12/10/2012 04:03 pm ET

T Cell Therapy Recipients In Remission Years Later, Giving Leukemia Patients Cause For Hope

When 7-year-old Emma Whitehead's leukemia returned a second time, her prospects were not good.

She had been battling the disease for more than a year and had endured several rounds of intense chemotherapy. Though the survival rate for children with acute lymphoblastic leukemia -- the most common type of childhood cancer -- is now over 90 percent, Emma was part of the small percentage of patients whose cancer does not respond to chemo.

When the cancer recurred, Emma's parents turned to an experimental treatment still in clinical trials: using Emma's own genetically engineered blood cells to treat her cancer.

"We needed to try something new, different and cutting-edge," her mother, Kari, said in a press release. Three weeks later, Emma was in complete remission.

New data from that trial, presented at the annual American Society of Hematology meeting on Sunday and Monday, suggests that genetically engineered T cells -- a type of white blood cell -- can effectively treat cases of advanced leukemia, a cancer of the bone marrow and blood. Nine out of the first 12 patients to receive infusions responded to the new treatment, including two children, one of whom is Emma. Two of the first three patients to receive the treatment are in full remission two years out.

"We're treating people who have no curative options," said Dr. Stephen Grupp, the oncologist who treated Emma at The Children's Hospital of Philadelphia. "Chemo isn't working; there isn't another experimental therapy; they're not eligible for bone marrow transplant. They have no options at all."

The treatment, which was developed by scientists at the Perelman School of Medicine at the University of Pennsylvania and has been used to treat patients at both the Children's Hospital of Philadelphia and the Hospital of the University of Pennsylvania, requires researchers to isolate patients' T cells, which help the body fight infection. They then genetically engineer the cells in a lab to attack B lymphocytes, a type of cell that becomes cancerous in many leukemias.

"In a very simplistic way, we collect cells from the blood, specifically T cells," Grupp told HuffPost. "We genetically engineer them to go after cancer cells and kill them, and we put them back into the patient."

Within roughly one week of infusion, all of the patients who responded to the treatment experienced side effects, Grupp said. The most mild symptoms were high fever and muscle ache, which typically lasted for up to 10 days. But several patients, including Emma, got much sicker. She had to be admitted to the pediatric intensive care unit. The same mechanisms that were destroying cancer cells also spurred a significant inflammatory response. As a result of the T cells growing in her body, she also developed elevated levels of a certain protein, which was making her ill. Grupp and his colleagues gave her a drug that is typically prescribed to rheumatoid arthritis patients in order to block inflammatory responses, and Emma got "dramatically better" in just a matter of hours. It has now been eight months since her treatment, and she has no cancer, Grupp said.

But researchers caution that their results, while promising, are still preliminary.

"The results are dramatic, but it is very early," said Michael Kalos, director of the translational and correlative studies lab at Penn. "We are actively looking to treat more patients and see how it works."

Thus far, 10 adult patients and two children have been treated in the Penn T cell therapy trial, and nine have responded to the treatment (it is too soon to tell whether one patient has had any response). Though the two children in the trial both experienced what researchers call a "complete response" -- meaning there were no traces of their cancer -- the second child relapsed one month after the initial treatment.

"Why do we have some complete responses, why do we have some patients with partial responses, and why do we have a small number [of patients] who don't respond?" Kalos asked. Those answers are not yet clear. It could have to do with the genetically engineered cells themselves; it could be that the patient's tumors are interacting with the therapy in particular ways; it could stem from some aspect of the patient's immune system or biology -- or it could be a combination of all those things, Kalos said.

But pharmaceutical companies are interested. In August, Novartis announced an exclusive research and licensing agreement with the University of Pennsylvania to develop and "commercialize" the targeted immunotherapies. The hope, Grupp told HuffPost, is that the treatment might some day replace bone marrow transplantation for patients with B cell leukemia -- a physically, financially and emotionally draining treatment.

"Our hope is that these results will lead to widely available treatments for high-risk B cell leukemia and lymphoma," he said in a statement.

The researchers are also interested in exploring T cell therapy for other types of cancers, Kalos said, citing lung, pancreatic and prostate cancers as three possible targets. (It cost the researchers about $20,000 per patient to engineer the T cells, but experts caution that the price tag does not translate into real-world pharmaceutical costs.)

As for the "C" word -- "cure" -- both Grupp and Kalos emphasized that this treatment is still experimental. Typically, researchers won't use the word confidently until a patient has been in remission for at least five years.

"We want to stress that this isn't a substitute for chemo," said Grupp. "We do need more time before we really know how well it is working. We're very excited, but also very cautious."