Researchers at the Dartmouth-Hitchcock Medical Center have developed a vaccine made from dendritic cells — which, as part of the body’s immune system, target hostile antigens — that induces an immune system response against metastatic tumors.
Led by chief of general surgery Richard Barth Jr., the researchers grew dendritic cells from a sample of a patient’s blood, mixed them with proteins from the patient’s tumor and injected the mixture into the patient as a vaccine.
The result? The vaccine stimulated an anti-tumor response from T-cells, white blood cells that protect the body from disease.
For the study, Barth operated on 26 patients to remove tumors that had spread from their colon to their liver. The surgery alone would no doubt help the patients avoid further tumors, but most of them would eventually die from tiny metastases that were undetectable at the time of surgery.
Administered one month after surgery, the new vaccine induced T-cell immune responses against the patient’s own tumor in more than 60 percent of the patients.
Five years after treatment with the new vaccine, 63 percent of the patients who demonstrated an immune response against their own tumor were alive and tumor-free.
On the other hand, 18 percent of the patients who did not develop that immune response were alive and tumor-free.
“There were two basic questions we wanted to answer: one, can we generate an antitumor response, and two, does it matter?” Barth asked in a statement. “From our research, the answer to both questions is yes.”
Previous studies showed that dendritic cell vaccines could not reduce or eliminate measurable metastatic tumor deposits. What the researchers discovered is that though the small number of T-cells that are generated by a vaccine can’t destroy a large tumor, they can wipe out microscopic deposits of tumor cells.
The researchers plan to conduct further studies to more fully understand how the new vaccine works and its impact on longevity. But it’s a major step toward radiation-free cancer treatment.
Their work was published this week in the journal Clinical Cancer Research.