Delayed Effect of Dendritic Cells Vaccination on Survival in Glioblastoma: A Systematic Review and Meta-Analysis
ABSTRACT
BACKGROUND: Dendritic cell vaccination (DCV) strategies, thanks to a complex immune response, may flare tumor regression and improve patients‘ long-term survival. This meta-analysis aims to assess the efficacy of DCV for newly diagnosed glioblastoma patients in clinical trials.
METHODS: The study databases, including PubMed, Web of Knowledge, Google Scholar, Scopus, and Cochrane, were searched by two blinded investigators considering eligible studies based on the following keywords: „glioblastoma multiforme“, „dendritic cell“, „vaccination“, „immunotherapy“, „immune system“, „immune response“, „chemotherapy“, „recurrence“, and „temozolomide“. Among the 157 screened, only 15 articles were eligible for the final analysis.
RESULTS: Regimens including DCV showed no effect on 6-month progression-free survival (PFS, HR = 1.385, 95% CI: 0.822-2.335, = 0.673) or on 6-month overall survival (OS, HR = 1.408, 95% CI: 0.882-2.248, = 0.754). In contrast, DCV led to significantly longer 1-year OS (HR = 1.936, 95% CI: 1.396-2.85, = 0.001) and longer 2-year OS (HR = 3.670, 95% CI: 2.291-5.879, = 0.001) versus control groups. Hence, introducing DCV could lead to increased 1 and 2-year survival of patients by 1.9 and 3.6 times, respectively.
CONCLUSION: Antitumor regimens including DCV can effectively improve mid-term survival in patients suffering glioblastoma multiforme (GBM), but its impact emerges only after one year from vaccination. These data indicate the need for more time to achieve an anti-GBM immune response and suggest additional therapeutics, such as checkpoint inhibitors, to empower an earlier DCV action in patients affected by a very poor prognosis.