Oncolytic DNX-2401 virotherapy plus pembrolizumab in recurrent glioblastoma: a phase 1/2 trial.

Immune-mediated anti-tumoral responses, elicited by oncolytic viruses and augmented with checkpoint inhibition, may be an effective treatment approach for glioblastoma. Here in this multicenter phase 1/2 study we evaluated the combination of intratumoral delivery of oncolytic virus DNX-2401 followed by intravenous anti-PD-1 antibody pembrolizumab in recurrent glioblastoma, first in a dose-escalation and then in a dose-expansion phase, in 49 patients. The primary endpoints were overall safety and objective response rate. The primary safety endpoint was met, whereas the primary efficacy endpoint was not met. There were no dose-limiting toxicities, and full dose combined treatment was well tolerated. The objective response rate was 10.4% (90% confidence interval (CI) 4.2-20.7%), which was not statistically greater than the prespecified control rate of 5%. The secondary endpoint of overall survival at 12 months was 52.7% (95% CI 40.1-69.2%), which was statistically greater than the prespecified control rate of 20%. Median overall survival was 12.5 months (10.7-13.5 months). Objective responses led to longer survival (hazard ratio 0.20, 95% CI 0.05-0.87). A total of 56.2% (95% CI 41.1-70.5%) of patients had a clinical benefit defined as stable disease or better. Three patients completed treatment with durable responses and remain alive at 45, 48 and 60 months. Exploratory mutational, gene-expression and immunophenotypic analyses revealed that the balance between immune cell infiltration and expression of checkpoint inhibitors may potentially inform on response to treatment and mechanisms of resistance. Overall, the combination of intratumoral DNX-2401 followed by pembrolizumab was safe with notable survival benefit in select patients (ClinicalTrials.gov registration: NCT02798406).

Small Molecules and Immunotherapy Agents for Enhancing Radiotherapy in Glioblastoma.

Glioblastoma (GBM) is an aggressive primary brain tumor that is associated with a poor prognosis and quality of life. The standard of care has changed minimally over the past two decades and currently consists of surgery followed by radiotherapy (RT), concomitant and adjuvant temozolomide, and tumor treating fields (TTF). Factors such as tumor hypoxia and the presence of glioma stem cells contribute to the radioresistant nature of GBM. In this review, we discuss the current treatment modalities, mechanisms of radioresistance, and studies that have evaluated promising radiosensitizers. Specifically, we highlight small molecules and immunotherapy agents that have been studied in conjunction with RT in clinical trials. Recent preclinical studies involving GBM radiosensitizers are also discussed.

Dose-escalated accelerated hypofractionation for elderly or frail patients with a newly diagnosed glioblastoma.

BACKGROUND: The standard of care for elderly glioblastoma patients is 40 Gy in 15 fraction radiotherapy with temozolomide (TMZ). However, this regimen has a lower biologic equivalent dose (BED) compared to the Stupp regimen of 60 Gy in 30 fractions. We hypothesize that accelerated hypofractionated radiation of 52.5 Gy in 15 fractions (BED equivalent to Stupp) will have superior survival compared to 40 Gy in 15 fractions. METHODS: Elderly patients (≥ 65 years old) who received hypofractionated radiation with TMZ from 2010 to 2020 were included in this analysis. Overall survival (OS) and progression free survival were defined as the time elapsed between surgery/biopsy and death from any cause or progression. Baseline characteristics were compared between patients who received 40 and 52.5 Gy. Univariable and multivariable analyses were performed. RESULTS: Sixty-six newly diagnosed patients were eligible for analysis. Thirty-nine patients were treated with 40 Gy in 15 fractions while twenty-seven were treated with 52.5 Gy in 15 fractions. Patients had no significant differences in age, sex, methylation status, or performance status. OS was superior in the 52.5 Gy group (14.1 months) when compared to the 40 Gy group (7.9 months, p = 0.011). Isoeffective dosing to 52.5 Gy was shown to be an independent prognostic factor for improved OS on multivariable analysis. CONCLUSIONS: Isoeffective dosing to 52.5 Gy in 15 fractions was associated with superior OS compared to standard of care 40 Gy in 15 fractions. These hypothesis generating data support accelerated hypofractionation in future prospective trials.

Targeted Therapy for BRAF Mutant Brain Tumors.

OPINION STATEMENT: Molecular heterogeneity has confounded attempts to target individual pathways in brain tumors. However, gliomas with BRAF mutations have been identified as being uniquely vulnerable to targeted therapies. Such mutations are predominantly seen in brain tumors of the adolescent and young adult population. Given that accurate and timely identification of such mutations is essential for offering appropriate treatment, treatment centers should offer both immunohistochemical and sequencing methods for detection of these mutations to guide treatment. Additional studies of these tumors at recurrence would also allow identification of breakthrough resistance mechanisms that may also be targetable for treatment. Due to the relative rarity of these tumors, multicenter collaborative studies will be essential in achieving long term control of these tumors.

Prognostic implications of epidermal and platelet-derived growth factor receptor alterations in 2 cohorts of IDHwt glioblastoma.

BACKGROUND: Glioblastoma remains a deadly brain cancer with dismal prognosis. Genetic alterations, including IDH mutations, 1p19q co-deletion status and MGMT promoter methylation have been proven to be prognostic and predictive to response to treatment in gliomas. In this manuscript, we aimed to correlate other mutations and genetic alterations with various clinical endpoints in patients with IDH-wild-type (IDHwt) glioblastoma. METHODS: We compiled a comprehensive clinically annotated database of IDHwt GBM patients treated at the Ohio State University Wexner Medical Center for whom we had mutational data through a CLIA-certified genomic laboratory. We then added data that is publicly available from Memorial Sloan Kettering Cancer Center through cBioPortal. Each of the genetic alterations (mutations, deletions, and amplifications) served as a variable in univariate and multivariate Cox proportional hazard models. RESULTS: A total of 175 IDHwt GBM patients with available MGMT promoter methylation data from both cohorts were included in the analysis. As expected, MGMT promoter methylation was significantly associated with improved overall survival (OS). Median OS for MGMT promoter methylated and unmethylated GBM was 26.5 and 18 months, respectively (HR 0.45; P = .003). Moreover, EGFR/ERBB alterations were associated with favorable outcome (HR of 0.37 (P = .003), but only in MGMT promoter unmethylated GBM. We further found that patients with EGFR/ERBB alterations who also harbored PDGFRA amplification had a significantly worse outcome (HR 7.89; P = .025). CONCLUSIONS: Our data provide further insight into the impact of genetic alterations on various clinical outcomes in IDHwt GBM in 2 cohorts of patients with detailed clinical information and inspire new therapeutic strategies for IDHwt GBM.

Erratum to: Characterizing Benefit from Temozolomide in MGMT Promoter Unmethylated and Methylated Glioblastoma: A Systematic Review and Meta-analysis.

[This corrects the article DOI: 10.1093/noajnl/vdaa082.].

The role of VEGF receptor inhibitors in preventing cerebral radiation necrosis: a retrospective cohort study.

BACKGROUND: Radiation necrosis (RN) is a potential complication after radiation therapy for brain tumors. It is hypothesized that VEGF plays an important role in the pathophysiology of RN. Bevacizumab, a monoclonal antibody against VEGF-A, is often successful in the management of RN. The objective of this study is to assess whether VEGF receptor (VEGFR) inhibitors, a group of oral tyrosine kinase inhibitors (TKIs), can prevent or reverse RN. METHODS: We retrospectively studied a cohort of 102 patients with renal cell carcinoma and brain metastases seen at The Ohio State University James Cancer Center between January 1, 2011 and April 30, 2019. We identified those who developed RN and analyzed the temporal relationship between the use of VEGFR TKIs and the development of RN. RESULTS: The cumulative incidence of RN is 13.7% after radiation treatments that included LINAC-based stereotactic radiosurgery, fractionated stereotactic radiotherapy, or Gamma Knife radiosurgery. There was no statistically significant difference in the cumulative incidence of RN between patients taking TKIs and patients who were off TKIs (9.9% and 11.5% respectively, P = .741). The median time to development of RN was only numerically shorter in patients taking TKIs (151 vs 315 days, P = .315). One patient developed RN after stopping cabozantinib. Eight patients developed RN while on cabozantinib, pazopanib, or sunitinib. One patient was started on axitinib during active RN without significant improvement subsequently. CONCLUSIONS: VEGFR TKIs do not consistently prevent RN. The therapeutic effects of VEGFR TKIs against RN warrant further research.

Characterizing benefit from temozolomide in MGMT promoter unmethylated and methylated glioblastoma: a systematic review and meta-analysis.

BACKGROUND: The current standard of care for the management of patients with newly diagnosed glioblastoma (GBM) includes maximal safe resection followed by radiotherapy (RT) with concurrent and adjuvant temozolomide (TMZ). While it is well established that TMZ has better efficacy in patients with MGMT promoter methylation, it remains an area of debate whether TMZ should be omitted when treating GBM patients with unmethylated MGMT. METHODS: We conducted a systematic review and meta-analysis to provide separate estimates of median overall survival (OS) and progression-free survival (PFS) for patients with methylated and unmethylated GBM treated with RT with or without TMZ. We searched multiple databases from inception to January 13, 2020. RESULTS: The median OS for patients with unmethylated GBM treated with RT/TMZ pooled from 5 phase III studies (N = 655) was 14.11 months (95% confidence interval [CI], 13.18-15.04) with a median PFS of 4.99 months (95% CI, 4.25-5.72). In contrast, the median OS for patients with methylated GBM pooled from 6 studies (N = 753) was 24.59 months (95% CI, 22.19-26.99) with a median PFS pooled from 7 studies (N = 805) of 9.51 months (95% CI, 7.41-11.61). There is a paucity of prospective data pertaining to OS/PFS in unmethylated patients treated with RT only and therefore a direct comparison was not possible. CONCLUSIONS: This meta-analysis provides estimates of survival for patients with MGMT methylated or unmethylated GBM treated with RT/TMZ. Further research is needed to delineate whether TMZ should be withheld for patients with unmethylated GBM outside of the setting of clinical trials.

False-positive 1p/19q Testing Results in Gliomas: Clinical and Research Consequences.

BACKGROUND: The revised fourth edition of the World Health Organization Classification of Tumors of the Central Nervous System-published in 2016-established 1p19q codeletion as the molecular hallmark for the diagnosis of oligodendrogliomas. Fluorescence in situ hybridization (FISH) is currently the most commonly used modality for 1p19q testing. However, as with most laboratory testing, 1p19q FISH testing has a false-positive rate, potentially resulting in an erroneous diagnosis of oligodendroglioma with significant implications for the choice of therapy and prognosis. METHODS: The authors describe a case series of 5 patients treated at the Ohio State University James Cancer Center to illustrate the problem of false-positive 1p19q FISH results. RESULTS: In our case series, the authors present a spectrum of possibilities for conflicting 1p19q testing results and the clinical consequences. The authors present 4 cases that, in retrospect, are believed to have had a false 1p19q FISH results. One other case may represent a true transformation of oligodendroglioma to glioblastoma or a second malignancy. Neuro-oncologists should pay attention to additional molecular markers, namely ATRX, TP53, and MGMT methylation status, before discussing the pathology with the patient and formulating a treatment plan. CONCLUSIONS: Pathologists and neuro-oncologists should be aware of false-positive 1p19q FISH results as they can significantly change treatment and prognosis for glioma patients. Moreover, this issue should be taken into account when designing clinical trials specific to this disease cohort.

Ipilimumab-induced necrotic myelopathy in a patient with metastatic melanoma: A case report and review of literature.

Ipilimumab is a novel humanized monoclonal antibody directed against cytotoxic T lymphocyte antigen 4, a T-cell surface molecule involved in down-regulation and suppression of the T cell response to stimuli. Patients treated with ipilimumab are at risk for immune-related adverse events involving the skin, digestive tract, liver and endocrine organs. Few case reports of immune-related adverse effects involving central or peripheral nervous system due to ipilimumab are published. These include inflammatory myopathy, aseptic meningitis, severe meningo-radiculo-neuritis, temporal arteritis, Guillain-Barre syndrome, and posterior reversible encephalopathy syndrome. We report the first case of ipilimumab-induced progressive necrotic myelopathy.

Central pontine and extrapontine myelinolysis: the great masquerader-an autopsy case report.

Central pontine myelinolysis is a demyelinating disorder characterized by the loss of myelin in the center of the basis pontis usually caused by rapid correction of chronic hyponatremia. The clinical features vary depending on the extent of involvement. Demyelination can occur outside the pons as well and diagnosis can be challenging if both pontine and extrapontine areas are involved. We herein report a case of myelinolysis involving pons, lateral geniculate bodies, subependymal region, and spinal cord. To the best of our knowledge, this case represents the second case of spinal cord involvement in osmotic demyelination syndrome and the first case of involvement of thoracic region of spinal cord.

Papillary endothelial hyperplasia presenting as recurrent malignant glioma.

The initial management of patients with malignant gliomas depends on accurate histologic diagnosis which, in turn, directs appropriate treatment planning. However, the diagnosis of recurrent disease is often based solely on radiological data which can occasionally be misinterpreted as showing recurrent tumor. Lack of awareness of conditions that mimic recurrent tumor and potentially confound radiological diagnosis can lead to inappropriate therapeutic decisions. We report the case of a patient whose imaging studies suggested recurrence of malignant glioma; however, surgical resection of the lesion guided by MRI scans resulted in the correct diagnosis of papillary endothelial hyperplasia and led to appropriate management of this condition that mimicked tumor recurrence. In this report, we provide a comprehensive review of this rare entity and emphasize the importance of adequately pursuing appropriate diagnostic considerations prior to making definitive treatment decisions.