Evaluate the Efficacy and Safety of ADCV01 as an Add-On Treatment for Primary Glioblastoma Multiforme (GBM) Patients

The patients with primary glioblastoma multiforme (GBM) have high mortality and morbidity. Even with best conventional therapy (surgery, radiation, and chemotherapy), the most of median survivals are less than 2 years. The one-year progression-free survival (PFS) is less than 20%. Recently, the immune therapy is a new promising therapy for GBM from the evidences of published experimental data and clinical trials.

However, the outcomes of immune therapy are still equivocal. The critical point of immune therapy is strongly influenced by tumor microenvironment. Up to now, for example, immune checkpoint inhibitor such as programmed cell death protein ligand 1 (PD-L1) and programmed cell death protein 1 (PD-1) was found to induce exhaustion of CD8 T cell by of PD-1/PD-L1 reaction. Unfortunately, GBM cells always have high PD-L1 expression. It means the higher PD-1 level of T-cell indicates the higher immune suppression by GBM tumor cells.

In the investigators preclinical study, the best murine survival was found to be the combination outcome of dendritic cell (DC) with anti-PD-1 therapy which was better than that of DC therapy only. From previously ADCV-treated patients, the median of PD-1/CD8 was 0.21. When the PD-1/CD8 ratio less than 0.21, this patient is defined as with low PD-1 level.

From the investigators previous experience, patients with low PD-1/CD8 ratio had far better 2-year overall survival (OS) than patients with high PD-1/CD8 ratio in ADCV treatment. On the other hand, it showed that OS and PFS had significant reverse correlation with PD-1 level of Tcell during DC immunotherapy. Considering the needs and benefit of patients, the new autologous dendritic cell vaccine (ADCV01) is proposed to be added on conventional therapy in low PD-1 expressed GBM patients and evaluate its safety and efficacy.

In this study, only newly diagnosed primary GBM (wild-type Isocitrate Dehydrogenase 1, IDH-1) patients will be enrolled in this clinical trial. In addition to fulfilling all inclusion criteria without matching any of the exclusion criteria, patients will undergo tumor resection and less than 25% of residual tumor size, followed by being subjected to histological analysis. Examinations of molecular diagnostics including IDH-1 for confirmation of IDH-1 wild-type GBM according to the 2016 WHO Classification of Tumors of the Central Nervous System, and cut-off criteria for expression levels of PD-1 and CD8 (PD-1/CD8 ratio less than 0.21) will be screened for the eligibility to participate in this study and MGMT status will also be determined.

After tumor resection, all eligible patients will receive standard radiotherapy (RT) plus Temozolomide (Temodal, TMZ), followed by adjuvant treatment of TMZ. Patients assigned to the investigational group will receive ADCV01 administration as an add-on treatment after operation in this study.

This study aims to treat eligible patients with ADCV01 as an add-on immunotherapy along with post-surgery GBM treatment and compare the treatment to the conventional therapy (RT plus standard TMZ chemotherapy) alone on the basis of PFS in an unbalanced allocation (investigational group : control group = 2:1). After tumor resection, patients assigned to the control group will receive RT plus TMZ, followed by the scheduled evaluation visits. For patients assigned to the investigational drug group, a standard of 10 doses of ADCV01 (2±0.5 × 10^7 cell/dose) in addition to conventional therapy will be administered.

The assessment of tumor response is based on [Update Response Assessment Criteria for High-Grade Gliomas, Response Assessment in Neuro-Oncology (RANO)] assessed by the on-site investigator and Blinded Independent Central Review (BICR) independently. If needed, the repeat operation for decompressive craniotomy evaluated by the on-site neurosurgeon for relief of increased intracerebral pressure (IICP), or for lifesaving will be allowed in both groups. However, in this study, the reoperation for recurrent tumor will be allowed.

RT will be given if feasible considering the total RT accumulatively given is not enough when tumor recurs (total dose 60 Gy). Gamma knife will not be used for recurrent tumor in this study which is different application from previous research.

Regardless of receiving re-operation or not in both groups, TMZ treatment will be shifted to anti-angiogenic therapy (AVASTIN®) 10 mg/kg/2weeks for 6 doses after patients have recurrence of GBM. Pseudo-progression may lead to either premature termination of therapy or unnecessary debulking surgeries. Therefore, adjuvant TMZ is recommended to be continued for a minimum of 3 cycles (along with ADCV01 treatment in the first 3 months of the adjuvant TMZ period), after which other imaging techniques (e.g., Gdenhancing MRI and proton magnetic resonance spectroscopy) should be used to ascertain progression. TMZ is not continuously used whenever recurrence. On this end, the treatment course is complete.

If the recurrent GBM in patients assigned to the investigational group is occurred before completing 10 doses of ADCV01 treatments, the patient will be treated by the remaining ADCV01 and complete the originally scheduled treatment.

In this phase II study, 24 eligible primary GBM patients who are with low PD-1/CD8 ratio will be recruited. There will be 16 patients with combination of ADCV01 and conventional therapy, and 8 patients with conventional therapy only. In this trial, the treatment efficacy of ADCV01 measured by one-year PFS rate will be evaluated at the end of phase II study. Because PFS was surrogate endpoint of overall survival in GBM by literature-based meta-analysis from 91 clinical trials, the 1-year PFS rate will be the primary endpoint of GBM clinical trial.

This study is designed with open-label and randomized parallel group. To date, 34 clinical trials of DC for GBM published up to 2017 in ClinicalTrials.gov, there are 5/34 trials designed by double blinded method and 2/34 trials by single blinded and most of 27/34 trials by open-label (please see ref. ClinicalTrials.gov). The other reason for open-label is that the apheresis for control patients is an invasive procedure. GBM is a not easily curable disease; patients with MGMT methylation have a better survival than with unmethylation. In this trial, MGMT status will be evaluated in all tumor specimens for further subgroup analysis.