The search for effective coronavirus treatments is taking a big step forward with some help from the National Institutes of Health: The  NIH has launched a phase 3 clinical trial that could reveal which experimental antibody treatments for COVID-19 are the most effective.

A number of treatment candidates will be administered to hospitalized COVID-19 patients at participating institutions across the U.S. But the first that will be tested in the study is LY-CoV555 from Eli Lilly (NYSE:LLY). It's derived from an antibody originally identified in a patient who recovered from a serious case of COVID-19.

A gloved hand holding a coronavirus blood sample.

Image source: Getty Images.

In addition to a placebo, the ACTIV-3 trial will compare how LY-CoV555 stacks up against several injectable treatments from other pharmaceutical companies. The agency hasn't mentioned the next candidate on the list for the study, but we can reasonably expect Regeneron (NASDAQ:REGN) to field its dual antibody cocktail, REGN-COV2. 

Regeneron has already begun a phase 3 trial with REGN-COV2 in partnership with the NIH to see if it can protect people who have had close exposure to COVID-19 patients. Regeneron's candidate is also in the final stages of an adaptive trial among hospitalized patients that is designed to support its eventual FDA approval.

This isn't the first phase 3 trial of LY-CoV555 that Lilly has started in partnership with the NIH. On Monday, the company began a study, called Blaze-2 that will enroll up to 2,400 nursing home residents and employees who care for them. The NIH will also start a phase 2 trial of LY-CoV555 in which it will be administered to around 220 patients with mild to moderate cases of COVID-19; that study could be upgraded to a 2,000-patient phase 3 trial if the phase 2 portion is successful.