Regeneron starts testing COVID-19 antibody cocktail in humans

Regeneron has begun clinical development of its anti-SARS-CoV-2 antibody combination REGN-COV2. The adaptive phase 1/2/3 clinical trials will assess the effects of the antibodies on hospitalized and nonhospitalized COVID-19 patients.

Having validated the application of its platform to infectious diseases with an Ebola drug, Regeneron quickly emerged as a front-runner in the race to develop antibodies against the coronavirus. Eli Lilly ultimately became the first company to get an anti-SARS-CoV-2 antibody candidate into humans, but Regeneron has followed close behind by hitting its mid-June target.

Regeneron is kicking its clinical development program off with two trials, one in hospitalized patients and another in nonhospitalized patients. In the first part of the trial, Regeneron will look at virologic and safety endpoints before adding clinical endpoints into the mix in phase 2. The phase 1 and 2 trials will inform the design and size of phase 3 studies in each population.

The exploration of the therapeutic applications of REGN-COV2 forms half of Regeneron’s COVID-19 clinical development program. Regeneron also plans to run studies in two other populations to gauge the effectiveness of REGN-COV2 in preventing infections with SARS-CoV-2.

One of the prophylactic studies will enroll healthcare workers and other uninfected people who are at high risk of exposure to the virus. The other prophylactic study will administer the antibodies to uninfected people who are closely exposed to COVID-19 patients, for example because they live with someone who is infected with SARS-CoV-2.

Regeneron, like other developers of anti-SARS-CoV-2 antibodies such as AstraZeneca, thinks there is room for its approach to conveying immunity despite the proliferation of vaccine candidates. For one thing, Regeneron Chief Scientific Officer George Yancopoulos said antibodies could be available “much sooner than a vaccine.” Even if vaccines come to market, Yancopoulos sees antibodies having a long-term role in the protection of elderly and immunocompromised patients.

Amgen, AstraZeneca, GlaxoSmithKline and Lilly are among the other drug developers working on antibodies that could have therapeutic and preventive applications against SARS-CoV-2. While Lilly is testing a single antibody, Regeneron, like AstraZeneca, has settled on a combination of two antibodies that target different areas of the receptor-binding domain on the spike protein.

In explaining its decision to go with a two-drug combination, Regeneron cited research, which is set to be published in Science, into the potential for viruses to escape treatment through mutation. As Regeneron sees it, hitting the virus with a one-two antibody punch lessens the risk that a mutant, drug-resistant form will emerge and become the dominant strain. 

Regeneron looked for antibodies to include in its combination in the blood of patients who had recovered from COVID-19 and in mice genetically modified to have human immune systems. By casting its net wide, Regeneron thinks it has hit upon potent antibodies against the virus.