Researchers from the Duke Cancer Institute (NC, USA) report encouraging results for a phase I trial of a dendritic vaccine in 11 patients with glioblastoma. The findings were published recently in Clinical Cancer Research.
Previous research has demonstrated that cytomegalovirus proteins are expressed in more than 90% of sampled glioblastomas, these proteins are restricted to glioma cells and not the surrounding brain tissue.
In this pahse I trial, Duke Cancer Institute researchers targeted the cytomegalovirus antigen pp65 by utilizing dendritic cells in combination with dose-intensified temozolomide. The team then evaluated patient antitumor immune responses and survival rates in the 11 patients with glioblastoma.
The team demonstrated that patients with pp65-dendritic cells exhibited increased pp65 immunity and long-term survival extending beyond the predicted rates. The researchers also highlighted that there were no treatment limiting adverse events and no adverse events related to the cellular portion of the vaccine.
Lead author Kristen Batich (Duke Cancer Institute) commented: “This is a small study but it’s one in a sequence of clinical trials we have conducted to explore the use of an immunotherapy that specifically targets a protein on glioblastoma tumors. While not a controlled efficacy study, the survival results were surprising, and they suggest the possibility that combining the vaccine with a more intense regimen of this chemotherapy promotes a strong cooperative benefit.”
The team further demonstrated that their approach significantly slowed the progression of patients’ tumors. Usually, glioblastoma tumors start to regrow after standard treatment at a median of 8 months but for study participants, recurrence occurred at a median of 25 months.
Senior author John Sampson (Duke Cancer Institute): “These are surprisingly promising clinical outcomes. However, it is important to emphasize that this was a very small study that used historical comparisons rather than randomizing patients to two different treatments, but the findings certainly support further study of this approach in larger, controlled clinical trials.”