A phase 3 clinical trial of a potential COVID-19 antibody therapy developed by Eli Lilly (NYSE:LLY) has been halted permanently, the company reported Monday night. No additional eligible participants will be dosed with LY-CoV555, also known as bamlanivimab. LY-CoV555 was being tested in combination with Gilead Sciences' recently FDA-approved remdesivir antiviral drug to treat the disease.

The stop was ordered by the government's National Institutes of Health (NIH) on the recommendation of an independent advisory committee. The NIH had been sponsoring the study.

The decision followed a temporary halt to the trial mandated by the NIH on Oct. 13 after a participant in the study experienced an adverse event.

A coronavirus colony.

Image source: Getty Images.

At the time, an Eli Lilly spokeswoman said the pause was effected "out of an abundance of caution" for safety issues. Further details were not provided.

As for the permanent halt, it is being mandated because NIH researchers concluded based on the already-collected trial data that Eli Lilly's antibody candidate probably wouldn't be effective in patients hospitalized with severe cases of COVID-19.

LY-CoV555 is a monoclonal antibody -- a synthetic protein that can be used to target certain antigens, and block their activities, flag them for attack by other aspects of the immune system, or deliver material to help defeat them.

Despite the NIH's permanent halt to the study, Eli Lilly pledged to continue other research being conducted with its candidate treatment, both as a monotherapy and in combination with another monoclonal antibody called etesevimab, to treat COVID-19.

While this news is disappointing, it should be noted that halts and cancellations of clinical trials for drug candidates are commonplace.

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