On Apr. 22, 2021, the NIH announced that a phase 3 trial to test the safety and efficacy of therapeutics for COVID-19 had begun enrolling patients hospitalized with life-threatening cases of COVID-19, including those with acute respiratory failure.

The randomized, blinded, placebo-controlled clinical trial, called ACTIV-3 Critical Care began by testing Zyesami, a formulation of aviptadil acetate, produced by NeuroRx, Wilmington, Delaware, and the antiviral remdesivir (Veklury), developed by Gilead. Aviptadil is a synthetic version of Vasoactive Intestinal Peptide or VIP, which is made naturally in the human body and appears to have lung-protective antiviral and anti-inflammatory effects.