Relief Therapeutics and NeuroRx have met the patient enrollment target of 165 agreed with the US Food and Drug Administration (FDA) in the trial of RLF-100 (aviptadil), a formulation of Vasoactive Intestinal Polypeptide (VIP) for Covid-19.

The ongoing Phase IIb/III trial is evaluating RLF-100 for treating respiratory failure in critical Covid-19 patients.

According to the FDA, respiratory failure requires intensive care with mechanical ventilation, non-invasive ventilation or high-flow nasal oxygen to maintain sufficient levels of blood oxygen.

NeuroRx CEO and founder Prof Jonathan Javitt said: “Although enrolment has been uniquely challenged by the devastating effects of the pandemic, straining the capacity of hospitals and exposing our investigators and study coordinators to personal peril from Covid-19 in the course of their duties, we are proud to meet our enrollment target as planned.

“Achieving this milestone in the midst of the pandemic has only been possible because of the extraordinary dedication of the doctors, nurses, pharmacists, and study coordinators who continued to work around the clock to develop this much-needed therapy.”

No FDA-approved drug has currently shown efficacy in the intensive care unit (ICU) admitted patients with respiratory failure.

Apart from this, more than 200 patients with critical Covid-19 and respiratory failure have been treated in an FDA-approved expanded access protocol (EAP) for RLF-100.

They were unable to enter the Phase IIb/III randomised trial because of severe comorbidities such as an organ transplant, heart attack or cancer.

Another Phase IIb/III trial with RLF-100 for inhaled use in patients with moderate and severe disease to prevent progression to respiratory failure is likely to begin soon.

Last month, NeuroRx and Relief Therapeutics announced initial successful results from expanded access use of RLF-100 in patients with critical Covid-19 and severe comorbidities, with 72% of them admitted into ICU surviving.