Gilead Sciences has launched a Phase Ia clinical trial of an inhaled version of remdesivir to treat Covid-19 patients in the outpatient setting.

The randomised, placebo-controlled study will evaluate the safety, tolerability and pharmacokinetics of the new formulation in 60 healthy participants aged 18-45 in the US.

According to current scientific understanding, SARS-CoV-2 frequently infects the upper respiratory tract in the early stages of the disease.

The company expects that direct delivery of its drug to the primary site of infection with a nebulised, inhaled solution could allow targeted and accessible administration in non-hospitalised patients. This approach may also lower systemic exposure to the drug.

Data from this Phase Ia trial will help to plan a further clinical study of the inhaled formulation, primarily in patients whose infection has not progressed to hospitalisation.

Gilead Sciences chief medical officer Merdad Parsey said: “With promising data emerging from the randomised, clinical trials of intravenous remdesivir administered to hospitalised patients, it became clear that efforts were needed to investigate the drug’s potential in the outpatient setting.

“Significant research efforts have been undertaken to deliver remdesivir in an inhaled, nebulised format.

“Research on this inhaled solution of remdesivir represents an important pillar of our ongoing work that aims to potentially enhance patient outcomes with remdesivir and enable more patients to access this treatment.”

The company received approval from the US Food and Drug Administration (FDA) last month to investigate an inhaled version of remdesivir in human clinical trials as a potential treatment for Covid-19 patients.

Other trials of remdesivir in combination with anti-inflammatory drugs, in vulnerable patient populations, and in outpatient settings, are ongoing or are planned for future initiation.

Apart from the Phase II/III trial being conducted in paediatric patients hospitalised with Covid-19, the company is planning studies in pregnant women and patients with end-stage renal disease.