Relief Therapeutics and NeuroRx have expanded the Phase II/III clinical trial of RLF-100 (Aviptadil) to include Covid-19 patients on ventilators, high flow oxygen, and noninvasive ventilation (CPAP).

RLF-100 is a formulation of synthetic human Vasoactive Intestinal Peptide (VIP), which received orphan drug designation from the US Food and Drug Administration (FDA) in acute respiratory distress syndrome and chronic lung diseases.

The multi-centre Phase II/III trial will assess the drug candidate in patients with critical Covid-19 and respiratory failure. RLF-100 is expected to reduce mortality and improve blood oxygenation by protecting alveolar type II cells from the SARS-CoV-2 virus.

NeuroRx CEO Jonathan Javitt said: “The SARS-CoV-2 attacks the body by entering the small population of Alveolar Type II cells in the lung, almost like hitting the needle in the haystack. Without Type II cells, the lung cannot transmit oxygen, which is exactly what happens in Covid-19.

“We know from 50 years of scientific research that VIP binds specifically to the Type II cell and protects that cell against cytokines (inflammatory molecules) and a wide array of toxic and infectious injuries.”

NeuroRx, which is Relief Therapeutics’ development partner in the US, is leading the study, which is being conducted under investigational new drug clearance and the FDA’s Corona Treatment Acceleration Program (CTAP).

The companies started patient enrolment and treatment for the Phase IIb/III trial of RLF-100 earlier this month. The drug was initially meant to treat patients with acute respiratory distress syndrome (ARDS) caused by Covid-19.

Set to enrol 120 participants, the multi-centre, randomised, placebo-controlled Phase IIb/III trial will compare intravenous (IV) RLF-100 plus maximal intensive care to placebo with maximal intensive care.

The primary endpoints of the study will be mortality and index of respiratory distress.