An effective but underused COVID-19 monoclonal antibody therapy now may be more accessible for long-term care facilities that aren’t equipped to deliver intravenous infusions. 

The Food and Drug Administration has updated its emergency use approval of REGEN-COV, halving the treatment dose and allowing it to be administered by injection if necessary, rather than by infusion.

The new dosage is 1,200 mg (600 mg casirivimab and 600 mg imdevimab), an amount that was shown to reduce the risk of hospitalization or death by more than 70% in a phase 3 clinical trial. The first choice of delivery should be by intravenous infusion, but “injections are an alternative when IV infusion is not feasible and would lead to a delay in treatment,” drugmaker Regeneron Pharmaceuticals said in a Friday announcement.

REGEN-COV is authorized for reducing the likelihood of hospitalization and severe disease in non-hospitalized COVID-19 patients. In trial participants, the new lower dose “rapidly protected household contacts from exposure to SARS-CoV-2 at home, with 72% protection against symptomatic infections in the first week, and 93% in subsequent weeks,” the drugmaker reported at the time.

Regeneron’s and Eli Lilly and Co’s versions were authorized for use in November, and the federal government stockpiled the drugs in anticipation of demand. By February, fully 67% of monoclonal antibody treatments for COVID-19 had been administered in assisted living communities, according to an analysis of Medicare claims data. But the data was limited to 18 states, suggesting that despite its promise, use of the treatment was lagging below expectations in many states, investigators said. (GlaxoSmithKline’s version of the therapy was approved in early June.)

Although U.S. COVID-19 infections are at an all-time low, thousands continue to become ill. Researchers are encouraging clinicians to encourage greater use and confidence in these treatments. 

Drugmaker Regeneron agrees. “Unfortunately, to date only a fraction of patients eligible for antibody treatments have received them, which we hope will change based on this updated FDA authorization,” said George Yancopoulos, M.D., Ph.D., the company’s president and chief scientific officer.

REGEN-COV is the only antibody therapy currently available across the United States, according to the drugmaker. Others have been halted in certain states in response to circulating gene variants.