Personalized Mesothelioma Vaccine Tested in Humans

Dendritic cell-based immunotherapy safely induces T-cell response against tumor cells

TUESDAY, March 9 (HealthDay News) -- A personalized vaccine for mesothelioma derived from the patients own dendritic cells (DCs), and antigens from their own tumor, safely and effectively induces a T-cell response against tumor cells, according to a study published online Feb. 18 in the American Journal of Respiratory and Critical Care Medicine.

Joost P. Hegmans, Ph.D., of the Erasmus Medical Center in Rotterdam, Netherlands, and colleagues recruited 10 patients who were recently diagnosed with malignant pleural mesothelioma of the epithelial subtype. The researchers cultured immature DCs from each patient's blood and exposed the DCs to antigens from their tumors. When the DCs matured, they were used to create a personalized vaccine composed of DCs pulsed with autologous tumor lysate and including a keyhole limpet hemocyanin (KLH) as surrogate marker for an immune response. The vaccines were injected into the patients in three doses over a two-week period, as well as tested on tumor cells in vitro.

The researchers found that subsequent serum samples from the patients exhibited a significant increase of antibodies to KLH. In the four patients for whom there were enough tumor cells to test, the vaccine induced apparent cytotoxicity against the tumor cells in vitro. Furthermore, in three vaccinated patients, there were signs of tumor regression, though this could not be conclusively attributed to the vaccine. There were no signs of autoimmune disease, and moderate fever was the only side effect observed.

"This study demonstrated that autologous tumor lysate-pulsed DC-based therapy is feasible, well-tolerated, and capable of inducing immunological response to tumor cells in mesothelioma patients," the authors write.

The study was funded by the Stichting Asbestkanker Rotterdam, Stichting Coolsingel, Nico Heijmer Foundation, and the Mesothelioma Applied Research Foundation.

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