NeuroRx and Relief Therapeutics have found that RLF-100 (aviptadil) led to rapid recovery from respiratory failure in critically ill patients with Covid-19.

Aviptadil is a formulation of Vasoactive Intestinal Polypeptide (VIP), which is present in high concentrations in the lungs and known to block various inflammatory cytokines. NeuroRx and Relief partnered to develop the drug in Covid-19 indication.

The drug candidate secured fast track designation from the US Food and Drug Administration (FDA) to treat respiratory distress associated with Covid-19.

A Phase II/III clinical trial of RLF-100 is ongoing. It is also being administered on an emergency basis to patients who are too ill to be enroled into the trial.

According to the companies, the first report of rapid clinical recovery under emergency use of the drug was from Houston Methodist Hospital doctors.

The report said that a 54-year-old man who contracted Covid-19 while on treatment for rejection of a double lung transplant came off a ventilator within four days of treatment with RLF-100.

Similar results were subsequently reported in more than 15 patients treated under emergency use.

A rapid clearance of classic pneumonitis findings on x-ray, an improvement in blood oxygen and a 50% or greater average reduction in laboratory markers for Covid-19 inflammation were observed in patients with critical form of the disease.

Also, independent research at a biocontainment laboratory in Brazil showed that the drug candidate inhibited the SARS coronavirus replication in human lung cells and monocytes.

NeuroRx CEO and chairman Jonathan Javitt said: “No other antiviral agent has demonstrated rapid recovery from viral infection and demonstrated laboratory inhibition of viral replication.

“We are conducting placebo-controlled trials to see whether the observations made in the case-control and open-label studies will be confirmed for less ill patients with Covid-19-related respiratory failure.”

An independent data monitoring committee will conduct an interim analysis of these data later this month.