The Food and Drug Administration on Monday granted emergency clearance to bamlanivimab, an antibody-based coronavirus treatment from Eli Lilly.
The emergency use authorization, a special approval handed out during a public health emergency, allows Lilly's drug to be used outside of clinical trials to treat people with COVID-19 who are at high risk of developing severe disease or needing hospitalization.
Though bamlanivimab is cleared for use in patients 12 years or older, the major risk factors highlighted by the FDA include age older than 65 years, or chronic underlying health conditions.
Public health experts view bamlanivimab, and other antibody drugs like it, as potentially critical tools against COVID-19. So far, however, the evidence supporting their potential benefit is preliminary and equivocal, coming from early data across hundreds of people with COVID-19. Supply constraints, along with other logistical hurdles that could limit their use, also make it unclear just how big of a role they will eventually play.
Still, the FDA's decision is a step forward in scientists' race to develop new coronavirus drugs: Bamlanivimab is the first medicine specifically designed for treating SARS-CoV-2 infections to be authorized by the agency. Past authorizations, including for Gilead's now approved COVID-19 drug Veklury, have involved repurposed or adapted treatments.
Antibody drugs are synthetic versions of the immune proteins produced by the body in response to infections. In addition to Lilly's, three other COVID-19 antibody treatments from Regeneron, AstraZeneca, and partners Vir Biotechnology and GlaxoSmithKline are in late-stage studies. The drugs are being tested in a variety of treatment settings, from patients with mild-to-moderate disease to those who have recently been exposed to infected individuals. Regeneron recently requested an emergency authorization from the FDA for its candidate.
For much of the summer, these drugs received less attention than the front-running vaccines, which hold the promise of ultimately ending the pandemic. Unlike an effective vaccine, any benefit from an antibody drug would likely only last weeks or months and therefore can't provide long-lasting immunity from infection or disease.
Recently, however, early results emerged from Lilly's and Regeneron's trials, suggesting the two drugs might help people with more mild COVID-19 cases. Their profile was raised further after President Donald Trump and former New Jersey Gov. Chris Christie received, respectively, Regeneron's and Lilly's drugs while being treated for COVID-19.
By clearing bamlanivimab, the FDA appears to be acknowledging its potential. But the agency's authorizations for the malaria pill hydroxychloroquine and, later, blood plasma, were marred by controversy, raising questions about the regulator's independence from an administration that's publicly criticized the FDA for moving too slowly.
Trump, following his recovery from COVID-19, appeared to pressure the agency on antibody drugs, too, touting Regeneron's drug as a "cure" and boasting in early October of emergency authorizations that were "all set."
Even though the FDA has now followed through by clearing bamlanivimab, the upside of antibody drugs remains unclear. The limited and somewhat mixed results disclosed to date leave uncertain the magnitude of the benefit they actually provide, particularly for people who might otherwise get better on their own.
Notably, the dose approved by the FDA, 700 milligrams, didn't appear to lower virus levels by as much as a higher dose tested.
The agency said that it is "reasonable to believe" bamlanivimab may be effective in treating non-hospitalized COVID-19 patients with mild-to-moderate disease based on the "totality of scientific evidence available." The most important evidence in its favor was a reduction in hospitalizations and emergency room visits, compared to a placebo, in early tests.
"We will continue to evaluate new data on the safety and efficacy of bamlanivimab as they become available," said Patrizia Cavazzoni, acting director of the FDA's Center for Drug Evaluation and Research, in the statement.
Supplies of COVID-19 antibodies are currently limited, and will be for some time, meaning their use will likely be restricted to those who need them most. Lilly, for instance, said it could manufacture about 1 million doses of bamlanivimab for use globally through the end of this year.
Through an October agreement, the U.S. government pre-purchased the first 300,000 doses and will handle allocation of the drug to states under the FDA's emergency authorization. States will then allocate doses to hospitals — a system similar to what the Trump administration ended up operating for distribution of Veklury, after early hang-ups.
Lilly won't be able to increase capacity "substantially" until 2021, the company said.
The doses bought by the government would be provided to patients in the U.S. for free, though that doesn't include administration costs. Doses outside of the agreement will cost $1,250 per treatment course. A spokesperson told Biopharma Dive via email that the company's goal is "to have no out-of-pocket costs for our antibody treatments, wherever possible."
Other hurdles to wider use will also need to be addressed. Lilly's antibody appears so far to drive the biggest benefit early in the course of disease for patients with medical risk factors, such as higher age, weight or certain pre-existing health conditions.
The drug appears less useful for sicker patients. Bamlanivimab failed to help people hospitalized with COVID-19 in a government-run study, and unspecified safety concerns led Regeneron to halt testing of some hospitalized patients in a separate trial.
The FDA, referring to such issues, noted that antibodies "may be associated with worse clinical outcomes" when given to hospitalized patients who need high-flow oxygen or mechanical ventilation. Lilly added that its drug should be administered within 10 days of symptoms and "as soon as possible" after symptoms begin.
Getting the drug to the right patients when they need it the most may be difficult. Patients would need to get testing results, and treatment, before the disease progresses too far. The drug would also have to be infused by a healthcare professional, which could be challenging to carry out.
In a recent op-ed, for instance, former FDA commissioner Scott Gottlieb noted "special administration sites" at hospitals or modular sites might have to be set up to avoid sending infected patients to clinics where they might endanger others.
Lilly is developing both a single antibody and a combination treatment, the latter of which is similar to the therapy being developed by Regeneron.