5 Most Promising Covid-19 Drugs
With a coronavirus vaccine still a distant possibility, we could all use a little good news right now: These are the drugs that Covid-19 experts are most excited about.
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Given that a vaccine for the new coronavirus is months away, at best, doctors are turning to existing and experimental drugs to treat Covid-19 and save lives now. And even when a vaccine or vaccines become available, the world will still need treatments for Covid-19. When hydroxychloroquine for Covid-19 washed out, it underscored the need for caution and good research on safety and efficacy for potential medications. “It’s unlikely that we will ever get back to normal without a combination of one or more good vaccines and one or more good treatments,” says H. Dirk Sostman, MD, president of the Houston Methodist Academic Institute.
Two phases of Covid-19
The Covid-19 illness generally proceeds in two phases. “There’s the primary viral infection where the virus gets access either through the nose or mouth or eyes and multiplies itself,” explains Dr. Sostman. But that’s not actually what gives you the chills, fever, cough, and more. That’s the immune system fighting back. While an immune response is usually a good thing, in some patients the virus triggers a “cytokine storm” in which the body’s own defenses gush out immune cells called cytokines that attack the lungs and other organs. The treatments that follow tackle one or the other of these phases: Either they prevent the virus from replicating and spreading through to the lungs, or they calm dangerous immune responses—the cytokine storm.
Originally developed to combat Ebola, this antiviral is the only drug available that stops SARS-CoV-2, the virus that causes Covid-19 from replicating, and the only one the U.S. Food and Drug Administration (FDA) has approved specifically (under a special emergency use authorization) to treat Covid-19, says Dr. Sostman.
“There’s actually good evidence that it reduces the length of the illness and I would say pretty good evidence that it reduces mortality,” he notes. A randomized controlled study published in May 2020 in the New England Journal of Medicine found that hospitalized patients taking remdesivir recovered in about 11 days versus 15 days for those who only took a placebo. Just over 7 percent of people on remdesivir died compared with 12 percent in the placebo group. Given early enough, it can also help tame the cytokine storm as well, says Dr. Sostman.
Dexamethasone is a powerful steroid that helps quell inflammation from that out-of-proportion immune reaction. It’s been available for decades and has a good safety record. In a non-peer-reviewed study released in June 2020, dexamethasone cut deaths by one-third in Covid-19 patients on a ventilator and by one-fifth in patients who needed oxygen but not ventilation. In other words, says Dr. Sostman, “the sickest of the sick.” It did not help people who weren’t that severely ill.
“It’s very well tolerated and basically every hospital in the country has access to that,” says Matthew G. Heinz, MD, a hospitalist in Tucson, who has treated Covid-19 patients with both remdesivir and dexamethasone. “It has demonstrated benefit especially in those who are seriously ill and have been hospitalized and especially those in the ICU. It’s not going to hurt and it very well could help.”
A recent study published ahead of print in Antiviral Research shows that heparin, a blood thinner that’s been around for decades, actually binds to the notorious spike protein on SARS-CoV-2 and inactivates the virus. The idea is that the virus attaches to the drug instead of healthy cells, helping neutralize the infection. (That spike protein is also a target for vaccine developers: Blocking it means that the virus can’t infect cells.)
Hospitals are already using heparin products in hospitalized Covid-19 patients, says Dr. Heinz, who also headed the Obama Administration’s domestic response to the Ebola crisis. It makes sense given that so many patients with Covid-19 have blood clots, some of them resulting in stroke. The American Society of Hematology already recommends that all patients hospitalized with Covid-19 should receive anti-clotting therapy such as heparin.
These drugs represent a versatile approach to treating a number of diseases—and potentially Covid-19. Scientists are able to clone specific (monoclonal) immune proteins (antibodies) to target threats, whether it’s a cancer cell or a virus. The monoclonal antibodies spur the immune system to recognize and attack an invader. “Once they lock onto the virus, that’s a signal for other cells in your body to basically eat it up,” Dr. Sostman explains.
Another way doctors use monoclonal antibodies is to suppress an unhealthy immune response in people with autoimmune diseases such as lupus and rheumatoid arthritis. (Autoimmune means the body’s own immune system is harming healthy tissue.) Doctors have tried giving tocilizumab, a monoclonal antibody for rheumatoid arthritis, to Covid-19 patients, and the drug shows promise in slowing the cytokine storm. In a small trial, doctors administered tocilizumab to severely ill Covid-19 patients who had pneumonia, needed oxygen, and, in most cases, were intubated. The patients improved, requiring less oxygen and mechanical ventilation. (The study was published in Clinical Infectious Diseases in June 2020.)
That trial needs follow-up as there was no group of patients who got a placebo. However monoclonal antibodies, in general, offer promising potential for treating Covid-19: Researchers are isolating coronavirus antibodies from patients and cloning them to create drugs that specifically target the virus. Several versions are in clinical trials, says Dr. Sostman.
Early results have shown some promise for interferon, a protein released by cells when they’re infected by a virus. The protein signals to neighboring cells that an infection is underway and to ramp up anti-viral defenses. Interferon is currently used to treat non-Hodgkin’s lymphoma and other cancers, viruses like hepatitis C, and multiple sclerosis. A study by researchers at the University of Southampton in England and drug company Synairgen reported that interferon, an inhaled drug, slashed the chances of developing severe illness among patients hospitalized with Covid-19 by 79 percent. Interferon as a Covid-19 therapy is not yet ready for prime time, says the National Institutes of Health, because there just isn’t enough data yet.
Other existing antivirals such as ribavirin (for hepatitis C) have not shown much success against Covid-19, says Dr. Sostman. But there are new ones in the pipeline. “A lot of pharmaceutical companies are developing antiviral drugs that they think are promising for this,” he says. (Next: Read up on new Covid-19 symptoms and complications.)
- H. Dirk Sostman, MD, president of the Houston Methodist Academic Institute
- U.S. Food and Drug Administration: "Coronavirus (COVID-19) Update: FDA Issues Emergency Use Authorization for Potential COVID-19 Treatment"
- New England Journal of Medicine: "Remdesivir for the Treatment of Covid-19 — Preliminary Report"
- medRxiv: "Effect of Dexamethasone in Hospitalized Patients with COVID-19: Preliminary Report"
- Matthew G. Heinz, hospitalist, Tucson
- Antiviral Research: "Characterization of heparin and severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) spike glycoprotein binding interactions"
- American Society of Hematology: "COVID-19 and VTE/Anticoagulation: Frequently Asked Questions"
- National Cancer Society: "cytokine storm"
- Clinical Infectious Diseases: "Compassionate Use of Tocilizumab for Treatment of SARS-CoV-2 Pneumonia"
- National Cancer Society: "Monoclonal Antibodies"
- National Library of Medicine: "Interferon"
- National Health Service UK: "Inhaled drug prevents COVID-19 patients getting worse in Southampton trial"
- National Institutes of Health: "Interferons (Alfa, Beta)"