Jason Marder watched the inevitable decline of his younger brother, who died of Alzheimer's disease at the age of 50. Then, just after his 60th birthday, he too, began to exhibit subtle, early symptoms -- forgetfulness and difficulty focusing on conversations.
At his birthday party, "I noticed he had a hard time keeping track of the presents," said he wife, Karin Marder. "He would forget small things -- like saying he went to the movies when he didn't."
The memory loss progressed, and in 2004, Marder got the dreaded diagnosis: Alzheimer's, a disease that affects 5.1 million Americans.
"It was devastating," said his wife, who works in business apparel. "I thought our lives were going to end."
But today, eight years after his diagnosis, Marder isn't any worse off. He has shown no further memory loss and has remained stable.
The Marders credit intravenous immunoglobulin, or IViG, therapy and a clinical trial that is swirling in controversy this week after an announcement of study results by the Alzheimer's Association International Conference 2012 in Vancouver.
Some doctors hailed the therapy as "exciting," something that could potentially stabilize the disease, while others said the research is inconclusive and the study -- with only 16 subjects -- was too small.
Nonetheless, today Marder, now retired from working in apparel, continues his independent lifestyle, playing tennis and biking in his native New York City.
"Things are going really nicely. I can't complain," said Marder, now 70. "I don't feel any going backwards."
"This drug saved his life," said Karin Marder. "He's independent. He gets on the subways, bikes up and down the Hudson River, gets to go out with friends. He goes to the senior center twice a week. He does creative writing."
For the past five years, Marder has been part of a clinical trial with Dr. Norman R. Relkin, director of the Memory Disorders Program at New York-Presbyterian/Weill Cornell Medical Center.
Relkin presented data that found,overall, that 11 study participants who received the immunotherapy Gammagard (IViG) for three full years showed improvements in cognition, memory, daily functioning and mood.
"We are seeing encouraging results," Relkin told ABCNews.com. And despite negative publicity, "I don't want people to give up hope for symptomatic treatment of the disease".
Intravenous Immunoglobulin is a mixture that contains molecules pooled from plasma, a component of human blood. It is used to treat various autoimmune, infectious and idiopathic diseases, and its supply is therefore limited.
IViG works by using the body's natural defense or immune system and anti-amyloid antibodies. A protein called beta amyloid accumulates in the brain of those who have Alzheimer's.
"We don't know exactly what it targets, but we do know it contains all antibodies that the body produces," said Relkin. "It alters the function of the immune system and decreases inflammation in the brain".
He said that his research team found the rate of brain shrinkage had slowed and the study had "exceeded criteria" to go forward with a phase III trial.
"Typically, untreated Alzheimer's disease shows cognitive decline in three to six months," said Relkin. "Those treated with typical AD drugs show decline in six to nine months. Four out of four patients in the [phase IIB] extension trial were unchanged over a three-year period."
As for Marder, he still has some memory problems, but he can dress himself, cook, clean and walk around the neighborhood.
"I can be away from him for one to two nights," said his wife, Karin.
Every two weeks, a nurse comes to Marder's home and sets up the infusion, which takes about four hours.
"I am happy to spend the time," he said. "Then I walk out of my house and go bike riding."
Besides a minor rash that crops up three to five days after getting the drug, Marder has had no ill side effects with the treatment. "He hasn't even had a cold in five years," said Marder's wife.
Still, treatment is not advised for patients who have had a major stroke or heart attack, because it can increase the risk of vascular events.
IVIG may not just be a therapy that treats symptoms, according to Dr. Richard Caselli, a neurologist at the Mayo Clinic. The drug seems to block the "destructive process" of inflammation mechanisms in the brain.
"Its strength and therefore importance is that it seems to show a stabilizing effect over a sustained period of time," he said. "Its weakness as the authors state is the small number of patients as well as its unblinded open label format."
But Dr. Normal Foster at the Center for Alzheimer's Care, Imaging and Research at the University of Utah, said the selective reporting of the study's results are "suspicious."
"Not everyone who received treatment was included in the analysis," he said. "The results are intriguing, and I can see why they might want to share them, but they can't be relied upon."
Dr. James E. Galvin, director of the the Pearl Barlow Center for Memory Evaluation and Treatment at New York University's Langone Medical Center, said there may be "technical and logistical limitations" in how many patients might obtain the drug.
But Dr. Sam Gandy, director of Mount Sinai Center for Cognitive Health, said the study, though small, is "still good news, indeed."
He, like other experts, said more studies were needed to prove the drug's promise.
Marder showed no symptoms of the disease in his speech, memory or mood when interviewed by ABCNews.com. He said he first began noticing he was having trouble with his memory a decade ago.
"I thought it was all part of aging," he said.
After a series of tests with a neurologist that were inconclusive, he was preventively put on the drug Aricept. But within a matter of months, an official diagnosis of Alzheimer's disease was made.
"I was devastated," he said. "It blows you away."
As his confusion and forgetfulness worsened, Marder was put on Namenda, as well as Aricept, both of which he has continued for nine years.
Every six months Relkin puts Marder through a series of cognitive tests and so far, the decline has been minimal.
But now, the Marders worry that they may not get the drug if it does not get FDA approval when phase III clinical trials end next year.
And it's expensive – estimated to cost a patient $2,000 to $5,000 every two weeks, including the drug, equipment and a nurse to administer it.
Relkin has told the Marders there were other drugs, but Marder said, "I just want them to keep going."
Marder continues to play tennis and can ride his bike up the 11-mile stretch from Battery Park to the George Washington Bridge -- and back.
"He still has memory issues, no question," said his wife. He tends to repeat himself, but the drug has kept him stable. "There's no doubt he has Alzheimer's, but we would have expected him to progress downward by now."
Luckily, Marder has the self-awareness to know what the drug has done for him.
"It's heaven," he said. "I don't know where I could have been without it."