After virus mutations spurred the FDA to yank Eli Lilly's COVID-19 drug from the market, public health experts told Becker's their predictions for the future of COVID-19 treatments.
The winter surge in COVID-19 cases is less severe than those of past seasons, but it is compounded by high vaccination rates for the primary series, low uptake of the bivalent boosters and omicron subvariants evolving rapidly. John Grabenstein, PhD, scientific communications director for Immunize.org and former global executive director for medical affairs in Merck's vaccine division, said developing new COVID-19 drugs is akin to creating keys for a changing lock.
Monoclonal antibodies that are so specific in their makeup, for instance, are "fading away."
"The lock has changed, and that key has no longer worked," Dr. Grabenstein said of Eli Lilly's monoclonal bebtelovimab. "The virus changed shape in a way that made the antibody product not relevant, not able to work anymore."
There's also a public messaging concern with the naming of the subvariants, according to Georges Benjamin, MD, executive director of the America Public Health Association. The slightly similar names among the plethora of omicron subvariants belies the degrees to which they differ.
"We name these things in a way that makes people think that there's not much of a change, but these new strains are pretty complex," Dr. Benjamin said. "They often have mutations in multiple places on the viral surface, they sometimes have changes that make the virus more infectious, sometimes it makes it a little more lethal. We haven't seen a lot of that, but we have seen it impact our therapeutics."
He said there's "enormous potential" for less-specific products, such as popular antiviral treatment Paxlovid, to drop in efficacy.
The most pressing unanswered questions, according to Dr. Benjamin, include how the BA.4/BA.5-targeted boosters will hold up against emerging subvariants — such as XBB, XBB.1.5 and BF.7 — if the dosing and duration of Paxlovid is correct among rebound concerns, and what the financial cost will be when the federal government stops paying for COVID-19 vaccines and drugs.
Dr. Grabenstein likened the race of matching treatments to the coronavirus to running on a treadmill — moving, but moving in one place. The vaccines "have been more forgiving of changes," he said, but as new mutations throw obstacles on the track, some medications might not make the next lap.
Here's the full list of drugs with approval or emergency use authorization to prevent or treat COVID-19, per the FDA:
Monoclonals:
- Evusheld (tixagevimab and cilgavimab) — which may be pulled — has emergency use authorization to neutralize the virus as a pre-exposure prophylaxis treatment
Antivirals:
- Veklury (remdesivir) is approved for some hospitalized COVID-19 patients
- Paxlovid (nirmatrelvir and ritonavir) has emergency use authorization for mild-to-moderate COVID-19 symptoms in COVID-19 patients 12 and older
- Lagevrio (molnupiravir) has emergency use authorization for adults who have COVID-19, are at high-risk of severe symptoms and when alternative therapies are not clinically appropriate
Immune modulators:
- Actemra (tocilizumab) is approved to treat COVID-19 in patients "who are receiving systemic corticosteroids and require supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation"
- Olumiant (baricitinib) is approved to treat hospitalized COVID-19 adults who require "supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation"
- Kineret (anakinra) has emergency use authorization to treat adults hospitalized with COVID-19, pneumonia, require supplemental oxygen and are at risk for progressing to severe respiratory failure