With drug researchers and developers working hard to establish treatments for COVID-19, one medication is seeing promising buzz.
Remdesivir, an investigational antiviral medication that inhibits viral RNA synthesis, was created by Gilead Sciences in 2009 as a potential treatment for hepatitis C. While remdesivir did not work as initially hoped as an HCV treatment, it later showed promise during the height of the Ebola outbreak when scientists explored which antivirals could help patients.
Due to its status as an antiviral, initial tests were conducted to gauge remdesivir’s potential to treat COVID-19, and so far the results are positive enough that the FDA issued an emergency use authorization (EUA) allowing doctors to use remdisiver to treat hospitalized COVID-19 patients. An EUA is a declaration that circumstances exist to justify the emergency use of drugs and biological products that have not been FDA-approved, particularly when no other effective alternatives are available, assuming the benefits appear to outweigh the risks.
This EUA was based on review of topline data from a randomized, double-blind, placebo-controlled trial conducted by the National Institute of Allergy and Infectious Diseases (NIAID), an institute within the National Institute of Health (NIH), and from a Gilead-sponsored open-label trial that evaluated different durations of remdesivir.
The NIAID trial involved 1,063 hospitalized patients with advanced COVID-19 and lung involvement. Those who received remdesivir recovered 31% faster than similar patients who received placebo, with an 11-day recovery time versus a 15-day recovery time. Results also suggested a survival benefit with a mortality rate of 8% for the remdesivir group versus an 11.6% mortality rate with the placebo group.
The Gilead-sponsored trials included two Phase 3 studies to evaluate the safety and efficacy of remdesivir for COVID-19. Both trials were randomized, open-label, multicenter studies, each assessing different dosing durations delivered intravenously. The first study involved 400 patients with severe COVID-19 who received five or 10 days of remdesivr, while the other study involved 600 patients with moderate COVID-19 who received five or 10 days of remdesivir.
It was found that patients receiving a 10-day treatment course of remdesivir achieved similar improvement in clinical status compared with those taking a 5-day treatment course. Furthermore, no new safety signals were identified with remdesivir across either treatment group, and patients in the study who received remdesivir within 10 days of symptom onset had improved outcomes compared with those treated after more than 10 days of symptoms.
Gilead claims that if a five-day regimen is as effective as a 10-day regimen, then they could significantly expand the number of patients who could be treated with remdesivir.
These initial trials have since been backed by other clinical studies.
The New England Journal of Medicine published a study on the compassionate use of remdesivir for patients hospitalized with COVID-19. Approximately 53 patients with COVID-19 were analyzed after receiving a 10-day course of the drug delivered intravenously at a dosage of 200 mg on the first day, followed by 100 mg every following day. Eighteen days after treatment, clinical improvement was seen in 36 patients.
Furthermore, the Journal of the American Medical Association (JAMA) published a review of pharmacologic treatments for COVID-19, finding remdesivir to be the most promising therapy for COVID-19 due to its potent in vitro activity against the virus. Furthermore, within lung infection models, remdesivir prevented lung hemorrhage and reduced viral lung titers more than comparator agents.
However, not all research bodes well. The Lancet published trial information on a randomized, double-blind, placebo-controlled, multicenter trial across 10 hospitals in Hubei, China, where 237 patients received either remdesivir or placebo for 10 days. In this trial, remdesivir use was not associated with a difference in time to clinical improvement.
But while most of the initial research is positive, there is still not enough data to definitely show that remdesivir is an effective treatment for COVID-19. The FDA’s decision to grant remdesivir an EUA to treat COVID-19 is not the same as FDA approval; the EUA is for emergency use in the face of a crisis.
According to the FDA’s remdesivir fact sheet, remdesivir is investigational because it is still being studied and more information could soon come to light. However, it is believed remdesivir may shorten the time to recovery for some people. Remdesivir may help decrease the amount of coronavirus in the body, potentially speeding recovery. Possible side effects may include infusion related-reactions, as this EUA is for IV administration once a day for up to 10 days, and increases in levels of liver enzymes, which may be a sign of inflammation or damage to cells in the liver.
In regard to these potential liver issues, healthcare providers must conduct blood tests to check the liver prior to administering remdesivir, and once daily while patients receive remdesivir.
According to the FDA’s EUA for remdesivir, the distribution of authorized remdesivir will be controlled by U.S. Government for use consistent with terms and conditions within the EUA.
Gilead will supply remdesivir to authorized distributors or directly to a U.S. Government agency, who will distribute to hospitals and other healthcare facilities.