Tixagevimab with Cilgavimab for the Prevention of COVID-19

We are flying to California tonight! Our schedule is here if anyone wants to follow along and meet up with us. I’ll try to blog along the way.

Today, I want to write about tixagevimab with cilgavimab (Evusheld) for the prevention of COVID-19. This is the AstraZenica product authorized under the Food and Drug Administration’s EUA in December 2021. It is aimed toward patients with moderately to severely compromised immune systems due to a medical condition or due to taking immunosuppressive medications or treatments who may not mount an adequate immune response to COVID-19 vaccination.

One example of a patient looking to take tixagevimab with cilgavimab is Dr. Brian Koffman, a 70-year-old retired family physician in Chula Vista with chronic lymphocytic leukemia. His immunosuppression puts him at risk for severe COVID, and the vaccine series is likely less effective. The Evusheld may help prevent the severe covid.

It’s an interesting monoclonal antibody combination. One recent study in Science Translational Medicine found that the drug may provide up to 12 months of protection and benefit individuals at high-risk of COVID-19. These are pharmacokinetic predictions, not 100% proven, but they may turn out to be the case.

There are potential downsides to Evusheld. First is that results from a clinical trial suggest a possible increased rate of adverse cardiac events in individuals with cardiovascular risk factors. Examples of serious adverse events were myocardial infarction and congestive heart failure, but it is unclear if the monoclonal antibodies caused the cardiac events. I haven’t seen the number needed to treat versus number needed to harm for the medication, and we need to monitor this closely.

Second is that the efficacy of the combination against the Omicron variant remains uncertain. More studies are needed as Omicron evolves, particularly the new lineage BA.2. (This new lineage may be decreasing activity of another COVID medication, sotrovimab, although the manufacturer estimates that the medication will still be active against BA.2).

A question raised is who will get the preventive treatment with tixagevimab with cilgavimab – people with education and resources, or marginalized, underserved populations. A health equity approach is needed to ensure that the potentially lifesaving medication is fairly distributed.

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