In revised treatment guidelines, the World Health Organisation (WHO) has strongly advised against the use of two antibody drugs - sotrovimab and casirivimab-imdevimab - for patients with Covid-19, adding that these are likely to be ineffective against currently circulating variants such as Omicron.
The review, conducted by WHO Guideline Development Group of international experts and published in peer-reviewed journal The BMJ on Friday, replaces previous conditional recommendations for the use of the two drugs.
These drugs work by binding to the Sars-CoV-2 spike protein, neutralising the virus's ability to infect cells. Both had received emergency use authorisation by the US FDA for treatment of severe Covid-19, as earlier trials showed some effect against the Delta variant of the virus, which had ravaged the world through most of 2021. "After weighing up all the evidence, the panel judged that almost all well-informed patients would not choose to receive sotrovimab or casirivimab-imdevimab," read the note.
When making a strong recommendation against the use of monoclonal antibodies for patients with Covid-19, the group considered in vitro (lab-based) neutralisation data.
"… sotrovimab and casirivimab-imdevimab evaluated in clinical trials have meaningfully reduced neutralisation activity of the currently circulating variants of Sars-CoV-2 and their subvariants. There was consensus among the panel that the absence of in vitro neutralisation activity strongly suggests absence of clinical effectiveness of these monoclonal antibodies," they said.
Experts in India say that it is good that WHO has formally updated the guidelines as there was enough evidence to suggest that monoclonal antibodies will not work anymore. "In major Indian cities, antibodies have been used on select patients but that was in the previous wave. These drugs are directed against the spike protein and any changes in the spike protein would mean that they won't work unless the drugs are modified as well. Ministry of health had already indicated this and now even WHO has announced, which makes perfect sense," said Dr Yatin Mehta, chairman, institute of critical care and anaesthesiology, Medanta-The Medicity, Gurugram.