A Monoclonal Antibodies’ Prospective Place in the COVID-19 PrEP Market

There is a marked difference in the COVID-19 vaccine effectiveness (VE) in the immunocompromised population. It is well-known and has been written in the literature in a number of studies. In a Centers for Disease Control and Prevention (CDC) MMWR report published earlier this year, the study demonstrated the vaccine’s effectiveness was drastically reduced in this population.

“VE against COVID-19–associated hospitalization was 38% in the first 7–59 days after receipt of an updated COVID-19 vaccine dose and 34% in the 60–119 days after receipt of an updated dose,” the investigators wrote.¹

Despite the limited efficacy, the most recent CDC guidelines still recommend people in this population get the COVID-19 vaccine. “People ages 6 months and older who are moderately or severely immunocompromised should get the 2024–2025 COVID-19 vaccine to help protect against severe disease, hospitalization, and death,” CDC writes on its website ²

Another potential preventative strategy is a monoclonal antibody(mAb), pemivibart (Pemgarda), which was developed by Invivyd. Pemivibart is a half-life extended monoclonal antibody. It was engineered from adintrevimab, Invivyd’s investigational mAb. It is a monoclonal injection (4500 mg) for intravenous use.

Earlier this year, pemivibart received an FDA emergency use authorization for the pre-exposure prophylaxis (PrEP) of COVID-19 for both adults and adolescents at least 12 years of age, and weighing at least 40 kg (88.1 lbs) who are immunocompromised.³ The antibody is indicated for those individuals who are unlikely to mount an adequate immune response to COVID-19 vaccination, and recipients of pemivibart should not be currently infected with or have had a known recent exposure to an individual infected with COVID-19.³

“For those of whom vaccination is recommended, we would recommend that they take the vaccine, and then, in combination with that, should [pemivibart] be prescribed by their physician, then they would administer the antibody for PrEP,” Invivyd’s Chief Scientific Officer Robert Allen, PhD, said. “And the only stipulation is you need to wait about 2 weeks between receipt of the vaccination and receipt of the antibody to give the vaccine a full chance at being effective.”

Back in August, Invivyd reported data from 2 cohorts of its ongoing CANOPY study. Participants received 2 doses of pemivibart (cohort A and B) or placebo (cohort B) administered via intravenous infusion 3 months apart; safety, serum virus neutralizing antibody (sVNA) titers and clinical endpoints were assessed at pre-specified timepoints over the 180-day period.

Table 1. Based on CANOPY 6-month data cutoff (May 21, 2024). Cohort B Modified Full Analysis Set includes all randomized participants without current SARS-CoV-2 infection at baseline as measured by central lab RT-PCR.
Table credit: Invivyd

In cohort A, there were 298 participants, and cohort B had 317 participants in the pemivibart arm and 160 in the placebo arm. Table 1 and Table 2 offer further data on the individual cohorts.

Table 2. Based on CANOPY 6-month data cutoff (May 21, 2024). Cohort A Full Analysis Set includes all participants who received a full dose of study drug at the initial dosing.
Table credit: Invivyd

Allen explains that although variants are evolving, the protection of pemivibart remains efficacious. “If we look at the most prevalent variants right now, and you can use the CDC Nowcast as a as a reference there, we continue to show very good activity and with no meaningful loss of activity since we’ve had this EUA against the prevalent variants.”