Are COVID-19 Antivirals Almost Here?



Several treatments for coronavirus are in testing or have been used on patients, but drawbacks remain. 


Coronavirus won't go away now that it's here. High-risk people including older adults and those with underlying diseases, especially those involving the heart and lungs, are particularly anxious to hear that there is more than Tylenol and Gatorade to alleviate symptoms. Thus far, no drugs or vaccines are approved to treat the coronavirus. A worldwide effort is underway to find something that stops the disease. Here are a few possible candidates:

Favipiravir (Avigan). This Japanese drug, already in use to treat the flu, appears somewhat effective at mitigating coronavirus as well. It was used on 340 people in Wuhan and Shenzhen, says Zhang Xinmin, of China's science and technology ministry. "It has a high degree of safety and is clearly effective in treatment," Zhang reports.

The results are encouraging. Patients given the drug got a negative virus test a median of four days later, instead of 11 days later for a group not given the drug. In the same group, 91% of patients taking the drug demonstrated improved lung conditions on X-rays, compared with only 62% of those not on the drug. Additionally, the drug seemed to shorten the course of the disease, from 4.2 days for those who didn't take it to 2.5 days for those who did. The Chinese trial was non peer-reviewed.

The antiviral drug is manufactured in China (like many American pharmaceuticals) for developer Fujifilm Toyama Chemical. It got approval as an experimental treatment for COVID-19 back in February.

However, there is a drawback. Patients with severe symptoms don't respond as well as those with milder signs of the disease."We've given Avigan to 70 to 80 people, but it doesn't seem to work that well when the virus has already multiplied," says a source from the Japanese Health Ministry on background to the Mainichi Shimbun newspaper. No results are yet available from ongoing trials in Japan.

Healthcare Workers At Greater Risk for COVID-19


During the 2002 SARS epidemic, a fifth of all cases were in healthcare workers. The nature of their jobs puts these professionals at more risk than the rest of the population. Already, a handful of nurses went into quarantine in New York after exposure to a patient being treated there, and more than two dozen health care workers were forced to go under observation after interacting with patients who were not diagnosed with coronavirus until after their death. Three healthcare workers have already tested positive in Northern California, while dozens more went under observation.

That's why it's so critical that patients with symptoms of the disease are tested, and that healthcare professionals have access to masks, gloves, and gowns. The CDC recommends N95 masks that have filters to protect workers from others. Doctors, nurses and other personnel have to be healthy to treat patients. "During major disasters and outbreaks, we have massive patient surges that affect the medical system. We need as many healthcare workers as possible. If they're ill, they contribute to that patient surge without being able to contribute as responding personnel," says Terri Rebmann, a nurse researcher and director of the Institute for Biosecurity at Saint Louis University. "It's an issue of a numbers game."


Kevzara. Already approved for the treatment of rheumatoid arthritis, Kevzara is being evaluating its use on severe cases of coronavirus. New York drugmaker Regeneron is heading up trials of the drug in the U.S., while France-based Sanofi is leading trials outside the U.S., including in Italy. In a statement, the drugmakers say they hope to find the drug calms the overactive immune response in the lungs of critically ill patients. They also hope to find decreased death rates and a reduction in the need for mechanical ventilation, supplemental oxygen and hospitalization.

The drug was used on 21 patients ill with coronavirus in China with positive results. However, there is currently no peer-reviewed literature to assess. Regeneron and Sanofi are working closely with the U.S. Food and Drug Administration and the Biomedical Advanced Research and Development Authority to obtain quick, documented results.

The two companies are simultaneously working on a number of other experimental therapies, including potential vaccines.

Remdesivir. The furthest along in development of any potential anti-viral drug that will work on the coronavirus, Remdesivir has a decade-long history. Born in the lab as one of many compounds created by American drug behemoth Gilead, the molecule was for years known as "3a". That was until it showed potential to fight a global pandemic: Ebola.



"Drug discovery and development is usually a very long and tedious process and you could have many failures on the path to an approved product," notes Tomas Cihlar, Gilead's vice president of virology.

He's had  plenty of experience. Remdesivir was included in a landmark trial of four therapies to fight Ebola. A pair of other treatments dramatically reduced deaths while Remdesivir showed less promising results.

Currently, the drug is not only involved in five COVID-19 trials, but has also been made available to some patients in the U.S. It was given to the first American patient as part of a compassionate use program. When the man, who had visited relatives in Wuhan, took a turn for the worse, Gilead overnighted the drug to the hospital in Washington state. An intravenous drip was started and the man began to improve the next day.

However, there's a dark cloud on the horizon. Three patients treated with the medication had elevated liver enzymes, according to an unpublished paper "circulating ahead of an official peer review," according to journalist Cory Renauer. Although the patients all recovered from COVID-19, they reported significant gastrointestinal distress as well.

These and other organizations, including university medical centers, are scrambling for antivirals and possible vaccine candidates. With a huge payout in the offing as potentially every human on the planet would clamor for immunity to the new disease, old therapies are being dusted off and given a second look.

Drug companies expect antivirals to be on the shelves in a matter of months, while a vaccine is at least a year away, according to experts.


Sources:

https://www.livescience.com/flu-drug-could-treat-coronavirus.html
https://www.bloomberg.com/news/articles/2020-03-16/sanofi-and-regeneron-to-begin-initial-covid-19-treatment-trials
https://www.biospace.com/article/a-paper-raises-some-safety-concerns-for-gilead-s-covid-19-treatment/
https://www.theverge.com/2020/3/5/21166088/coronavirus-covid-19-protection-doctors-nurses-health-workers-risk




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