Northwestern Medicine in the US has started patient enrolment for a global clinical trial of Sanofi and Regeneron Pharmaceutical’s rheumatoid arthritis drug sarilumab (Kevzara) to treat severely ill, hospitalised Covid-19 patients.

Kevzara is a fully-human monoclonal antibody designed to inhibit the interleukin-6 (IL-6) pathway via attachment to the IL-6 receptor.

According to preliminary findings, excessive IL-6 may be involved in the development of acute respiratory distress in Covid-19 patients.

The clinical trial will evaluate sarilumab’s ability to mitigate the overactive inflammatory responses in the lungs damaged by Covid-19 when compared to placebo.

Northwestern Medicine is leveraging in-house developed diagnostic tests to detect infection in patients being treated with sarilumab.

Northwestern Memorial Hospital Medical Intensive Care Unit medical director Richard Wunderink said: “The drug is being given to people with very severe Covid-19 infection who have a high chance of dying or prolonged critical care requirements without specific therapy.

“Sarilumab blocks the IL-6 receptor in the body, theoretically making cells resistant to the ill effects of excessive IL-6. There is always a concern that this will limit the immune response, so it is important to monitor patients for evidence of infection and treat it.”

In late March, Sanofi started a Phase II/III trial of sarilumab to treat patients hospitalised with severe Covid-19 infection outside of the US.

Sanofi’s partner, Regeneron Pharmaceuticals, is responsible for performing the study’s counterpart in the US, which commenced earlier in March.

The US trial has two parts. In the first part, severe Covid-19 patients will be enrolled at up to 16 sites. It will investigate the drug’s impact on fever and the need for supplemental oxygen.

The second will assess longer-term outcomes, such as preventing death and mitigating the need for mechanical ventilation, supplemental oxygen, or hospitalisation.

Northwestern Medicine is conducting an international trial of remdesivir, Gilead Sciences‘ experimental anti-viral drug for Ebola. It is also assessing other experimental antibiotics for some patients.