Vaccine/antibody therapy effective, milder side effects in melanoma and ovar...(ths after receiving GVAX and every two t...),Health

In contrast to previous, more intensive antibody doses, none of the patients had severe side effects, although they all developed mild, low-level inflammatory conditions (usually a rash that went away in a few days). Moreover, in eight of the participants, tumors throughout the body either receded or became stable. The three other patients experienced less dramatic improvements that became apparent after several months of therapy.

Similarly encouraging results were obtained in nine patients with advanced ovarian cancer, although two of them did develop severe inflammatory problems. Although large die-offs of tumor tissue were less common than in the melanoma group, some of the ovarian cancer patients did experience such results.

To understand what was happening at a basic cellular level, researchers studied tumor samples from six patients following antibody treatment. They found that tumor death was greatest in samples with high ratios of CD8+ T cells -- the foot soldiers of immune system attack -- to FoxP3+ regulatory T cells, which can reduce the immune response.

"Our results suggest that combination therapies of GVAX vaccine and CTLA-4-blocking antibodies could be enhanced by agents that target regulatory T cells such as FoxP3+," remarks Hodi, who is also an assistant professor of medicine at Harvard Medical School. "Future work will focus in that direction."

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