Vaccine Shows Progress for Breast and Kidney Cancer

In an early-stage clinical trial, two women with metastatic breast cancer experienced significant tumor regression after being treated with an experimental cancer vaccine. Another woman with metastatic breast cancer and five kidney cancer patients had their disease stabilize following vaccination.

The so-called “fusion cell vaccine” is prepared by fusing whole tumor cells taken from the patient, with dendritic cells (DCs), Boston-based researchers led by Dr. David Avigan from Beth Israel Deaconess Medical Center report in Clinical Cancer Research. With most DC-based vaccines, DCs are combined with a specific tumor protein, or antigen, that elicits an immune response, an approach that has been met with “some success in early trials,” Avigan said in a telephone interview with Reuters Health. The problem, he added, is that “we don’t know all of the tumor-specific proteins and in some tumors we have very few of them. The other concern is that tumors may outsmart this kind of approach.” With the whole cell approach, “you get the immune stimulating machinery of the DC along with multiple antigens from the tumor, including ones that we might not know about or ones that are specific to that patient. That might create a broader response.” In animal experiments, fusion cell vaccination induced an immune response and led to tumor regression or eradication in some instances. In the clinical trial, tumor cells and DCs from patients with metastatic breast cancer or kidney cancer were exposed to growth factors and then fused together. A total of 23 patients were vaccinated with fusion cells at three-week intervals and tumor response was judged at one, three, and six months after the last vaccination. The vaccine was well tolerated and “importantly,” Avigan observed, “there was no clinical evidence of autoimmunity,” which is of potential concern when using whole cell vaccine approaches. About half of the patients achieved an immune response against their tumor. In two breast cancer patients, tumors shrank significantly. One of them responded with “near complete regression of an 8 x 6-cm chest wall mass.” Moreover, five patients with kidney cancer and one with breast cancer had stabilization of their disease. Based on these encouraging preliminary results, Avigan concluded, “larger studies are planned to determine who really would benefit most from fusion cell vaccination and what the real efficacy might be.” (Source: Clinical Cancer Research: Reuters Health News: July 2004.)