Organizers are struggling to find sponsors.
Kenyans Edna Kiplagat and Bernard Koech are the headliners.
The professional and age-group competition aimed at growing the visibility and popularity of road racing.
Four other runners are in medically-induced comas due to excessive heat.
Is the marathon boom over?
The annual race takes place on May 5.
Ben True was the men's victor.
Columbus takes over from Houston starting in 2016.
The top-5 men all broke 60 minutes.
The exact date and location of the event are still to be determined.