Delhi HC Rejects FMC Plea, Clears Natco to Launch Cyantraniliprole Ahead of Patent Expiry

Multiple suits and appeals regarding FMC’s patents on similar molecules have been fought since 2019. Natco first filed a revocation petition challenging Claim 12 in 2023, and obtained regulatory approvals before commercialization in 2025.

Natco argued it had “cleared the way” by approaching authorities and courts before launching its product—an increasingly recognized defense in patent disputes.

FMC claimed Natco’s formulation uses the same patented intermediate and the infringement would irreparably harm FMC’s rights, especially as only three months remained before patent expiry. FMC insisted its invention was novel, scientifically validated, and had survived 18 years without challenge.

It accused Natco of a mala fide launch of the product during an ongoing argument, calling it inequitable conduct.

Natco countered that Claim 12 lacked novelty, citing prior claiming and asserting a credible challenge to patent validity. It said FMC’s patent counterpart in China had already been revoked and argued FMC delayed suing despite clear disclosures. It also emphasized that millions had already been invested in commercial production since April 2025, making the injunction economically destructive.

The Court found:

• Natco successfully demonstrated a prima facie vulnerability of the patent.
• FMC’s injuries, if proven, are monetary, not irreparable.
• Only two months remained before patent expiry.
• Natco had taken deliberate legal and regulatory steps to “clear the way”.

The Court categorically held:

“Accordingly, the plaintiffs have failed to make out a prima facie case for grant of interim injunction… this Court is not inclined to grant an injunction to the plaintiffs.”

The Court allowed Natco to continue selling its product but directed it to disclose data on quantities and revenues earned.

To view the court order, click the link below: