TORONTO -- Health Canada is warning about the "potential risk of treatment failure" for a Canadian-made COVID-19 monoclonal antibody, saying it may not protect against infection from some variants.
In a statement issued on Wednesday, Health Canada said that bamlanivimab may fail to treat certain variants of SARS-CoV-2, the virus which causes COVID-19. The agency said the potential risk was identified through "global surveillance."
The agency said the antibody treatment is "expected to retain clinical benefit" against the B.1.1.7 variant, which was first identified in the United Kingdom.
However, Health Canada is advising health-care professionals that bamlanivimab "exhibited reduced activity against SARS-CoV-2 variants" with the E484K and L452R mutations.
This includes the B.1.351 variant first identified in South Africa, the P.1 variant first found in Brazil, the B.1.427/B.1.429 variant reported in California, and the B.1.526 variant first identified in New York.
"Local epidemiology of variants should be taken into consideration before empiric use of bamlanivimab as single monoclonal antibody therapy. Bamlanivimab should be used only in regions where there is a known or confirmed low prevalence of lineages containing E484K and/or L452R SARS-CoV-2 variants," Health Canada said in the statement.
The agency said the treatment should also only be used if other monoclonal antibodies that retain neutralization activity across these variants are not available.
Bamlanivimab is a monoclonal antibody directed against the spike protein of SARS-CoV-2. The drug mimics the immune system's ability to fight off the virus and was developed by AbCellera Biologics Inc. in Vancouver with the support of the federal government.
According to Health Canada, bamlanivimab may prevent symptoms from becoming worse and reduce hospitalizations in high-risk patients who are infected with COVID-19.
The one-dose treatment, which is sold by Eli Lilly Canada, Inc., can be used in health-care facilities such as hospitals, as it is given by infusion into the veins of patients.
Amid increasing variant spread, Health Canada now says patients using bamlanivimab should continue to be monitored for COVID-19 signs and symptoms of infection.
The agency said patients treated with bamlanivimab should also be provided additional treatment where required.
In an emailed statement to CTVNews.ca, Eli Lilly Canada said that Health Canada's update on the risk of the treatment is "not related to any safety concerns" as it continues to work against COVID-19 and the B.1.1.7 variant.
"In Canada, more than 95 per cent of overall Canadian cases caused by variants are attributed to the U.K. variant (B.1.1.7 variant), which bamlanivimab retains neutralization effects against," the company said in the statement.
Since Health Canada first authorized the drug in November, Eli Lilly Canada says there has been "additional Phase 3 research to support its use with high statistical confidence."
According to the company, more than 400,000 patients have been treated with bamlanivimab in over 20 countries.
While countries around the world have been using the drug for months, almost none of Canada's 26,000 doses that were purchased for $40 million and distributed amongst the provinces have been used. Doctors say this is because a plan on how to administer the drug was never made.
Health Canada's new warning about the antibody treatment comes after the U.S. Food and Drug Administration's recently revoked bamlanivimab's Emergency Use Authorization.
A Health Canada spokesperson previously told CTVNews.ca via email that the status change in the U.S. was done at the request of Eli Lilly, "given evidence that it is ineffective when used alone against certain COVID-19 variants of concern circulating in the U.S. and the availability of alternative therapies in the U.S."
Bamlanivimab was the first monoclonal antibody approved in Canada for use in treating COVID-19. There are currently four other types of antibody drugs made by different companies waiting for approval by Health Canada.
