David Katz, chief investment officer at Matrix Asset Advisors, which owns Gilead shares, noted that multiple clinical studies remained ongoing for remdesivir and said, "we would not be selling (the stock) into weakness today."
Gilead is awaiting results of a trial of remdesivir, which previously failed as an Ebola treatment, in 400 patients hospitalized with severe Covid-19, with data expected later this month.
A separate trial in China testing the drug in patients with more moderate symptoms last week was also suspended due to a lack of eligible patients.
Brad Loncar, whose Loncar Investments runs a cancer immunotherapy ETF, was not ready to draw conclusions from the latest China data.