Background
Melinta Therapeutics markets Minocin, an injectable intravenous antibiotic containing minocycline. Although the drug first entered the market in 1972, Melinta later reformulated the product by adding magnesium, adjusting the pH, and reducing the injection volume—improvements that reduce hemolysis (red blood cell destruction) at the injection site. The reformulated product is protected by U.S. Patent Nos. 9,084,802 (“’802 patent”) and 9,278,105 (“’105 patent”), which claim methods of treating bacterial infections using an aqueous solution of minocycline with a magnesium cation at specified molar ratios and pH levels.
Nexus Pharmaceuticals filed an Abbreviated New Drug Application (ANDA) seeking FDA approval for a generic version of Minocin. Melinta sued under the Hatch-Waxman Act’s infringement provision, 35 U.S.C. §271(e)(2). After a four-day bench trial in the Northern District of Illinois, the district court found infringement, rejected Nexus’s invalidity arguments (obviousness, indefiniteness, inadequate description, and lack of enablement), and permanently enjoined Nexus from manufacturing or selling its generic product until the patents expire.
On appeal, Nexus challenged the district court’s claim construction, particularly the meaning of “composition” and “administering” as they relate to dilution, and whether the specification adequately described the hemolysis-reduction feature.
The Court’s Holding
In a nonprecedential opinion, Judge Bryson affirmed the district court’s judgment on the ’802 patent, finding no error in its claim construction or infringement finding, and declined to reach the ’105 patent issues because the ’802 patent alone supported the injunction.
The key claim-construction dispute concerned whether the closed transition phrase “consists of” in the ’802 patent’s claims excludes the addition of a diluent prior to intravenous administration. Nexus argued its generic product—which requires dilution before injection—could not infringe because a diluent is not listed among the claimed ingredients. The Federal Circuit agreed with the district court that “composition” refers to the concentrated reconstituted solution prior to dilution, and “administering” means giving the diluted composition to a patient. The court found this construction supported by the specification’s reconstitution instructions, expert testimony that a skilled artisan would understand dilution is required for IV administration, and prescribing information dating back to 1973.
On written description, the court rejected Nexus’s argument that the specification failed to adequately disclose the hemolysis-reduction feature. The court found the specification contained sufficient data and disclosure to convey that magnesium addition reduces injection-site hemolysis relative to a formulation without magnesium.
Key Takeaways
- The closed transition “consists of” in pharmaceutical method claims does not necessarily exclude routine preparation steps (like dilution) that a skilled artisan would understand are required for the claimed route of administration.
- In IV-formulation patents, courts will interpret claims in light of standard pharmaceutical practice—including that concentrated solutions must be diluted before injection—even when the claims use restrictive language.
- Generic manufacturers challenging reformulation patents must overcome intrinsic evidence (specifications, prescribing information) and extrinsic evidence (expert testimony) supporting the patentee’s claim construction.
Why It Matters
This decision reinforces that pharmaceutical patent claims will be read in the context of standard clinical practice. For generic companies pursuing ANDA applications involving injectable drugs, the opinion signals that arguments based on narrow readings of “consists of” claims—attempting to design around by pointing to required preparation steps—face an uphill battle when the specification and clinical practice unambiguously contemplate those steps.
For brand pharmaceutical companies, the decision validates the strategy of obtaining reformulation patents that claim method-of-administration features (like hemolysis reduction) as a barrier to generic entry. The Federal Circuit’s willingness to affirm a permanent injunction blocking a generic’s market entry based on a single patent underscores the continuing power of Hatch-Waxman litigation to maintain market exclusivity for reformulated products.