The US National Institutes of Health (NIH) has initiated a Phase III clinical trial, named ACTIV-3, to evaluate various types of monoclonal antibodies as potential treatments for hospitalised Covid-19 patients.

The randomised, controlled trial has an adaptive design and a master protocol, allowing modification to include additional investigational therapies. It can also recruit additional participants in the middle of the study.

NIH said that the trial will be conducted at select hospitals globally that are covered under the existing clinical trial networks.

NIH director Dr Francis Collins said: “Under Operation Warp Speed, the US Government has brought together multiple agencies to accelerate the development, manufacture, and distribution of medical countermeasures for Covid-19.

“The ACTIV studies are just a few examples of this critical activity, which emphasises flexibility and minimises delays to generate scientifically sound results.”

ACTIV-3 uses a two-stage design. If an independent data and safety monitoring board (DSMB) review finds a treatment to be safe and effective in stage one, the therapeutic will be advanced to to stage two, which will enrol more subjects.

If a therapeutic is found to be unsafe or unlikely to be effective, it will be dropped.

Initially, the trial will assess Eli Lilly’s experimental monoclonal antibody LY-CoV555, which is being studied in alliance with Abcellera Biologics. LY-CoV555 is also being studied in NIH’s ACTIV-2 study in mild to moderate Covid-19 patients.

Lilly recently launched the Phase III BLAZE-2 trial of LY-CoV555 to prevent Covid-19 in residents and staff at long-term care facilities in the US.

The ACTIV-3 trial’s initial stage is set to enrol around 300 participants hospitalised with mild to moderate Covid-19 with fewer than 13 days of symptoms. Subjects will receive LY-CoV555 and standard of care, including the antiviral remdesivir.

Participants will be followed for 90 days after enrolment and will undergo regular examinations.