New York, Aug 21 (IANS): A drug normally used in rheumatoid arthritis and cancer treatments -- tocilizumab -- improves hospital survival in critically ill Covid-19 patients admitted to the intensive care unit (ICU), say researchers.

The study, published in the journal The Lancet Rheumatology, included 630 patients who were admitted to the ICUs of 13 Hackensack Meridian Health hospitals in New Jersey.

Among other treatments, tocilizumab was considered for off-label usage for the patients whose respiratory symptoms were declining; many of whom were requiring mechanical ventilator support.

In the observational study, 210 patients received tocilizumab, and the other 420 did not.

"Our work in treating this terrible virus, and learning more about it each day, continues to benefit thousands of patients as the pandemic continues," said Robert C Garrett, CEO from the Hackensack Meridian Health in the US.

Covid-19 has three phases: the early or viral phase (with fast viral replication), the pulmonary phase (marked by inflammation and pneumonia as the body tries to fight the virus in the lungs) and the inflammatory phase (in which excessive inflammation reaches and affects many organs and patients are often in the ICU).

As part of both the pulmonary and inflammatory phases, the immune system is "supercharged" and secretes in the blood numerous cytokines, particularly interleukin (IL)-6, which induces further inflammation.

Tocilizumab is a monoclonal antibody, which binds and blocks the interleukin (IL)-6 receptor and helps damper the inflammatory response.

The activity of tocilizumab was first shown in chimeric antigen receptor (CAR) T-cell therapy, where a similar phenomenon of overactive and growing T cells induce a "cytokine storm."

This provided a rationale to try tocilizumab in Covid-19 patients.

The findings showed a statistically significant decrease in hospital-related deaths among the patients who received the tocilizumab.

A roughly 36 per cent decrease in hospital-related mortality among the ICU patients who received the drug, as compared with patients in the ICU who didn't receive it.

Importantly, it appeared that higher levels of a blood test marker of inflammation, C-reactive protein, could predict which ICU patients might benefit most from the tocilizumab therapy, potentially allowing doctors to tailor therapy to those most in need.

"These real-time findings have helped to point us the way forward," the study authors wrote.

Earlier this month, another study published in the International Journal of Infectious Diseases, found that t patients experiencing severe Covid-19 symptoms had improved outcomes when administered an Interleukin-6 (IL6ri) inhibitor, sarilumab or tocilizumab.