In Metacel Pharmaceuticals LLC v. Rubicon Research Private Ltd., the Court of Appeals for the Federal Circuit (CAFC) held that the optional product storage temperatures stated in Rubicon’s proposed generic product label did not induce infringement of US Patent No. 10,610,502 because Rubicon’s proposed label only optionally permits the refrigeration storage claimed by Metacel’s patent, and clearly instructs room temperature storage.¹ In so holding, the CAFC affirmed a district court grant of summary judgment of noninfringement.²

Background

Induced patent infringement occurs when one person actively causes another to directly infringe a patent.³ Patentees frequently assert inducement in Hatch-Waxman cases, which involve pharmaceutical products. The instructive nature of pharmaceutical prescribing information or labeling may cause pharmaceutical companies to instruct doctors or patients to practice method of use patent claims. Brand pharmaceutical companies patent the instructions in their own labeling. Because the FDA largely requires generic applicants to copy the brand labeling, generic labels often include instructions from the brand label that are claimed in a patent, giving rise to an inducement claim.

Hatch-Waxman inducement cases have evolved into two types: 1) those with labels that require at least some doctors or patients to infringe, such as AstraZeneca LP v. Apotex, Inc. (involving patent claims to method of dosing that those following the generic label would titrate down to inevitably infringe);⁴ and 2) those that merely permit doctors or patients to infringe as an option, such as HZNP Medicines LLC v. Actavis Laboratories, UT, Inc. (involving patent claims that required certain steps—applying the topical formulation, allowing it to dry, and then applying sunscreen or insect repellant—that those following the label may opt not to follow because the label did not require applying anything after the topical formulation).⁵

District Court Granted Summary Judgment

Metacel owns the brand product OZOBAX ®, which is an oral solution of baclofen.⁶ Metacel has one patent in the Orange Book for OZOBAX: the ’502 patent.⁷ Claim 1 in the ’502 patent is directed to a method of relaxing muscles by administering an oral solution of baclofen that is stored “at from about 2 to about 8° C.”⁸

Rubicon filed an Abbreviated New Drug Application (ANDA) to market and sell a generic version of OZOBAX.⁹ Rubicon’s proposed label states to store the medicine at 20° to 25° C (room temperature), and that it can also be stored at 2° to 8°C (refrigerated).¹⁰

Metacel sued Rubicon, alleging that Rubicon’s ANDA product would infringe the ’502 patent because Rubicon’s product labeling instructs storage from about 2 to about 8° C.¹¹

Following discovery, Rubicon moved for summary judgement of noninfringement.¹² The district court granted Rubicon’s motion, explaining that Rubicon’s proposed labeling only optionally allows refrigeration and instructs room temperature storage, so infringement will not occur.¹³

CAFC Affirmed

The CAFC held that the district court summary judgement grant.¹⁴ It cited HZNP for the proposition that, for cases involving method of use patents, this Court examines whether the proposed label encourages, recommends, or promotes infringement.¹⁵ Labels that merely describe the infringing use as an option, without encouraging or requiring it, do not induce infringement.¹⁶ The CAFC explained that Rubicon’s proposed label does not encourage refrigeration, as claimed by the ’502 patent.¹⁷ The label instructs downstream users to store the product at room temperature, and if they choose to refrigerate the product then the label provides them with a refrigeration temperature range (2°C to 8°C).¹⁸ The CAFC reasoned that because the storage at 2°C to 8°C is merely optional for downstream users, there is no induced infringement.¹⁹

Looking Forward

This case is non-precedential but shows that optional instruction language in a drug label—even if covered by a patent—may not result in induced infringement. Generic applicants should note optional language in product labeling and plan to seek summary judgment of no induced infringement, if sued based on that language. Brand companies should seek labeling from the FDA that requires instructions be followed in certain circumstances, rather than labeling that merely present options. If claimed in a patent, required label instructions could protect against generic competition.

Footnotes

¹ Id. at *3.

² Metacel Pharmaceuticals LLC v. Rubicon Research Private Ltd., No. 2023-2386, 2025 WL 1178384, at *2 (Fed. Cir. Apr. 23, 2025).

³ See 35 U.S.C. § 271(b).

⁴ 633 F.3d 1042 (Fed. Cir. 2010).

⁵ 940 F.3d 680 (Fed. Cir. 2019).

⁶ Metacel, 2025 WL 1178384, at *1.

⁷ Id.

⁸ Id.

⁹ Id.

¹⁰ Id. at *2.

¹¹ Id.

¹² Id.

¹³ Id.

¹⁴ Id. at *3.

¹⁵ Id.

¹⁶ Id.

¹⁷ Id. at *4.

¹⁸ Id.

¹⁹ Id.

Srika Madan also contributed to this article.