The antibody cocktail against SARS-CoV-2 is now available in India, and is being touted as “life-saving”. We need to spread the right kind of information before this expensive cocktail goes down the same route of drug shortages, desperate pleas and black market sales 1/n
REGEN-COV (Casirivimab and Imdevimab) is a mixture of antibodies against the spike protein of SARS-CoV-2. The two antibodies work on different parts of the spike protein and this potentially enhances the effectiveness of the cocktail 2/n
At a dose of 1200mg (600mg of each antibody), the phase 3 trial found a 70% reduction in the composite end-point of Covid-19- related hospitalization or all-cause death when compared to placebo. medrxiv.org/content/10.110… 3/n
Where does the “70% reduction” come from? The outcome (hospitalization or death) was observed in 1.0% of those who received the cocktail vs 3.2% in those who didn’t. The absolute risk reduction (ARR) was 2.2%, while the relative risk reduction (RRR) was 70% 4/n
Why is this distinction important? This paper by @cspramesh explains it very well. ncbi.nlm.nih.gov/pmc/articles/P… 5/n
From the above paper 6/n 
The “life-saving”: 1 of 736 individuals who received the cocktail died, and 1 of the 748 persons in the placebo arm. Just as it would be wrong to say that the data suggests that those who received placebo were less likely to die, it would be wrong to call this “life-saving” 7/n
Table from the pre-print: Most of the benefit is in preventing hospitalization (which is great), but the “life-saving” part, which might be true, has not been proven yet, IMHO. 8/n
In whom does the drug work? The study used the drug within 72 hours of testing positive and within 7 days of symptom onset in persons with at least one high-risk factor. Here’s the “don’ts” from the prescribing information from the company (with a caveat about variants) 9/n
What’s the bottom line? If 3 of 100 high-risk individuals were to get hospitalized with COVID-19, the use of the cocktail would prevent 2 of them from getting hospitalized when used within 7 days of symptom onset (which is impressive) 10/n
If you have already been hospitalized because of low oxygen levels, or you have severe COVID, this drug is not likely to work. A study that was looking at the same for another antibody cocktail was terminated prematurely because of a lack of effect clinicaltrials.gov/ct2/show/NCT04… 11/n
This editorial in the @NEJM emphasizes the lack of effect among hospitalized patients nejm.org/doi/full/10.10… 12/n
If you’d like to know more, we discussed this in a recent episode of #FYI with @Sonal_MK @ndtv with Dr.Shahid Jameel, Dr.Sumit Ray and @DRVEERPGUPTA ndtv.com/video/shows/fy… n/n
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