Use of Lilly, Regeneron COVID-19 antibodies 'widespread' after FDA ban, potentially costing US more than $70M: study

Staring down waning efficacy in the face of the coronavirus’s omicron variant, the FDA early this year put the kibosh on a pair of monoclonal antibody (mAb) combo therapies from Eli Lilly and Regeneron. Even still, the meds' use remained “widespread” in the U.S. this past winter, potentially costing the nation tens of millions for treatments that were unlikely to offer much benefit to patients.

Use of Eli Lilly’s bamlanivimab-etesevimab and Regeneron’s casirivimab-imdevimab peaked during the week of Dec. 22, 2021, when 91,036 total doses were reported, according to a new JAMA Network study. While mAb use “gradually declined” after FDA deauthorization and dropped throughout the remainder of the study period—which ran until June 29—Lilly's and Regeneron’s antibody combos continued to be administered after FDA deauthorization on Jan. 24, the study authors note.

Despite the FDA revising Lilly's and Regeneron’s authorizations, however, hospitals and health systems administered more than 158,000 doses of these mAbs in early 2022, the JAMA study contends. Given that Medicare mAb payments range from $450 to $750 per dose, spending on these deauthorized treatments likely eclipsed $71 million, the study continues.

“Whether deauthorized treatments will be covered by payers and whether the FDA will take regulatory action against entities violating its guidance remains unknown,” the study authors continued.

As for why use of Lilly's and Regeneron’s banned antibodies remained so ubiquitous, the JAMA study pinned the blame—in part—on conflicting state government guidance and lack of hospital awareness of the deauthorization.

The study authors note that “although the FDA announcements clearly stated that these mAbs were no longer authorized for use,” it didn’t fully revoke the meds’ emergency nods “because of the possibility that future COVID-19 variants could retain susceptibility.” This could have in turn led to “misinterpretation” by healthcare professionals.

Overall, there was “wide variability in mAb administration by state,” the study found. New York and Florida, for instance, were the biggest users, accounting for 20% and 24% of mAb administration for the period, respectively. Wisconsin and Arizona were next in line but handed out less that half of New York's total, whiles states like Vermont and New Hampshire logged no prescriptions. 

Looking at the variability in a different way by assessing use as a percentage of each state's remaining supply, 15 states administered up to 10% of their supply while 11 states doled out more than 50% of their leftover antibody stocks.

JAMA ran its study from Oct. 27, 2021, to June 29, 2022, collecting data from the U.S. Department of Health and Human Services and state hospitals. All U.S. hospitals and health systems must report the number of therapeutic mAb courses administered in the prior week as well as the amount currently on hand, the study authors explained.

All is not lost for Lilly on the COVID-19 front, meanwhile. Lilly nabbed authorization for its omicron-busting antibody bebtelovimab back in February, and it recently laid plans to deploy the drug on the commercial market.

Regeneron, for its part, recently axed a clutch of trials weighing its antibody combo, dubbed REGEN-COV, across a range of patients and clinical stages. The company terminated the trials, which ranged from early to late stage, because of “[e]merging SARS-CoV-2 variants impacting susceptibility to study drug,” recent updates on state.