Anticancer immunotherapies seem like a better bet, although results are mixed. Despite immune checkpoint inhibitors’ sometimes dramatic success against some other tumor types, they have “so far had a limited success rate” among patients with glioblastoma, according to Mr Schaller.

Investigational cancer vaccines, however, show more promise. One approach that made recent headlines was a combination of high-dose temozolomide chemoradiation therapy with vaccination against a cytomegalovirus protein frequently expressed in glioblastoma tumors.2


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“Shown to be effective in preclinical animal experiments, these approaches are being tested in clinical trials with glioblastoma patients,” Mr Schaller said. “A potential benefit is the ability to personalize the peptide vaccine to the patient’s own tumor based on sequencing of tumor sample obtained during biopsy.”

Dendritic cells, furthermore, initiate adaptive immune responses. Early clinical trials suggest that dendritic cell cancer vaccines might prolong survival among glioblastoma patients. 3 But for dendritic vaccines to stimulate effective and durable immune cell attacks on tumors, some hurdles must be overcome. 4

“There are many technical opportunities to try to fine-tune and optimize dendritic cell vaccines, including those associated with antigen loading, optimal antigen selection (quantity and quality), dosing schedule, route of administration, choice of adjuvant, and timing relative to other therapies like radiation and chemotherapy,” Dr Reardon told Cancer Therapy Advisor. “But I feel the major issue has to do with combining effective vaccine strategies with approaches to overcome immunosuppressive factors exploited by tumors that can extinguish effective anti-tumor immune responses elicited by vaccines.”

But it is not yet clear how best to do that.

“The bottom line is that we do not know and further research is critically needed,” Dr Reardon said. 

References

  1. Reardon DA, Mitchell DA. The development of dendritic cell vaccine-based immunotherapies for glioblastoma. Semin Immunopathol. 2017;39:225-39. doi: 10.1007/s00281-016-0616-7
  2. Batich KA, Reap EA, Archer GE, et al. Long-term survival in glioblastoma with cytomegalovirus pp65-targeted vaccination. Clin Cancer Res. 2017;23(8):1898-1909.
  3. Schaller TH, Sampson JH. Advances and challenges: vaccination strategies for glioblastoma. Expert Rev Vaccines. 2017;16(1):27-36.
  4. Filley AC, Dey M. Dendritic cell based vaccination strategy: an evolving paradigm. J Neurooncol. 2017 Apr 22. doi: 10.1007/s11060-017-2446-4 [Epub ahead of print]