Q. Why is this in news ?
A. The US Food and Drug Administration (FDA) approved remdesivir as the first drug to treat COVID-19. The drug is designed to obstruct the replication of the virus in the body and has become the first drug to get official approval from the FDA for the treatment of the disease.
Since the pandemic began, there has been debate about the efficacy of this drug, which was originally developed for treating Ebola, which is not caused by a coronavirus. So what does its approval mean and how does the FDA approve drug treatments?
Q. So, what has the FDA said?
- The FDA has approved the use of the antiviral drug remdesivir to treat hospitalised adult and pediatric patients of COVID-19 who weigh at least 40 kg. The agency has clearly stated that the drug should be administered only in hospitals or healthcare settings that are capable of providing acute care.
Q. What does FDA’s approval mean?
- Before Thursday, there were no FDA-approved drugs meant for the treatment of COVID-19. In May, the agency issued an Emergency Use Authorisation (EUA) for remdesivir, which meant that it could be used for adult and pediatric patients who were hospitalised and were facing the severe disease. Then in August, it extended the EUA to include treatment of suspected and laboratory-confirmed hospitalised patients irrespective of disease severity.
- However, Thursday’s approval does not cover the entire population that was permitted its use under the EUA. The EUA allows doctors to use the drug even with hospitalised pediatric patients who weigh between 3.5-40 kg or are less than 12 years old and weigh at least 3.5 kg. Clinical trials assessing the efficacy of remdesivir in these population groups are ongoing.
Q. How does the FDA approve drugs?
- In a guidance document the FDA released in May, it said that drugs to treat or prevent COVID-19 should be evaluated in randomised, placebo-controlled, double-blind trials.
- Approval of a new drug requires substantial evidence of effectiveness and a demonstration that it is safe for use by the patients. To approve a drug, the agency conducts a benefit-risk assessment that is based on scientific standards.
- Therefore, FDA approved remdesivir after it analysed data from three randomised, controlled phase 3 clinical trials that included patients who were hospitalised and experienced mild to severe COVID-19.
- One of the most important trials among these was the National Institute of Allergy and Infectious Diseases (NIAID) sponsored trial that compared 10 days of treatment with the antiviral drug versus with placebo. The trial found that for the group that took the drug, the median days to recovery was 11 days versus 15 days in the placebo group. Further, the odds of improvement after 15 days of treatment favoured the drug.
- The second trial was a phase three trial sponsored by Gilead and evaluated the safety and efficacy of the drug when administered for five days versus ten days in hospitalised COVID-19 patients who were experiencing severe disease. The trial found that the treatment effects were the same with both treatment plans.
- The third trial, also sponsored by Gilead evaluated the efficacy of a 5-day versus a 10-day treatment plan in case of hospitalised patients experiencing moderate disease. The trial found that the odds of improvement at day 11 favoured the 5-day treatment plan.
Q. What are the different types of treatments for COVID-19 being studied by the FDA?
- The FDA is studying over five different treatment types for COVID-19. These include antiviral drugs such as remdesivir that stop the virus from multiplying once it’s inside the body. Such drugs are used to treat diseases including HIV, Herpes and Hepatitis C among others.
- Other treatment types being studied are immunomodulators (supposed to control the body’s immune response from going overboard), neutralising antibody therapies (should help the infected individual to fight the virus with the help of manufactured antibodies or animal-sourced antibody therapies), cell therapy (cellular immunotherapies) and gene therapy (making use of products to manipulate or modify the expression of a gene).
Q. How does remdesivir act against coronavirus?
- When the novel coronavirus enters the body, it releases genetic material, which is then copied using the body’s mechanism. At the replication stage, the key viral protein is an enzyme called RdRp that makes copies of the virus and enables it to spread. Further, in order to make the copies of the genetic material, raw material from the viral RNA is broken down by another enzyme.
- When a patient is given remdesivir, it mimics some of this material and gets incorporated in the replication site. With remdesivir replacing the material it needs, the virus fails to replicate further.
- Even so, remdesivir does not prevent deaths in COVID-19 patients, the drug is simply meant to halt the replication of the virus. A study sponsored by the WHO that studied the effects of antiviral drugs on mortality including remdesivir, hydroxychloroquine and lopinavir found that the antiviral drugs had little to no effect on hospitalised COVID-19 patients, when overall mortality, ventilator initiation and duration of stay were considered.
Q. What are the possible side-effects of the drug?
- Possible side-effects include increased levels of liver enzymes, which can be a sign of liver injury, allergic reactions, changes in blood pressure and heart rate, low oxygen blood levels, fever, shortness of breath, wheezing, rash, nausea, swelling of the lips, around eyes or under the skin and sweating or shivering.