May 27, 2011 -- When former pro basketball player Ray Johnston asked his doctor about his odds of living to see his 33rd birthday, he said the answer was "not good." Johnston was 31 at the time.
Instead of caving in to his prognosis, Johnston, an aspiring musician, took his group -- the Ray Johnston Band -- on tour.
"I'm a realist, but above all, I'm an optimist," he told ABCNews.com.
But Johnston didn't always feel optimistic. His initial diagnosis of acute promyelocyctic leukemia, a rare but curable form of cancer, in August 2004, cut short his basketball career with the Dallas Mavericks.
"There were so many times where I was mad. I asked why. I was 24 years old, perfectly healthy," said Johnston. "I did everything you were supposed to do to keep your body in tip-top shape."
But every time his cancer therapies brought him to remission, Johnston's cancer returned. Johnston was diagnosed with leukemia five times within seven years.
In 2009, when Johnston experienced his most aggressive recurrence, he'd exhausted all other therapies his doctors thought would work for him.
"He'd been through a lot of therapies, and it's clear we had a tough time keeping things together," said Dr. Robert Collins, director of the bone marrow transplantation and hematologic malignancies program at the University of Texas Southwestern Medical Center.
As a last-ditch effort to save Johnston's life, Collins petitioned for compassionate use of tamibarotene, a retinoid that causes cancer cells to mature and die quicker. Tamibarotene, a pill approved only in Japan for cancer treatment, is available only in clinical trials in the U.S., for which Johnston didn't qualify.
Within a few months, Johnston said the pain in his shoulder -- where his tumors were found -- subsided. And a PET scan confirmed both his and Collins' hopes.
"I was pleasantly amazed by his response," said Collins. "He probably had about 25 tumors or so, and within a few weeks we could see it shrinking. The disease was resolving completely."
While tamibarotene seemed to have worked for Johnston, Collins said research under way for the drug would determine who else would benefit. Studies found that tamibarotene is 10 times stronger in treating acute promyelocyctic leukemia than other types of retinoids used to treat the disease. But the drug's level of safety and its long-term success remain unclear.
"You can imagine that if it was helpful in this case, it could be helpful for others," said Collins.
Collins said he had no financial or research ties to the drug or its U.S. manufacturer, CytRx.
"It makes us hopeful it will be approved by the FDA," he said.
Nearly a year after starting his tamibarotene regimen, Johnston is still in remission.
"It bought me 16 months that I never thought I would have," said Johnston.
Johnston said he's happy he decided to take the Ray Johnston Band on the road. While he didn't realize it at the time, that became one of many goals he listed for himself.
By 2013, Johnston wants the Ray Johnston Band to sell out the House of Blues in Dallas, and by 2016, the Nokia Theater there. By 2021, its on to packing the house at the American Airlines Center -- something he missed out on during his short-lived career with the Mavericks.
But Johnston, who, despite the early prognosis, expects to turn 33 next February, said his more immediate goals are the ones he hasn't shared with too many others.
"Today it's to be smiling and breathing," he said. "And for me, tamibarotene is an ingredient for that."