Temozolomide does not favour immune response; secondary GBM to be excluded

Rationale of the Study: Treatment for GBM currently consists of surgical resection of the tumour mass followed by radio- and chemotherapy. Nonetheless overall prognosis still remains bleak, recurrence is universal, and recurrent GBM patients clearly need innovative therapies. Dendritic cells (DC) immunotherapy could represent a well-tolerated, long-term tumour-specific treatment to kill all (residual) tumour cells which infiltrate in the adjacent areas of the brain. Preclinical investigations for the development of therapeutic vaccines against high grade gliomas, based on the use of DC loaded with a mixture of glioma-derived tumor have been carried out in rat as well as in mouse models, showing the capacity to generate a glioma-specific immune response. Mature DC loaded with autologous tumor lysate have been used also for the treatment of patients with recurrent malignant brain tumors; no major adverse events have been registered.

Results about the use of immunotherapy for GBM patients are encouraging, but further studies are necessary to find out the most effective and safe combination of immunotherapy with radio- and chemotherapy after exeresis of the tumour mass.

Aim of the study: Primary objective of the study is to evaluate treatment tolerability and to get preliminary information about efficacy. Secondary objective is to evaluate the treatment effect on the immune response. Additional objective is to identify a possible correlation between methylation status of the MGMT promoter and tumor response to treatment.

A two-stage Simon design will be considered for the study. The primary objectives of the study include the evaluation of a PFS6 rate in treated patients. Assuming as outcome measure the percentage of PFS6 patients and of clinical interest an increase to 35% (P1) of the historical control response rate of 20% (P0), the null hypothesis will be rejected (a=0.05, b=0.2) at the end of the first stage if the response rate will be 5/22 treated patients (Fisher's exact test). In the second stage patients will be enrolled up to 72 overall. The study will be successful if at least 19 subjects out of 72 have PFS6 months after the beginning of the treatment.

Study Design: Phase I, 2-stage Simon design (Simon et al., 1997), single-centre, un-controlled, open label, non randomized study.

The therapeutic program will include radical surgical resection of the tumor, followed by immunotherapy. Immunotherapy will comprise 4 biweekly vaccinations first (injections I, II, III, IV), 2 further monthly vaccinations (injections V, VI) and a final vaccination (injection VII) 2 months after the sixth one.

Injections I, V, VI and VII will contain 10 million tumor lysate-loaded DC, while the others will be of 5 million cells only. In correspondence to the third vaccine injection (week 7), 6 cycles of maintenance TMZ (mTMZ) will start. On the basis of the patient clinical status, further vaccine boosts will be considered as appropriate addition at the standard vaccination cycle.

Study Population: The first stage of the study will include 22 patients with recurrent GBM. The overall population at the end of the study will consist of 72 patients.

Inclusion Criteria:

• Patients of both genders.
• Age 18 years and 70 years.
• Postoperative Karnofsky Performance Status >=70.
• Diagnosis of recurrent GBM (World Health Organization [WHO] grade IV astrocytoma).
• Diagnosis confirmed by the reference histopathology.
• Total or subtotal resection of tumor mass, confirmed by assessment of the neurosurgeon and by postoperative radiological assessment.
• Amount of non-necrotic tissue for lysate preparation and DC loading >= 1 gr, stored at -80°C.
• Corticosteroids daily dose <= 4 mg during the 2 days prior to leukapheresis.
• Life expectancy > 3 months.
• Signed informed consent.

Exclusion Criteria:

• Pregnancy.
• Participation in other clinical trials with experimental drugs simultaneously or within 1 month before this trial entry.
• Presence of acute infection requiring active treatment.
• Mandatory treatment with corticosteroids or salicylates in anti-inflammatory dose.
• Presence of sub-ependymal diffusion of the tumor.
• Haematology: leukocytes < 3,000/μl, lymphocytes < 500/μl, neutrophils < 1,000/μl, hemoglobin <9 g/100 ml, thrombocytes < 100,000/μl 2 days prior to leukapheresis.
• Documented immune deficiency.
• Documented autoimmune disease.
• Positive serology for HIV or hepatitis B or C.
• Allergies to any component of the DC vaccine.
• Known intolerance to TMZ.
• Other active malignancy.