Two antiviral drugs that seemed like a promising treatment for the novel coronavirus, or COVID-19, failed during clinical trials in seriously ill patients in China.

“No benefit was observed,” the researchers wrote in The New England Journal of Medicine.

The study, published Wednesday, tested Kaletra, a combination of two antiviral medicines, lopinavir and ritonavir, that are normally used to treat H.I.V.

“This randomized trial found that lopinavir–ritonavir treatment added to standard supportive care was not associated with clinical improvement or mortality in seriously ill patients with COVID-19 different from that associated with standard care alone,” the study read.

The drugs had been used to treat coronavirus patients in both Queensland and South Korea, though the discouraging results of the trial will point researchers towards other drugs.

One potentially promising drug is chloroquine, an anti-malarial prescription drug that has been used since the 1940s. Tesla CEO Elon Musk endorsed the idea of using it on Twitter, and a few days later President Donald Trump ordered the Food and Drug Administration to fast track research into its effectiveness against COVID-19.

There is currently a large trial of remdesivir taking place in Seattle. Since the drug is not currently approved by the FDA for treating coronavirus, hospitals must be a part of the study to receive dosages. Hospitals not involved in the study may be able to apply for “compassionate use,” special permission sometimes granted by the FDA to receive an experimental drug outside of a study.

Even with trials being fast-tracked, drug approval takes a long time. At the current rate of research, most estimate the earliest a treatment drug for COVID-19 would be available on the market is July.

“There are trials going on for some of these things in some areas,” Town said. “All are rapidly enrolling, but their data won’t be back in time for a lot of places to make these decisions.”