Obama said affected countries should focus on building a "strong public infrastructure," adding: "I think we have to let the science guide us... I don't think all the information is in on whether this drug is helpful."
He emphasized that Ebola, a hemorrhagic virus that kills more than half of those infected, "is not an airborne disease". "This is one that can be controlled and contained very effectively if we use the right protocols."
But he said: "the countries affected are the first to admit that what's happened here is the public health systems have been overwhelmed. They weren't able to identify and then isolate cases quickly enough."
"As a consequence, it spread more rapidly than has been typical with the periodic Ebola outbreaks that occurred previously," he added.
He said the United States is working with European partners and the World Health Organization to provide resources to help contain the epidemic. "We're focusing on the public health approach right now, because we know how to do that, but I will continue to seek information about what we're learning with respect to these drugs going forward."
A total of 932 people have died since March in Sierra Leone, Guinea, Liberia and Nigeria, with 1,711 confirmed cases since the beginning of the year.
Ebola is spread through direct contact with the bodily fluids of an infected person. Symptoms include fever, muscle aches, red eyes, diarrhea, vomiting and bleeding.