A clinical trial of an innovative vaccine is occurring. The vaccine could offer hope to patients with advanced ovarian cancer. The vaccine, which is derived from the patient’s tumor cells, is designed to jumpstart the patient’s immune system to attack and kill cancer cells.
Ovarian cancer is the fifth leading cause of cancer-related deaths in American women, causing more than 15,000 deaths per year. In about two-thirds of patients, the cancer has spread beyond the ovaries to other parts of the body by the time it is diagnosed. Current treatment is to surgically remove as much of the tumor as possible, followed by chemotherapy. But despite improvements in surgical techniques and chemotherapy, most patients with advanced ovarian cancer relapse at some point. The five-year survival rate for patients with advanced ovarian cancer is less than 30%. There is no cure for patients with relapsed or metastatic ovarian cancer who have failed first-line treatment.
The vaccine trial, conducted by Loyola University Medical Center in Maywood, Illinois, is enrolling patients with advanced ovarian cancer. Following surgery, tumor cells are dissolved in a solution called lysate, which contains fragments of the cancer cells. The lysate is joined with some of the patient’s immune system cells to create the vaccine. (The immune system cells used in the vaccine, called dendritic cells, are taken from the patient’s bloodstream.)
A dendritic cell is a type of white blood cell, sometimes called a “presenting cell.” A dendritic cell primes the immune system by presenting fragments of a tumor cell to the immune system’s killer cells. In effect, the dendritic cells “educate” killer cells to attack and kill cancer cells.
A patient receives as many as nine vaccine shots, spaced two weeks apart. The vaccine is injected into lymph nodes in the pelvis.
Ovarian cancer appears more likely to respond to such immune system therapy than other solid-tumor cancers such as breast, lung, and kidney cancers, stated principal investigator Patrick Stiff, MD, who is also director of Loyola’s Cardinal Bernardin Cancer Center.
One patient in the trial had relapsed twice from ovarian cancer before receiving the experimental vaccine. After her first round of chemotherapy, she was in remission for three-and-a-half years. But after a second round of chemotherapy, her remission lasted only three months.
Shorter and shorter remissions are typical in ovarian cancer. But after the patient received the ovarian vaccine, the cycle was reversed – the cancer was in retreat a full 10 months. Moreover, the vaccine did not have the toxic side effects of chemotherapy. She felt a bit nauseous after a few of the injections. “But compared to chemotherapy, the vaccine was a walk in the park,” she said.
Stiff stated, “To see such a significant remission is unusual for any type of therapy for ovarian cancer, especially with a therapy that is nontoxic.”