Atossa Therapeutics has reported positive interim safety data from the second cohort of participants in a Phase I clinical trial of its Covid-19 drug candidate, AT-301, given as nasal spray.

AT-301 is being developed for at-home use to mitigate Covid-19 symptoms and slow the infection rate in order to enable a person’s immune system to more effectively fight the virus.

The drug candidate is intended for patients who do not require hospitalisation.

In the second cohort of the Phase I trial, eight healthy participants were administered a single escalated dose of AT-301A (placebo) or AT-301B (active drug).

Based on the positive data from this cohort, the safety committee recommended that the trial can now recruit participants for the next cohort.

The company reported positive safety interim data from the first cohort of eight participants earlier this month.

Being performed in Australia, the ongoing double-blinded, randomised and placebo-controlled safety Phase 1 trial of AT-301 nasal spray is designed to enrol 32 healthy adults in two groups.

Part A of the trial involves two single-dose cohorts, where subjects receive either active drug AT-301B or the placebo AT-301A at two different doses.

Meanwhile, Part B is a multiple-dose arm with cohorts administered with either AT-301A or AT-301B for 14 days at two different doses.

The primary objective is the safety and tolerability of single and multiple doses of AT-301 administered via nasal instillation. Secondary objectives include the incidence and severity of local irritation and bronchospasm after nasal instillation of AT-301.

Atossa Therapeutics president and CEO Steven Quay said: “Recent data from the CDC suggests that more than 90% of people testing positive for Covid-19 do not require hospitalisation.

“With this in mind, we are developing our AT-301 nasal spray for home-use because there are no currently FDA-approved treatments to help these patients with early disease to recover faster.”

Atossa also intends to test its AT-301 nasal spray as a prophylaxis to prevent or mitigate Covid-19.