Search

Upregulation of IL-6 has been associated with worse prognosis in COVID-19 patients. Impact on IL-6 signalling has mostly been limited to clinical outcomes in IL-6 receptor antagonist trials. We performed a phase 2, randomised, double-blind, placebo-controlled trial (NCT04380961) of US-based hospitalised adults (<85 years) with laboratory-confirmed SARS-CoV-2 infection and severe (low levels of supplemental oxygen) or critical disease (high levels of oxygen supplementation). Patients received sirukumab 5 mg/kg or placebo single dose IV on Day 1 plus standard of care. The primary endpoint was time to sustained clinical improvement up to Day 28 based on an ordinal scale. Secondary endpoints included clinical improvement, all-cause mortality, and safety. Following an interim analysis, the protocol was amended to only recruit patients with critical COVID-19. From May 2020 to March 2021, 209 patients were randomised; 112 had critical disease (72 sirukumab, 40 placebo) at baseline. Median time to sustained clinical improvement in critical patients was 17 and 23 days in the sirukumab and placebo groups (HR, 1∙1; 95% CI, 0∙66–1∙88; p > 0∙05). At Day 28, 59∙4% versus 55∙0% of patients achieved clinical improvement with sirukumab versus placebo and rates of all-cause mortality were 24∙6% versus 30∙0%, respectively. Rates of grade ≥3 adverse events were comparable between the sirukumab and placebo groups (25∙9% vs 32∙9%; all patients). In critical COVID-19 patients who received sirukumab, there was no statistically significant difference in time to sustained clinical improvement versus placebo despite objective sequestration of circulating IL-6, questioning IL-6 as a key therapeutic target in COVID-19. • Adults with severe or critical COVID-19 were randomised to sirukumab or placebo. • Sequestration of IL-6 upstream of the IL-6R allows testing of the IL-6 hypothesis. • Sirukumab sequestered circulating IL-6 available for cis and trans signalling. • Time to sustained clinical improvement was not significantly different by group. • 24.6% vs 30.0% of critically ill patients died with sirukumab vs placebo. [ABSTRACT FROM AUTHOR]