Adagio Therapeutics has spied a path to FDA authorization for its tarnished COVID-19 antibody. Having been brought low in an omicron farrago, Adagio is now looking to positive phase 2/3 data against earlier variants to help secure ADG20 a spot among the arsenal of preventive and therapeutic antibodies.
Massachusetts-based Adagio pitched its anti-SARS-CoV-2 antibody as the answer to the emergence of new variants, arguing that its targeting of a highly conserved epitope would ensure efficacy even as the virus evolved. That pitch was seemingly vaporized by omicron, which was initially linked to a 300-fold reduction in neutralizing activity only for Adagio to change its tune one month later after other in vitro studies suggested the antibody remains effective against the variant.
CEO Tillman Gerngross left after the farrago, but Adagio kept going. Although Adagio paused enrollment in the 300-mg dose arms of its two clinical trials, it continued to gather data on the existing participants and seek a path forward for ADG20. Now, Adagio has the data it hopes will define its next steps.
In the COVID-19 prevention study, Adagio linked the use of ADG20 in pre-exposure prophylaxis to a 71% reduction in symptomatic disease compared to placebo. The reduction in post-exposure prophylaxis was 75%. In the treatment trial, ADG20 reduced hospitalization or death in patients with mild to moderate COVID-19 by 66%. Efficacy rose to 77% in the subgroup who were treated within three days of symptom onset.
Adagio plans to talk to the FDA about the data and file for emergency use authorization in the second quarter. The success of the strategy will depend on the FDA’s willingness to authorize a drug developed in the time of delta for use in the omicron era.
The two trials got underway in April and July 2021 and, as such, were mainly conducted before the rapid rise of the omicron variant, making it hard to gauge how ADG20 would fare in the current environment.
Adagio has analyzed the limited omicron data available from the studies. The pre-exposure enrolled 402 participants after the emergence of omicron. In an exploratory analysis of that subgroup, Adagio linked ADG20 to a relative risk reduction of 59% and 47% with a median follow-up duration of 56 and 77 days, respectively.
Many investors were in no mood to question whether the data can get ADG20 to market and establish it as a significant product, seizing on the update to send Adagio’s battered stock price up 60% to above $6.