Context: Last week, the US Food and Drug Administration (FDA) gave emergency approval to use the drug remdesivir for critical COVID-19 patients. 

More about the news:

  • There are six major trials or studies under way for remdesivir. It is one of the lines of treatment being investigated under the Solidarity trials under the aegis of the World Health Organization (WHO). 
  • And yet, a study published in The Lancet put a question mark about the benefits of using the drug.

What is remdesivir?

  • It was manufactured in 2014 to treat Ebola, by US-based biotechnology firm Gilead Sciences. 
  • It has since been used to treat MERS and SARS, both caused by members of the coronavirus family. This was, however, not with much success. 

Ebola: Ebola virus (EBOV) outbreak has swept through Western Africa. EBOV is a filovirus that causes severe hemorrhagic fever in humans with up to a 90?se fatality rate if untreated. 

MERS: In September 2012, Middle East Respiratory Syndrome coronavirus (MERS-CoV) emerged as a novel virus that can result in severe respiratory disease with renal failure, with a case fatality rate of up to 38%. 

SARS: Severe Acute Respiratory Syndrome coronavirus (SARS-CoV), a close relative of MERS-CoV, was the etiological agent(infectious substance) responsible for an outbreak centered around Guangdong Province in the southeast of China.

What benefits have been found so far?

  • The drug’s ability  to prevent virus’s  spread in human cells: SARS-CoV2 replicates itself inside the human cell with the help of an enzyme called RdRp. 
  • When remdesivir is injected intravenously, it inhibits this enzyme and effectively blocks replication of the coronavirus. 

What are the doubts on the efficacy of the drug?

  • Some of the trials were limited in scope. The number of patients who completed the study was too low to enable any statistically meaningful conclusions. 
  • A study found adverse drug reaction in 18 people and stopped remdesivir treatment prematurely in them.
  • Cardiac events (cardiac arrest or acute coronary syndrome) and treatment discontinuation due to respiratory failure were events associated with both remdesivir and placebo
  • Data from fully-powered trials are needed to determine the safety profile of remdesivir as treatment for COVID-19.

Drugs for COVID-19 treatment in India: Indian doctors are trying ritonavir, lopinavir, and even immunosuppressant tocilizumab, but not remdesivir. 

How much of it is available?

  • By May end the Gilead plans to produce enough stock for 1.4 lakh patients. 
  • Gilead has for now stopped meeting individual requests for supply under its Compassionate Use programme, except for pregnant women and children with severe infection.
  • The Gilead spokesperson said India is not on its Compassionate Use programme for the drug. 

About Solidarity trials:

The Solidarity trial is a multinational Phase III-IV clinical trial organized by the World Health Organization and partners to compare four untested treatments for hospitalized people with severe COVID-19 illness. The trial was announced in March 2020, and as of now, over 100 countries were participating. 

  • The WHO will focus on the four most promising therapies:
    • An experimental compound called Remdesivir: Originally designed for Ebola and related viruses, but showed no effect. However, this drug did have antiviral effects against SARS and MERS causing coronaviruses in animal models.     
    • The antimalarial drugs chloroquine and hydroxychloroquine: This drug has been trending on many social media and news outlets as a potential cure for COVID-19. However, results from a clinical trial did not convince the scientific community (WHO working group report).
    • A drug combination used in HIV patients, which includes lopinavir and ritonavir: This combination was tested in a small cohort in China, but did not show any effect on very ill patients. Researchers hypothesise that the lack of effect was because it was tested on severe COVID-19 patients. 
    • Interferon-β in combination with lopinavir and ritonavir: This drug combination was shown to have an effect in an animal model of MERS.
  • Phase III is designed to assess the effectiveness of the new interventioN, while Phase IV trial is also known as postmarketing surveillance trial, or informally as a confirmatory trial.
  • India is part of the large global study designed by the WHO — the Solidarity trial.
Image Source: Economic Times