UPDATE: Jan. 4, 2022: The U.S. resumed deliveries of Eli Lilly's and Regeneron's drugs on Dec. 31, citing "variability" in the presence of the omicron variant.
- The U.S. government has paused distribution of COVID-19 antibody drugs from Eli Lilly and Regeneron, citing their apparent lack of potency against the fast-spreading omicron variant.
- Data from the Centers for Disease Control and Prevention indicates the omicron variant now accounts for about three-quarters of U.S. COVID-19 cases, which have spiked dramatically. Lab tests have shown it is "unlikely" that Regeneron's drug or Lilly's two antibody treatments retain activity against the variant, according to a letter from the U.S. Assistant Secretary for Preparedness and Response.
- The ASPR's decision will remain in place pending new data from the CDC. In the meantime, shipments of Vir Biotechnology and GlaxoSmithKline's antibody drug, sotrovimab, have resumed. Vir's drug is the only antibody currently authorized as a treatment that is expected to neutralize omicron, but supplies are limited.
Given omicron's apparent ability to evade most antibody drugs, the pause in distribution of Regeneron's and Lilly's treatments is not unexpected and mirrors similar decisions in response to previous variants. But it's a significant setback, especially as it affects both drugs.
Synthetic antibodies have been some of the best tools doctors have to keep COVID-19 patients out of hospitals and alive, even though use has been sporadic and uneven. Both showed in clinical trials a dramatic ability to prevent COVID-19's worst health outcomes. While Lilly's drug has struggled against some earlier variants like beta and gamma, it and Regeneron's were still effective against delta, making them important countermeasures during the summer surge.
Some 2.7 million treatment courses have been administered since July, Jeff Zients, the White House's COVID-19 response coordinator, said in a briefing Wednesday.
Omicron, though, has proved a more worrisome threat due to the large number of mutations in its spike protein, the target for Regeneron's and Lilly's drugs. Those changes have also created a challenge for vaccine makers, many of which have produced data showing that booster shots are needed to maintain protection against infection.
But vaccines, even with just two shots, appear to still guard people from severe disease as vaccination helps the body produce a broader array of immune defenders. The situation is different for antibody drugs, which don't help if they can't grasp the virus and stop it from infecting cells.
That appears to be the case for Regeneron and Lilly. Both have said they are developing newer antibodies, but they won't be ready for months, leaving the U.S. vulnerable as omicron surges nationwide.
While emerging data from South Africa and the U.K. hint that omicron may be less deadly than prior strains, experts warn it's too early to draw conclusions. The sheer number of infections the variant is likely to cause — outgoing National Institutes of Health director Francis Collins fears the daily case total could reach as high as 1 million — could still lead to a significant number of hospitalizations and deaths, particularly among the unvaccinated.
Vir and GSK's antibody, meanwhile, is in short supply even though the U.S. reportedly conserved doses ahead of omicron's spread. Shipments resumed this week, with about 55,000 doses going out for delivery. According to Zients, the U.S. soon expects to secure a total of more than 1 million courses of the antibody, with 300,000 to be available in January.
AstraZeneca's antibody drug, Evusheld, also appears to neutralize omicron. Yet, it's only cleared for use to prevent infections in people who can't receive a vaccine, or whose immune system won't respond to one. The U.S. will have about half a million doses on hand in January and expects to buy "significantly more" over the next three months, Zients said.