Adagio to seek FDA authorization for antibody to prevent and treat COVID

The move comes even though the Waltham biotech’s latest trial data was collected before Omicron.

Trisha Sackett worked on isolating antibodies at Adimab in Lebanon, N.H., in December. Waltham-based Adagio Therapeutics was spun out of Adimab in July 2020.Craig F. Walker/Globe Staff

Adagio Therapeutics plans to seek emergency use authorization from the Food and Drug Administration for its COVID-19 antibody, which it hopes may prevent and treat the disease.

The announcement comes after a tumultuous period for the Waltham biotech. Its stock plunged in December when Adagio published data showing poor efficacy for the antibody against Omicron, two weeks after it claimed the treatment would work. Then in February, cofounder and CEO Tillman Gerngross announced his resignation.

The plan to seek FDA authorization initially sent Adagio’s stock soaring nearly 53 percent percent, to $5.88, Wednesday, before retreating slightly. But that enthusiasm may not take into account the fact that the data the company is using for its application come from two clinical trials that were conducted before Omicron became the dominant strain. Adagio’s previously released data show Omicron reduced the efficacy of its antibody, called adintrevimab, 300-fold.

Adagio plans to file for authorization with the FDA before the second half of the year but will continue its trial to evaluate higher doses of the treatment, as well as research related to re-engineering the antibody and and to identify new ones.

In a COVID-19 treatment trial, Adagio found its treatment reduced the risk of hospitalization and death by 66 percent for high-risk patients with mild to moderate cases compared with a placebo. There was a 77 percent risk reduction when patients received treatment within three days of experiencing symptoms.

The second trial evaluated the antibody’s ability to prevent COVID-19 among two groups — one that had been exposed to the virus and one had not been exposed. Adagio found its antibody reduced the risk of symptomatic COVID-19 by 71 and 75 percent respectively in those groups.

“These data give us confidence in the potential role adintrevimab can play in physicians’ arsenals,” said David Hering, the company’s interim chief executive, in a statement.

Unlike most antibody treatments, which are administered via infusion, Adagio’s is administered through a single intramuscular injection. Hering, who also serves as Adagio’s chief operating officer, said that company expects to have 1 million doses of adintrevimab in 2022.

Though Adagio’s data are pre-Omicron, the company said patients in the prevention trial were still 47 percent less likely to develop symptomatic disease 77 days after the emergence of Omicron.

New COVID-19 variants have continually eroded the effectiveness of antibody treatments as the pandemic has progressed. Last week, US health officials halted deployment of an antibody from GlaxoSmithKline and Vir in places where the BA.2 coronavirus variant is the dominant strain, including all states in New England, after determining it wasn’t working.

Adagio did not share clinical data related to BA.2, but an article published by Endpoints News cited an outside study that found the company’s treatment “has virtually zero activity” against that variant.

Hering said he remains hopeful because he believes the FDA will take a “variant-based approach” to COVID-19 antibody authorizations, allowing companies to adjust their dosage to make the treatment effective against new strains. Adagio plans to send the agency Phase 1 data on adintrevimab at four times the original dosage, which requires multiple injections, he said.

Adagio spun out of Lebanon, N.H.-based Adimab, another Gerngross antibody company, in July 2020. It went public just over one year later, raising more than $300 million from investors.

Now, following the shakeup in Adagio’s executive ranks, one of the company’s largest investors is planning to overhaul the biotech’s board of directors. Mithril Capital Management, cofounded by Peter Thiel and Ajay Royan, will nominate three new members during Adagio’s annual meeting in May — Clive Meanwell, Marc Elia, and Tamsin Berry — according to document filed with the Securities and Exchange Commission on Wednesday.

In an e-mail Royan sent to Adagio investors from Polaris Partners, Adimab, M28 Capital (of which Elia is the founder), and Population Health Equity Partner (of which Meanwell is the executive chairman and Berry is a partner), he indicated that those groups agreed to back Mithril’s nominations.

“Here’s to the success of Adagio and its righteous fight against the scourge of this pandemic and others yet to come,” Royan wrote.