Covid treatment sotrovimab can cause drug-resistant mutation, study finds

The Covid-19 virus is resistant to the drug sotrovimab, and without the monitoring of patients given the treatment the virus could spread in the community.

The New England Journal of Medicine published the world's first findings regarding the use of sotrovimab in the first 100 patients in western Sydney during the Delta outbreak in 2021.

Many countries have Sotrovimab available to treat vulnerable patients who are at risk of dying from Covid-19 infections. Sotrovimab must be administered within the first five days of Covid-19 to prevent severe symptoms. It is one of the few human- engineered antibodies that can target Omicron.

There are more covid cases across Australia.

Four of the patients developed resistance to sotrovimab six to 13 days after treatment, according to the lead author of the study. The whole genome sequence of the virus analysed from the patients before and after sotrovimab treatment uncovered a few patients that made the drug effectively inactive.

We don't know if sotrovimab helps to destroy the virus before it develops resistance. Drugs are often given to treat Covid-19 patients. We are trying to advocate for patients that progress to severe disease despite the treatment that we investigate usinggenomics to see whether they have acquired any resistance genes.

It was important to keep an eye on them because once the patients acquired the mutations, they could still take samples from them and grow the virus in the laboratory, which meant they were still infectious. The patients were at risk of passing the virus on to others.

We don't want to see resistant virus in the community because that will mean that a lot of other people can't use this drug as well.

It would be wise for those who developed resistance to isolation to remain separate from their family until the virus had cleared. After sotrovimab treatment, the virus persisted in the patients for up to 24 days.

It is the first report of resistance to sotrovimab.

Prof Peter Collignon is an infectious diseases physician and drug resistance expert with the Australian National University.

The only way to know if this is a rare event is to keep an eye on it.