No abstract

Immune checkpoint inhibitors (ICPIs) have recently emerged as a novel treatment for cancer. These agents, transforming the field of oncology, are not devoid of toxicity and cause immune-related side effects which can involve any organ including the nervous system. In this study, we present 9 patients (7 men and 2 women) with neurologic complications secondary to ICPI treatment. These included meningoencephalitis, limbic encephalitis, polyradiculitis, cranial polyneuropathy, myasthenic syndrome and myositis. Four patients received dual ICPI therapy comprised of programmed cell death-1 and cytotoxic lymphocyte associated protein-4 blocking antibodies. Median time to onset of neurologic adverse event during immune checkpoint inhibitor treatment was 8 weeks (range 5 days-19 weeks). In all patients ICPIs were stopped and corticosteroids were initiated, resulting in a marked improvement in seven out of nine patients. Two patients, one with myositis and one with myasthenic syndrome, died. In two patients ICPI therapy was resumed after resolution of the neurological adverse event with no additional neurologic complications. This series highlights the very broad spectrum of neurological complications of ICPIs, emphasizes the need for expedited diagnosis and suggests that withholding treatment early, accompanied with steroid therapy, carries the potential of complete resolution of the neurological immune-mediated condition. Thus, a high level of suspicion and rapid initiation of corticosteroids are mandatory to prevent uncontrolled clinical deterioration, which might be fatal.

Results of these in vivo human studies indicate that the time course to closure of the disrupted BBB for low-molecular-weight complexes is longer than previously estimated. The barrier is widely open during the first 40 minutes after osmotic BBB disruption and returns to baseline levels only after 6 to 8 hours following the induction of good or excellent disruption. These findings have important clinical implications for the design of therapeutic protocols.

The preliminary data show a promising high response rate of recurrent high-grade gliomas to chemotherapy with bevacizumab and irinotecan. The regimen is associated with minimal toxicity.

This regimen is safe, with the best 2-year OS and PFS achieved in any Radiation Therapy Oncology Group primary CNS lymphoma trial. Randomized trials that incorporate this regimen are needed to determine its efficacy compared with other strategies.

Normal brain cells depend on glucose metabolism, yet they have the flexibility to switch to the usage of ketone bodies during caloric restriction. In contrast, tumor cells lack genomic and metabolic flexibility and are largely dependent on glucose. Ketogenic-diet (KD) was suggested as a therapeutic option for malignant brain cancer. This study aimed to detect metabolic brain changes in patients with malignant brain gliomas on KD using proton magnetic-resonance-spectroscopy (H-MRS). Fifty MR scans were performed longitudinally in nine patients: four patients with recurrent glioblastoma (GB) treated with KD in addition to bevacizumab; one patient with gliomatosis-cerebri treated with KD only; and four patients with recurrent GB who did not receive KD. MR scans included conventional imaging and H-MRS acquired from normal appearing-white-matter (NAWM) and lesion. High adherence to KD was obtained only in two patients, based on high urine ketones; in these two patients ketone bodies, Acetone and Acetoacetate were detected in four MR spectra-three within the NAWM and one in the lesion area -4 and 25 months following initiation of the diet. No ketone-bodies were detected in the control group. In one patient with gliomatosis-cerebri, who adhered to the diet for 3 years and showed stable disease, an increase in glutamin + glutamate and reduction in N-Acetyl-Aspartate and myo-inositol were detected during KD.H-MRS was able to detect ketone-bodies in patients with brain tumors who adhered to KD. Yet it remains unclear whether accumulation of ketone bodies is due to increased brain uptake or decreased utilization of ketone bodies within the brain.

No abstract

Patients with progressive primary brain tumors (PBT) are attracted to promising new treatments, even prior to convincing data. Anti-PD1 immunotherapies have been in the spotlight since publication of groundbreaking results for metastatic melanoma with pembrolizumab (PBL). Our objective was to report on the response and toxicity of PBL in patients with advanced PBT. We retrospectively reviewed the charts of 22 patients (17 adults and 5 children) with recurrent central nervous system tumors treated with PBL. We analyzed prior antineoplastic therapies, steroid usage, and outcomes. Patients received a median of two neoplastic therapies prior to PBL, and a median of three infusions of PBL in adults and four in children. Twelve patients (9 adults and 3 children) started PBL on steroids (median dose in adults 4 mg; range 2-8, and in children 1.5 mg, range 0.5-4) and five patients received steroids later during PBL treatment. Twelve patients (10 adults and 2 children) received concomitant bevacizumab with PBL. Side effects were minimal. All patients showed progressive tumor growth during therapy. Median OS from the start of PBL was 2.6 months in adults and 3.2 months in children. Two GB patients underwent tumor resection following treatment with PBL. Tumor-lymphocytic response in these cases was unremarkable, and PD-L1 immuno-staining was negative. In this series of 22 patients with recurrent primary brain tumors, PBL showed no clinical or histologic efficacy. We do not recommend further use of PBL for recurrent PBT unless convincing prospective clinical trial data are published.