DeSantis Misleads on Omicron-Resistant COVID-19 Antibody Treatments - FactCheck.org — factcheck.org

A man enters the Regeneron Clinic at a monoclonal antibody treatment site in Pembroke Pines, Florida, on Aug. 19. (Photo by Chandan Khanna/AFP via Getty Images) But there’s virtually no reason to think those past results will hold against the highly mutated omicron variant. Because of its mutations, the shape of the omicron variant’s spike protein is different — and these particular antibodies can’t neutralize the omicron variant very well if at all, as numerous lab studies have shown. Many of these studies tested whether the antibodies were effective in limiting infection of cells in a petri dish using viruses engineered to express coronavirus variant-specific spike proteins, or what are known as pseudoviruses. Such experiments can evaluate how well various antibodies fare against variant viruses, but are safer and faster to do than similar experiments using live, infectious virus. A paper published in Nature by scientists in Hong Kong and at Columbia University, for example, found a dramatic reduction — more than 1,000 times — in the ability of the Regeneron and Eli Lilly antibodies to neutralize an omicron pseudovirus, compared with an ancestral pseudovirus. “Strikingly,” the authors wrote, all four of the tested combination drugs lost “substantial activity” against omicron, “likely abolishing or impairing their efficacy in patients.” Several other unpublished papers that have not yet been peer-reviewed similarly found little or no neutralization activity of the antibodies used in the Regeneron and Eli Lilly cocktails against omicron pseudoviruses.  When tested against full-fledged, infectious omicron virus, the Regeneron and Eli Lilly antibodies also have failed. A Dec. 23 report published in Nature, for example, found all of the antibodies in those treatments, either individually or in combination as they appear in the cocktails, were “inactive” against an omicron virus isolated from a traveler returning to Belgium from Egypt.  Similarly, a Jan. 19 Nature Medicine study found the Regeneron and Eli Lilly antibody combinations used as treatments “lost all neutralizing activity” against an omicron virus taken from an infected American. These findings are also consistent with what the companies have found. “Evaluation of both pseudovirus and authentic virus confirm that they are not effective at treating the currently predominant Omicron variant,” Eli Lilly said in a statement of its antibody cocktail, adding that the company and the FDA “agree that it is not medically appropriate” to use the product.  In a statement to FactCheck.org, Regeneron called the FDA’s decision to limit the use of its drug “appropriate” and said that its previously effective cocktail “does not work against Omicron in lab tests, which tells us that unfortunately it is also not going to work in people infected with this variant.” Both companies have other monoclonals that they say should work against omicron. Eli Lilly’s bebtelovimab is under review by the FDA for an emergency use authorization, while Regeneron is prepping to begin clinical testing of its candidate. Clinical Data Loophole DeSantis’ claim that there is no clinical data showing the Regeneron and Eli Lilly antibody treatments are ineffective is technically accurate, but he’s hiding behind that lack of data, rather than being transparent about the fact that all other available evidence to date strongly suggests the therapies are largely, if not entirely, useless.  The Florida Department of Health has made arguments similar to DeSantis’, citing a limitation mentioned in a study that it claims supports its position. “Florida disagrees with the decision that blocks access to any available treatments in the absence of clinical evidence. To date, such clinical evidence has not been provided by the United States Food and Drug Administration (FDA),” the department said in a press release announcing the closure of the state’s antibody treatment sites following the FDA’s decision on the EUA. “As stated in one of the pre-print studies cited on the NIH website, ‘despite observing differences in neutralizing activity with certain mAbs, it remains to be determined how this finding translates into effects on clinical protection against B.1.1.529.'” But this is not the “gotcha” that it might appear to be. The senior author of that study, Dr. Michael S. Diamond, an infectious disease specialist and microbiologist and immunologist at the Washington University School of Medicine in St. Louis, told FactCheck.org that the cell culture findings should be confirmed in animals, but that some of that work has already been done. And pending confirmation isn’t a reason to ignore the existing data. Diamond’s study, which is now published in Nature Medicine, is the one that found the Regeneron and Eli Lilly antibody cocktails “lost all neutralizing activity” when tested against live omicron virus. It also tested other monoclonals, including one from AstraZeneca that is used to prevent coronavirus infection, which had around a 30-fold reduction in neutralizing activity against omicron. That monoclonal, Diamond said in an email, “is likely to be less effective but needs to be tested in vivo (animal models),” adding that it’s not known what a 30-fold reduction means, “but it cannot be good.” In contrast, he said, the Eli Lilly and Regeneron products “are likely to lose efficacy completely” (his emphasis) — and there now is some data in animals backing that idea. Diamond pointed to an unpublished study posted to a preprint server on Jan. 24 that found in a mouse model, treatment with the Regeneron cocktail had no measurable virological effect against the omicron variant, despite being given at a higher dose than with previous variants. While that experiment did not test Eli Lilly’s product, Diamond said that given the cell culture data, it’s “highly likely” the results would be the same. “[W]hile we acknowledge in vivo studies are required, all data point to a major loss in efficacy of Lilly and Regeneron” antibodies, Diamond said, and “now data by another group … supports this point.” Moreover, he said, waiting on clinical data isn’t practical in this situation. “I think there is no way to test in humans fast enough. I would prefer to give drugs (antibodies, small molecules) that do not show such loss in efficacy based on cell culture and animal data,” he said. “This is my reading of the FDA.” Editor’s note: SciCheck’s COVID-19/Vaccination Project is made possible by a grant from the Robert Wood Johnson Foundation. The foundation has no control over our editorial decisions, and the views expressed in our articles do not necessarily reflect the views of the foundation. The goal of the project is to increase exposure to accurate information about COVID-19 and vaccines, while decreasing the impact of misinformation.

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