A Case for Drafting Patent Claims on Production Methods

Patent prosecutors often overlook claims directed to production methods. After all, infringement can be difficult to detect and prove when the patented method is practiced behind the closed doors of a manufacturing facility. In contrast, identifying potential infringement of composition or device claims is often more straightforward.

From a pharmaceutical innovator's perspective, another drawback is that manufacturing methods generally cannot be listed in the Orange Book unless the resulting product itself is novel. As a result, such patents may not trigger a Paragraph IV Notice, support a 30-month stay, or serve as a direct barrier to generic approval in the same way that composition or method-of-use patents can.

That said, there can be strategic value in maintaining patents that are not Orange Book-listed and therefore are less likely to be asserted—or challenged—through traditional Hatch-Waxman pathways.

Manufacturing Method Patents Can Expand Protection

Regardless of Orange Book considerations, manufacturing method patents may provide protection beyond what a composition patent offers alone because they are governed by a dedicated infringement provision, 35 U.S.C. § 271(g):

"Whoever without authority imports into the United States or offers to sell, sells, or uses within the United States a product which is made by a process patented in the United States shall be liable as an infringer...."

This provision offers the following advantages to patent holders:

• Protects against offshore manufacturing: Competitors cannot necessarily avoid infringement by practicing a patented manufacturing process outside the United States and importing the resulting product.
• May reach domestic activities: Depending on the jurisdiction, Section 271(g) may also apply to products made in the United States using a patented process.
• Creates downstream exposure: Some courts have held that entities that sell or use products made by a patented process can be liable for direct infringement, even if they did not perform the process themselves.^[1]

A Growing Split Among Courts

Several district courts have adopted a textual interpretation of Section 271(g) that permits downstream liability for sellers and users of products made using a patented process. Courts following this approach include:

• Central District of California
• Southern District of California
• District of Delaware (Judges Connolly and Goldberg)
• Northern District of Illinois
• Western District of Louisiana
• Eastern District of New York^[2]

Other courts have declined to apply the statute so broadly, including:

• Northern District of California
• District of Delaware (Judge Robinson)
• District of Massachusetts
• Eastern District of Texas^[3]

This split is a source of uncertainty but also potential strategic opportunities for patent owners.

Key Takeaways for Patent Owners and Drafters

Manufacturing method claims should not be dismissed simply because they can be more challenging to enforce. When available, they may provide valuable protection that complements composition and method-of-use claims.

Consider the following:

• Include production method claims whenever the underlying technology supports them.
• View manufacturing patents as a tool to broaden protection around a commercial product.
• Evaluate how Section 271(g) may provide leverage against importers, sellers, and users—not just manufacturers.
• Consider forum-specific interpretations of Section 271(g) when assessing enforcement strategies and litigation risk.

While the district court split remains unresolved, patent drafters and portfolio managers can take advantage of the potential reach of manufacturing method claims and the additional enforcement pathways they may create.

[1] Peter A. Hecker, Patent Infringement Under 35 U.S.C. § 271(g) for Goods Made in the United States, 19 UIC Rev. Intell. Prop. L. 64 (2019), https://repository.law.uic.edu/ripl/vol19/iss1/3/; Zachary B. Messick & Brenden S. Gingrich, Reseller or Distributor Beware? Downstream Liability for Infringing a Patented Process, Knobbe Martens Biotechnology Blog (July 11, 2023), https://www.knobbe.com/blog/reseller-or-distributer-beware-downstream-liability-infringing-patented-process/.

[2] See Fate Therapeutics, Inc. v. Shoreline Biosciences, Inc., 664 F. Supp. 3d 1125, 1134 (S.D. Cal. 2023); McRO, Inc. v. Namco Bandai Games Am., Inc., 23 F. Supp. 3d 1113, 1119–21 (C.D. Cal. 2013); Designing Health, Inc. v. Erasmus, No. CV 98-4758 LGB, 2002 WL 34536686, at *9 n.6 (C.D. Cal. Feb. 26, 2002); Genentech, Inc. v. Amgen Inc., No. CV 17-1407-CFC, 2020 WL 708433, at *1 (D. Del. Feb. 12, 2020); Kyowa Hakka Bio, Co. v. Ajinomoto Co., No. CV 17-313, 2018 WL 834583, at *8–9 (D. Del. Feb. 12, 2018); Avery Dennison Corp. v. UCB Films PLC, No. 95 C 6351, 1997 WL 665795, at *1 & n.2 (N.D. Ill. Oct. 20, 1997); United Gen. Supply Co. v. 2nds in Bldg. Materials, Inc., No. CV 15-1975, 2017 WL 524720, at *2 (W.D. La. Feb. 7, 2017); Shamrock Techs., Inc. v. Precision Micron Powders Inc., No. CV 91-0869, 1991 WL 335362, at *2 (E.D.N.Y. Aug. 8, 1991).

[3] Bos. Sci. Corp. v. Johnson & Johnson, 534 F. Supp. 2d 1062, 1081 (N.D. Cal. 2007); Hughes Aircraft Co. v. Nat'l Semiconductor Corp., 857 F. Supp. 691, 697–99 (N.D. Cal. 1994); Asahi Glass Co. v. Guardian Indus. Corp., 813 F. Supp. 2d 602, 614 (D. Del. 2011); Monsanto Co. v. Syngenta Seeds, Inc., 431 F. Supp. 2d 482, 487 (D. Del. 2006), aff'd, 503 F.3d 1352 (Fed. Cir. 2007); Brit. Telecomm. v. SBC Commc'ns Inc., No. CIV. 03-526 SLR, 2004 WL 5264272, at *3 (D. Del. Feb. 24, 2004); Zond, Inc. v. SK Hynix Inc., No. CIV.A. 13-11570-RGS, 2014 WL 346008, at *4 (D. Mass. Jan. 31, 2014); Momenta Pharms., Inc. v. Amphastar Pharms., Inc., 962 F. Supp. 2d 348, 353 (D. Mass. 2013), aff'd in part, vacated in part, remanded sub nom. Momenta Pharms., Inc. v. Teva Pharms. USA Inc., 809 F.3d 610 (Fed. Cir. 2015); Pat. Harbor, LLC v. Twentieth Century Fox Home Ent. LLC, No. 6:10CV607 LED-JDL, 2012 WL 12842299, at *2–3 (E.D. Tex. Sept. 7, 2012).

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