Mayo study finds antibody treatment can help COVID-19 patients

A subset of COVID-19 patients who received infusions of lab-made antibodies ran a lower risk of requiring hospital care for their illnesses, according to a Mayo Clinic study released Monday.

The report suggests that certain monoclonal antibody treatments can help patients with mild to moderate symptoms who are at high risk of serious COVID-19 illness due to other health conditions.

The findings come as Minnesota health officials are reporting a surge of patient interest in antibody treatments as case counts have ballooned with the spread of the highly infectious delta variant. There's been so much interest, in fact, that health systems in the Twin Cities have been running short on treatment slots, forcing some patients to travel to greater Minnesota for care.

"We do know that metro facilities have been transferring their referrals ... due to lack of infusion appointment availability as all health systems struggle with staffing issues," said Alexandra Waterman, medical surge coordinator for the Minnesota Department of Health. "We do expect continued growth in demand."

Mayo Clinic was the first health system in Minnesota last year to offer certain COVID-19 patients the antibody infusions that are given shortly after patients get sick. Former President Donald Trump received an early version of the treatment when he took ill with the pandemic virus last year.

Since November and December, the federal government has been providing free access to drugs used in the treatment, although initial demand from patients was underwhelming.

The antibodies are designed to block the pandemic virus from attaching to and entering human cells.

While the treatment is promising, it shouldn't be viewed as an alternative to vaccines, said Dr. Raymund Razonable, a Mayo Clinic infectious diseases specialist and senior author of the new study.

"Monoclonal antibodies provide immediate but short-term immunity, while vaccination will provide longer-term immunity," he said in a statement.

Researchers at Mayo followed nearly 700 patients who received a combination of casirivimab and imdevimab, antibody treatments that the Food and Drug Administration has cleared for emergency use. The study tracked patients treated between December 2020 and April and compared outcomes between those who received the drug combination and a group of similar patients who didn't receive infusions.

Two, three and four weeks after treatment, hospitalization numbers were significantly lower in the group that received the treatment, according findings in the journal Lancet EClinical Medicine.

"Among [high-risk] patients who develop COVID, they should seek this treatment as early as possible in order to prevent the disease from progressing to serious illness," Razonable said in an interview.

High-risk patients are those age 65 and older or younger people with one of several health conditions such as high body mass index, chronic kidney disease or diabetes.

As more patients have learned about antibody treatments and evidence for their effectiveness has improved, there's been a substantial increase in patient demand, said Dr. Andrew Olson, medical director for COVID-19 hospital medicine at M Health Fairview.

The Minneapolis-based health system is in the process of doubling its capacity for providing the infusion treatment, Olson said.

In the meantime, some patients in the metro like Curtis Urban are willing to travel for the treatment. The 58-year-old Eagan resident said he was directed by his local doctor's office to the Mayo Clinic in Rochester last week for an infusion.

"I jumped all over it," Urban said, adding that he also was quick earlier this year to get vaccinated against COVID-19. "I want to get past this as quickly as possible."

Federal regulators this summer provided emergency authorization for use of the antibodies as a way to potentially prevent infection — another reason that demand is on the rise, doctors say.

In response, Bloomington-based HealthPartners started offering antibodies this month to patients exposed to SARS-CoV-2, who receive treatment via injections rather than infusions, said Dr. Mark Sannes, an infectious disease specialist.

At Duluth-based Essentia Health, demand increased from about 10 treatments per week in mid-July to 93 infusions during one week in mid-August. Kate Dean, executive director of the Essentia Institute of Rural Health, said in an e-mail: "The number of positive COVID cases is rising as people in our communities are being exposed to and infected with the highly virulent Delta variant of SARS-CoV-2."

Olson stressed that patients shouldn't forget about COVID-19 immunizations.

"If you compare the effectiveness of monoclonal antibodies versus a vaccine, the vaccine is way more effective," he said. "They are not a replacement for those who choose not to get vaccinated."

Christopher Snowbeck • 612-673-4744

Twitter: @chrissnowbeck