Should dendritic cell-based tumor vaccination be incorporated into standard therapy for newly diagnosed glioblastoma patients?

Methods behind oncolytic virus-based DC vaccines in cancer: Toward a multiphase combined treatment strategy for Glioblastoma (GBM) patients

Glioblastoma (GBM) remains an orphan cancer disease with poor outcome. Novel treatment strategies are needed. Immunotherapy has several modes of action. The addition of active specific immunotherapy with dendritic cell vaccines resulted in improved overall survival of patients. Integration of DC vaccination within the first-line combined treatment became a challenge, and immunogenic cell death immunotherapy during chemotherapy was introduced. We used a retrospective analysis using real world data to evaluate the complex combined treatment, which included individualized multimodal immunotherapy during and after standard of care, and which required adaptations during treatment, and found a further improvement of overall survival. We also discuss the use of real world data as evidence. Novel strategies to move the field of individualized multimodal immunotherapy forward for GBM patients are reviewed.

Proof of Concept Study: Mesoporous Silica Nanoparticles, From Synthesis to Active Specific Immunotherapy

Nanomaterials are increasingly valued tools in drug delivery research as they offer enhanced stability, controlled release and more effective drug encapsulation. Though yet to be introduced in clinical trial, mesoporous silica nanoparticles are promising delivery systems, due to their high chemical and mechanical stability while remaining biodegradable. This work provides proof of concept for particle based vaccines as cost-effective alternatives for dendritic cell immunotherapy. Synthesis and surface chemistry of the nanoparticles are optimized for protein conjugation and nanoparticles are characterized for their physicochemical properties and biodegradation. Ovalbumin is used as a model protein to load nanoparticles to produce a nanovaccine. The vaccine is tested in vitro on dendritic cultures to verify particle and vaccine uptake, toxicity, maturation effects and explicitly ovalbumin cross-presentation on MHC class I molecules. The optimized synthesis protocol renders reproducible mesoporous silica nanoparticles, resistant against agglomeration, within the required size range and have carboxylic surface functionalization necessary for protein conjugation. They are biodegradable over a time span of 1 week. This period is adjustable by changing synthesis parameters. UV sterilization of the particles does not induce quality loss, nor does it have toxic effects on cells. Treatment with mesoporous silica nanoparticles increases expression of MHC and costimulatory molecules of dendritic cells, indicating an adjuvant effect of nanoparticles on the adaptive immune system. Nanovaccine uptake and cross-presentation of ovalbumin are observed and the latter is increased when delivered by nanoparticles as compared to control conditions. This confirms the large potential of mesoporous silica nanoparticle based vaccines to replace dendritic-based active specific immunotherapy, offering a more standardized production process and higher efficacy.

Brain Tumor Immunotherapy: What have We Learned so Far?

High grade glioma is a rare brain cancer, incurable in spite of modern neurosurgery, radiotherapy, and chemotherapy. Novel approaches are in research, and immunotherapy emerges as a promising strategy. Clinical experiences with active specific immunotherapy demonstrate feasibility, safety and most importantly, but incompletely understood, prolonged long-term survival in a fraction of the patients. In relapsed patients, we developed an immunotherapy schedule and we categorized patients into clinically defined risk profiles. We learned how to combine immunotherapy with standard multimodal treatment strategies for newly diagnosed glioblastoma multiforme patients. The developmental program allows further improvements related to newest scientific insights. Finally, we developed a mode of care within academic centers to organize cell-based therapies for experimental clinical trials in a large number of patients.

Dendritic cell-based vaccine for the treatment of malignant glioma: a systematic review

OBJECTIVE

Glioblastoma multiforme (GBM) has a poor prognosis. The purpose of this systematic review and meta-analysis was to analyze the outcomes of clinical trials which compared immunotherapy with conventional therapy for the treatment of malignant gliomas.

METHODS

PubMed, Cochrane and Google Scholar databases were searched for relevant studies. The 2-year survival rate was used to evaluate effectiveness of immunotherapy.

RESULTS

Of 171 studies identified, six comparative trials were included in the systematic review. Immunotherapy was associated with a significantly longer OS and 2-year survival compared to conventional therapy.

CONCLUSION

Immunotherapy may improve the survival of patients with GBM.

Clinical efficacy of tumor antigen-pulsed DC treatment for high-grade glioma patients: evidence from a meta-analysis

BACKGROUND

The effectiveness of immunotherapy for high-grade glioma (HGG) patients remains controversial. To evaluate the therapeutic efficacy of dendritic cells (DCs) alone in the treatment of HGG, we performed a systematic review and meta-analysis in terms of patient survival with relevant published clinical studies.

MATERIALS AND METHODS

A total of 409 patients, including historical cohorts, nonrandomized and randomized controls with HGG, were selected for the meta-analysis.

RESULTS

The treatment of HGG with DCs was associated with a significantly improved one-year survival (OS) (p<0.001) and 1.5-, 2-, 3-, 4-, and 5-year OS (p<0.001) compared with the non-DC group. A meta-analysis of the patient outcome data revealed that DC immunotherapy has a significant influence on progression-free survival (PFS) in HGG patients, who showed significantly improved 1-,1.5-, 2-, 3- and 4-year PFS (p<0.001). The analysis of Karnofsky performance status (KPS) demonstrated no favorable results for DC cell therapy arm (p = 0.23).The percentages of CD3+CD8+ and CD3+CD4+ T cells and CD16+ lymphocyte subset were not significantly increased in the DC group compared with the baseline levels observed before treatment (p>0.05), whereas CD56+ lymphocyte subset were significantly increased after DC treatment (p = 0.0001). Furthermore, the levels of IFN-γ in the peripheral blood of HGG patients, which reflect the immune function of the patients, were significantly increased after DC immunotherapy (p<0.001).

CONCLUSIONS

Thus, our meta-analysis showed that DC immunotherapy markedly prolongs survival rates and progression-free time, enhances immune function, and improves the efficacy of the treatment of HGG patients.

Formulations for Intranasal Delivery of Pharmacological Agents to Combat Brain Disease: A New Opportunity to Tackle GBM?

Despite recent advances in tumor imaging and chemoradiotherapy, the median overall survival of patients diagnosed with glioblastoma multiforme does not exceed 15 months. Infiltration of glioma cells into the brain parenchyma, and the blood-brain barrier are important hurdles to further increase the efficacy of classic therapeutic tools. Local administration methods of therapeutic agents, such as convection enhanced delivery and intracerebral injections, are often associated with adverse events. The intranasal pathway has been proposed as a non-invasive alternative route to deliver therapeutics to the brain. This route will bypass the blood-brain barrier and limit systemic side effects. Upon presentation at the nasal cavity, pharmacological agents reach the brain via the olfactory and trigeminal nerves. Recently, formulations have been developed to further enhance this nose-to-brain transport, mainly with the use of nanoparticles. In this review, the focus will be on formulations of pharmacological agents, which increase the nasal permeation of hydrophilic agents to the brain, improve delivery at a constant and slow release rate, protect therapeutics from degradation along the pathway, increase mucoadhesion, and facilitate overall nasal transport. A mounting body of evidence is accumulating that the underexplored intranasal delivery route might represent a major breakthrough to combat glioblastoma.