- An experimental antibody treatment from Regeneron appears to help patients with mild cases of COVID-19 shake their symptoms sooner, reducing coronavirus levels in their bodies, according to early clinical results announced on Tuesday.
- The results aren't definitive. They come from a "descriptive analysis" of the first 275 patients enrolled in an adaptive trial, a group that Regeneron split into those whose bodies had, or hadn't, already mounted an immune response against the coronavirus. But they suggest Regeneron's drug helped clear the virus and alleviate symptoms, with more pronounced results in patients who hadn't produced antibodies against the coronavirus on their own.
- Regeneron is one of the leaders in the race to develop engineered antibodies to either prevent or treat coronavirus infections. The results, while preliminary, are a step toward figuring out what kind of role the drugs might play in curbing the pandemic. Regeneron said it is already talking with regulators and suggested the data could support an emergency authorization.
The urgency of the coronavirus pandemic is pushing drugmakers to try unorthodox, adaptive trial designs to quickly assess both the typical course of COVID-19 and to study how drugs may change it.
Such is the case with Regeneron, which developed and pressed into study an antibody drug combination in a mere few months.
In one of several trials, the company enrolled 1,300 symptomatic COVID-19 patients who hadn't been hospitalized, testing an initial group of 275 to gauge how much virus was circulating in their bodies and whether they were "seropositive," meaning they had generated, on their own, antibodies against SARS-CoV-2.
Researchers sought to establish if those antibodies correlated with an ability to clear coronavirus infections, and to discover whether people without them might be helped by a synthetic antibody drug.
The results released Tuesday are first to emerge from that fact-finding mission. According to Regeneron, patients with high levels of the virus were often seronegative, and vice versa. This status appeared to lead to worse outcomes for patients with mild COVID-19. And that was "the most important observation" from Regeneron's data, wrote SVB Leerink analyst Geoffrey Porges, because it suggests that measuring patients viral and antibody levels could help guide care.
Using a targeted treatment approach like this for mild COVID-19 patients "could help significantly reduce the burden on hospital services, and also reduce the number of adverse outcomes from the disease," Porges wrote.
The company's antibody regimen, for instance, appeared to have a large effect in seronegative patients, while those who were seropositive recovered about as quickly without the drug as with it. There was little difference between the two drug doses Regeneron tested.
Patients with higher viral loads at the start of the study experienced correspondingly greater reductions in viral levels seven days following treatment with Regeneron's drug, called REGN-COV2. Seronegative patients who received REGN-COV2 were also free of symptoms more quickly — after a median of six days for those on the low dose, eight for high-dose patients and 13 for volunteers who got placebo.
"The benefits seem to be the greatest in the patients who need it the most," Regeneron president and chief scientific officer George Yancopoulos said on a conference call Tuesday.
REGN-COV2 is given intravenously, which could limit outpatient use outside of clinical trials, however. And targeting patients who are either seronegative or who have high virus levels would require specific testing.
Both doses were well tolerated, the company said: infusion reactions were seen in two placebo patients and two of those on REGN-COV2.
More than 2,000 people have been enrolled in studies of REGN-COV2 in different settings, including among hospitalized COVID-19 patients, and no unexpected side effects have been reported by an independent data monitoring committee.
Regeneron now aims to confirm the apparent benefits it reported Tuesday in a second study cohort that's already enrolled.
Yancopoulos indicated data from that group, if they confirm the initial findings, would be enough to support a full drug approval. The company says it's discussing whether the current data could allow for earlier use, such as through an emergency use authorization.
Porges predicted regulators are likely to push Regeneron for an early look at the study in hospitalized patients before clearing REGN-COV2 for use. If the data are "trending in the same direction" as the results seen in mild patients, "then an EUA would seem to be justified," he wrote.
With Tuesday's data, Regeneron follows Eli Lilly, which earlier this month reported promising, but limited data on a coronavirus antibody drug it developed with Canadian biotech AbCellera. Vir Biotechnology, AbbVie and AstraZeneca are also developing antibody drugs for SARS-CoV-2.
Regeneron has enough manufacturing capacity to make about 300,000 doses of REGN-COV2 this year, much of which has already been paid for through a $450 million contract with the U.S. government. A recent alliance with Roche should help enable the company to produce millions of doses next year.
Editor's note: This story has been updated to include analyst commentary and additional details on manufacturing.