Monoclonal Antibody Treatments Called Ineffective Against Omicron

Monoclonal antibody treatments no longer an option when it comes to treating the Omicron variant of COVID-19, the US Food and Drug Administration (FDA) ruled this week. In revising its previous approval of the therapies, the FDA stated that they’re unlikely to be effective against Omicron and wants to spare patients the risk of side effects such as injection site soreness or allergic reactions.

The agency stated that it “revised the authorizations for two monoclonal antibody treatments—bamlanivimab and etesevimab (administered together) and REGEN-COV (casirivimab and imdevimab)—to limit their use to only when the patient is likely to have been infected with or exposed to a variant that is susceptible to these treatments.”

The decision comes in light of Centers for Disease Control and Prevention (CDC) data that suggests the Omicron variant is responsible for over 99% of COVID-19 cases in the US. Because it is highly unlikely a patient will be infected with any variant other than Omicron, the FDA said that no monoclonal antibody treatment is to be administered at this time.

The FDA added however that “there are several other therapies—Paxlovid, sotrovimab, Veklury (remdesivir), and molnupiravir—that are expected to work against the Omicron variant, and that are authorized or approved to treat patients with mild-to-moderate COVID-19 who are at high risk for progression to severe disease, including hospitalization or death. Health care providers should consult the NIH [National Institutes of Health] panel’s COVID-19 treatment guidelines and assess whether these treatments are right for their patients.”

Monoclonal antibodies are made in a laboratory to mimic the antibodies produced by the body’s immune system. Monoclonal antibodies, introduced to the body through intravenous (IV) injection, look for and attach to the SARS-CoV-2 spike protein, blocking the virus’s ability to enter cells and slowing down the infection.

Monoclonal antibody treatment has been shown to reduce the risk of COVID-19 hospitalization, as well as decrease the amount of virus in a person’s blood.

The decision to rescind approval of monoclonal antibody treatment for the Omicron variant has been met with some resistance, most notably from Florida Governor Ron DeSantis.

DeSantis called upon the Biden Administration to reverse the decision, saying, “Without a shred of clinical data to support this action, Biden has forced trained medical professionals to choose between treating their patients or breaking the law…. This indefensible edict takes treatment out of the hands of medical professionals and will cost some Americans their lives.”

DeSantis argued that even if less effective against Omicron, monoclonal antibody treatment is “better than nothing.”

In a statement from Patrizia Cavazzoni, MD, the director of the Center for Drug Evaluation and Research, the FDA emphasized, “While it’s critical that we have ways to treat those who contract COVID-19, the authorized treatments are not a substitute for vaccination in individuals for whom COVID-19 vaccination and a booster dose are recommended. Data has clearly demonstrated that the available, safe and effective vaccines can lower your risk of developing COVID-19 and experiencing the potential associated serious disease progression, including hospitalization and death.”

This article originally appeared in Contagion®.