麻豆传媒

Regeneron's REGN-COV2 monoclonal antibody combination met its primary endpoint and a key secondary endpoint in a phase II/III trial involving high-risk patients with mild to moderate COVID-19, .

Compared to patients receiving standard of care plus placebo, patients randomized to combined doses of REGN-COV2, the average daily decrease in viral load through day 7 for patients with a high viral load -- the primary outcome -- was 0.68 log₁₀ copies/mL greater than in patients randomized to placebo (P<0.0001).

Patients also showed a 1.08 log₁₀ greater reduction in the intervention group by day 5 relative to placebo.

Moreover, the two-antibody combination significantly reduced COVID-19-related "medical visits" by 57% through day 29, defined as hospitalizations, emergency room or urgent care visits, or physician office or telemedicine visits.

Notably, though, the vast majority of patients avoided medical visits whether they received the active agents or placebo. Regeneron said 2.8% of patients in combined REGN-COV2 dosing groups and 6.5% of patients in placebo reported a medical visit.

According to , those numbers yield a number needed to treat of 27: meaning 27 patients would have to receive the treatment to prevent one medical visit. Regeneron did not provide a breakdown for the composite outcome's individual components.

Infectious Diseases Society of America experts previously commented in general about monoclonal antibody treatments, noting one of the therapy's drawbacks was cost, estimating it would be many thousands of dollars. They also cited the difficulty in scaling up production to treat hundreds of thousands of patients.

Regeneron also said REGN-COV2 treatment led to 72% fewer COVID-19-related medical visits among patients with more than one risk factor (such as older than age 50, cardiovascular, metabolic, lung, liver or kidney disease), but without giving the absolute percentages of patients experiencing the composite outcome.

And most importantly, there was no proof the patients got any better -- Regeneron said "there was no planned formal statistical analysis of symptom alleviation in this analysis."

Previously, the company released on 275 patients a month ago; the new data cover an additional 524 patients.

Mean patient age in the trial was about 42, and 53% were women. Half were Hispanic, while 9% were African American. In terms of serology status, 38% were seropositive, 51% were seronegative and 11% were unclear or unknown serology status.

Similar to the earlier descriptive analysis, Regeneron noted patients with a higher viral load and/or no detectable antibodies at baseline derived greater benefit from the intervention, though there was no significant virological or clinical difference with the high-dose (8 grams) group and the low dose (2.4 grams) group.

Examining safety, the manufacturer said the drug was well-tolerated, with a higher proportion of serious adverse events in the placebo group (2.3% placebo, 1.6% low dose REGN-COV2, 0.8% high-dose). Not surprisingly, infusion reactions were more common in the high-dose group (1.5%) versus low dose (0%) and placebo (0.4%).

Regeneron said the phase III trial is continuing in non-hospitalized patients. REGN-COV2 is also being studied in a phase II/III trial for hospitalized patients with COVID-19, a phase III trial for prevention of COVID-19 in household contacts of infected individuals, and as part of the phase III in hospitalized patients in the U.K.

The company said it plans to submit these data for publication, and the results were shared with the FDA as part of an emergency use authorization submission already filed.

Comment