Regeneron Antibody Drug a Game Changer for COVID-19 Prevention

When REGEN-COV treatment is administered, it can provide a “passive immunity” by limiting the ability of the coronavirus to develop into a symptomatic illness. Michael Nagle/Bloomberg via Getty Images

A new study found that REGEN-COV, …

When REGEN-COV treatment is administered, it can provide a “passive immunity” by limiting the ability of the coronavirus to develop into a symptomatic illness. Michael Nagle/Bloomberg via Getty Images
  • A new study found that REGEN-COV, a monoclonal antibody drug, can reduce the risk of coronavirus transmission by 81 percent.
  • Experts say these findings are very encouraging and suggest that REGEN-COV is highly effective at preventing the symptomatic transmission of the coronavirus.
  • They also say these findings mean healthcare professionals now have an option to speed antibody treatment against COVID-19.

One jab with Regeneron Pharmaceuticals' monoclonal antibody drug reduced the infection risk of volunteers exposed to the coronavirus by 81 percent, the company announced April 12 in a press release.

This was a phase 3, double-blind, placebo-controlled trial. It was jointly run by the National Institute of Allergy and Infectious Diseases (NIAID).

Results showed that the drug (REGEN-COV), when administered beneath the skin by injection, reduced the risk of symptomatic infections by 81 percent in people who did not have an infection when the trial began.

81% reduced risk of infection

According to Regeneron, this trial assessed the effect of REGEN-COV on more than 1,500 participants who did not have a coronavirus infection, coronavirus antibodies, or any COVID-19 symptoms.

These participants shared the same household as someone who tested positive for the coronavirus within the prior 4 days.

Participants were randomized to be given either one 1,200-milligram dose of REGEN-COV or a placebo, administered by injection.

“These findings are very encouraging and suggest that REGEN-COV is highly effective at preventing symptomatic COVID-19 in household contacts of SARS-CoV-2 infected individuals,” said Dr. Dan H. Barouch, co-principal investigator of the trial and director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center, in a statement.

Significantly speeds and simplifies treatment

Experts say these findings mean healthcare professionals now have an option to speed antibody treatment against the coronavirus.

According to Dr. Sean Liu, medical director of the Mount Sinai COVID Clinical Trials Unit, intravenous (IV) infusions require specialized facilities and commonly require several hours to complete a single visit.

He said Regeneron’s findings indicate a simple injection can be given in much less time, and in a typical doctor's office — and still be effective.

Liu explained that when administered in this preventive setting, REGEN-COV provides a “passive immunity” by limiting the ability of the coronavirus to develop into a symptomatic illness.

Liu emphasized the drug is meant to preemptively treat people who have been exposed to the virus, not people who already have COVID-19.

“REGEN-COV is given during a one-time visit as four subcutaneous injections to healthy persons who have not been diagnosed with COVID-19 but who have had a significant exposure to COVID-19. For example, a household member recently becomes infected with COVID-19,” Liu told Healthline.

What is monoclonal antibody treatment?

Joan Kapusnik-Uner, PharmD, vice president of clinical content at First Databank, a provider of integrated drug and medical device databases, explained that monoclonal antibodies are manufactured antibodies very much like those the human immune system would make after a viral infection.

“Administering more than one type of monoclonal antibody in a combination, a so-called ‘cocktail,’ increases the chance that a viral infection with SARS-CoV-2 will be prevented from worsening,” she explained.

“Said another way, two drugs, also known as monoclonal antibodies, given together are better than one for treating COVID-19,” she continued.

Kapusnik-Uner added that coronavirus variants that are becoming known are also better treated with this drug combination.

Regeneron jab may have same or better safety profile compared to IV

“This is great preliminary news regarding efficacy data for the subcutaneous route of administration (injection) of Regeneron’s antibody cocktail, casirivimab plus imdevimab,” Kapusnik-Uner said.

She added that while IV infusions may, infrequently, cause adverse effects in 1 to 2 percent of people, the jab could have a similar or better safety profile.

“But it is really the improved logistics that make this new option so exciting,” she said.

According to Kapusnik-Uner, this new preliminary study data and others show that we need to continue to increase access to monoclonal antibody cocktails.

“The adage of ‘the sooner the better’ seems to hold true for this antibody cocktail — whether for newly diagnosed COVID-positive patients who are high-risk patients where it prevents hospitalization, morbidity, and mortality, or for the new primary prophylaxis,” she said.

Vaccines best way to end pandemic, but Regeneron drug plays important role

“The vaccine rollout has been very exciting and deserves its extensive media coverage as vaccines remain the primary means by which the world will overcome the COVID-19 pandemic,” Liu said.

But he cautioned that, currently, vaccines are not yet available to everyone, and many people decline vaccination.

Liu pointed out one population in particular that could benefit from antibody treatment is people with compromised immune systems.

“There are large populations of people who have compromised immune systems where vaccines will not be as effective. These are all prime opportunities for antibody therapies,” he said.

Liu added that if the coronavirus variants find a way to escape vaccine protection, antibody therapies will continue to play a strong role against the ongoing pandemic.

Greater awareness of this treatment option needed, especially for high-risk people

“We need to continue to raise awareness that these types of antibody cocktails, from both Regeneron and Eli Lilly, are available and are very effective treatments in high-risk patients when given early on in an infection to halt disease progression,” Kapusnik-Uner said.

She also said that access to monoclonal antibody treatments “via outpatient infusion centers or mobile services exists,” but they may be unavailable in certain locations due to logistical barriers.

“Complicating things further is the fact that outpatient infusion centers may also be providing services to oncology (cancer) patients, who should not come in contact with COVID-positive patients seeking antibody therapy,” she said.

Kapusnik-Uner believes that this new subcutaneous therapy option will really improve overall access, and she looks forward to seeing Regeneron’s new data published.

The bottom line

Drugmaker Regeneron conducted a phase 3 clinical trial and found its monoclonal antibody treatment can effectively prevent coronavirus infections when given as a shot, rather than by IV.

Experts say this will speed treatment to people who need it, and protect high-risk people who otherwise would have to share IV facilities with people who potentially have a coronavirus infection.

They also say that while vaccines will remain our best way to end the pandemic, antibody treatments offer a valuable alternative for people who won’t benefit as much from vaccination, like people with compromised immune systems.