Safety and Efficacy of Pemivibart, a Long-Acting Monoclonal Antibody, for Prevention of Symptomatic COVID-19: Interim Results From a Phase 3 Randomized Clinical Trial (CANOPY).

Abstract

We report an interim analysis of safety and efficacy of pemivibart in individuals with (cohort A) or without (cohort B) significant immunocompromise in the phase 3 CANOPY trial. Eligible participants (aged ≥18 years; negative for current severe acute respiratory syndrome coronavirus 2 infection) received 2 intravenous 4500-mg pemivibart infusions (cohort A) or were randomized 2:1 to receive blinded pemivibart or placebo infusions (cohort B) 90 days apart. Safety was a primary end point for both cohorts. The primary immunobridging end point for cohort A has been reported elsewhere. Composite incidence of reverse-transcription polymerase chain reaction-confirmed symptomatic coronavirus disease 2019 (COVID-19), COVID-19 hospitalization, and all-cause mortality was an exploratory end point. In September-November 2023, 306 participants received pemivibart (cohort A), and 317 received pemivibart and 162 placebo (cohort B). The most common study drug-related adverse events were infusion-related reactions (cohort A: 11 of 306 [3.6%]; cohort B: 7 of 317 [2.2%] for pemivibart and 0 of 162 for placebo). Four of 623 participants (0.6%) who received pemivibart experienced anaphylactic reactions (serious in 2). In cohort A, the composite COVID-19 incidence through month 6 was 11 of 298 (3.7%; 2 deaths). In cohort B, 6 of 317 pemivibart (1.9%; no deaths) and 19 of 160 placebo (11.9%; no deaths) recipients met the end point through month 6 (84.1% standardized relative risk reduction [95% confidence interval, 60.9-93.5; nominal P < .001]), and 15 of 317 pemivibart (4.7%; 1 death) and 29 of 160 placebo (18.1%; no deaths) recipients met the end point through month 12 (73.9% standardized relative risk reduction [52.8-85.6; nominal P < .001]). Twelve-month protection was conferred with no additional dosing. Pemivibart provided prophylactic efficacy against COVID-19 and was well tolerated by most participants. Anaphylaxis was an important safety risk. NCT06039449.