Monoclonal Antibodies

June 21, 2021

Syllabus- General Studies 3(Science and Technology)

Context

An experimental monoclonal antibody cocktail, REGEN-COV2, has been found to be a life-saving treatment for some of the most severely affected Covid-19 patients; results of a clinical trial in the UK have shown.

Monoclonal Antibodies

To fight a viral infection, our bodies create proteins known as antibodies.
Monoclonal antibodies are artificial antibodies that mimic the activity of our immune systems. They are produced through a process that involves extracting specific antibodies from human blood and then cloning them.
These monoclonal antibodies are designed to target a virus or a specific part of one — for instance, REGEN-COV2 is a cocktail of two monoclonal antibodies developed to target the SARS-CoV-2 spike protein.
The monoclonal antibodies bind to specific parts of the spike protein, blocking its ability to infect healthy cells.
Besides Covid-19, monoclonal antibodies have been used in the treatment of cancers as well as Ebola and HIV.

Importance in Covid Treatment

Research during the pandemic has increased optimism in monoclonal antibodies’ ability to help reduce the risk of hospitalisation.
Some monoclonal antibodies have shown the ability to retain activity against multiple variants of the virus.

Limitations

So far, these therapies have shown the most success in high-risk groups with mild to moderate Covid-19.
They are not approved for use in those hospitalised with severe Covid-19 and those requiring oxygen.
It is very important to provide them to “the right patients at the right time” for the greatest benefits, especially in resource-constrained settings.
Some emerging variants like the Delta Plus “variant of interest” have also displayed the ability to nullify the use of monoclonal antibodies, according to Dr V K Paul, NITI Aayog’s Member-Health and the Chair of the National Expert Group on Vaccine Administration against Covid-19.

Observations from new study

Regeneron’s monoclonal antibody cocktail reduces the risk of death by a fifth compared to those who had received standard care. “Thus, for every 100 such patients treated with the antibody combination, there would be six fewer deaths,” the university said in a release.
The therapy reduced the hospital stay of patients lacking their own natural antibody response by four days. It also reduced their risk of requiring a ventilator.
These findings basically mean that the therapy would be most beneficial for those who have not been able to develop their own antibody response, even if they had developed severe symptoms or been hospitalised.

Availability in India

REGEN-COV2 is available in India through a tie-up between Swiss drug giant Roche and Indian company Cipla.
The therapy, a combination of monoclonal antibodies casirivimab and imdevimab, had received the Central Drugs Standard Control Organisation’s restricted emergency use permission in May.
Recently in June, another antibody cocktail therapy — Eli Lilly’s bamlanivimab and etesevimab —received a similar emergency approval.
Both antibody cocktails are indicated for use in those with mild to moderate Covid-19 who do not require oxygen and who are at a high risk of progressing to severe disease.
GlaxoSmithKline, which on May 26 had announced the US FDA’s Emergency Use Approval for Sotrivimab, is exploring options to make the monoclonal antibody therapy available for India.
In India, Zydus Cadila plans to take an antibody cocktail, ZRC-3308, through trials.

Pricing

Such therapies are expensive because they are difficult to make and take a lot of time.

In India, Cipla is supplying 100,000 packs of REGEN-COV2 at a maximum retail price of approximately Rs 1.20 lakh per pack. With one pack offering treatment for two patients, the price of a dose for one patient is Rs 59,750, inclusive of all taxes.

Monoclonal antibodies comparison with convalescent plasma therapy

India last month dropped the use of convalescent plasma as an “off-label” option from its guidance on Covid-19 treatment. Over the last eight months, evidence from trials has shown it has no significant benefits in improving patient outcomes.

Compared with plasma, scientists have expressed more confidence in the promise of monoclonal antibodies. Both antibody-based therapies, they differ in the way they are made.

Convalescent plasma therapy involves providing antibodies from a recovered Covid-19 patient’s plasma.

Monoclonal antibodies are when you take a specific antibody and mass-manufacture it in a factory.

This means that those receiving this therapy would be getting all the antibodies the recovered patient has made.

For antibody cocktails, you provide a combination of two or more such antibodies.

Monoclonal antibodies are “extremely pure” due to their homogenous nature.
The data from clinical trials of monoclonal antibodies at that time indicated they are a “very promising form of prevention and treatment,” Dr Fauci had said.

Question- What are monoclonal antibodies? How is it different from plasma therapy?

Article- https://indianexpress.com/article/explained/explained-monoclonal-antibodies-covid-7368039/