Explained | What are monoclonal antibodies?

A fresh case of Nipah virus was confirmed in Kerala’s Kozhikode, where two people were killed last week.

With the new Nipah infection in the state, taking the total number of active cases to four, the Indian Council of Medical Research (ICMR) has decided to procure from Australia 20 more doses of monoclonal antibody for its treatment. 

The University of Queensland manufactures the monoclonal antibody for use against Hendra virus, which is a bat-borne virus. 

Hendra is a rare but deadly henipavirus that infects fruit bats. It can be transmitted to horses, and then passed on to humans who have had close contact with an infected horse.

The monoclonal antibody developed was found to be of use also against the Nipah virus infection.

What are monoclonal antibodies?

• Antibodies are proteins generated by the immune system. They are one of the primary ways the body defends itself against disease.

• Polyclonal antibodies are mixtures of naturally occurring antibodies expressed from different immune cells. They are extracted from human or animal blood and are used in serum or convalescent plasma-based therapies to treat diseases including COVID-19, rabies and snakebite.

• Monoclonal antibodies are single antibodies expressed from identical immune cells that can be manufactured at commercial scale using cell systems. In simpler terms, monoclonal antibodies are immune system proteins that are created in the lab.

One of the most powerful tools in modern medicine

• From the time the first monoclonal antibody (mAb) was generated in 1975 and the first monoclonal antibody fully licenced in 1986, the field of monoclonal antibody development represents a novel way in which to target specific mutations and defects in protein structure and expression in a wide range of diseases and conditions.

• Monoclonal antibodies are one of the most powerful tools in modern medicine.

• These proteins act specifically against their targets — anything from viruses and bacteria to cancerous cells — and can safely and effectively prevent or treat a growing number of diseases, some of which were previously difficult to treat. 

• Millions of people have benefited from mAb-based therapies since the first one was licensed.

• The majority of licensed mAbs are used to treat non-communicable diseases, including cancers and autoimmune diseases. 

• Today’s successful cancer immunotherapies — including more than 40 licensed mAbs that directly or indirectly stimulate the immune system to attack and kill tumour cells — are revolutionising cancer treatment and have significantly improved overall and long-term survival compared to conventional approaches such as chemotherapy.

• Antibodies are now being explored for treatment and prevention of a wide range of viral diseases including Zika, dengue, Ebola, influenza and HIV.

• The use of mAbs to both prevent and treat HIV infection is another flourishing area of research. Several antibodies that can act against the diverse strains of the virus (so-called broadly neutralising antibodies or bnAbs) are in development and may offer new hope in battling HIV, which still newly infects about two million people each year.

• Increasingly, combination mAbs are also being developed to address the emergence of drug-resistant strains or escape mechanisms for many diseases, including HIV, antimicrobial resistant infections and cancer. Combining mAb products can increase the breadth of functional activity and improve response rates.

• Given the growing number of non-communicable and infectious diseases for which mAbs are or might be an effective treatment or preventive, there is clearly a global need for these products. 

Global need, but no global access

• Despite a global disease burden, access to monoclonal antibody products is predominantly restricted to high-income countries. This imbalance is preventing the vast majority of the world’s population from benefiting from monoclonal antibody treatments and preventives and it is only likely to grow as more monoclonal antibodies enter the market.

• Many mAbs are not available in low and middle-income countries because of long delays in regulatory filing, approval and launch of these products, which creates a huge gap in access.

• Capacity constraints, unclear or undefined regulatory policies and a lack of market incentive are all barriers to companies more broadly registering mAb products.

• One barrier to achieving global access to innovative mAbs is that they are unaffordable for most of the world’s population. Existing price-control mechanisms and access strategies are insufficient to make mAbs widely affordable.