itolizumab-a-monoclonal-antibody-to-treat-covid-19-patients-summary

Context: Recently, pharma major Biocon had received the approval of the Drugs Controller General of India (DCGI) to market Itolizumab for treatment of COVID-19. 

More on the news:

  • The drug will be used to treat cytokine release syndrome (CRS) in moderate to severe acute respiratory distress syndrome patients due to COVID-19.
  • Itolizumab is a monoclonal antibody which is used to treat acute psoriasis.

Background:

  • In the case of COVID-19, there are yet no proven drugs to treat moderate or severe manifestations of the disease. 
  • Among the therapies being tested is convalescent plasma, which is a constituent of blood and recovered from those who have successfully fought the disease. 
    • This blood contains antibodies produced within a week or two of being infected.

About monoclonal antibodies:

  • Monoclonal antibodies are proteins cloned in the lab to mimic antibodies produced by the immune system to counter an infection. 
  • They have their genesis in serum, the colourless constituent of blood that contains antibodies. 
  • These proteins bind to an antigen, the fragment of an infectious virus in the case of SARS-CoV-2, and either destroy it or block its action. 
  • How different from plasma therapy?
    • While plasma therapy involves injecting the entire antibody-soup into another sick patient, a monoclonal antibody can be made by isolating specific antibodies and multiplying them via various techniques. 
    • Isolating plasma and serum is laborious and time-consuming when it must be administered to every patient. 
      • However, several techniques have been perfected that allow antibodies once isolated to be easily replicated. 
      • These are stored in vials and can be injected into patients.

Cytokine Release Syndrome (CRS):

  • According to the experts, many who died due to COVID-19 infection were victims of a cytokine storm - when the immune system goes into overdrive to flush out the virus. 
    • Pro-inflammatory cytokines recruit a host of specialised immune system cells to neutralise antigens. 
    • Cytokines are small secreted proteins released by cells that have a specific effect on the interactions and communications between cells.
  • However, these cytokines can aggravate inflammation and injury in lung cells as well as in several other organs. 
  • A challenge in treatment is how to prevent this over-reaction. 
    • One way is to use antibodies that can block a particular protein, called CD6, found on the surface of T-cells (a class of cells that play a central part in the body’s defence system).
    • There is also a lot of research going on in using such antibodies to prevent the replication of the virus. 
    • Downside: Sometimes antibodies are known to help viral entry and replication in target cells which can worsen the disease. 

Does Itolizumab hold promise?

  • Since 2003, Itolizumab has been an approved drug for acute psoriasis and has passed safety and efficacy trials for that disease. 
  • Efficacy not been demonstrated: Experts have pointed out that the efficacy of the drug in treating COVID-caused Acute Respiratory Disease Syndrome has not been conclusively demonstrated. The drug, as part of a clinical trial, has only been tested on 30 patients. 

Psoriasis 

  • It is a skin disorder that causes skin cells to multiply up to 10 times faster than normal. 
  • This makes the skin build up into bumpy red patches covered with white scales. 
  • Causes: Exact cause of psoriasis is not known, but experts believe that something wrong with the immune system causes inflammation, triggering new skin cells to form too quickly. 

Source: https://www.thehindu.com/sci-tech/health/the-hindu-explains-why-is-a-psoriasis-drug-being-used-to-treat-covid-19-patients/article32126359.ece

Image Source: TH