Dive Insight:

Before these trial results, Adagio already had some data that cast doubt on whether adintrevimab would help protect against omicron. In December, the biotech announced that lab tests of adintrevimab, also known as ADG20, showed a 300-fold reduction in neutralizing activity when compared to the original coronavirus strain.

The announcement triggered a major stock sell-off, erasing nearly $3 billion in Adagio’s market valuation. Later analyses suggested that adintrevimab retained more of its neutralizing activity against omicron than initially thought. However, amid the confusion CEO Tillman Gerngross announced his resignation.

Wednesday’s news are more positive, although data were only available via a company press release and, with limited trial results versus omicron, it’s unclear how the FDA might view the drug.

Adagio tested adintrevimab in three settings across two trials. The first was in people at risk of coronavirus exposure because of their work or living situations and in people who have been exposed but were not symptomatic. The second trial evaluated whether the drug kept high-risk individuals who have tested positive from being hospitalized or dying.

The prevention trial showed success in both the pre- and post-exposure groups, reducing the relative risk of symptomatic disease by 71% three months after treatment in pre-exposure and by 75% in post-exposure, compared to a placebo.

In the pre-exposure group, about 28% enrolled after omicron became dominant. Among those individuals, researchers found a 59% relative reduction in the risk of symptomatic disease after eight weeks and 47% at 11 weeks when compared to a placebo. The small number of people exposed to omicron — just 402 volunteers — could raise questions over whether adintrevimab’s apparent efficacy versus the variant will hold up when studied more widely.

In the trial in high-risk patients with symptomatic disease, adintrevimab reduced the relative risk of hospitalization or death by 66% four weeks later when compared to placebo. In that trial, 19% of patients tested positive for omicron. Of those, there were only two hospitalizations and no deaths, both in the placebo group.

Adagio said it has secured 1 million doses of adintrevimab for 2022, and is also testing to see how well a higher dose works. The company is also trying to re-engineer the antibody so that it binds more tightly to both omicron strains while retaining neutralizing activity against older variants.

Shares in Adagio rose by more than half in Wednesday morning trading, though they’re still worth a fraction of the $17 price they debuted at last year.