FRANKFURT (Reuters) – AstraZeneca’s cancer drug Calquence has shown initial signs of helping hospitalised COVID-19 patients get through the worst of the disease, as researchers scramble to repurpose existing treatments to help fight the deadly infection.

Results from the preliminary research involving 19 patients, which was backed by the United States National Institutes of Health, encouraged the British drugmaker to explore the drug’s new use in a wider clinical trial announced in April.

Eleven patients had been on oxygen when they started the 10-14 day Calquence course and eight of them could afterwards be discharged, breathing independently, according to results in a paper co-authored by Astra’s head of oncology research, Jose Baselga.

Eight patients were on mechanical ventilation when they were put on Calquence, and four of them could be discharged, though one died of pulmonary embolism.

“These patients were in a very unstable situation, they would have had a dire prognosis … Within one to three days the majority of these patients got better in terms of ventilation and oxygen needs,” Astra’s Baselga told Reuters.

Severe cases of COVID-19 are believed to be triggered by an over-reaction of the immune system known as cytokine storm and initial research has brought Calquence, and other drugs that suppress certain elements of the immune system, into play.

Autoimmune disease drugs that are being tested for their ability to quell the cytokine storm include Regeneron and Sanofi’s Kevzara, Roche’s Actemra as well as Morphosys and GlaxoSmithKline’s otilimab.

In its approved use, Calquence competes with AbbVie and Johnson & Johnson’s established treatment Imbruvica as a treatment for chronic lymphocytic leukaemia, a common type of adult leukaemia.