Pfizer Inc won expert backing for using its blockbuster vaccine in adults to fight pneumonia, meningitis and other diseases caused by pneumococcus bacteria.
The FDA usually approves products that win support from its advisory panels, and is due to make a final decision in January.
The agency is considering the vaccine under its accelerated approval process, meaning the FDA believes the medicine represents an unmet medical need.
The vaccine is designed to fight 13 forms of a bacterium called streptococcus pneumoniae, or pneumococcus.
Pneumonia caused by the pneumococcal organism is one of the biggest causes of death in older people and its incidence begins to increase after age 50.
The Prevnar vaccine is currently only approved for children, but Pfizer has said an expanded population of adults could generate more than $1.5 billion in annual sales for what is already among the world's biggest selling vaccines.
The Prevnar franchise, known as Prevenar in Europe and other countries, generated about $3.7 billion in global sales last year.