This month, fifteen thousand doses of new COVID-19 treatment, Sotrovimab landed in Australia. The drug has been shown to keep people with mild COVID symptoms from developing more severe cases that might lead to hospitalisation or death. According to the Health Department, people with COVID-19 symptoms who receive a single intravenous dose of the drug are 79 per cent less likely to be hospitalised or die from the disease. Dr Linda Hueston, Chief Serologist at NSW Health Pathology – ICPMR, says that the rapid response to the spike protein used in Sotrovimab was impressive.
“Sotrovimab is a monoclonal antibody which provides spike antibody to the patient in very high concentration. Monoclonal antibodies are similar to antibodies the body would naturally make in response to infection but are mass-produced in a laboratory and are designed to recognise a specific component of the virus — in this case the spike protein on its outer shell. You are essentially transfusing IgG antibodies directed against the spike protein into a patient, so they immediately have functional antibody in their circulation. It can take 7 to 10 days for IgG antibody to appear post PCR positive results and then a few more days to achieve a high level. When Sotrovimab was given to people who tested PCR positive/antibody negative by our tests, we saw a huge antibody response within 17 hours (the time between first and second sample).
“This is the first COVID-19 specific treatment that I am aware of, and whilst we have only just started using Sotrovimab here in Australia, it gives an impressive response in antibody testing. Normally you would see a spike-only response like this after vaccination. The first couple of times I saw it, I couldn’t understand how it was happening in cases who had no vaccination history, were clearly very early in the infection process, and lacked any nucleoprotein antibody. Now we need to find out how long the transfused IgG antibodies last, whether it shortens viraemia, what effect it may have on a patient’s own antibody production and how it affects patient outcome,” said Dr Hueston.
The Sotrovimab treatment requires a single dose to be administered through an intravenous (IV) infusion in a health care facility. The drug aims to provide further options to protect vulnerable Australians at risk of developing severe COVID-19, however, not all Australians with COVID-19 will need to access the treatment. It is expected that Sotrovimab will be targeted for the treatment of Australians over 55 years old who have COVID-19 and also have comorbidities.[1]
“I don’t think there has been enough time for the clinicians to determine how it has affected patient management in Australia yet. However, the fact that this is the first COVID-19 specific treatment is an important achievement in such a short space of time in the course of the pandemic. On the basis of what is learnt in the next few months, Sotrovimab and other similar drugs will provide meaningful specific treatment for COVID-19 in vulnerable Australians,” said Dr Hueston.
