Blood Cell Therapy Used to Successfully Treat Melanoma

By: Madeline Ellis

Published: Saturday, 21 June 2008

Melanoma is the most common and the most deadly form of skin cancer. First appearing as a tiny mole, it grows relentlessly and gradually works its way under the skin, spreading cancer cells throughout the body. In 2008, 62,000 people in the U.S. will be diagnosed with melanoma and almost 8,500 patients will die from it, according to the American Cancer Society. However, a new study gives cause for hope, after researchers used a patient's cloned T cells (helper cells) to put an advanced cancer into complete remission.

Patient "Number Four," a 52-year-old man from Oregon, was one of nine patients who took part in an experimental melanoma treatment program at the Fred Hutchinson Cancer Research Center in Seattle. His Stage 4 melanoma had spread to a groin lymph node and to a lung. A team led by Cassian Yee, M.D., an associate member of the Clinical Research Division at the Center, removed CD4+T cells, a type of white blood cells, from the man and then, over the next three months, grew 5 billion of the cells in the lab. The lab-grown cells were injected back into the patient.

The results were nothing short of amazing. Just two months after treatment, PET and CT scans revealed no sign of tumors anywhere in the patient's body, without harmful side effects. An analysis showed that his immune system had targeted not only one type of protein target on cancer cells, but two others as well. And two years later, when he was last checked, the patient was still disease free.

Patient "Number Four" received a higher dose than the first three patients, who had no response at all, but the same or lower dose than the subsequent five patients, who saw some response, but none as dramatic as that of "Number Four." Dr. Yee said they aren't sure why "he was the lucky one," but that the treatment might have spurred the patient's immune system to expand its cancer-fighting ability in new ways.

"The results of this study are truly dramatic," said Dr. Darrell Rigel, a dermatology researcher at the New York University Cancer Institute and past president of the American Academy of Dermatology. "This is the first time we've ever seen a melanoma melt away like this in someone with advanced disease," he said. Dr. Rigel had no role in the study.

Dr. Yee cautioned that these results represent only one patient with a specific type of immune system whose tumor cells expressed a specific antigen. "For this patient we were successful, but we would need to confirm the effectiveness of therapy in a larger study," he said. He also predicted that, if proven successful in more patients, this therapy could be used for the 25 percent of all late-stage melanoma patients who have the same immune-system type and tumor antigen.

Immunotherapy, which uses a patient's own immune system to fight cancer, is a growing area of research. The method aims to develop less toxic treatments than standard chemotherapy and radiation. "Immunotherapy has become the most promising approach" to late-stage, death-sentence skin cancers, said Dr. Rigel.

The study was published in the June 19 issue of the New England Journal of Medicine.