Copper prices rose on Wednesday on optimism over progress in U.S.-China trade talks and signs that researchers might be closer to a treatment for the coronavirus.

Three-month copper on the London Metal Exchange gained 0.2% to $6,543.50 a tonne by 0404 GMT, while the most-traded October copper contract on the Shanghai Futures Exchange advanced 0.2% to 51,390 yuan ($7,444.16) a tonne.

British drugmaker AstraZeneca has begun trials of its antibody-based drug for the treatment and prevention of COVID-19, the latest development in a global race to combat the pandemic.

Top U.S. and Chinese trade officials reaffirmed their commitment to a Phase 1 trade deal, which has seen China lagging on its obligations to buy American goods.

"The general feel is that trade talks went smoothly. Vaccine news is encouraging. Copper stocks are below 100,000 tonnes in the LME warehouses, while the U.S. dollar has resumed its downward trend," said a Singapore-based metals trader.

A weaker U.S. dollar makes greenback-priced LME metals cheaper to buyers holding other currencies.