Circulating PD-L1 levels change during bevacizumab-based treatment in recurrent glioma.

PURPOSE: In primary brain tumors, the efficacy of immune-modulating therapies is still under investigation as inflammatory responses are restricted by tight immunoregulatory mechanisms in the central nervous system. Here, we measured soluble PD-L1 (sPD-L1) in the plasma of patients with recurrent glioblastoma (GBM) and recurrent WHO grade II-III glioma treated with bevacizumab-based salvage therapy. METHODS: Thirty patients with recurrent GBM and 10 patients with recurrent WHO grade II-III glioma were treated with bevacizumab-based salvage therapy at the Medical University of Vienna. Prior to each treatment cycle, EDTA plasma was drawn and sPD-L1 was measured applying a sandwich ELISA with a lower detection limit of 0.050 ng/ml. Leukocyte counts and C-reactive protein (CRP) levels were measured according to institutional practice. RESULTS: Median number of sPD-L1 measurements was 6 per patient (range: 2-24). At baseline, no significant difference in sPD-L1 concentrations was observed between WHO grade II-III glioma and GBM. Intra-patient variability of sPD-L1 concentrations was significantly higher in WHO grade II-III glioma than in GBM (p = 0.014) and tendentially higher in IDH-mutant than in IDH-wildtype glioma (p = 0.149) In WHO grade II-III glioma, sPD-L1 levels were significantly lower after one administration of bevacizumab than at baseline (median: 0.039 ng/ml vs. 0.4855 ng/ml, p = 0.036). In contrast, no significant change could be observed in patients with GBM. CONCLUSIONS: Changes in systemic inflammation markers including sPD-L1 are observable in patients with recurrent glioma under bevacizumab-based treatment and differ between WHO grade II-III glioma and GBM.

Sorafenib for patients with pretreated recurrent or progressive high-grade glioma: a retrospective, single-institution study.

Therapeutic options for patients with pretreated advanced high-grade glioma (HGG) are limited. Sorafenib, a small molecule with multiple potential beneficial actions, appears particularly promising. We reviewed the outcomes of 30 patients with recurrent or progressive HGG treated with sorafenib within a named patient program. Overall, 16 patients suffered from recurrent or progressive glioblastoma multiforme and 14 patients had grade 3 gliomas. All but four patients had previously undergone surgical debulking; all but one patient had received previous standard multimodal treatment; and 18 patients (60%) had received more than one line of chemotherapy, in median three. Progression-free survival (PFS), defined as the time from initiation of sorafenib to treatment discontinuation because of tumor progression or death, was selected as the endpoint. The use of sorafenib resulted in a median PFS of 3 months [95% confidence interval (CI) 1.9-4.1 months] in patients with glioblastoma and of 3.1 months (95% CI 1.4-4.8 months) in patients with other HGG. The PFS-6 for the whole cohort was 23%. Sixteen patients reported adverse events, mostly moderate, with hypertension as the most frequently reported toxicity (seven patients). One patient died of cerebral bleeding (grade 5 toxicity). The overall survival after initiation of sorafenib was 6 months (95% CI 3.9-8.0 months) for patients with glioblastoma multiforme and 10 months (95% CI 3.1-16.9 months) for patients with HGG. In this retrospective analysis of heavily pretreated patients with HGG, sorafenib monotherapy was associated with tumor stabilization in a small subset of patients. The risk-benefit ratio was acceptable in the context of an apparent clinical benefit in patients with a fatal disease.

Value of 1H-magnetic resonance spectroscopy chemical shift imaging for detection of anaplastic foci in diffusely infiltrating gliomas with non-significant contrast-enhancement.

OBJECTIVE: In diffusely infiltrating gliomas (DIG), positron emission tomography (PET) imaging is a powerful method for detection of anaplastic foci. Recently, (1)H-magnetic resonance spectroscopy chemical shift imaging (CSI) using choline/creatine (Cho/Cr) or choline/N-acetylaspartate (Cho/NAA) ratios has emerged as a new non-invasive, widely available alternative. The authors therefore correlated CSI with (11)C-methionine (MET)-PET data in a series of DIG with non-significant contrast-enhancement (CE). METHODS: Thirty-two patients with DIG were examined with single-slice CSI on a T MRI and MET-PET. Maximum pathological intratumoural ratios of CSI (=CSI(max)) and maximum tumour-to-normal-brain PET ratios (=PET(max); T/N ratio) were determined. Coregistration of MRI with CSI and PET was performed, and the topographic overlap of CSI(max) and PET(max) was analysed. Histological criteria of anaplasia as well as cell proliferation rate were assessed in tumour samples inside and outside CSI(max). RESULTS: CSI showed a pathological ratio in all patients, whereas PET demonstrated a pathological T/N ratio in 21/32 patients. Topographical correlation of CSI(max) and PET(max) revealed a ≥ 50% overlap in 18/21 and <50% overlap in 3/21 patients, respectively. Cho/Cr(max) and Cho/NAA(max) showed a ≥ 50% overlap in 24/32 and a <50% overlap in 8/32 patients. Cell proliferation rate was significantly higher inside than outside the CSI(max) (13.6% vs 6.9%, p<0.001). CONCLUSION: The results indicate that CSI is a promising method for detection of anaplastic foci within DIG with non-significant CE. Intraoperative use of CSI by multimodal neuronavigation may increase the reliability of detection of malignant areas in glioma surgery and therefore optimise allocation of patients to adjuvant treatments.