As part of the Hot Line Session 10 (on COVID-19) at ESC Congress 2022 today, PHRI Senior Scientist John Eikelboom and PHRI Scientist Sanjit Jolly presented on the outpatient and inpatient trials of the Anti-Coronavirus Therapy (ACT) study.

Within three months of WHO’s declaration of the COVID-19 pandemic, researchers at PHRI pivoted to this topic.

Meta-analyses identified by a search of PubMed from January 2020-present did not indicate a benefit of colchicine in outpatients or inpatients with COVID-19, but the estimate obtained from the only large trial in outpatients suggested a reduction in hospitalisation or death. One randomized trial of aspirin in outpatients with COVID-19 was stopped early because of low event rates and therefore the potential benefit was unknown.

John Eikelboom

A large team of PHRI researchers, including infectious diseases specialists colleagues at McMaster University, decided to test colchicine for anti-inflammatory therapy, and rivaroxaban and/or aspirin for antithrombotic therapy, in COVID-19 patients in the community and in hospital.

In both the outpatient and inpatient ACT trials, patients were randomized between August 27, 2020, and February 10, 2022.

Outpatient trial

The ACT outpatient, open-label, 2 x 2 factorial randomized controlled trial evaluated anti-inflammatory therapy with colchicine, and antithrombotic therapy with aspirin, for prevention of disease progression in 2881 community (non-hospitalized) patients with COVID-19 at 48 sites in 11 countries.

“The results provide no support for the use of colchicine or aspirin to prevent disease progression or death in outpatients with COVID-19,” said Eikelboom at ESC 2022. “The world still needs additional inexpensive, widely-applicable treatments for COVID-19.”

“The lower-than-expected rate of hospitalization in the ACT outpatient trial may reflect lower virulence of emerging COVID-19 variants, increasing immunity in the population due to infection and use of vaccination, the increasing use of effective treatments, and changing patterns of medical care,” noted Eikelboom. (Download his ACT outpatient slides.)

Inpatient trial

The ACT inpatient trial – also an open-label, factorial RCT – looked at colchicine and the combination of rivaroxaban and aspirin in 2611 patients hospitalized with COVID-19 at 62 sites in 11 countries. Neither of those therapies were found to prevent disease progression or death.

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