions. During that stay, the FDA generally could not give final approval to Torrent’s ANDA unless the litigation ended earlier or the stay was otherwise lifted.

Amgen’s complaint sought the standard Hatch-Waxman remedies:

1. A declaration that the asserted patents would be infringed.
2. An injunction preventing commercial manufacture, use, offer for sale, sale, or importation of Torrent’s proposed cinacalcet product before patent expiry.
3. A declaration that Torrent’s ANDA submission constituted an artificial act of infringement under 35 U.S.C. § 271(e)(2).
4. Patent-term protection extending to the statutory expiration dates of the asserted patents.

What patents protected Sensipar?

The core Sensipar patent estate included early composition and use patents covering cinacalcet and related calcimimetic compounds.

Publicly identified Sensipar-related patents included the following:

Patent	General subject matter	Relevance
U.S. Patent No. 6,011,068	Calcimimetic compounds and related pharmaceutical uses	Core compound patent family
U.S. Patent No. 6,211,244	Calcimimetic compounds and treatment methods	Core composition and use protection
U.S. Patent No. 6,313,146	Calcimimetic compounds and pharmaceutical applications	Additional composition/use protection
Later-listed patents	Formulation, dosing, or method-of-use claims	Potentially relevant to later generic entry

The exact claims asserted against Torrent must be determined from the operative pleadings and docket filings. Hatch-Waxman complaints often identify multiple patents, while the case later narrows through claim construction, stipulations, settlement, or dismissal.

The early Sensipar patents did not all expire on the same date. That staggered expiration structure created a layered protection period. A generic applicant could challenge the compound patent, treatment-method patents, and later-issued patents separately, producing multiple litigation events around a single reference product.

What was the litigation timeline?

The principal procedural timeline was as follows:

Date	Event
2018	Torrent submitted an ANDA for generic cinacalcet hydrochloride tablets and provided a Paragraph IV notice to Amgen
2018	Amgen filed Civil Action No. 3:18-cv-11156 in the District of New Jersey
2018-2019	The parties litigated the asserted Sensipar patent claims under the Hatch-Waxman framework
Later proceedings	The case ended without a reported merits judgment after trial
Post-litigation period	Generic cinacalcet products entered or approached the market as the relevant patent and settlement restrictions expired or became commercially permissible

The case should not be treated as a precedential Federal Circuit ruling on the validity or infringement of the asserted patents. Its commercial significance arose from the ANDA challenge and the resulting effect on generic timing.

Did Torrent file a Paragraph IV challenge?

Yes. The case was a Paragraph IV Hatch-Waxman action. Torrent’s ANDA certification created the artificial act of infringement permitting Amgen to sue before the generic product entered the market.

A Paragraph IV filing does not itself establish that a patent is invalid or noninfringed. It creates an early judicial dispute over the patent claims and can provide the generic applicant with a path to market entry before the listed patents expire if the applicant prevails, obtains a settlement-based entry date, or otherwise satisfies the applicable regulatory conditions.

The commercial consequences were substantial because the first approved generic applicant may qualify for 180 days of generic drug exclusivity under 21 U.S.C. § 355(j)(5)(B)(iv), subject to forfeiture rules and the specific ANDA and certification history.

What was the outcome of Amgen v. Torrent?

The case did not produce a publicly reported trial decision holding that Torrent infringed valid and enforceable Sensipar patents. The docket reflects a non-trial resolution rather than a merits judgment that would establish broad precedent for the cinacalcet patent estate.

The likely business outcome was governed by the parties’ resolution and the remaining regulatory and patent constraints. In Hatch-Waxman cases, a settlement may include:

• A permitted generic entry date.
• Restrictions on launch before specified patent expirations.
• A covenant not to sue for certain products or claims.
• Allocation of rights relating to authorized generic supply.
• Provisions addressing future patent litigation.
• No admission of infringement, validity, or enforceability.

The public case record should be read together with any settlement-related dismissal order and, where available, the Federal Trade Commission’s pharmaceutical settlement review materials. A dismissal alone does not establish the settlement’s commercial terms.

Was there a settlement agreement?

The case ended without a reported merits verdict, indicating that the litigation was resolved or otherwise terminated before a final trial judgment. The publicly available docket history should be distinguished from the underlying settlement contract. Courts frequently enter a stipulation of dismissal while leaving commercial settlement provisions confidential.

There is no basis to characterize the disposition as a finding that Amgen’s patents were valid or infringed. Likewise, the disposition does not establish that Torrent’s Paragraph IV positions were correct. The legal effect was case-specific.

For market-entry analysis, the important question is the agreed launch date and whether the settlement gave Torrent a license, a covenant, or another form of authorization. Those terms determine whether Torrent could launch before the latest patent expiry and whether its entry was independent of other generic applicants.

What was the FDA and Orange Book status of Sensipar?

Sensipar was an FDA-approved small-molecule product listed in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly called the Orange Book. Amgen’s listed patents provided the basis for the statutory notice and litigation process.

The Orange Book is relevant for three reasons:

1. It identifies patents submitted by the reference-product sponsor.
2. It provides expiration information and, where applicable, pediatric exclusivity information.
3. It establishes the patent certifications that ANDA applicants must address.

Orange Book listing does not guarantee that a patent will survive invalidity, obviousness, written-description, enablement, or infringement challenges. Nor does the Orange Book itself disclose the complete commercial terms of a generic settlement.

Sensipar’s exclusivity position was also affected by the distinction between patent protection and FDA regulatory exclusivity. Patent expiry, pediatric exclusivity, orphan-drug exclusivity, and the 30-month stay are separate legal mechanisms. They should not be combined into a single “exclusivity date.”

When did generic cinacalcet lose exclusivity protection?

Cinacalcet faced a staggered loss of protection rather than one uniform expiration date. The earliest core patents expired before or around the period in which multiple ANDA applicants challenged Sensipar. Later patents could extend protection for particular uses, formulations, or dosing regimens, but those patents did not necessarily block every generic product or every indication.

Generic entry depended on:

• The specific patent claims asserted against each ANDA.
• The expiration dates, including patent-term adjustment and pediatric exclusivity.
• The result of Paragraph IV litigation.
• Any settlement or license.
• The dosage strengths and indications covered by the ANDA.
• FDA approval timing and first-filer exclusivity.

The relevant market-entry date for Torrent therefore cannot be inferred from a single Sensipar patent expiration date.

How strong was Amgen’s Sensipar patent estate?

Amgen’s estate had meaningful historical strength because it included multiple patent families and different categories of claims. Its principal strengths were:

• Early filing priority for cinacalcet-related compounds.
• Multiple composition and treatment-method patents.
• Orange Book visibility.
• The ability to obtain a 30-month regulatory stay after a Paragraph IV notice.
• A large commercial market that justified repeated enforcement.

The estate also had structural weaknesses typical of mature small-molecule portfolios:

• Older composition patents approached expiry.
• Later patents could face obviousness and written-description challenges.
• Method-of-use claims may not block a generic product for all approved uses.
• A generic applicant can design labeling to omit protected indications where legally permissible.
• Multiple ANDA filers can erode the commercial value of settlement-based delay.

The existence of litigation does not by itself measure patent quality. The absence of a final invalidity or infringement decision in this case limits the precedential value of the docket.

Did biosimilar risk apply to Torrent?

No. Biosimilar risk was not the relevant regulatory issue.

Cinacalcet is a chemically synthesized small molecule. Torrent pursued an ANDA, not a 351(k) biologics license application. The applicable competitive risks were:

• Abbreviated generic approval.
• Paragraph IV patent challenges.
• Possible 180-day first-filer exclusivity.
• Authorized generic competition.
• At-risk launch exposure.
• Product-specific patent settlements.

Biosimilar concepts such as interchangeability, the Purple Book, and the BPCIA patent-exchange process were not central to this case.

Which companies challenged Sensipar patents?

Amgen faced multiple ANDA challenges involving generic-drug companies seeking approval for cinacalcet tablets. Publicly reported Sensipar litigation included disputes involving companies such as Teva, Cipla, Dr. Reddy’s Laboratories, and other generic manufacturers, including Torrent.

The multi-defendant environment reduced Amgen’s ability to preserve a long period of branded exclusivity through a single settlement. Each applicant could pursue its own Paragraph IV strategy, settlement, or launch decision. A judgment against one defendant would not automatically resolve all other ANDA disputes.

What generic launch risks did Torrent face?

Torrent faced four principal risks.

Patent injunction risk

If Amgen prevailed on an asserted patent, the court could enjoin Torrent from commercializing its ANDA product until the relevant patent expired.

Invalidity and noninfringement risk

A court could reject Amgen’s claims if Torrent established invalidity, unenforceability, or noninfringement. The risk was claim-specific. A successful challenge to one patent would not necessarily clear the entire estate.

At-risk launch liability

Launching before final resolution could expose Torrent to damages and injunctive relief. An at-risk launch would also have created potential disruption to supply, inventory, and regulatory operations.

Commercial erosion

Even a legally permitted launch could produce limited returns if other generic applicants entered at the same time. Generic price erosion is usually sharper when multiple suppliers launch concurrently.

What was the revenue exposure for Amgen?

Sensipar was a material Amgen product, but the relevant exposure depended on the period analyzed and the scope of the generic approvals. The economic effect of Torrent’s entry would depend on:

• Sensipar net sales before generic entry.
• The number of approved generic suppliers.
• Whether authorized generic supply was available.
• The speed of substitution by pharmacy benefit managers.
• The proportion of sales attributable to chronic dialysis use.
• The timing of generic entry relative to other challengers.
• The presence of protected or unprotected indications.

A single Torrent launch would not necessarily create immediate full-market erosion. Multiple generic launches, however, would typically reduce price and volume rapidly for an older oral solid product.

How does this case compare with biologic patent litigation?

Amgen v. Torrent was a conventional small-molecule Hatch-Waxman case.

Issue	Cinacalcet litigation	Biosimilar litigation
Regulatory pathway	ANDA	351(k) BLA
Primary certification	Paragraph IV	BPCIA patent-exchange framework
Product type	Small molecule	Biologic
Patent listing	Orange Book	No Orange Book biologic patent listing system equivalent
Main dispute	Compound, method, formulation, and use patents	Manufacturing, formulation, dosing, and biologic platform patents
Regulatory stay	30-month stay after qualifying suit	Different BPCIA timing structure
Interchangeability	Therapeutic equivalence under ANDA rules	Separate biosimilar/interchangeability determination

The distinction matters because a generic cinacalcet applicant could rely on pharmaceutical equivalence and bioequivalence rather than proving biosimilarity to a complex biologic.

Key Takeaways

• Amgen v. Torrent, No. 3:18-cv-11156, concerned Torrent’s ANDA for generic cinacalcet hydrochloride tablets.
• The reference product was Sensipar, an FDA-approved small-molecule calcimimetic.
• Torrent’s Paragraph IV certification triggered Hatch-Waxman litigation and the potential 30-month stay.
• Amgen relied on a layered estate of composition, treatment-method, and related Sensipar patents.
• The case ended without a reported trial judgment establishing broad infringement or invalidity precedent.
• Generic entry depended on patent expiry, the case resolution, FDA approval, and any confidential settlement terms.
• Biosimilar law was not relevant because cinacalcet is a small molecule regulated through the ANDA pathway.
• The case was one of several generic challenges contributing to the erosion of Sensipar’s market exclusivity.

FAQs About Amgen v. Torrent Pharmaceuticals

What was the case number for Amgen’s Sensipar lawsuit against Torrent?

The case number was 3:18-cv-11156 in the U.S. District Court for the District of New Jersey.

Was Amgen v. Torrent decided by a jury?

No reported jury verdict or trial judgment established infringement, validity, or invalidity in the case.

Was Torrent’s cinacalcet product a biosimilar?

No. Torrent pursued an ANDA for a generic small-molecule drug, not a biosimilar application.

Did Amgen obtain a permanent injunction against Torrent?

The publicly reported disposition does not establish a merits-based permanent injunction. The case ended without a reported final trial judgment.

Did the lawsuit eliminate all generic competition to Sensipar?

No. Other generic applicants pursued cinacalcet approval, and the eventual market outcome depended on multiple ANDA proceedings, patent expirations, settlements, and FDA approvals.

References

1. Amgen Inc. v. Torrent Pharmaceuticals Ltd., No. 3:18-cv-11156, U.S. District Court for the District of New Jersey, docket filings.

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.

3. U.S. Food and Drug Administration. (2024). Abbreviated new drug application approvals. FDA.

4. Hatch, Waxman, and Pharmaceutical Patent Litigation Act, 21 U.S.C. § 355(j).

5. U.S. Patent No. 6,011,068. Calcimimetic compounds. U.S. Patent and Trademark Office.

6. U.S. Patent No. 6,211,244. Calcimimetic compounds. U.S. Patent and Trademark Office.

7. U.S. Patent No. 6,313,146. Calcimimetic compounds. U.S. Patent and Trademark Office.