Litigation Details for OSI Pharmaceuticals Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2009)

OSI Pharmaceuticals Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2009)

Docket		Date Filed	2009-03-19
Court	District Court, D. Delaware	Date Terminated	2012-05-01
Cause	35:271 Patent Infringement	Assigned To	Sue Lewis Robinson
Jury Demand		Referred To
Parties	MYLAN PHARMACEUTICALS INC.
Patents	6,900,221; 7,087,613; 9,352,013
Link to Docket	External link to docket

Details for OSI Pharmaceuticals Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2009)

Date Filed	Document No.	Description	Snippet	Link To Document
2009-03-19				External link to document

OSI Pharmaceuticals Inc. v. Mylan Pharmaceuticals Inc. | 1:09-cv-00185 Litigation Summary and Patent Analysis

Last updated: August 3, 2026

OSI Pharmaceuticals Inc. v. Mylan Pharmaceuticals Inc., No. 1:09-cv-00185, was a Hatch-Waxman patent case in the U.S. District Court for the District of Delaware involving Mylan’s proposed generic version of Tarceva, the erlotinib hydrochloride tablet marketed by OSI and Genentech. The case centered on U.S. Patent No. 5,747,498, which covered quinazoline compounds, including erlotinib.

The litigation was part of the broader generic-entry challenge to Tarceva. The asserted patent had a March 12, 2020 expiration date, subject to any applicable pediatric extension. The case did not create a reported Federal Circuit precedent materially changing the law governing erlotinib patents or Paragraph IV litigation.

What drug and patent were involved in OSI v. Mylan?

The case involved erlotinib hydrochloride, the active pharmaceutical ingredient in Tarceva.

Item	Detail
Brand product	Tarceva
Active ingredient	Erlotinib hydrochloride
Dosage form	Oral tablet
Brand sponsors	OSI Pharmaceuticals and Genentech
Defendant	Mylan Pharmaceuticals Inc.
Court	U.S. District Court for the District of Delaware
Case number	1:09-cv-00185
Filing year	2009
Principal patent	U.S. Patent No. 5,747,498
Patent title	Quinazoline derivatives
Patent expiration	March 12, 2020, before any pediatric extension
Statutory framework	Hatch-Waxman Act, including 21 U.S.C. § 355(j)

Tarceva was approved by the FDA in November 2004 for locally advanced or metastatic non-small-cell lung cancer after failure of at least one prior chemotherapy regimen. The FDA later approved additional indications, including pancreatic cancer in combination with gemcitabine.[1]

U.S. Patent No. 5,747,498 disclosed and claimed quinazoline compounds with activity against epidermal growth factor receptor, or EGFR. Erlotinib is an EGFR tyrosine kinase inhibitor within the patent’s chemical scope.[2]

What triggered the OSI Pharmaceuticals v. Mylan lawsuit?

Mylan filed an abbreviated new drug application seeking FDA approval for generic erlotinib hydrochloride tablets. Its ANDA included a Paragraph IV certification asserting that the relevant Tarceva patent was invalid, unenforceable, or would not be infringed by Mylan’s proposed product.

OSI responded by filing a patent-infringement action under 35 U.S.C. § 271(e)(2). That statutory claim treats the submission of an ANDA containing a Paragraph IV certification as an artificial act of infringement for purposes of resolving patent rights before commercial launch.

The complaint was filed in the District of Delaware in March 2009. The filing triggered the Hatch-Waxman 30-month stay, which generally prevents FDA approval of the ANDA during the statutory period unless the litigation is resolved earlier or the court orders otherwise.[3]

Which patent claims did OSI assert against Mylan?

The principal asserted patent was U.S. Patent No. 5,747,498.

The patent’s claim scope covered substituted quinazoline compounds and pharmaceutical compositions containing those compounds. OSI’s infringement theory was directed to Mylan’s proposed erlotinib product, including the active ingredient and pharmaceutical dosage form described in the ANDA.

The central patent issues were:

1. Whether Mylan’s proposed erlotinib tablets would infringe the asserted claims.
2. Whether the asserted claims were invalid for anticipation or obviousness.
3. Whether the patent was enforceable.
4. Whether the proposed generic product could receive FDA approval before patent expiration.

The public record identifies the case as an ANDA dispute involving Tarceva and the ’498 patent. The case did not result in a widely cited claim-construction or validity opinion establishing a new rule for quinazoline patents.

What were Mylan’s likely Paragraph IV defenses?

Mylan’s Paragraph IV position placed patent validity and infringement directly at issue. The standard defenses in this type of case include the following.

Invalidity

Mylan could challenge the asserted claims under 35 U.S.C. §§ 102 and 103. The likely theories were:

• Anticipation based on earlier quinazoline compounds or compositions.
• Obviousness based on prior EGFR inhibitor disclosures.
• Obviousness based on selecting or optimizing substituents within a known quinazoline scaffold.
• Lack of predictable expectation of success concerning potency, selectivity, pharmacokinetics, or clinical utility.

Chemical patent litigation often turns on whether the prior art provided a reason to make the claimed compound and a reasonable expectation that it would have the claimed biological properties.

Noninfringement

Mylan could argue that its proposed formulation did not satisfy one or more limitations of the asserted claims. In an ANDA case, the court evaluates the product and manufacturing information described in the ANDA, not an unrelated future product.

Enforceability

Mylan could also raise inequitable conduct or related enforceability defenses if it believed material information had been withheld from the U.S. Patent and Trademark Office with intent to deceive. Such defenses require proof of materiality and specific intent under the governing law.

The publicly available record does not support treating any one of these defenses as a definitive merits holding in favor of Mylan.

How did the litigation affect Tarceva’s FDA exclusivity?

The litigation created regulatory delay risk for Mylan, but the patent remained the principal barrier to approval and commercial launch.

Tarceva had already received FDA approval before the case was filed. The relevant regulatory protections were separate from patent protection:

Protection	Significance
New chemical entity exclusivity	Applied at initial FDA approval, subject to the approval date and applicable statutory rules
Orphan-drug exclusivity	Could protect specific approved indications if the FDA granted orphan designation
Patent protection	Controlled the principal generic-entry risk in the Mylan litigation
30-month stay	Delayed FDA approval after a Paragraph IV notice unless litigation ended earlier

FDA exclusivity and patent listing are distinct. FDA exclusivity may prevent approval of an ANDA even when no patent blocks approval. Conversely, an Orange Book-listed patent may delay approval through a Paragraph IV litigation stay even after regulatory exclusivity has expired.[4]

What was the Orange Book status of Tarceva?

The relevant Orange Book listing for Tarceva included U.S. Patent No. 5,747,498. The patent expiration date was March 12, 2020, with a possible six-month pediatric extension if statutory requirements were met.

The Orange Book listing gave the patent a direct role in ANDA litigation. A generic applicant seeking approval before expiration had to submit one of the statutory patent certifications. A Paragraph IV certification exposed the applicant to an infringement action, while a Paragraph III certification would defer approval until patent expiration.

The listing did not itself establish infringement or validity. It created the procedural mechanism for resolving those issues before generic launch.

When did the Tarceva patent lose exclusivity?

The ’498 patent expired on March 12, 2020, before any applicable pediatric extension. If the patent received a six-month pediatric extension, the effective exclusivity date would have moved to September 12, 2020.

The practical exclusivity timeline was:

Date	Event
April 1995	Earliest priority period associated with the ’498 patent family
June 1998	U.S. Patent No. 5,747,498 issued
November 2004	FDA approved Tarceva
March 2009	OSI filed the Mylan ANDA litigation
March 12, 2020	Listed patent expiration
September 12, 2020	Potential pediatric-extension endpoint
After expiration	Generic approval and launch became dependent on FDA approval, settlements, other patents, and commercial strategy

The patent term did not run for 20 years from the issue date. For modern U.S. patents, term generally runs from the relevant nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and pediatric exclusivity.

Did the case establish a major patent-law precedent?

No major reported precedent is generally associated with the docket.

The case was commercially significant because it addressed generic entry for a marketed oncology drug, but it did not produce a widely recognized appellate ruling on:

• Obviousness of erlotinib;
• The scope of the ’498 patent;
• ANDA-induced infringement;
• Paragraph IV notice requirements;
• Orange Book listing standards; or
• Generic-label method-of-use infringement.

The most important legal effect was procedural. OSI’s filing allowed the parties to litigate patent rights before Mylan could obtain FDA approval or launch its proposed erlotinib product.

What litigation risks existed for Mylan?

Mylan faced several risks beyond a conventional damages action.

FDA approval delay

The Hatch-Waxman stay could delay FDA approval for up to 30 months from the date of the Paragraph IV notice, unless the court entered judgment earlier or another statutory event ended the stay.

Injunctive relief

If OSI prevailed, the court could prohibit FDA approval or commercial manufacture and sale of Mylan’s product until patent expiration.

At-risk launch exposure

If Mylan launched before final resolution or before the relevant patent expired, it could face damages, an injunction, and possible enhanced damages depending on the circumstances.

Formulation and manufacturing exposure

A generic applicant must ensure that the product described in its ANDA does not infringe relevant composition, formulation, process, or method claims. Even if the active ingredient is no longer protected, separate patents can create launch risk.

For Tarceva, the principal publicly identified barrier in this case was the compound patent. The available case record does not establish that OSI secured a separate formulation or manufacturing judgment against Mylan in this docket.

Were formulation patents or method-of-use patents involved?

The case is principally associated with the erlotinib compound patent, U.S. Patent No. 5,747,498.

Tarceva’s broader patent estate could include additional patent categories:

• Compound patents covering erlotinib or related quinazoline compounds.
• Pharmaceutical-composition patents.
• Solid-state or salt-form patents.
• Manufacturing-process patents.
• Method-of-treatment patents.
• Indication-specific patents.

Those categories must be separated from the claims actually asserted in No. 1:09-cv-00185. The case should not be characterized as a formulation-patent dispute unless the operative pleadings or court orders establish that formulation claims were litigated.

Method-of-use claims can raise separate issues under 35 U.S.C. § 271(e)(2), particularly when the ANDA label directs use for a patented indication. A generic applicant may attempt a section viii statement carving out a patented use from its label. The public record for this docket does not establish a final method-of-use ruling.

Did OSI and Mylan reach a settlement?

The public docket is treated as a terminated Hatch-Waxman action, but the case record does not provide a broadly reported merits decision that resolved the ’498 patent’s validity or infringement in favor of either party.

A Hatch-Waxman termination may result from settlement, dismissal, covenant not to sue, consolidation, or another procedural resolution. The termination alone does not establish the commercial terms, launch date, royalty structure, or whether Mylan received a license.

No reliable public source should be used to infer a “licensed early entry” date or payment arrangement without the settlement agreement, a court filing describing its terms, or a regulatory record confirming the arrangement.

How strong was the OSI Tarceva patent estate?

The estate was commercially strong during the period covered by the Mylan case because:

• The ’498 patent covered the active molecule used in Tarceva.
• The patent remained in force for roughly 11 years after the 2009 complaint.
• The product was an approved oncology therapy with established clinical use.
• A Paragraph IV challenge exposed Mylan to a statutory infringement action and delayed FDA approval.
• Compound patents generally create a broader barrier than patents limited to a particular formulation or indication.

The estate’s strength declined as the patent approached expiration. Once the compound patent expired, any remaining protection depended on unexpired formulation, method-of-use, manufacturing, regulatory, or pediatric-exclusivity rights.

What generic-entry scenarios applied to Tarceva?

The principal launch scenarios were:

1. Mylan prevailed on validity or infringement and received FDA approval before patent expiration.
2. OSI prevailed, preserving the patent barrier until expiration.
3. The parties settled with a negotiated launch date.
4. The FDA approved a product after the patent expired, subject to any remaining exclusivity.
5. Mylan launched after expiration but faced separate patents or regulatory restrictions.

The commercial impact depended on whether Mylan obtained an ANDA approval, whether other ANDA applicants entered, whether the product was therapeutically substitutable, and whether the market had multiple generic suppliers.

What was the commercial exposure for OSI and Genentech?

Tarceva generated material oncology revenue for its commercial sponsors. Revenue exposure came from the potential substitution of lower-priced erlotinib tablets after generic approval.

The impact of generic entry was likely to depend on:

• The number of approved ANDAs.
• The timing of first generic launch.
• Whether first-filer exclusivity applied.
• The extent of pharmacy substitution.
• The distribution of Tarceva sales across indications.
• The availability of alternative EGFR therapies.
• Price erosion following multiple generic entries.

The case itself did not determine total Tarceva revenue loss. It determined whether Mylan could overcome or defer the patent barrier through the ANDA process.

Key Takeaways

• OSI Pharmaceuticals Inc. v. Mylan Pharmaceuticals Inc., No. 1:09-cv-00185, was a Delaware Hatch-Waxman case involving generic erlotinib hydrochloride.
• The principal patent was U.S. Patent No. 5,747,498.
• The patent covered quinazoline compounds, including erlotinib, the active ingredient in Tarceva.
• OSI filed the action after Mylan submitted a Paragraph IV certification.
• The patent’s listed expiration date was March 12, 2020, potentially extended to September 12, 2020 for pediatric exclusivity.
• The case did not produce a widely cited appellate precedent on erlotinib validity, ANDA infringement, or Orange Book law.
• The public record does not establish a merits judgment or reliable settlement terms that should be used to infer Mylan’s launch date.
• The case’s commercial importance arose from the strength and duration of Tarceva’s compound patent protection.

FAQs

Was Tarceva’s active ingredient protected by a compound patent?

Yes. Erlotinib was covered by U.S. Patent No. 5,747,498, which claimed quinazoline compounds and related pharmaceutical compositions.

Was OSI v. Mylan a Paragraph IV case?

Yes. The lawsuit followed Mylan’s Paragraph IV certification concerning the patent listed for Tarceva.

Did Mylan launch generic erlotinib before the ’498 patent expired?

The docket alone does not establish an authorized pre-expiration launch date. Generic approval and launch depended on the case’s resolution, any settlement, FDA action, and remaining patent or exclusivity rights.

Did Tarceva have biosimilar competition?

No. Tarceva is a small-molecule drug, not a biologic. The relevant competitive pathway was an ANDA for generic erlotinib, not a biosimilar application under the Public Health Service Act.

What was the key patent risk after the compound patent expired?

The remaining risks could include unexpired formulation, method-of-use, manufacturing, or regulatory protections. A compound-patent expiration does not automatically eliminate every possible restriction on a generic product.

References

1. U.S. Food and Drug Administration. (2004). FDA approves Tarceva for treatment of lung cancer.
2. U.S. Patent and Trademark Office. (1998). U.S. Patent No. 5,747,498: Quinazoline derivatives.
3. U.S. District Court for the District of Delaware. (2009). OSI Pharmaceuticals Inc. v. Mylan Pharmaceuticals Inc., No. 1:09-cv-00185, docket record.
4. U.S. Food and Drug Administration. (2023). Approved drug products with therapeutic equivalence evaluations, 43rd ed. [Orange Book].