EUSA Pharma has secured approval from the US Food & Drug Administration (FDA) for a Phase III clinical trial protocol of intravenous siltuximab plus standard of care in hospitalised patients with Covid-19 associated Acute Respiratory Distress Syndrome (ARDS).

The company will now proceed with the randomised, double-blind, placebo-controlled clinical trial to evaluate the safety and efficacy of siltuximab, a monoclonal antibody.

Siltuximab can directly neutralise interleukin (IL)-6, an inflammatory cytokine detected at elevated levels in multiple inflammatory conditions, including Covid-19 and specifically binds to IL-6 to inactivate its induced signalling.

EUSA Pharma CEO Lee Morley said: “Treatment approaches neutralising IL-6 could therefore play a key role in mitigating further detrimental inflammation and progression to respiratory failure, which can be fatal.

“We thank the FDA for recognising the importance of this clinical trial and the quick approval we received. Our plan now is to initiate the study as quickly as possible with the hope of seeing improved clinical outcomes in these critically ill patients.”

For the trial, about 400 patients with viral ARDS and elevated serum levels of IL-6 are expected to be enrolled.

The primary objective of the trial is to evaluate all-cause mortality at 28 days by adding siltuximab to standard of care, compared to placebo plus standard of care.

Its secondary objectives include time to seven-category ordinal scale of clinical status improvement, ventilator-free days within 28 days, and organ failure-free days.

The newly approved confirmatory clinical trial is important as the previous findings require validation in a well-controlled randomised study. Furthermore, limited published data is available on the safety and efficacy of siltuximab in Covid-19.