On Nov. 13, 2020, NeuroRx and Relief Therapeutics announced that to-date, 150 patients (out of a targeted enrollment of 165) had been enrolled in the ongoing phase 2b/3 trial of RLF-100 (aviptadil) for treating respiratory failure in patients with critical COVID-19.

Respiratory failure was defined, according to FDA guidance, as the need for intensive care with mechanical ventilation, non-invasive ventilation, or high-flow nasal oxygen in order to sustain adequate levels of blood oxygen.