A New Jersey man who seemed to be dying of leukemia is the first patient to get an experimental cancer treatment that uses a defanged form of HIV.

William Ludwig, then 65, is one of only three patients who have received the bold treatment at the University of Pennsylvania for his form of leukemia, called CLL.

The procedure removed a billion of Ludwig's T-cells that normally fight infections and then genetically altered them to attack his cancer cells. The treatment uses a disabled form of HIV1 to carry cancer-fighting genes into the patient's T-cells to genetically alter them. The altered T-cells would reproduce chimeric antigen receptors that would seek out and eradicate cancer cells.

The results were groundbreaking.

A few weeks after administering the treatment there was no trace of any leukemic cells in Ludwig's blood or bone marrow. His CT scan was free of any bulging lymph nodes. His doctors estimate the altered T-cells killed off 2,000 pounds of cancer cells.

Now a year later, Bill Ludwig is on his feet playing golf and doing yard work. Doctors cannot say that he is completely cured but the altered T-cells in his blood are tailored to multiply and could fight off any relapses in the future.

The research team led by Dr. Carl June is optimistic about the results. Two other patients who have undergone the treatment are in remission. And although the treatment is still experimental and not available outside of clinical studies, scientists say this could be a turning point in the fight against cancer.

"The results exceeded our expectations quite a bit. Our entire team is really excited. And as well, the patients are excited," June told MSNBC.com

The new treatment wouldn't just be for leukemia patients, other cancers may also be treated with this new approach.

Other experts in the field hailed the new treatment as a major advance.

"It's great work," said Dr. Walter J. Urba of the Providence Cancer Center and Earle A. Chiles Research Institute in Portland, Ore. "I feel very positive about this new technology. Conceptually, it's very, very big."

But he warned cancer patients that the new treatment still has a ways to go and that it has to be repeated in more patients.

Urba may get his wish as June's team is planning on testing the treatment with other patients with different tumors. His next goal is administering the treatment to patients with hard-to-treat cancers like mesothelioma and pancreatic cancer.