What is sotrovimab? An Alberta physician explains how the new COVID-19 drug approved by Health Canada works

This should not be considered a substitute for vaccination.

Anna Junker 4 minute read November 15, 2021

COVID-19 monoclonal antibody therapy, sotrovimab, developed by GSK and Vir Biotechnology. supplied

This week, chief medical officer of health Dr. Deena Hinshaw announced Alberta is rolling out sotrovimab, a new drug recently approved by Health Canada to treat COVID-19.

Postmedia spoke with infectious disease physician Dr. Ilan Schwartz to learn about sotrovimab, how it works and who is eligible to receive it.

This interview has been edited for length and clarity.

What is sotrovimab?

Sotrovimab is a monoclonal antibody, a lab-made version of a protein your body would typically make to fight off the virus. Antibodies are the artillery that we use against foreign invaders like viruses and they’re trained by prior immunization or infection. Individuals who have not been vaccinated or infected with COVID-19 don’t have antibodies against the virus, hence a role for augmenting their own immune response by providing an exogenous source of these antibodies.

How is the drug provided?

It’s a one-time intravenous infusion that needs to be given in the first five days of symptom onset. To date, there’s been logistical challenges for patients infected with COVID-19 and at an early enough phase, which also corresponds to the period of highest infectivity. The idea of bringing such patients into an IV infusion site, which is primarily used for people with cancer, has been very problematic.

It’s been overcome now by Alberta Health Services through the deployment of mobile integrated health (MIH) units — community paramedics who go into patients’ homes to provide treatment. It’s an exciting and innovative use of these health professionals. It’s also not a particularly efficient or scalable solution. Fortunately, most of the population has become vaccinated and there’s only a small portion that will still benefit from this.

Who is eligible to receive sotrovimab?

Individuals who are unvaccinated and are over 65 as well as individuals who are recipients of organ or bone marrow transplants irrespective of age or vaccination status are eligible at this time. The patients or their physicians are encouraged to either self refer or to refer patients through Health Link.

What do we know about its effectiveness?

Twenty patients currently need to be treated with this therapy in order to prevent one patient from going to the hospital. The drug is about 80 per cent effective in preventing hospitalization. It’s pretty good, certainly a lot better than any other outpatient therapy that has been tried so far and approved by Health Canada.

Could this deter the unvaccinated from getting immunized?

Although the program is as efficient and effective as possible, it doesn’t have the same efficiency and responsiveness as your body’s own ability to produce antibodies after vaccination. Not everybody is going to qualify for this treatment. We’re currently restricted to individuals that reside near one of these MIH units, and not every area, particularly rural areas, are going to have access. Some may fall through the cracks as a lot of patients feel fairly well within that first five days and may not reach out to their doctor to even get diagnosed. This should not be considered a substitute for vaccination. At the end of the day, vaccination is the safest, most effective and most cost-effective way to prevent severe disease.

How costly is sotrovimab?

It’s procured by Health Canada and I haven’t seen the contract but the sticker value for this drug in the United States is US$2,100 per dose. The cost of administering this treatment, which requires a team of paramedics to be in a patient’s home while giving an infusion for over an hour and then for another hour afterwards to monitor for allergies, is substantial. It’s certainly not a project that can be scaled up. If we can keep people out of the hospital, then it’s likely to be cost-effective given these hospital stays are, I think, on average, about $25,000 per admission, or $75,000 if you require ICU admission.

How does it feel to have a drug available to treat COVID-19?

It’s bittersweet. It’s nice that we now have something to offer patients. The irony is that we need it a lot less now than at earlier phases in the pandemic when fewer individuals were vaccinated. As not just an infectious disease physician, but one that specializes in patients with organ transplantation, I’m really happy that we have this and that we can offer this to those individuals who have gotten vaccinated, who have followed all the public health restrictions but who have still become infected and who are at very high risk of requiring hospitalization or dying.

The other side of things is that now we have something to offer unvaccinated individuals who, ironically, have rebuffed our very strong and heartfelt recommendations to get vaccinated in the first place. But it’s about harm reduction at this point and if individuals choose not to get vaccinated and if we have a therapy that can keep them from getting really sick or dying, of course we’re obligated to use it.