FDA Could Soon Limit Use of Only Drug for COVID Prevention

Pemivibart (Pemgarda) should only be used for pre-exposure prophylaxis of COVID-19 in immunocompromised patients when the combined national frequency of SARS-CoV-2 variants with substantially reduced susceptibility to the drug is less than or equal to 90%, the FDA announced on Monday.

The agency revised the emergency use authorization (EUA) for the long-acting monoclonal antibody based on available information about SARS-CoV-2 variant susceptibility to pemivibart and national variant frequency, Patrizia Cavazzoni, MD, director of the FDA’s Center for Drug Evaluation and Research, wrote in a letter to pemivibart’s manufacturer, Invivyd.

“FDA is proactively incorporating this Limitation of Authorized Use in the event that variants with substantially reduced susceptibility to Pemgarda reach this threshold,” Cavazzoni wrote.

KP.3 and KP.3.1.1 are now the most frequently reported SARS-CoV-2 variants circulating in the U.S. at this time. Based on CDC’s Nowcast estimates from August 17, KP.3 comprises an estimated 17% of circulating variants in the U.S. and KP.3.1.1 comprises 37%, the latter up from 23% over the 2 weeks prior.

Although pemivibart is likely to retain adequate neutralization activity against the KP.3 variant, KP.3.1.1 may have substantially reduced susceptibility, the FDA warned.

The FDA issued the initial EUA for pemivibart in March of this year as COVID-19 pre-exposure prophylaxis in individuals ages 12 years and older (weighing at least 40 kg) who are not currently infected with SARS-CoV-2 and who have moderate-to-severe immune compromise due to a medical condition or immunosuppressive treatments.

Currently, pemivibart is the only available monoclonal antibody for the prevention of COVID-19 in patients at risk for severe disease.

In addition to the revision of the EUA, the FDA also revised the authorized fact sheets for healthcare providers to inform about the increased risk of developing COVID-19 for patients exposed to SARS-CoV-2 variants with reduced susceptibility to pemivibart. Detailed neutralization data can be found in the revised fact sheet.

The FDA recommended that healthcare providers discuss this risk with patients receiving pre-exposure prophylaxis and advise patients who develop signs or symptoms of COVID-19 to test for SARS-CoV-2 infection and promptly seek medical attention, including starting treatment for COVID-19, as appropriate, if they test positive.

Several COVID-19 treatments — nirmatrelvir/ritonavir (Paxlovid), remdesivir (Veklury), and molnupiravir (Lagevrio) — are expected to work against currently circulating variants, and are approved or authorized to treat patients with mild-to-moderate COVID-19 who are at high risk for progression to severe disease.