Oil prices spiked Wednesday after data showed inventories swelled less than expected. In the US, West Texas Intermediate crude oil, the U.S. benchmark, jumped 26 percent to $15.55 a barrel, receiving a boost from a trial indicating that Gilead Sciences’ drug remdesivir showed promise in treating COVID-19.

Stay-at-home orders during the COVID-19 pandemic have slashed fuel demand, dragging prices already hurt by a dispute between Saudi Arabia and Russia even lower. West Texas Intermediate rose sharply after the American Petroleum Institute said U.S. stockpiles rose by 10 million barrels in the week through April 24th, slightly less than the 10.6 million barrels that analysts were expecting.

Brent crude, the international benchmark, was up 11 percent at $22.73.