Bamlanivimab (LY-CoV555) prophylaxis prevents COVID-19 in care homes: results of BLAZE-2 study

Simon Collins, HIV i-Base

On 21 January 2021, new results reported that a monoclonal antibody called banlanivumab reduced the risk of COVID-19 symptoms when used either before infection or shortly afterwards.

This was a phase 3 study in both residents and staff in long-term care homes. The limited results were reported in a company press release, included significant benefits when used as primary prophylaxis. It also  included benefits in a smaller study group who were already positive for coronavirus when the study started.

The BLAZE-2 study randomised 965 participants who were negative for SARS-CoV-2 (299 residents and 666 staff) to either a single infusion of 4,200 mg of bamlanivimab or to placebo control. A second randomised cohort included 132 participants who tested positive at baseline (41 residents and 91 staff) and who were also randomised to either bamlanivimab or placebo to look at potential use as treatment.

Based on eight weeks of follow-up in all participants, bamlanivimab significantly reduced the primary endpoint risk of COVID-19 symptoms (odds ratio 0.43, p=0.00021), with a great reduction in risk for residents (odds ratio 0.20; p=0.00026).

Overall, there were 16 deaths, all among residents, but only 8/16 were linked to COVID-19: 4 in the prevention study and 4 in the treatment study, all in the control groups.

Further details were not included, other than to report that results for all key secondary endpoints also reached statistical significance in both the overall and resident populations.


These results show an important potential role of monoclonal antibodies for management of COVID-19.

They also show the importance of use before exposure or early in infection.

In October 2020, a phase 3 study in advanced COVID-19 was stopped early by the study DSMB for having no benefit in late-stage infection. [2, 3]


Despite these positive results, bamlanivimab is not longer used for any indication. This is because bamlanivimab loses sensitivity to variants that recently became dominant including Delta. This is likely to be a similar concern for other antibodies developed against original strains of SARS-CoV-2.


  1. Eli Lilly press release. Lilly’s neutralizing antibody bamlanivimab (LY-CoV555) prevented COVID-19 at nursing homes in the BLAZE-2 trial, reducing risk by up to 80 percent for residents. (21 January 2021).
  2. HTB. Monoclonal antibody stopped in ACTIV-3 study: bamlanivimab shows lack of benefit in people hospitalised with COVID-19. HTB (11 November 2020).
  3. Monoclonal antibody bamlanivimab is not effective in advanced COVID-19: lack of early signal stops study early. HTB (22 January 2021).

This report was first published on 6 February 2021. 

Links to other websites are current at date of posting but not maintained.