Lindis Biotech v. Amgen: Blincyto Patents Held Unenforceable After 1,360-Day Trial
Lindis Biotech GmbH brought a three-patent infringement suit against Amgen’s blockbuster BiTE antibody therapy Blincyto in the District of Delaware. After nearly four years of litigation, Judge Gregory B. Williams entered final judgment for Amgen — ruling that all three asserted patents are unenforceable due to inequitable conduct, a finding that effectively ends Lindis’s enforcement rights.
Inequitable conduct finding wipes out Lindis’s entire Blincyto patent portfolio
Lindis Biotech GmbH, a German biopharmaceutical company, filed suit against Amgen Inc. on January 10, 2022 in the District of Delaware, asserting three US patents — US10071158, US8709421, and US10576149 — covering BiTE (bispecific T-cell engager) antibody technology. The accused product was Blincyto (blinatumomab), Amgen’s FDA-approved CD19/CD3 bispecific antibody therapy used to treat relapsed or refractory B-cell precursor acute lymphoblastic leukemia, a drug that has become a flagship of Amgen’s oncology portfolio.
On October 1, 2025, Judge Gregory B. Williams entered final judgment entirely in favor of Amgen. The court found that Lindis committed inequitable conduct with respect to each of the three asserted patents — a particularly severe outcome, as an inequitable conduct finding renders patents unenforceable rather than merely invalid, and cannot be cured by reissue or design-around. Lindis’s infringement claims were dismissed with prejudice on the merits, while Amgen’s remaining counterclaims and defenses were dismissed as moot given the totality of the ruling.
The 1,360-day duration suggests complex claim construction, extensive expert discovery, and likely a jury trial on infringement before the inequitable conduct counterclaims were resolved — consistent with the extensive agent rosters on both sides. The attorneys’ fees deadline has been extended pending any appeal, preserving Amgen’s ability to argue the case is ‘exceptional’ under 35 U.S.C. § 285, which could mean a substantial fee award if no appeal is filed or appeal is unsuccessful. The precise nature of the alleged inequitable conduct — which representations to the USPTO were at issue — is not detailed in the public final judgment.
Filing to Judgment on the merits for Defendant in 1360 days
1,360 days — nearly 3.7 years from filing to final judgment in D. Del.
Final judgment for Amgen: three patents unenforceable for inequitable conduct
Inequitable conduct: the nuclear option in patent law
Inequitable conduct requires proof that a patent applicant intentionally withheld or misrepresented material information before the USPTO with intent to deceive. It is among the most severe patent defenses: a finding renders the patent permanently unenforceable, not merely invalid. Unlike anticipation or obviousness, the taint cannot be cured through reissue proceedings. Here, Amgen prevailed on this ground for all three asserted patents simultaneously.
Unenforceability — not merely invalidityLindis loses all enforcement rights across its Blincyto patent portfolio
The unenforceability finding means Lindis Biotech cannot assert US10071158, US8709421, or US10576149 against Amgen — or, practically, against any other party — going forward. The infringement claims were also dismissed on the merits, eliminating any damages claim. Lindis’s only realistic path forward is a successful appeal, which will require overturning the inequitable conduct finding under a clear-error standard on the factual questions of materiality and intent.
All three patents unenforceableAmgen secures Blincyto freedom-to-operate and a potential fee award
Amgen not only defeated the infringement claims but obtained the stronger remedy of unenforceability, clearing Blincyto from any future threat from these patents. The court preserved Amgen’s right to move for attorneys’ fees under 35 U.S.C. § 285 once the appeal window closes, suggesting Amgen may seek to have the case declared exceptional — a potentially significant financial outcome on top of the liability victory.
§ 285 fee motion preservedBiTE antibody space: enforceability risk raised for patent filers
The ruling reinforces that bispecific antibody patent holders face heightened scrutiny over USPTO prosecution conduct. For BiTE and other bispecific formats entering enforcement campaigns, this case signals that defendants will aggressively probe prosecution history for inequitable conduct. Companies holding antibody platform patents — particularly those with complex interference or priority disputes — should audit their prosecution files before initiating litigation.
Prosecution conduct audit warrantedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Lindis Biotech, GmbH | Company | German biopharma — holder of BiTE antibody patents US10071158, US8709421 & US10576149Search in Eureka ↗ |
| Defendant | Amgen, Inc. | Company | Amgen Inc. — global biopharmaceutical company, maker of Blincyto (blinatumomab)Search in Eureka ↗ |
| Plaintiff counsel | Brian R. Michalek | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Courtland C. Merrill | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Henry A. Platt | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | James Darlington Taylor , Jr. | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Jessica Marie Jones | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Matthew J. Antonelli | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Michelle Streifthau-Livizos | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Patrick Lockwood | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Robert C Gill | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Veronica McCarty | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff counsel | Zachary Jacobs | Attorney | Counsel for Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff law firm | Potter, Anderson & Corroon LLP | Law Firm | Representing Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff law firm | Saul Ewing Arnstein & Lehr LLP | Law Firm | Representing Lindis Biotech, GmbHSearch in Eureka ↗ |
| Plaintiff law firm | Saul Ewing LLP | Law Firm | Representing Lindis Biotech, GmbHSearch in Eureka ↗ |
| Defendant counsel | Blake Greene | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Brian Kao | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Carolyn S. Wall | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Courtney M. Prochnow | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Gianna Carina Penezic | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Hassen Sayeed | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | J. Drew Diamond | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | James L. Higgins | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Jing Ying Zhao | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Joseph P. Hamilton | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Lara J. Dueppen | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Lindsay H. Autz | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Lisa Barons Pensabene | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Luann L. Simmons | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Melanie K. Sharp | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Michael J. Wise | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Sorin Zaharia | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Stephanie Vangellow | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant counsel | Taylor E. Hallowell | Attorney | Counsel for Amgen, Inc.Search in Eureka ↗ |
| Defendant law firm | O’Melveny & Myers LLP | Law Firm | Representing Amgen, Inc.Search in Eureka ↗ |
| Defendant law firm | Young, Conaway, Stargatt & Taylor LLP | Law Firm | Representing Amgen, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Gregory B. Williams | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The final judgment language is unusually comprehensive, adjudicating inequitable conduct on Amgen’s counterclaims (Counts 3 and 6) and simultaneously dismissing Lindis’s infringement claims on the merits — leaving no viable claim standing for the plaintiff. The express preservation of the § 285 attorneys’ fees motion, tied to appellate finality, reflects standard Delaware district court practice but signals that Amgen intends to pursue fees seriously. The dismissal of all other counterclaims ‘as moot’ confirms the inequitable conduct finding was outcome-determinative, making any technical invalidity or non-infringement analysis unnecessary.
US10071158, US8709421 & US10576149 — BiTE antibody immunotherapy platform
The three asserted patents — US10071158 (App. No. 14/247029), US8709421 (App. No. 11/977856), and US10576149 (App. No. 15/934403) — relate to BiTE (bispecific T-cell engager) antibody technology, the platform underlying Amgen’s Blincyto. BiTE constructs are single-chain bispecific antibody fragments designed to simultaneously bind a tumour antigen (CD19 in Blincyto’s case) and the CD3 epsilon subunit on T-cells, redirecting cytotoxic T-cells to kill cancer cells. The application dates span a multi-year prosecution history, consistent with a platform technology that was extended and refined across multiple continuation or continuation-in-part applications.
BiTE technology is one of the most commercially valuable antibody engineering platforms in oncology, with Blincyto generating hundreds of millions in annual revenue for Amgen. The assertion of three patents across different application numbers suggests Lindis was attempting to build a broad claim fence around core BiTE mechanisms — a strategy that increases litigation leverage but also multiplies prosecution history exposure. The unenforceability finding across all three patents simultaneously is consistent with a shared prosecution actor or a common disclosure deficiency spanning the patent family, though the specific conduct remains undisclosed in the public record.
Should you run an FTO against US10071158, US8709421 & US10576149?
Biopharmaceutical companies, antibody engineering teams, and immuno-oncology developers working on bispecific T-cell engager constructs, CD19 or CD3-targeting biologics, or any BiTE-format therapy should monitor this patent family. Although these three patents have been rendered unenforceable in this proceeding, the underlying technology claims remain relevant for understanding the landscape — and an appeal could reverse or limit the unenforceability ruling, restoring enforceability of some or all claims.
PatSnap Eureka’s FTO Search Agent can map the full claim scope of US10071158, US8709421, and US10576149 against your BiTE or bispecific antibody pipeline, identify related family members not adjudicated in this case, and flag any prosecution history patterns that may signal enforceability risk. Use Eureka to benchmark your freedom to operate in the bispecific antibody space and track any post-appeal changes to these patents’ enforceability status in real time.
Run a freedom-to-operate analysis on US10071158 to assess your product’s exposure
Run FTO in Eureka →Similar BiTE antibody patent infringement cases in US district courts
Explore related bispecific antibody patent disputes filed in Delaware and other US district courts involving immunotherapy platform enforcement and inequitable conduct defenses.
What this case signals for the BiTE antibody IP enforcement landscape
The Lindis v. Amgen outcome delivers a clear warning to biopharmaceutical patent holders: prosecutorial conduct can be litigated as aggressively as technical infringement.
Inequitable conduct is back as a primary weapon in biopharma patent litigation
After Therasense (Fed. Cir. 2011) raised the bar for inequitable conduct by requiring proof of specific intent to deceive, the defense fell out of favour. This case — where Amgen successfully invalidated all three asserted patents on that ground — suggests sophisticated defendants with resources and deep prosecution history access will continue to deploy it offensively in high-stakes biopharma disputes.
Patent holders should audit prosecution files before filing an infringement suit
Lindis’s outcome demonstrates the litigation risk of asserting patents without first stress-testing prosecution history for prior art disclosure gaps, inventor oath accuracy, and any potential misrepresentations to the USPTO. An internal inequitable conduct audit has become a necessary pre-filing step for any biopharma plaintiff, particularly in cases involving complex PCT prosecution chains or collaborative research origins.
Lindis v Amgen — key questions answered
Final judgment was entered for Amgen on October 1, 2025. The Delaware District Court found that Lindis Biotech committed inequitable conduct with respect to all three asserted patents — US10071158, US8709421, and US10576149 — rendering them permanently unenforceable. Lindis’s infringement claims against Blincyto were also dismissed on the merits.
Inequitable conduct in US patent law occurs when a patent applicant intentionally withholds or misrepresents material information before the USPTO with specific intent to deceive. A successful inequitable conduct defense renders the patent unenforceable — a harsher outcome than invalidity, because the patent cannot be revived through reissue. The Therasense standard (Fed. Cir. 2011) requires proof of both materiality and intent, making the defense difficult to win, which makes Amgen’s success across three patents notable.
Lindis Biotech asserted three US patents: US10071158 (Application No. 14/247029), US8709421 (Application No. 11/977856), and US10576149 (Application No. 15/934403). All three relate to BiTE bispecific T-cell engager antibody technology, which is the mechanism of action underlying Blincyto (blinatumomab), Amgen’s therapy for relapsed or refractory B-cell precursor acute lymphoblastic leukemia.
The final judgment expressly preserved Amgen’s right to move for attorneys’ fees and costs under 35 U.S.C. § 285, which allows fee awards in ‘exceptional’ patent cases. The deadline for any such motion was extended to 60 days after the appeal deadline expires (if no appeal is filed) or 60 days after the conclusion of all appeals. Amgen has not yet filed a fee motion as of the judgment date.
The ruling signals that bispecific antibody patent holders asserting platform patents face substantial risk if their USPTO prosecution history contains potential inequitable conduct vulnerabilities. Defendants with resources — like Amgen — will aggressively assert inequitable conduct counterclaims. Patent holders in the BiTE and broader bispecific antibody space should conduct thorough prosecution audits before initiating infringement litigation, particularly where patents share inventors or prosecution counsel across a family.
PatSnap Eureka searches patents and litigation data to answer instantly.