Ovarian Cancer Treatment: Is a Vaccine Possible?

An innovative vaccine that aims to give women with ovarian cancer a longer period of remission may be in the pipeline, according to researchers at Loyola University Medical Center, who are honing in on the role of the immune system in fighting ovarian cancer.

The Loyola pilot study, which has so far enrolled 4 patients, is based on the scientific exploration of using dendritic cells to create an individualized vaccine that can treat cancer by targeting reemerging cancer cells before they amass and spread.

Since registering the trial with the NIH’s ClinicalTrials.gov database in 2008, the researchers have worked to refine and optimize the vaccine. The goal is to enroll 16 patients with advanced ovarian cancer to prove efficacy before moving forward with a larger-scale trial, said Patrick Stiff, MD, principal investigator of the vaccine trial and director of Loyola’s Cardinal Bernardin Cancer Center.

After traditional surgical treatment for ovarian cancer, the patient’s tumor cells are dissolved in lysate and then joined with some of the patient’s dendritic cells to form the vaccine. The patients are then given up to 9 vaccinations over a period of 3 to 4 months to prompt their own immune system to destroy any reemerging cancer cells.

The approach is similar to what happens with traditional immunization vaccines that are given to prevent a specific illness in that the vaccine is tailored to prompt a person’s immune system to ward off ovarian cancer, Stiff said.

Considering that 70% of women successfully treated for ovarian cancer will experience a cancer recurrence, the hope is to bolster the immune response enough to either prolong the time before relapse or prevent a relapse entirely, explained Stiff.

“As we have optimized it, we are seeing a little more clinical benefit,” Stiff said, but he added that there is a long way to go in this research. In addition, the parameters for who qualifies for the study are rigid; patients whose bodies are too overrun with recurring disease do not qualify, reported Stiff.

“From a patient standpoint, like any new therapy, we’re excited about technology and starting to see improvement, but it is by no means a guarantee,” Stiff said. “We get referrals from all over the country…. This is not for a patient who has failed 15 regimens and is dying. It is not for those in hospice. This is for patients who are going to die but are still in good shape.”

The Loyola study is one of about 20 around the country that is trying to harness the success of Provenge (sipuleucel-T), the FDA-approved vaccine that uses a patient's own immune system to fight prostate cancer, and apply it to ovarian cancer, said Bill Chambers, director of the Clinical Cancer Research and Immunology Program at the American Cancer Society.

“We’ve tried to develop effective immunotherapies for quite a long time,” said Chambers. “Only recently has some of the promise of that approach been fulfilled, and only in a couple of settings.”

Barbara Goff, MD, director of gynecologic oncology at the University of Washington, said research focused on better understanding how to manipulate the immune system in fighting ovarian cancer plays an important role in the overall treatment of the disease. However, she noted that it must be approached in concert with current therapies. “It’s never going to replace surgery and chemotherapy, not in the near future,” Goff said. “It’s something that we use as an adjuvant, particularly in people who have had surgery and chemotherapy.”