Repurposing existing drugs will be a quicker way to tackle the coronavirus pandemic than developing a vaccine, scientists have argued.
In a paper published Thursday in the British Journal of Pharmacology, a team of international experts said that while there was no "magic bullet" for treating Covid-19, successfully identifying a drug for the virus was likely to take less time than rolling out a vaccine.
According to the paper, a vaccine which is both effective and scalable would likely take more than a year to reach the market, echoing previous assertions from biotech experts that developing a safe-to-use immunization will take between 12 and 18 months.
Steve Alexander, associate professor of molecular pharmacology at the University of Nottingham and one of the paper's authors, suggested that drugs currently being used to treat other illnesses could be "repurposed."
"There's unlikely to be a single magic bullet — we will probably need several drugs in our armory, some that will need be used in combination with others," he said. "The important thing is that these drugs are cheap to produce and easy to manufacture (so that) we can ensure access to affordable drugs across the globe."
There are currently at least 108 Covid-19 vaccines being developed around the world, according to the WHO.
However, "it's still going to take a long time before those vaccines are shown to be effective and can be manufactured at the scale needed to make an impact," Alexander said, noting that not all of them would work. "The more drugs that can be tested, the more likely we are to get something which is effective."
Researchers suggested trialing medications that target the parts of human cells that the Covid-19 virus attaches itself to.
"Any drug to treat Covid-19 will need to focus on the three key stages of infection: preventing the virus entering our cells in the first place, stopping it replicating if it gets inside the cells, and reducing the damage that occurs to our tissues, in this case, the lungs and heart," said Anthony Davenport, a professor of cardiovascular pharmacology from the University of Cambridge and one of the authors of the review.
There are two key proteins on the surface of our cells that the coronavirus binds to, allowing it to enter the body and replicate, researchers said. While one of those proteins, known as TMPRSS2, appeared to be common, however the other, ACE2, tended to be present at low levels but increased in prevalence depending on sex, age and smoking history.
Tracking down existing drugs that worked by targeting those proteins could speed up the development of an effective treatment for the coronavirus, according to Davenport.
"We can focus on repurposing drugs that already have regulatory approval or are in the late stages of clinical trials," he said. "If they can now be shown to be effective in Covid-19, they could be brought to clinical use relatively quickly."
The scientists behind the paper said Gilead Science's remdesivir — a drug originally developed to treat Ebola — was a "promising candidate." Last week, the drug was granted emergency authorization for use in the U.S., after data showed it helped shorten the recovery time of some hospitalized Covid-19 patients.
The paper stressed that it was important to move quickly to identify potential drugs, however. Cases of the virus were likely to fall in the summer, researchers speculated, which meant there would be fewer people who could be recruited to clinical trials ahead of a possible second wave of the virus in the autumn.
While the paper estimated that more than 300 clinical trials were taking place globally, scientists warned that many drugs being studied were unlikely to be effective for widespread use.