Regeneron pitches COVID-19 antibody cocktail for 'passive vaccination' with fresh trial data

As the demand for COVID-19 vaccines from Moderna, Pfizer and AstraZeneca continues to outstrip supply and alternative vaccines struggle to make it out of the pipeline, the world is desperate for new ways to end the pandemic. Regeneron says it's offering a potential solution.

The New York-based biotech released preliminary data from an ongoing phase 3 trial of its antibody cocktail REGEN-COV (previously REGN-COV2) in people at high risk of contracting COVID-19 because of exposure to family members with the disease. The results justify using the drug for “passive vaccination,” the company said today.

REGEN-COV was 100% effective at preventing symptoms of COVID-19 in the trial as compared to placebo, the company announced. Passive vaccination with the drug slashed the overall rate of infection by half. All the infections that did occur among trial participants on the drug were asymptomatic, lasted no more than one week and showed a “short duration” of the viral shedding that can drive the illness to other people, Regeneron said.

"Even with the emerging availability of active vaccines, we continue to see hundreds of thousands of people infected daily, actively spreading the virus to their close contacts,” said Regeneron’s chief scientific officer, George Yancopoulos, M.D., Ph.D., in a statement. “The REGEN-COV antibody cocktail may be able to help break this chain by providing immediate passive immunity to those at high risk of infection, in contrast to active vaccines which take weeks to provide protection.”

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REGEN-COV was designed to block SARS-CoV-2, the cause of COVID-19, by combining two antibodies that bind in different ways to the spike protein that shuttles the coronavirus into cells.

The antibody cocktail won emergency use authorization from the FDA in November for patients with mild COVID-19 at high risk of progressing to severe infection. Besides studying the drug for prevention, Regeneron is testing it in two phase 3 trials in hospitalized patients and one in non-hospitalized patients.

The new data came from the first 409 of 2,000 patients enrolled in the prevention trial, Regeneron said. The company expects to release full phase 3 results early next quarter.

While there’s still work to be done to prove REGEN-COV is useful, the drug could indeed find a niche in prevention, given the less-than-smooth rollout of the mass vaccination effort.

Even though Pfizer confirmed pharmacists can get six doses out of each vial of its vaccine—not five as originally believed—the special syringes needed to extract that extra dose are in short supply. And both Pfizer and Moderna are grappling with a host of other challenges including distribution hiccups and the lack of a national plan for getting the vaccines into the arms of patients.

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The vaccine supply shortfall could be filled by other pharma players—but likely not immediately. Yesterday, Merck & Co. unexpectedly dropped out of the COVID-19 vaccine race, citing a disappointing immune response in phase 1 trials of its two candidates.

Johnson & Johnson has promised a phase 3 readout on its COVID-19 vaccine soon, and the results will be closely watched, especially because its shot only requires one dose. But a quick ramp-up is in no way guaranteed. While J&J originally planned to deliver 12 million doses of its vaccine by the end of February, Operation Warp Speed chief adviser Moncef Slaoui, Ph.D., suggested earlier this month that number might only be in the “single-digit” millions.

Meanwhile, Regeneron is doing what it can to ensure patients who want to take its antibody cocktail to prevent infection can do so easily, should it be authorized for that use. REGEN-COV is formulated as an injection, not an infusion, which the company argues will make administering it more convenient for patients.