Study: Vaccine for Breast, Ovarian Cancer Has Potential

Nov. 8, 2011 -- A vaccine for breast and ovarian cancer that has spread to other parts of the body shows promise, according to a preliminary study of 26 patients.

One woman who got the investigational vaccine now has no X-ray evidence of cancer, says study researcher James Gulley, MD, PhD. "In January, it will be four years [for her]," he tells WebMD.

As exciting as that is, he says, "a lot of work needs to be done to prove whether this can be effective [for more patients]." Gulley is director and deputy chief of the clinical trials group at the Laboratory of Tumor Immunology and Biology, National Cancer Institute.

Results of the vaccine were not as good in the other 25 patients. For them, the median time before the cancer progressed was about two months.

"That time frame is not anything to write home about," Gulley says.

Overall, however, the limited success in some patients and the complete success in one is good news, he says. "It gives us encouragement that we may be on to something here."

The study, funded by the National Cancer Institute, is published in Clinical Cancer Research.

Testing the Vaccine

Gulley's team enrolled 12 patients with breast cancer and 14 with ovarian cancer. They ranged in age from 32 to 75.

The patients had already undergone a variety of treatments but the cancer was progressing. Twenty one of the 26 had undergone three or more chemotherapy regimens. The patients received injections of the investigational PANVAC vaccine, given monthly until the disease worsened.

The vaccine targets two proteins, mucin-1 (MUC-1) and carcinoembryonic antigen (CEA), Gulley says. Both are over-expressed in many cancer cells.

"The vaccine is designed to have your body's immune system recognize and attack tumor cells making CEA and MUC-1," Gulley says.

The patient with no evidence of cancer had breast cancer and was the youngest in the study, at 32. "The cancer had gone to her liver, and to her lymph nodes in her chest," Gulley says. After the vaccine, the cancer began to shrink. "At 18 months, it was completely gone and remained gone. As far as we can tell, there is no radiographic evidence of disease."

Among the breast cancer patients, overall, however, the median time (half more, half less) before the cancer progressed was 2.5 months. The median overall survival was 13.7 months. Four had stable disease, defined as the cancer neither growing nor shrinking.

Among the ovarian cancer patients, the median time to progression was two months and the median overall survival was 15 months. Three had stable disease.

The follow-up was up to 37 months.

Side effects were mild, Gulley says. Most common was a reaction at the injection site, which was temporary. Two patients had musculoskeletal pain. One had anemia. Some got fevers, he says, which were relieved with fever reducers.