Vir and GlaxoSmithKline begin pivotal study of Covid-19 antibody drug

Vir Biotechnology, a San Francisco-based firm focused on infectious disease, and GlaxoSmithKline, the British drug giant, said Monday that they are beginning a study of an antibody drug aimed at treating Covid-19.

The study will enroll 1,300 patients around the world who have early symptomatic infection, and will test whether the treatment, VIR-7831, can prevent those patients from being hospitalized. The companies said that they expect initial clinical results of the study by the end of 2020, meaning that the treatment, if effective, might be available for emergency use in early 2021.

The Vir-GSK effort lags two others to develop antibodies, by Regeneron and Eli Lilly-AbCellera, by several months. Those companies began studies this summer, and have said they might deliver early results in September or October.

But George Scangos, the chief executive of Vir, and Hal Barron, the chief scientific officer at GSK, said in an interview with STAT that they expect their antibody could have advantages over other entrants.

Like the other drugs, VIR-7831 is what’s known as a monoclonal antibody — a manufactured version of antibodies derived from the immune system. It is based on an antibody found in a patient who recovered from severe acute respiratory distress syndrome (SARS), which is caused by a virus in the same family as SARS-CoV-2, the virus that causes Covid-19.

Scangos said that the companies believe that antibody may do a better job of not only directly neutralizing the virus, but also recruiting the immune system to attack cells that have been infected. “No antibody is going to block 100% of the cells from getting infected, and so we want to have a mechanism to kill the ones that busted through,” he said.

The companies also believe that, because of the way the antibody has been developed, it may require a lower dose and a shorter duration. Barron emphasized that this might mean that one could treat more patients.

“When you think about that and the fact that the dose of a monoclonal is obviously a lot higher than the protein needs for a vaccine, you’re talking potentially in the order of metric tons of monoclonal antibodies,” Barron said. So a smaller dose could matter.

The companies also said that they are working to conduct their studies as quickly as possible. “It’s not about when you start, it’s about when you finish,” Scangos said. They are conducting the study both inside and outside the U.S. 

One problem in running antibody studies has been in getting patients diagnosed quickly, so they can be treated soon after infection. The study is focusing on clinical trial sites that have rapid testing available, and in cases where it is not available the companies will aim to procure rapid test machines made by Cepheid.

Both executives, however, pushed back against the idea that U.S. regulators could grant an emergency use authorization for a drug based on data before safety and efficacy have been proved. 

“The more EUAs there are, the harder it is to do a legitimate trial,” Scangos said. “I think a concern for the field is the ability to do rigorous, therapeutic, blinded studies and be confident in the therapeutic effect and the safety of the drug.”

“I know there is this short-term urgency, and slightly, I would argue, myopic thinking,” said Barron. “I think it’s really important to do well-designed, controlled trials to determine efficacy.”

“Obviously we’re moving as fast as we can,” Barron said. “I’m the first to say every day matters. But it’s really important to make sure you have an understanding of a medicine that would get approval in terms of benefits and risks.” 

He added: “I personally believe we should be doing this correctly.”