Dive Insight:

Vir, an infectious disease drugmaker run by former Biogen CEO George Scangos, was among the first to begin working on antibody drugs for COVID-19, along with Lilly and Regeneron.

Each company took a slightly different path in how they chose to develop their medicines, however.

Lilly, for instance, developed a single antibody first and backed it up with a two-drug combination. Regeneron focused on a multi-drug cocktail from the start. Vir chose a single antibody, but extended its potential durability and targeted parts of the virus that are “highly conserved,” or potentially more resistant to viral mutations. Data suggests it can block the virus from entering cells as well as clear it from already infected cells.

All three have succeeded, producing drugs proven to keep people infected with the coronavirus from needing to be hospitalized. The FDA authorized Lilly’s single antibody, bamlanivimab, in November, and its two-drug combination in February. Regeneron’s treatment, REGEN-COV, has been on the market for months as well.

But the choices each company made early on have become more significant as virus variants have spread. Lilly was first to market with bamlanivimab and has generated the most revenue, with nearly $1.7 billion combined over the last two quarters. But bamlanivimab’s FDA clearance was revoked in April after the drug appeared ineffective against certain variants. The U.S. government has since halted distribution of its dual antibody regimen in eight states, citing weakness against circulating variants first identified in Brazil and South Africa.

Regeneron’s cocktail has so far held up and is recommended over Lilly’s in those states.

Sotrovimab could be another option. The fact sheet for the drug’s authorization indicates lab tests show the antibody retains activity against a number of variants, including the ones Lilly’s drugs have struggled with as well as the strain that was first detected in India. (Vir, GSK and Lilly are working together on a Phase 2 study combining bamlanivimab with sotrovimab as well.)

“It is important to expand the arsenal of monoclonal antibody therapies that are expected to retain activity against the circulating variants of COVID-19 in the United States,” said Patrizia Cavazzoni, M.D., director of the FDA’s Center for Drug Evaluation and Research, in a statement.

Other COVID-19 treatments are advancing, too. Adagio Therapeutics has another antibody drug in late-stage testing. Novartis and Molecular Partners on Tuesday began a Phase 3 trial of a protein drug meant, like antibody therapies, to prevent or treat coronavirus infections. Merck, Pfizer and others have oral antivirals in late-stage testing that could be more convenient and easier to distribute than antibodies.

Vir and GSK began collaborating on sotrovimab and another COVID-19 antibody drug in April 2020. They’ve since broadened their alliance to include development work on antibody drugs for influenza and other respiratory infections. GSK has bought $370 million of Vir’s shares.

Sotrovimab will be available in the U.S. “in the coming weeks,” the companies said. It’s the first marketed drug for Vir, which had its shares climb 10%, to about $50 apiece, in premarket trading Thursday.

The companies will file for a standard drug approval, which would stretch beyond the pandemic, in the second half of the year.