BEIJING -- The Supreme People's Court (SPC) of China on June 16 rejected the appeal of U.S. pharmaceutical company Eli Lilly and Co. against Jiangsu-based Changzhou Watson Pharmaceutical Co. Ltd. in a long-standing patent infringement case.

It also overturned a previous court ruling on patent infringement in favor of Eli Lilly, which ordered Changzhou Watson to pay Eli Lilly millions of yuan in compensation, after investigators concluded that "the alleged infringement does not fall into the scope of patent protection in the case."

This is the first time that SPC has designated technical investigators in a lawsuit to help clarify the technical details of the case.

Eli Lilly and Changzhou Watson have been locked in patent infringement disputes for over ten years over the latter's production of olanzapine, an anti-psychotic drug.

In 2003, Eli Lilly lodged a patent infringement litigation against Changzhou Watson and a lower Chinese court ruled in favor of Eli Lilly on grounds of Changzhou Watson's failure to meet the burden of proof.

In 2013, Eli Lilly sued Changzhou Watson again to seek economic compensation, and the latter was ordered to pay 3.5 million yuan (about $531,000).

Both Eli Lilly and Changzhou Watson challenged the ruling and appealed to the SPC.