Shares of the Menlo Park, California-based Forty-Seven were climbing 21.2% to $59.15, while Gilead Sciences was down nearly 3.8% to $69.90.
Foster City, California-based Gilead has explored several options, including a partnership, Bloomberg said, citing people familiar with the matter.
Forty Seven, which has been approached by other companies, is working on cancer treatments that harness the immune system to fight tumors, Bloomberg said.
Neither company responded immediately to a request for comment.
Bloomberg said that Gilead’s hepatitis C franchise turned the company into a pharmaceutical giant, but sales of the drugs have slipped from their peak and it has struggled to find new streams of revenue. In 2017, the company acquired Kite Pharma to establish a foothold in cancer therapy.
The World Health Organization earlier this week said Gilead Sciences antiviral remdesivir may be effective against the coronavirus. The company has been working with global health officials in responding to the coronavirus outbreak and officials have been experimenting with remdesivir.
On Thursday, Gilead said remdesivir will undergo advance human testing in Asia.
Gilead said that around 1,000 patients in the region, suffering from both moderate and severe symptoms of the respiratory-focused virus will be given varying doses of remdesivir as part of a Phase 3 study.
Fears about the coronavirus have been pummeling markets all week as the number of cases reached 83,000 worldwide, with new infections in Africa and New Zealand overnight.