Monoclonal Antibodies: Breakthrough treatment to prevent severe COVID-19 illness

What are Monoclonal Antibodies?

When the human body is attacked by any pathogen irrespective of whether it is a bacteria or a virus, the body’s immune system gets activated to trigger its defence mechanism. We form antibodies that destroy the pathogen. To fight certain diseases including COVID-19, cancer, rheumatological disorders and more, the scientists have artificially prepared antibodies in the laboratory. Since these antibodies are made in a single white blood cell by cloning it to make multiple identical copies, hence these are called ‘monoclonal’ antibodies.

In reference to COVID-19, the SARS CoV2 virus enters the human cell by attaching its spike protein (S Protein) to a receptor called ACE2. If we give monoclonal antibodies to a COVID-19 patient, the antibodies will bind to the viral spike protein and prevent it from entering  into the human cell.

Which are the 2 drugs used in Monoclonal Antibodies for the treatment of covid-19?

The combination consists of two monoclonal antibodies- Casirivimab and Imdevimab also knows as REGEN-COV.  These are human monoclonal antibodies developed as an investigational therapy for mild to moderate symptoms of COVID-19. This treatment can prevent case escalation from mild/moderate illness to severe requiring hospitalisation in 70% of the cases as per studies

Why is it Investigational?

An investigational treatment means there was insufficient time to conduct long-term trials on efficacy and safety of a drug. Since the COVID-19 cases have been rising constantly across the world and so many people have lost their lives, some drugs were approved as ‘Emergency Use Authorisation’ to save precious lives. REGEN-COV is one such investigational agent that was approved by the FDA in United States. It has the same status in India and as we gather more information about its effectiveness and safety, we will have more robust data.

Who all are eligible for this treatment?

• Any COVID-19 patient 12 years and older, weighing at least 40 kg and at high risk
• For patients in the mild to moderate category
• Not for patients on oxygen support
• Treatment for COVID-19 confirmed patients within 10 days of onset of symptoms

How is the treatment administered?

REGEN-COV consists of two drugs, casirivimab and imdevimab, given together as a slow drip through a vein. Both drugs are diluted and administered together as an infusion. The infusion takes approximately half an hour. It is an OPD procedure not requiring hospitalization. The patient is monitored for one hour after completing infusion for any possible side-effects.

Who is a suitable candidate for receiving this Monoclonal Antibody cocktail?

There are set protocols as to who should be receiving this drug. This combination is approved for treatment in the mild to moderate cases of COVID-19 as long as the patient is 12 years or older and at least 40 kg weight. Not everyone needs to be given this drug in case they have COVID-19. The risk factors which increase the likelihood of worsening of the disease and need to get admitted are the deciding factor for an appropriate candidate for this therapy. These include:

• Senior citizens ≥ 65 years
• Overweight and Obese patients
• Patients with heart problems including blood pressure, coronary artery disease or congenital heart problems in children and adults
• Patients with Chronic lung problems including moderate to severe asthma, COPD, Interstitial lung disease (ILD), pulmonary artery hypertension
• Diabetes Mellitus patients
• Chronic kidney disease patients
• Patients with Neurological disorders including cerebral palsy, stroke
• Patients on immunosuppressants for rheumatological conditions, cancer etc
• Patients with Blood disorders like sickle cell disease.

Before you undergo this treatment, you need to discuss the potential benefits and risks with your treating physician. Updated information regarding role of these antibodies against viral variants is being collated.

What information do you need to share with your physician before getting this treatment?

Update your doctor regarding your current medical conditions, medicines including supplements, allergies. Women need to disclose in case they are pregnant, planning pregnancy or are breast-feeding. There is limited data about using this combination in pregnancy and breastfeeding.

How safe is this treatment?

Allergic reactions, during and after the medication has been infused, include fever, shivering, nausea, headache, shortness of breath, low or high blood pressure, variations in heart rate, chest discomfort, confusion, fatigue, wheezing, swelling of lips and face, rash, itching, muscle pains, giddiness and sweating. There can be redness, bruising and pain at drip site. Most reactions are mild but some patients can have a severe reaction requiring hospitalisation.  That is why it is important to remain under observation at the hospital for at least an hour after  drug administration. Under no circumstances should this treatment be administered at home. Unanswered questions regarding this cocktail include a blunted immune response to SARS-CoV2 vaccine and changes in immune response to future infections with the virus. We will be wiser about these in the years to come.

Will patients on supplemental oxygen or already hospitalised for covid benefit from this treatment?

No, this is a therapy exclusively authorised for non-hospitalised patients maintaining oxygen saturation on room air. Use in moderately severe or severe cases in hospital may worsen outcomes.

What precautions should be followed after receiving Monoclonal Antibodies?

Receiving this treatment does not mean you are free from the disease. You need to continue self-isolation and continue medicines administered by your physician. They will monitor you for any worsening symptoms since that may happen despite receiving the monoclonal antibodies. In case you experience any side-effects, you need to notify them.