Nexus wins patent litigation for injectable cyclophosphamide

Nexus Pharmaceuticals shared that on May 9, 2025, it won a patent litigation involving injectable cyclophosphamide, a drug that has been approved for certain kinds of cancer.

Nexus had been pursuing a generic version to offer to patients.

Nexus said that according to the judge, “Nexus has established by clear and convincing evidence that an impermissible ‘zone of uncertainty’ exists.” The judge entered final judgment in Nexus’s favor.

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Ingenus Pharmaceuticals sued Nexus for patent infringement. A federal judge in the Northern District of Illinois found all claims in Ingenus’s patent were invalid. The judge’s invalidity decision was based on indefiniteness, because all patent claims used the word “stable”, but that term was found to be undefined. According to the judge, “Nexus has established by clear and convincing evidence that an impermissible ‘zone of uncertainty’ exists.” The judge entered final judgment in Nexus’s favor.

This decision paves the way for generic entry for Nexus’s injectable cyclophosphamide product. 

“We are pleased that the district court judge issued a thoughtful opinion concluding that Ingenus’s patent was invalid,” said CEO and president, Usman Ahmed. “Nexus appreciates the judgment, and we look forward to helping patients access generic alternatives for injectable cyclophosphamide.”

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