Experimental Gene Therapy Vaccine Gets Response in Some Prostate Cancer Cases

Maryland researchers who have been working on a gene therapy vaccine against cancer said that they had provoked a surprisingly strong immune response against prostate cancer, producing tumor regression in eight out of 11 patients. They said their “personalized” vaccine, made using cancer cells from each individual patient, activated the entire immune system to fight the cancer--although it did not cure any of their patients.

Writing in today’s Cancer Research, a team from Johns Hopkins University said it took cancer cells from the patients’ own prostate tumors, inserted the gene for a protein called GM-CSF, and grew them in a laboratory dish. GM-CSF activates the immune system to recognize tumors. Then the cells were zapped with X-rays to make sure the cells did not cause more cancer, and injected into the patients’ thighs.

Within four weeks of vaccination, the researchers found immune cells known as B-cells circulating and producing antibodies against prostate cancer cells. Another kind of immune cell, T-cells, were directly attacking the tumors.

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Compiled by Times medical writer Thomas H. Maugh II