Immune response in patients with newly diagnosed glioblastoma multiforme treated with intranodal autologous tumor lysate-dendritic cell vaccination after radiation chemotherapy

Abstract

Patients with glioblastoma multiforme (GBM) are profoundly immunosuppressed and may benefit from restoration of an antitumor immune response in combination with conventional radiation therapy and temozolomide (TMZ). The optimal strategies to evaluate clinically relevant immune responses to treatment have yet to be determined. The primary objective of our study was to determine immunologic response to cervical intranodal vaccination with autologous tumor lysate-loaded dendritic cells (DCs) in patients with GBM after radiation therapy and TMZ. We used a novel hierarchical clustering analysis of immune parameters measured before and after vaccination. Secondary objectives were to assess treatment feasibility and to correlate immune response with progression-free survival (PFS) and overall survival. Ten eligible patients received vaccination. Tumor-specific cytotoxic T-cell response measured after vaccination was enhanced for the precursor frequency of CD4+ T and CD4+ interferon γ-producing cells. Hierarchical clustering analysis of multiple functional outcomes discerned 2 groups of patients according to their immune response, and additionally showed that patients in the top quintile for at least one immune function parameter had improved survival. There were no serious adverse events related to DC vaccination. All patients were alive at 6 months after diagnosis and the 6-month PFS was 90%. The median PFS was 9.5 months and overall survival was 28 months. In patients with GBM, immune therapy with DC vaccination after radiation and TMZ resulted in tumor-specific immune responses that were associated with prolonged survival. Our data suggest that DC vaccination in combination with radiation and chemotherapy in patients with GBM is feasible, safe, and may induce tumor-specific immune responses.

FIGURE 1

Study design. Four weeks after completing combined RT-TMZ, patients had a prevaccination (V) apheresis, DTH panel placement, and MRI. One week later, the first vaccination (V1) was administered, and 2 additional vaccinations were given 2 weeks apart. Two weeks after the third vaccine patients had a post-V apheresis, DTH panel placement, and MRI, followed by 12 cycles of adjuvant TMZ. DDPA indicates dye dilution proliferation assay; DTH, delayed-type hypersensitivity reaction; ELISPOT, enzyme-linked immunosorbent spot assay; PBMNC, peripheral blood mononuclear cells; POST-V, postvaccination; PRE-V, prevaccination; RT, radiation therapy; TMZ, temozolomide; v, vaccination.

FIGURE 2

Eligibility of the 60 patients diagnosed with glioblastoma multiforme (GBM) during the study period. The reasons for exclusion of 49 patients were in 33 no tissue was available because only a biopsy was performed or patients did not sign informed consent to use the tissue; in 1 the tissue specimen yielded less than 8×10⁷ tumor cells, 5 had a low performance status, 7 declined participation; and 3 although eligible were not included because enrollment was completed. One patient had initial leukapheresis but her performance status deteriorated after a seizure, therefore was not treated. KPS indicates Karnofsky Performance Scale.

FIGURE 3

A, Heatmap of hierarchical clustering analysis of the postvaccination immune responses. Five patients with generally low ranks in immune function (pale yellow colors) formed cluster 1 on the left. Five other patients with higher ranks in immune function measures (dark red colors) formed cluster 2 on the right. B, Kaplan-Meier curves of progression-free survival and overall survival for the 2 clusters. The Kaplan-Meier progression-free survival curves for cluster 1 (median = 9 mo) and cluster 2 (median = 41 mo) are not statistically different based on a log-rank test (P = 0.09). The overall survival was significantly different between cluster 1 (median = 17 mo) and cluster 2 (median = not achieved) (P = 0.002). ELISPOT indicates enzyme-linked immunosorbent spot assay; IFN, interferon; PF, precursor frequency.