Vir, GSK's COVID-19 antibody starts rapid race through clinic

Vir Biotechnology and GlaxoSmithKline have begun dosing patients with a COVID-19 antibody in a phase 2/3 clinical trial. The study, which is expected to deliver data this year, is assessing whether the drug can prevent the hospitalization of high-risk patients recently infected with the coronavirus.

Investigators will enroll around 1,300 people globally and give them a single dose of anti-SARS-CoV-2 antibody VIR-7831 or placebo. By treating high-risk patients while their symptoms are moderate, at worst, Vir and GSK aim to show whether VIR-7831 can stop infectees from deteriorating. The primary endpoint will assess the proportion of deaths and hospitalizations in the 29 days after randomization.

Vir and GSK are well behind the front-runners in the race to bring an anti-SARS-CoV-2 antibody to market—Eli Lilly entered the clinic at the start of June—but are truncating development to stay in touching distance. The 1,300-patient trial will start after a 20-subject first-in-human study.

If the phase 2/3 clinical trial goes to plan, GSK thinks it could have data this year and win approval in the first half of 2021. That represents rapid progress through human testing by historical standards but may still lead to VIR-7831 entering a shrinking, fiercely competitive market.

Vaccines from developers including AstraZeneca, Moderna and Pfizer-BioNTech may be available before VIR-7831, leading to reduced numbers of people catching or suffering badly from the virus. It is also possible that other antibody developers, most likely Lilly or Regeneron, will have won approval for a rival to VIR-7831 by the time Vir and GSK get the OK to start selling their prospect.

Despite the competitive landscape, GSK and Vir are wagering significant sums on VIR-7831 and their other antibody prospects. Clinical trials of VIR-7831 in severely ill hospitalized patients and as a way to prevent symptomatic infection are in the works, as is a study of a second candidate that “shares the same characteristics as VIR-7831 but may in addition also function as a therapeutic and/or prophylactic T cell vaccine.”

Vir has secured manufacturing capacity in anticipation of the antibodies coming to market. Under the terms of agreements to reserve capacity at Samsung Biologics and WuXi Biologics, Vir and GSK are set to pay the providers regardless of whether they ultimately require their services. The Samsung deal alone will cost $362 million. Vir may have to pay Biogen a $100 million “access fee” under the terms of another agreement.

To generate a return on those investments, Vir and GSK will need to carve out a space for their drugs in what is likely to be a competitive sector. Anti-SARS-CoV-2 antibodies may be able to both treat COVID-19 and prevent infections, with the latter application being potentially important in some high-risk groups even after vaccines come to market. That creates opportunities for Vir and GSK, but they are the same opportunities companies such as AstraZeneca, Lilly and Regeneron are targeting.

Vir identified its antibodies in samples taken from COVID-19 survivors and used Xencor’s Fc-related technologies to extend their half-life. The use of half-life extension technologies sets Vir apart from some other antibody developers. Regeneron opted to advance unmodified antibodies in the belief the risks of half-life extension technologies outweigh their benefits. 

Regeneron and Vir have come up with different answers to other key questions, too. Vir is taking a one-antibody regimen, VIR-7831, forward in the belief targeting an epitope found on SARS-CoV-2 and the related coronavirus behind the 2003 SARS outbreak will reduce the risk of drug resistance. Lilly is also advancing a one-antibody candidate, partly to maximize production capacity, but Regeneron and AstraZeneca have opted to mitigate the threat of resistance by targeting two distinct epitopes.