Revolutionary Cancer Therapy Shows Promise in Terminally Ill Patients
A groundbreaking new therapy in which white blood cells were reprogrammed to attack
For the new therapy, white blood cells were extracted from terminally ill cancer patients, and then genetically reprogrammed to better recognize and target cancer cells. Once reintroduced into a patient's bloodstream, the juiced-up immune cells made it much more difficult for the cancer to spread and take hold. Oncologist Stanley Riddell from Seattle's
Fred Hutchinson Cancer Research Center
shared his team's findings on Monday at the annual meeting of American Association for the Advancement of
In one trial, 94 percent of terminally ill
patients went into remission. Patients with similar blood cancers experienced response rates greater than 80 percent, with more than half going into remission.
The details have yet to be published in a peer reviewed science journal, so we need to be cautious about these findings. Indeed, the researchers themselves said that the results are very preliminary and that more work needs to be done. It's not known, for example, how long the patients will remain in remission; the scientists aren't calling it a cure, even though symptoms disappeared in many cases. What's more, two patients actually died from the therapy after it triggered an extreme immune response. All participants involved in the study were terminally ill cancer patients with about two to five months to live, and none were responding to conventional treatments. But Riddell described the early data as "unprecedented," saying it's a "potential paradigm shift" in cancer treatment.
For the therapy, T cells, also known as T lymphocytes, were taken from the blood of cancer patients and then genetically altered to contain "receptor" molecules that target cancer. The technique only works for refractory B-cell malignancies-so-called "liquid" blood cancers-such as acute lymphoblastic leukemia, chronic lymphocytic leukemia, and non-Hodgkin's lymphoma.
T cells are a type of white blood cell that detects foreign or abnormal cells, including tumors, and kickstarts an immune response that targets the invading cells for attack. In some cases, however, these attacks aren't strong enough to destroy cancer cells, and the immune cells become exhausted. That, or the tumors themselves deploy resistance measures that constrain immune response. In the new therapy, a subset of T cells were armed with chimeric antigen receptors, or CARs, using gene transfer, making them better at targeting cancer cells. The enhanced immune cells produced "a potent and long-lasting response" to the cancer.
"The merging of gene therapy, synthetic
Looking ahead, the researchers want to locate target molecules that are typically expressed by human cancers and then design even more powerful receptors.