Pulminiq is an inhalant designed to treat chronic lung transplant rejection.
According to a report this week a panel voted 8 to 8 on whether a study of 56 patients offered adequate proof of the effectiveness of Pulminiq.
The outside panel of medical experts were deadlocked on the data as the UK drug manufacturer Chiron waits to hear the FDA's decision on its drug.
The FDA must reach a decision by mid-month on whether or not it will approve the drug.
Drug company Chiron said it would conduct another five-year study if Pulminiq is given approval.
Although the FDA usually follows the advice of its voting panelists, such votes rarely end in deadlock.