Itolizumab to Tocilizumab, monoclonal antibody therapies

Context

India faces shortages of the two monoclonal antibody therapies the Itolizumab and Tocilizumab.

About the monoclonal antibodies therapy

• In 1900s, the Nobel-prize winning German immunologist Paul Ehrlich proposed the idea of a ‘Zauberkugel‘ (magic bullet). It is a compound which selectively targets the pathogen.
• Muromonab-CD3 was the world’s first monoclonal antibody to be approved for clinical use in humans. 
• Muromonab-CD3is an immunosuppressant drug that is given to reduce acute rejection in patients with organ transplants.
• Monoclonal antibodies are created in the lab by exposing white blood cells to a particular antigen.
• In the case of Covid-19, monoclonal antibodies are produced by using the spike protein of the SARS-CoV-2 virus that facilitates the entry of the virus into the host cell.
• To increase the quantity of antibodies produced, a single white blood cell is cloned, which in turn is used to create identical copies of the antibodies.

Various monoclonal antibody therapies developed worldwide

Itolizumab

• It was developed by Bengaluru-based biopharma company Biocon.
• The Drugs Controller General of India had authorised it for “restricted emergency use” in the country in June 2020.
• Itolizumab targets CD6, a protein found in the outer membrane of a T-cell. 
• T-cellis a type of white blood cell that plays a central role in the body’s immune response.
• Itolizumab, by binding to CD6, tones down T-cell activation and causesreduction in synthesis of pro-inflammatory cytokines.

Tocilizumab

• This monoclonal antibody has got approved from the FDA to treat rheumatologic disorders.
• This antibody also inhibits IL-6 activity, and was proposed as a potential therapy for severe Covid.
• The drug is currently approved for off-label usein India, which means it can be used after informed consent of patients.

Bamlanivimab and etesevimab

• The US FDA authorisedthe emergency use of the combination bamlanivimab and etesevimab.
• Both the antibodies target the spike protein of the SARS-CoV-2 virus.

Casirivimab and imdevimab

• US-based biotechnology company Regeneron Pharmaceuticals developed a drug REGN-COV2.
• The drug REGN-COV2 is a cocktail of two antibodies, casirivimab and imdevimab.
• The drug is meant for use in mild-to-moderate Covid-19 patients who are not on oxygen support, but who may be at risk of severe disease.

Levilimab 

• The Russian biotechnology company BIOCAD developed the antibody levilimab (Ilsira). to
• It received approvalby the country’s Ministry of Health for Covid-19 treatment on 5 June last year.
• The antibody targets IL-6, a molecule that causes cytokine storm-related complications in severe Covid.