Japanese pharma manufacturer Shionogi & Co Ltd filed an administrative arbitration request for patent infringement with the Shanghai Intellectual Property Administration in November 2021.

This followed the granting of its patent for the "Prodrug of Substituted Polycyclic Aminoacyl Pyridone Derivatives" in March 2016. The patent number is ZL201180056716.8.

A prodrug is a pharmaceutical or chemical that is metabolized – that is, transformed within the body – into a pharmacologically active drug after swallowing it.

The defendant, Shanghai Sunway Pharmaceutical Technology Co Ltd, was accused of infringing on the patent rights by displaying and promising to sell the alleged infringing product, Baloxavir Marboxil, on its official website and on Chemicalbook, a chemical products platform.

A third party also purchased the product from the defendant, while the compound in Baloxavir Marboxil was within the scope of protection of claims 1-6 of the involved patent rights.

The defendant argued that it did not know that the product was covered by a patent and lacked subjective intent. The company has since ceased selling and displaying the product.

The Shanghai Intellectual Property Administration issued an administrative ruling on April 1, 2022, ordering the defendant to stop infringing on Shionogi's patent rights by ceasing the sales and promises to sell Baloxavir Marboxil.

The decision is said to serve as a reminder that intellectual property rights must be respected and that patent infringement can have severe legal consequences.