In early December, several medical professionals in Arizona sounded the alarm about difficulties patients were having obtaining monoclonal antibody therapies for COVID-19. A monoclonal antibody, or mAb, is a laboratory-made protein that mimics the immune system’s ability to fight off harmful pathogens such as viruses.
The Centers for Disease Control and Prevention (CDC) recommends mAb for people who test positive for COVID-19, have been symptomatic for less than 10 days, and are at high risk of COVID-19 disease progression. High risk is defined as people who are age 65 or older, people who are obese or overweight, pregnant women, and people with certain underlying medical conditions.
The process for determining eligibility and locating a treatment site was cumbersome and frustrating, and not something an ill person wanted to deal with. As a result, the Arizona Department of Health Services announced last week that healthcare practitioners can contact the Arizona Poison Control Systems COVID-19 Hotline on behalf of patients to find a site administering monoclonal antibody therapies.
But that won’t make it an easier to obtain treatment in the near future.
Three monoclonal antibody (mAb) products are currently authorized under an Emergency Use Authorization by the U.S. Food and Drug Administration (FDA) in an effort to prevent disease progression in COVID-19 positive patients at high risk for hospitalization or developing complications.
The CDC has says evidence suggests all three COVID-19 mAbs are effective against the Delta variant. The problem, however, is the U.S. Health and Human Services will indefinitely pause the allocation and distribution of two mAb products -bamlanivimab / etesevimab and casirivimab / imdevimab- as of Dec. 27.
The reason? Initial testing has shown those two products “have markedly reduced susceptibility” against the Omicron variant. So as of Dec. 27, sotrovimab is the sole COVID-19 monoclonal antibody product known to retain in vitro activity against Omicron.
For now, providers in Arizona are being encouraged to continue utilizing the existing supply of mAb products for eligible patients unless the patient is confirmed, or very likely, to be infected with the Omicron variant.
But with the majority of new COVID-19 patients in Arizona testing positive for Omicron, a high demand can be expected for sotrovimab, which is available only by infusion in a process that can take nearly two hours per patient.
Supply issues as caused Honor Health, one of Arizona’s largest healthcare systems, to cease providing any mAb until a new shipment of sotrovimab is received. ADHS has said supplies could be restocked later this week.
In Maricopa County, the local department of public health is working with healthcare providers, as well as state and federal partners to increase staffing resources in an effort to expand the administration of mAb treatments. And in the coming days, FEMA teams are expected to be assigned to some mAb sites in order to relieve the burden on emergency room resources.
Medical professionals across Arizona are also waiting for pharmacies to receive Pfizer’s newly FDA approved antiviral oral medication Paxlovid, which doctors can prescribe for COVID-19 positive patients. Paxlovid must be administered within five days of symptom onset but is not intended for patients requiring hospitalization.
However, several common medications negatively react with Paxlovid, leading to serious, even life-threatening complications. In addition, patients with kidney or liver problems should not take Paxlovid without discussing the risks with their health care provider.
The mAb availability issue is also expected to increase demand for AstraZeneca’s pre-exposure prophylaxis Evusheld (tixagevimab / cilgavimab) for moderate to severely immunocompromised patients for whom a COVID-19 vaccine is not recommended.
Such patients may have a compromised immune system due to a medical condition such as cancer or due to taking immunosuppressive medications following an organ transplant. Evusheld works by introducing two new antibodies to a patient to help develop an extra layer of protection.
Evusheld is also recommended for some patients with a history of severe adverse reaction to a COVID-19 vaccine or a component of a vaccine. However, Evusheld is not authorized for post-exposure prevention of COVID-19 or for the treatment of COVID-19.
Public health officials warn the initial supply is expected to only reach 10 percent of those eligible.