The success of Merck & Co.'s oral antiviral against COVID-19 immediately triggered concerns over the market prospect of antibody therapies. But, as one analyst sees it, those antibody products by Regeneron, GlaxoSmithKline and other companies still have an important role to play that pills can’t make up for.
COVID antibodies still have billions in sales with continuing strong demand at least into 2022 despite the possible availability of oral drugs, SVB Leerink analyst Geoffrey Porges predicted in a Friday note to clients.
Merck’s Ridgeback Biotherapeutics-partnered molnupiravir may capture a large share of the treatment market, but antibodies will likely benefit from a longer treatment window and could have an area all to themselves. Antibodies can potentially be used for disease prevention—both before and after exposure—and can offer long-term protection, Porges noted.
Current distribution data from the U.S. Department of Health and Human Services suggest an average 190,000 doses of COVID antibodies each week despite a recent decrease in new COVID cases. To Porges, this suggests “antibodies are finally being incorporated into routine treatment practices and protocols.” Over the next six to 12 months, supply of COVID antibodies will still be constrained, he estimated.
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At the current run rate, the Department of Health and Human Services will need to ship 4.9 million doses of antibody drugs to meet demand over the next six months, but the existing contract only covers 2.7 million, leaving a “supply gap” of 2.2 million doses for the next six months alone, Porges noted.
Regeneron’s cocktail, REGEN-COV, is taking the lion’s share of the current market. The company recorded $3.5 billion sales from the drug in the first half of 2021 and recently signed a $2.94 billion contract with the U.S. government to supply an additional 1.4 million doses by January 2022.
Eli Lilly’s combo of bamlanivimab and etesevimab has seen limited use thanks to its reduced potency against coronavirus variants. GSK and Vir Biotechnology’s recently authorized sotrovimab is gaining steam, with Wall Street expectations of $503 million in 2021 sales.
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In addition, a few days ago Brii Biosciences started a rolling submission for an emergency use authorization of its dual-drug regimen, BRII-196/198, setting up a potential decision in early 2022. In a National Institutes of Health-run phase 3 trial, the combo significantly reduced hospitalization and death over placebo in nonhospitalized patients.
More importantly, compared with treatment initiation within five days into symptomatic infection, BRII-196/198 showed similar efficacy when administered up to 10 days after symptom onset. Most small-molecule antivirals need to be given in a relatively tight time window early in infection to be efficacious, Porges noted. Molnupiravir, for example, was given in the first five days after symptom onset in its clinical trial.
For the Brii product, Porges projected $1.3 billion in stockpile orders from the U.S. and Chinese governments. The Street’s consensus currently puts the Sino-American biotech’s 2022 revenue at $485 million, according to Porges.
Besides treating certain mild to moderate patients, Regeneron’s and Lilly’s antibody combos are also used in the so-called post-exposure prophylaxis settings to prevent symptomatic disease in people who’ve come in contact with infected individuals in households.
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AstraZeneca has recently filed for emergency use authorization of its antibody cocktail, AZD7442. The drug reduced the risk of symptomatic COVID by 77% in the pre-exposure prophylaxis setting among immunocompromised people, who typically don’t respond as well to vaccines.
Oral drugs likely won’t be able to reach the prevention market given their mechanism, Porges said. By comparison, antibody drugs’ ability to stay active in the human body for a long time gives them the ability to offer longer-term protection against COVID. Therefore, “[t]argeted prophylactic administration could become a key use case for COVID antibodies as public health authorities try to ringfence regional or facility-localized outbreaks,” Porges said.
Eventually, convenience of administration and duration of protection will be “important differentiators” within the antibody class, Porges noted. AZD7442 comes in an intramuscular formulation, and REGEN-COV has an under-the-skin version, while others are so far only infusions.