Doctors had previously reported seeing their patients benefit by taking Avastin, but it's not clear which patients it helps the most.
According to Dr. Daniel Hayes, clinical of the breast oncology program at the University of Michigan, further studies would have determined what types of patients would benefit from the drug.
"I fear we are throwing the baby out with the bathwater," said Hayes, who was not involved in the hearing.
The final regulatory decision rests with the FDA Commissioner Peggy Hamburg. It is unclear when the final decision will be made.
Some cancer specialists said the decision could hold huge implications for the way their patients will be treated.
American Cancer Society's deputy medical officer Dr. Len Lichtenfeld attended the hearing and tweeted Tuesday, "No one has asked the question: What do we say to all the patients and families who testified this morning?"
"Patients no doubt will feel like the FDA is putting nails in their coffin," said Lillie Shockney, associate professor of breast cancer at the Johns Hopkins University School of Medicine. "Patients feel a personal need to try to fight this disease, even if it means that only a tiny number will benefit from a particular drug. Each patient prays that they are among that tiny number."
Crystal Hanna, 35, a mother of two from Parkersburg, W. Va., said she's certain she would not be alive today if it wasn't for Avastin. Hanna, who was diagnosed with stage 4 breast cancer in July 2010, said her cancer hadn't progressed and she was still taking Avastin.
"We're not just statistics," Hanna told ABC News. "I have a lot to live for. I am here to plead with them to have compassion for our life."
Still, the FDA studies found no overall benefit from the drug, and even suggested that some patients increased their risk of death because Avastin is, in some ways, toxic.
The panel asked whether the FDA's experts who testified believed that some patients could benefit from Avastin. "No, we do not agree," Dr. Patricia Keegan, director of the FDA's Division of Biologic Oncology Products in the Office of Oncology Drug Products, said.
"Despite the hopes of everyone inside and outside this room," Keegan testified, "there is no evidence that Avastin saves or extends lives."
ABC News' Lisa Stark contributed to this report