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Mark J. Feldstein, Ph.D.
Partner
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  • 901 New York Avenue, NW
  • Washington, DC 20001-4413
+1 202 408 4092
mark.feldstein@finnegan.com mark.feldstein@finnegan.com

Mark J. Feldstein, Ph.D.

Partner

  • +1 202 408 4092 +1 202 408 4092
  • mark.feldstein@finnegan.com mark.feldstein@finnegan.com
  • 901 New York Avenue, NW
  • Washington, DC 20001-4413
  • vCard

Mark Feldstein, Ph.D., focuses on U.S. district court litigation, primarily concerning the enforcement of U.S. patent rights and trade secret issues, and post-grant trial proceedings at the U.S. Patent and Trademark Office (USPTO), including inter partes review (IPR) and post grant review (PGR). He has particular experience with litigations arising from Abbreviated New Drug Applications (ANDAs) under the Hatch-Waxman Act.

Mark also maintains an active patent prosecution practice, preparing and prosecuting U.S. patent applications on behalf of domestic and foreign clients. In addition, he provides opinions and strategic guidance to clients on infringement, validity, enforceability, and clearance matters. In Acritas Stars, clients have praised his extensive knowledge of patent law; depth of technical and legal expertise, and the quality of advice; and determination to get things done. LMG Life Sciences has nominated Mark as the Post-Grant Proceedings Attorney of the Year and has also noted his contributions to the fields of "General Patent Litigation" and "Hatch-Waxman Patent Litigation."

Mark's practice encompasses a range of technologies, including pharmaceuticals, chemicals, biochemistry, polymers, small molecule chemistry, nanotechnology, optics, and medical and analytic devices. His proficiency in these areas is supported by extensive research experience. Prior to his legal career, Mark conducted research in ultrafast laser spectroscopy and scanning probe microscopy analysis applied to metallic, nano-structured, and conducting polymeric systems. As a National Research Council post-doctoral associate, Mark also designed and developed optically transduced biosensors and related signal processing software for the U.S. Naval Research Laboratory.

Mark is an adjunct professor of law at Georgetown University Law Center, teaching courses in patent prosecution practice and IP management. He regularly speaks to national and international audiences of both attorneys and scientists on issues of patent strategy, prosecution, and litigation. Mark is also an associate editor for texts published by the American Bar Association Section of Intellectual Property Law on ANDA litigation law and strategy, and by AIPLA/Bloomberg BNA on evidence in patent litigations.

Mark's pro bono activities include military veteran representation before the U.S. Court of Appeals for Veterans Claims.

Experience

Merck Sharp & Dohme LLC v. Hetero USA Inc., Lupin Limited et al.

Lead counsel representing Merck in Hatch-Waxman litigations involving the HIV drugs ISENTRESS®and ISENTRESS®HD.

2:23-cv-00094, 2:23-cv-02364, D.N.J., Judges Cecchi, Padin, Wettre

Sun Pharm. Indus., Inc. f/d/b/a Concert Pharm., Inc. v. Incyte Corp.

Lead counsel for Incyte in Federal Circuit appeal of IPR against a patent claiming deuterated versions of the active ingredient in Incyte’s FDA approved Jakafi® product (ruxolitinib); secured a unanimous affirmance of the PTAB’s obviousness determination.

19-2011, Fed. Cir., Judges Hughes, Linn, Stark
IPR2017-01256, PTAB, Judges Franklin, Hulse, Smith

Teva Pharmaceuticals International GmbH v. Eli Lilly and Company

Successfully represented Eli Lilly in defensive patent litigation and served as lead counsel in offensive inter partes reviews (IPRs) regarding products related to the treatment of migraines.

IPR2022-00738, -00739, -00796, PTAB, Judges Cotta, Wisz, Worth
1:21-cv-10954, D. Mass., Judge Burroughs

Risen (Suzhou) Pharma Tech Co., Ltd. v. Alzheon, Inc.

Successfully represented Alzheon, Inc. in inter partes reviews (IPRs) defending patents related to tramiprosate, a treatment for Alzheimer’s Disease. Continuing representation at the Federal Circuit.

IPR2022-01200, PGR2022-00051, PTAB, Judges Newman, Snedden, Wisz
22-2232, Fed. Cir.

Eli Lilly and Company v. Actavis Labs. UT Inc.

Representing Eli Lilly as lead counsel in Hatch-Waxman action against several defendants relating to Cialis®.

1:16-cv-01119, E.D. Va., Judges Nachmanoff, Trenga

Equistar Chemicals, LP v. ExxonMobil Chemical Patents Inc.

Successfully represented petitioner Equistar as lead counsel in an inter partes review (IPR), resulting in a ruling of unpatentability for all claims of a patent directed to an apparatus and process of manufacturing polyethylene in a high-pressure tubular reactor.

IPR2017-01534, PTAB, Judges Abraham, Roesel, Tornquist

Concert Pharmaceuticals, Inc. v. Incyte Corp.

Successfully defended Incyte Corp. against a PGR petition related to deuterated versions of the active ingredient in Incyte’s FDA approved Jakafi® product (ruxolitinib), achieving a non-institution decision from the PTAB.

PGR2017-00034, PTAB, Judges Paulraj, Sawert, Snedden

Eli Lilly and Company v. Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center
Represented Eli Lilly in two IPRs and on appeal to Federal Circuit.

IPR2014-00693, -00752, PTAB, Judges Green, Prats, Snedden
16-1547, Fed. Cir., Judges Bryson, Moore, Newman

Cumberland Pharmaceuticals Inc. v. Mylan Institutional, LLC
Counsel for Cumberland in ANDA litigation and breach of contract arbitration. Successful outcome in bench trial, arbitration, arbitration fee award, and appeal.

16-1155, -1259, Fed. Cir., Judges Moore, Reyna, Taranto
1:12-cv-03846, N.D. Ill., Judge Pallmeyer

Actelion Pharmaceuticals v. ICOS Corp.
Represents ICOS in two IPRs defending their formulation patents.

IPR2015-00561, -00562, PTAB, Judges Mitchell, Snedden, Yang

Borealis AG v. Berry Plastics Corp.
Represented Borealis as lead counsel in two IPRs, resulting patent owner filing statutory disclaimers to cancel all 64 challenged claims. 

IPR2016-00235, -00564, PTAB, Judges Chagnon, McKelvey, Medley, Snedden

AstraZeneca LP v. SigmaPharm Laboratories
Representing AstraZeneca in Hatch-Waxman litigations against several defendants involving the blood-thinning drug Brilinta®.

1:15-cv-01000, D. Del., Judge Andrews

Dow Chemical Co. v. Nova Chemicals Corp.
Represented NOVA Chemicals patent infringement suit relating to solution phase polymerized polyethylene compositions, in Markman hearing, damages trial, jury trial, and on appeal to the Federal Circuit.

1:05-cv-00737, D. Del., Judges Farnan, Stark
14-1431, -1462, Fed. Cir., Judges Dyk, Prost, Wallach

Shurtape Technologies, LLC v. 3M Co.
Represented 3M in Markman hearing.

5:11-cv-00017, W.D.N.C., Judges Keesler, Voorhees

In Re: Armodafinil Patent Litigation
Successfully represented Cephalon against several generic companies in Paragraph IV ANDA litigations pertaining to Nuvigil®, Cephalon’s prescription medicine used to improve wakefulness. The district court found the asserted claim patents valid and infringed and enjoined the defendants from marketing generic versions until patent expiry. The case was ultimately resolved through confidential settlement.

1:10-md-02200, D. Del., Judge Sleet

Eli Lilly and Company v. Teva Pharmaceuticals USA, Inc.
Successfully represented Eli Lilly in district court and Federal Circuit to enforce patent on osteoporosis drug Evista®. Won appeal regarding extension of thirty-month regulatory stay.

1:06-cv-01017, S.D. Ind., Judges Barker, Magnus-Stinson
09-1071; 10-1005, -1033, Fed. Cir., Judges Linn, Michel, Prost, Rader

Monsanto Co. v. Syngenta Seeds
Represented Syngenta in patent litigation involving glyphosate-resistant transgenic corn, leading to summary judgment of non-infringement and patent invalidity, which was later affirmed by the Federal Circuit.

1:04-cv-00305, D. Del., Judge Robinson
06-1472, Fed. Cir., Judges Gajarsa, O'Malley, Rader

Cryovac Inc. v. Pechiney Plastic Packaging, Inc. 
Represented Cryovac, in assertion of patent infringement against Pechiney Plastic Packaging (plastic film packaging) that resulted in jury finding of infringement, lost profits damages, and upholding validity of Cryovac's patent.

1:04-cv-01278, D. Del., Judge Jordan

Incyte Corporation et al. v. Sun Pharmaceutical Industries Limited et al.

Lead counsel for Incyte in patent litigation related to Sun Pharmaceuticals’ deuterated Janus kinase (JAK) inhibitor, LEQSELVI™.

2:24-cv-06944, D.N.J., Judge Padin

Merck Sharp & Dohme LLC v. Hetero USA Inc., Lupin Limited et al.

Lead counsel representing Merck in Hatch-Waxman litigations involving the HIV drugs ISENTRESS®and ISENTRESS®HD.

2:23-cv-00094, 2:23-cv-02364, D.N.J., Judges Cecchi, Padin, Wettre

Incyte Corp. v. Concert Pharmaceuticals, Inc.

Lead counsel for Incyte in Federal Circuit appeal of IPR against a patent claiming deuterated versions of the active ingredient in Incyte’s FDA approved Jakafi® product (ruxolitinib); secured a unanimous affirmance of the PTAB’s obviousness determination.

IPR2017-01256, PTAB, Judges Fitzpatrick, Hulse, Yang, Smith, Franklin
19-2011, Fed. Cir., Judges Hughs, Linn, Stark

Teva Pharmaceuticals International GmbH v. Eli Lilly and Company

Successfully represented Eli Lilly in defensive patent litigation and served as lead counsel in offensive inter partes reviews (IPRs) regarding products related to the treatment of migraines.

IPR2022-00738, -00739, -00796, PTAB, Judges Cotta, Wisz, Worth
1:21-cv-10954, D. Mass., Judge Burroughs

Risen (Suzhou) Pharma Tech Co., Ltd. v. Alzheon, Inc.

Successfully represented Alzheon, Inc. in inter partes reviews (IPRs) defending patents related to tramiprosate, a treatment for Alzheimer’s Disease. Continuing representation at the Federal Circuit.

IPR2022-01200, PGR2022-00051, PTAB, Judges Newman, Snedden, Wisz
22-2232, Fed. Cir.

Eli Lilly and Company v. Actavis Labs. UT Inc.

Representing Eli Lilly as lead counsel in Hatch-Waxman action against several defendants relating to Cialis®.

1:16-cv-01119, E.D. Va., Judges Nachmanoff, Trenga

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Insights

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Litigating Chemical Cases at the ITC: Procedural Considerations and Claiming Strategies

Litigating Chemical Cases at the ITC: Procedural Considerations and Claiming Strategies Litigating Chemical Cases at the ITC: Procedural Considerations and Claiming Strategies

January 29, 2025

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At the PTAB Blog

Trends in PTAB Trials Involving Drug and Biologic Patents Trends in PTAB Trials Involving Drug and Biologic Patents

June 26, 2024

Books

Biosimilars Litigation and Client Counseling Biosimilars Litigation and Client Counseling

June 17, 2024

American Bar Association

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Biologics and Biosimilars: FDA Initiatives and Guidance, Approvals and Exclusivity, Patent Prosecution, Litigation Biologics and Biosimilars: FDA Initiatives and Guidance, Approvals and Exclusivity, Patent Prosecution, Litigation

February 15, 2024

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Doctrine of Equivalents After VLSI Technology Decision: Navigating DOE Amid Tight Policing; Avoiding Pitfalls Doctrine of Equivalents After VLSI Technology Decision: Navigating DOE Amid Tight Policing; Avoiding Pitfalls

January 18, 2024

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Inducement to Infringe in Hatch-Waxman Litigation: Strategies for Patent Drafting, Prosecution, and Litigation Inducement to Infringe in Hatch-Waxman Litigation: Strategies for Patent Drafting, Prosecution, and Litigation

December 14, 2023

Webinar

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Professional Recognition

“He’s brilliant. He’s a patent litigator, he has excellent technical skills, and he’s an excellent attorney…”

Acritas Stars™

“He’s brilliant. He’s a patent litigator, he has excellent technical skills, and he’s an excellent attorney…”

Acritas Stars™

News

Press Release

Finnegan Recognized as a Leading Firm in the 2025 LMG Life Sciences Americas Rankings Finnegan Recognized as a Leading Firm in the 2025 LMG Life Sciences Americas Rankings

October 1, 2025

LMG Life Sciences

Media Mention

NJ Judge Blocks Sun Pharma from Launching Hair Loss Drug NJ Judge Blocks Sun Pharma from Launching Hair Loss Drug

November 4, 2024

Law360

Award/Ranking

Finnegan Remains a Tier 1 Firm in the 2024 LMG Life Sciences Rankings Finnegan Remains a Tier 1 Firm in the 2024 LMG Life Sciences Rankings

October 4, 2024

LMG Life Sciences

Award/Ranking

Finnegan Shortlisted for 14 LMG Life Sciences 2024 Americas Awards Finnegan Shortlisted for 14 LMG Life Sciences 2024 Americas Awards

July 18, 2024

LMG Life Sciences

Commentary

Fed. Circ. OKs Boston Drug Developer's Patent Win Fed. Circ. OKs Boston Drug Developer's Patent Win

March 11, 2024

Law360

Commentary

Too Many Cooks: Inventorship an Increasing Problem for Patent Counsel Too Many Cooks: Inventorship an Increasing Problem for Patent Counsel

November 21, 2023

Managing Intellectual Property
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Professional Activities

  • American Association of Pharmaceutical Scientists (AAPS)
  • Intellectual Property Owner's Association
    (Pharmaceutical & Biotechnology Issues Committee, U.S. Legislation Subcommittee, 2025-present)
Admissions and Education

Admissions

  • U.S. Patent and Trademark Office
  • District of Columbia
  • Maryland
  • U.S. District Court, District of Columbia
  • U.S. Court of Appeals, Federal Circuit
  • U.S. Court of Appeals, Veterans Claims

Education

Georgetown University Law Center
J.D., cum laude, 2001
University of Pennsylvania
Ph.D., Physical Chemistry, 1997
University of Chicago
M.S., Chemistry, 1992
George Washington University
B.S., Chemistry, cum laude, 1991
George Washington University
B.A., Philosophy, cum laude, 1991

Mark's Practices

Global IP Enforcement, Litigation, and Trials
Branded Hatch-Waxman (ANDA) Litigation and Trials
Patent Litigation and Trials
Trade Secrets
Patent Office Invalidation Proceedings
PTAB Invalidation Proceedings: IPR and PGR
Prosecution and Portfolio Management
Opinions and Counseling
Patent Drafting and Prosecution

Mark's Industries

AI, Electronics, and Information Technology
Nanotechnology
Chemicals, Industrials, and Materials
Additive Manufacturing
Chemical
Textiles
Energy
Clean Energy and Renewables
Oil and Gas
Life Sciences
Biologics
Biotechnology
Medical Device and Diagnostics
Pharmaceutical

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