NeuroRx has reported that the Phase IIb/III trial of Zyesami (aviptadil, previously RLF-100) showed multidimensional benefit in treating respiratory failure in critically ill Covid-19 patients.

It was initially approved as a 28-day study at the FDA’s guidance but NeuroRx added a 60-day endpoint last December.

The move comes after recognising that the traditional 28-day endpoint adopted in the 1990s for trials in Acute Respiratory Distress Syndrome is not suitable for critically ill Covid-19 patients as they are admitted in the ICU with modern technologies well beyond this period of time.

NeuroRx and some clinical trial sponsors informed the FDA on this trend and the FDA has published formal guidance altering the time needed for evaluating the prespecified endpoint of ‘alive and free of respiratory failure’ in critically ill patients to 60 days.

The interim data is being announced as it is unblinded as per the original protocol and the last patient in the trial has completed 60 days.

Data showed that Zyesami showed multiple benefits around its prespecified primary endpoint of recovery from respiratory failure with discharge from hospital and ICU (without relapse) by day 28 in critical Covid-19 patients receiving high flow nasal oxygen.

Patients receiving Zyesami showed 35% higher chances of recovery from respiratory failure with continued survival versus placebo at day 28.

In addition, Zyesami-treated patients had a 46% higher chance of recovering and returning home before day 28 in tertiary care hospitals.

A ten-day difference in median time to recovery and hospital discharge was also observed in the treatment group versus placebo at day 28.

NeuroRx noted that if these trends continue up to day 60, there exists a potential to reach statistical significance.

The company intends to seek Emergency Use Authorisation in this patient population on obtaining positive results at the day-60 endpoint.

NeuroRx CEO Jonathan Javitt said: “We look forward to reporting the final 60-day efficacy data shortly.

“Additional efficacy data on patients who require mechanical ventilation will be obtained from ongoing research supported by BARDA and the National Institutes of Health, in addition to our newly initiated study of inhaled use Zyesami in hospitalised patients who have not yet developed respiratory failure.”

Earlier this month, NeuroRx reported that preliminary results from its Phase IIb/III trial of Zyesami showed it reduced hospital stay among patients with respiratory failure due to critical Covid-19.