EUSA Pharma hopes IL-6 drug will succeed in COVID-19 where rivals failed

UK-based EUSA Pharma has begun a late-stage trial of its antibody siltuximab in COVID-19, hoping that the IL-6 inhibitor will succeed where class rivals from Roche and Sanofi/Regeneron have failed.

Hertfordshire-based EUSA said recruitment has begun in phase 3 trial involving patients with COVID-19 previously treated with corticosteroids and other respiratory viruses associated with serious respiratory complications.

This pivotal study is designed to confirm results from the smaller SISCO study that investigated siltuximab plus standard of care in COVID-19 patients with serious respiratory complications.

Primary outcome of the SILVAR study will be all-cause 28-day mortality.

Siltuximab is an IL-6 inhibiting drug that was originally developed and marketed by the Johnson & Johnson’s Janssen unit for the rare disorder idiopathic multicentric Castleman’s disease.

EUSA Pharma bought global rights to the drug from Janssen in $115 million.

Roche and Sanofi/Regeneron have already tried to alleviate symptoms with their respective IL-6 drugs, Actemra (tocilizumab) and Kevzara (sarilumab), but trials did not produce supportive results.

EUSA said that unlike previous studies of agents targeting the IL-6 signalling pathway, the SILVAR study has been rationally designed to select those hospitalised patients still suffering from serious viral acute respiratory distress syndrome (ARDS).

Patients selected will be in a hyperinflammatory state that will most likely benefit from the addition of an immunomodulator, such as siltuximab.

Respiratory failure from ARDS is the leading cause of mortality in patients with COVID-19.

Siltuximab binds to and neutralises IL-6, a chemical signal in the body that is recognised as a key driver of ARDS in COVID-19 and other respiratory infections.

The SISCO trial earlier this year in COVID-19 compared 30 patients treated with siltuximab with 30 matched controls, and showed that treatment with the drug led to a 54% reduction in risk of 30-day all-cause mortality.

EUSA Pharma’s CEO Lee Morley said: “This clinical trial represents an important step in finding a solution for hospitalised patients with serious respiratory complications due to an over reactive immune response to (coronavirus) infection that is not fully responsive to corticosteroid therapy, as well as those with any other respiratory virus infection associated with serious ARDS.”

Feature image courtesy of Rocky Mountain Laboratories/NIH