The race is on to find effective treatments against the new COVID-19 coronavirus spreading through China, and two new therapies show real promise, researchers say.
One is an experimental antiviral medicine that already being used by Chinese doctors on a "compassionate" basis in coronavirus patients and has shown effectiveness in monkey trials.
The other involves transfusing the plasma of people who've survived COVID-19 into patients still battling the illness, in hopes of boosting the recipient's immune defences.
The antiviral is a drug called remdesivir. It's so new that it's not yet approved for use by any drug regulator in the world. However, earlier this week the drug's maker Gilead announced that remdesivir is being given to Chinese patients infected with the new coronavirus because there are no approved treatments.
And in a study published in the Proceedings of the National Academies of Science, researchers found that remdesivir prevented disease in monkeys infected with Middle East respiratory syndrome coronavirus (MERS-CoV).
Good results in monkeys and people
An outbreak of MERS first arose in Saudi Arabia in 2012 and caused worldwide concern before it was brought under control.
Importantly, the MERS virus is closely related to COVID-19, so scientists believe that any agent that works against MERS should prove effective against the new coronavirus.
The new study was led by Emmie de Wit at the US National Institute of Allergy and Infectious Diseases. Her team found that remdesivir prevented disease when given to rhesus macaques before they were infected with MERS-CoV. It also improved the monkeys' condition when it was given to them after they were infected.
The study's promising results support further clinical trials in humans of remdesivir for both MERS-CoV and COVID-19, the research team said.
Several clinical trials of remdesivir for COVID-19 are already underway in China, and on 4 February Bloomberg News reported that the drug was being tested in patients with the new coronavirus by a medical team at the Beijing-based China-Japan Friendship Hospital.
One of the Chinese clinical trials will assess the effectiveness of remdesivir in as many as 270 patients with mild and moderate pneumonia caused by COVID-19, according to Chinese news outlet The Paper, Bloomberg News reported.
In prior studies, remdesivir protected lab animals against a variety of viruses and has also been shown to effectively treat monkeys infected with Ebola and Nipah viruses. The drug also has been assessed as a treatment for Ebola in people.
Two experts unconnected to the NIAID study were optimistic that the drug can be a weapon against the COVID-19 outbreak, which so far has sickened more than 64 000 worldwide and killed nearly 1 400.
The new research is "really exciting news", said Dr Eric Cioe Pena, who directs Global Health at Northwell Health in New Hyde Park, New York.
He pointed out that MERS is a much more deadly coronavirus infection compared to the new virus, so if remdesivir works against MERS, "many of those infected [with COVID-19] would benefit from treatment".
In fact, the vast majority of patients with the new coronavirus do recover from their illness, so remdesivir might only be stockpiled and used for the more severe cases, Pena believes.
Dr Robert Glatter is an emergency physician at Lenox Hill Hospital in New York City. He agreed that "the findings of this study in primates with MERS is quite encouraging, and support further investigation into the use of remdesivir in human trials, both for preventative and therapeutic use in those with severe infections with COVID-19."
He also believes the drug might prove especially useful for "higher-risk individuals with exposure to the virus", such as health care workers who are in close proximity to infected patients.
Remdesivir was even tried recently in the United States, Glatter pointed out.
"With success seen against other coronavirus infections, Gilead recently provided remdesivir to a patient with COVID-19 [treated] in Seattle. The patient recovered and was released from the hospital," Glatter said.
"The drug also appears to be safe," he added, "but the issue of emerging resistance [to remdesivir] will also need to be evaluated in upcoming trials."
On Thursday, Chinese doctors announced they were trying a second strategy against COVID-19: transfusing the blood plasma of people who'd survived the illness in others already battling the disease.
As reported by The New York Times, Dr. Zhang Dingyu, who directs the Jinyintan Hospital in Wuhan, the centre of the outbreak, called on residents who've recovered from COVID-19 to donate plasma to help others infected.
China National Biotec Group, a state-owned company, said that its testing found that giving critically ill patients immune antibodies from plasma donated by survivors led to a big drop in inflammation within one day of administration.
It's "a really good idea", Benjamin Cowling, a professor of epidemiology at the University of Hong Kong, told the Times. "It's basically transferring immunity from a patient who has recovered to a patient still fighting the infection, and then helping them to recover."
The technique has been used in influenza epidemics, Cowling pointed out, but when it comes to COVID-19, the approach still needs to be tested in clinical trials.
So far, the coronavirus outbreak has been largely confined to China. As of Friday, the US Centers for Disease Control and Prevention has recorded only 15 cases in the United States, with no deaths and transmission within the broader community.
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