The monoclonal antibody cocktail, effective against the B.1.617 variant (found in India) is being imported by Roche, a Switzerland-based leading healthcare company and marketed in India through Cipla Ltd has recently received Emergency Use Authorization (EUA) from Central Drug Standard Control Organization (CDSCO) for the treatment of mild to moderate Covid-19 in adults and pediatric patients above 12 years of age, weighing at least 40kg who are at a high risk of progression to further severity.

Former US President Donald Trump has also been treated with this antibody cocktail (Casirivimab and Imdevimab) when he contracted covid-19 in October 2020.

About the constituents and mechanism

The cocktail that was first developed by scientists at Regeneron, an American biotechnological company for the treatment of covid patients in U.S. is a combination of two different antibodies Casirivimab and Imdevimab. These antibodies bind tightly to the receptor of the virus’s spike protein and block its ability to infect other cells of the body.

The scientists evaluated hundreds of virus-neutralizing antibodies in mice that have been genetically engineered to have a human-like immune system and also identified similar antibodies from covid-19 recovered patients. As the virus mutates leading to the formation of various mutants, using a combination therapy lowers the chances of it losing the efficacy against a particular strain. Even if one of the antibodies lose its potency against the strain, the virus would not able be able to break away from both the antibodies without several mutation in distinct locations which enhances the potency of this combination as a whole.

“The REGEN-COV antibody cocktail was prospectively designed so that if variants arose affecting one component, the other component could compensate and still allow for potent neutralizing activity. In fact, as reported in ‘Science’ in June 2020, Regeneron scientists predicted the key mutation that has since appeared in the SARS-CoV-2 variants first identified in South Africa and Brazil, and further showed that this mutation would lower potency of the casirivimab antibody, but be compensated for by the strong potency of the imdevimab antibody,” says George D. Yancopoulos, President and Chief Scientific Officer, Regeneron.

Regarding the administration of the cocktail

• It can be administered between 48 hours to 7 days after the patient is being infected with the virus.

• Emergency use authorization has been approved by lowering the dose to 1200mg (600 mg casirivimab and 600 mg imdevimab).
• The combination should be administered either by intravenous (IV) infusion or with the help of subcutaneous injections.
• In adults and pediatric patients (aged above 12 and weighing at least 40 kg), there are several factors that puts them at a greater risk for developing severity or further complications. These factors can be identified as :
• Diabetes
• Obesity
• Hypertension
• Chronic kidney disease
• Chronic lung disease
• Pregnancy
• Older age(above 65 years)

• It is not authorized to be given to patients who require oxygen support due to covid-19.

Availability and pricing

The first batch of the antibody cocktail is now available and the second batch will be made available in mid-June. Each of the 100,000 packs available in India offer treatment for two patients.

The cocktail can be stored at 2-8 degree Celsius.

A combined dose of 600mg of Casirvimab and 600mg of Imdevimab is priced at ₹59,750 and is made available for treatment through leading hospitals across the country.

“We are guided by our strong sense of responsibility to address unmet patient need and look forward to leveraging our solid marketing and distribution strengths in India to provide broader, equitable access to this innovative treatment option in the country,” said Umang Vohra, MD & Global CEO, Cipla.

Trials results and Efficacy

In light of recent evidences from the phase III trials in 4,567 high-risk non-hospitalized Covid-19 patients it has been observed that the antibody cocktail casirivimab and imdevimab reduced hospitalization or death by 70% as compared to placebo treatment.

It also significantly shortened the duration of symptoms by four days. The data shows it has been effective in reducing viral load and the time to alleviate symptoms in non-hospitalized patients with COVID-19.