Experimental Vaccine Shows Promise for Ovarian Cancer
SATURDAY, April 6 -- A novel but preliminary new treatment for ovarian cancer has apparently produced complete remission for one patient with an advanced form of the disease, researchers are reporting.
The promising results of a phase 1 clinical trial for the immunotherapy approach also showed that seven other women had no measurable disease at the end of the trial, the researchers added.
Their results are scheduled to be presented Saturday at the American Association for Cancer Research's annual meeting in Washington, D.C.
Ovarian cancer is fairly rare -- an estimated 1.38 percent of females born today will be diagnosed with the condition -- but it's an especially deadly form of cancer because it is usually diagnosed in an advanced stage.
The new treatment uses a personalized vaccine to try to teach the body's immune system how to fight off tumors.
Researchers took bits of tumor and blood from women with stage 3 or 4 ovarian cancer and created individualized vaccines, said study lead author Lana Kandalaft, director of clinical development and operations at the Ovarian Cancer Research Center in the University of Pennsylvania's Perelman School of Medicine.
"Each patient's tumor is unique like a fingerprint," she added. "We're trying to rewire the immune system to target the tumor."
Once the immune system has learned how to more effectively fight the cancer, the researchers isolate immune cells called dendritic cells, coax them to multiply, then put them back into the body to strengthen it.
The research is only in the first of three stages that are required before drugs can be sold in the United States. The first-phase studies aren't designed to determine if the drugs actually work, but are instead supposed to analyze whether they're safe.
This study, funded in part by the U.S. National Institutes of Health, found signs of improvement in 19 out of 31 patients. All 19 developed an anti-tumor immune response. Of those, eight had no measurable disease and are on maintenance vaccine therapy. And one of the eight, whose cancer recurred several times, has been in remission for 45 months, the study authors said.
The researchers added a further step for 11 patients who responded to the vaccine treatment but still had residual disease. They removed immune cells called T cells from patients' blood, stimulated and expanded the cells in the laboratory, and then reinjected them into the patients. Of the 11 patients, seven had stable disease and one had a complete response, the investigators found.
Both treatments were given in conjunction with bevacizumab, a drug that controls blood vessel growth.
Side effects were mild, Kandalaft said. As for cost, she believes that it will be cheaper than some existing cancer drugs that cost $75,000 to $100,000 for a regimen.
The next step is to continue research into the treatment, she added.
A second study being presented at the meeting focused on an experimental drug to treat women whose ovarian cancer has developed resistance to platinum-based chemotherapy. The cancer inevitably gets worse in patients when chemotherapy no longer works.
The drug, being developed by the Genentech pharmaceutical company, is designed to deliver a kind of poison to cancer cells without being too toxic to the patient.
Researchers led by Dr. Joyce Liu, of the Dana-Farber Cancer Institute and Harvard Medical School in Boston, found that five patients out of 44 responded at least partially to the treatment. However, many who took the treatment suffered from several types of side effects.
A researcher who was not involved in the studies said the treatments all appear promising, although preliminary, and show how medicine is moving toward alternatives to chemotherapy.
"This is where we have to start. This is the future," said Dr. Linda Duska, a gynecologist at the University of Virginia.
For more about ovarian cancer, visit the U.S. National Library of Medicine.
Posted: April 2013