THE NEW PRODUCT — Pemivibart is a human IgG1 monoclonal antibody derived from adintrevimab, an investigational antibody that was effective against the Delta variant of SARS-CoV-2, but not against circulating Omicron variants.3 Unlike adintrevimab, pemivibart has activity against the currently dominant JN.1 Omicron lineage of SARS-CoV-2.4 Pemivibart is catabolized slowly (median half-life 44.8 days).5

CLINICAL STUDIES — No clinical efficacy data were required for authorization of pemivibart. Issuance of the EUA was based on the results of an unpublished immunobridging trial (CANOPY Cohort A; summarized in the FDA Fact Sheet) in 306 adults with moderate to severe immune compromise. Titer levels of anti-SARS-CoV-2 JN.1 neutralizing antibodies 28 days after administration of one dose of pemivibart were compared to extrapolated titer levels of anti-SARS-CoV-2 B.1.617.2 (Delta) neutralizing antibodies 28 days after administration of a single adintrevimab dose in historical controls.

Results from the trial were mixed; antibody levels with pemivibart met the prespecified criteria for immunobridging when an authentic virus neutralization assay was used, but not when a pseudotyped virus-like particle neutralization assay was used. A supplementary analysis found the immunogenicity of pemivibart against the JN.1 variant to be consistent with the immunogenicity of other antibodies against SARS-CoV-2 variants that they successfully targeted.5

ADVERSE EFFECTS — A hypersensitivity or infusion-related reaction occurred in 9% of patients in CANOPY Cohort A. Anaphylaxis occurred in 0.6% of 623 patients who received pemivibart in clinical trials. Pemivibart contains polysorbate 80, which is similar in structure to polyethylene glycol and has been associated with hypersensitivity reactions to COVID-19 vaccines; an immunology consult should be considered before use in patients who had a severe hypersensitivity reaction to a COVID-19 vaccine.

Influenza-like illness, fatigue, headache, and nausea have also occurred with use of pemivibart.5

DOSAGE AND ADMINISTRATION — The recommended dosage of Pemgarda is 4500 mg infused intravenously over at least 60 minutes. Patients should be monitored during and for at least 2 hours after the infusion. Additional doses can be given every 3 months. Pemivibart should not be used for post-exposure prophylaxis or treatment of COVID-19, within 2 weeks after administration of a COVID-19 vaccine, or as a substitute for vaccination.5

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