Phosphatidylinositol 3-kinase (PI3K) signaling is highly active in glioblastomas. We assessed pharmacokinetics, pharmacodynamics, and efficacy of the pan-PI3K inhibitor buparlisib in patients with ...recurrent glioblastoma with PI3K pathway activation.
This study was a multicenter, open-label, multi-arm, phase II trial in patients with PI3K pathway-activated glioblastoma at first or second recurrence. In cohort 1, patients scheduled for re-operation after progression received buparlisib for 7 to 13 days before surgery to evaluate brain penetration and modulation of the PI3K pathway in resected tumor tissue. In cohort 2, patients not eligible for re-operation received buparlisib until progression or unacceptable toxicity. Once daily oral buparlisib 100 mg was administered on a continuous 28-day schedule. Primary end points were PI3K pathway inhibition in tumor tissue and buparlisib pharmacokinetics in cohort 1 and 6-month progression-free survival (PFS6) in cohort 2.
Sixty-five patients were treated (cohort 1, n = 15; cohort 2, n = 50). In cohort 1, reduction of phosphorylated AKT
immunohistochemistry score was achieved in six (42.8%) of 14 patients, but effects on phosphoribosomal protein S6
and proliferation were not significant. Tumor-to-plasma drug level was 1.0. In cohort 2, four (8%) of 50 patients reached 6-month PFS6, and the median PFS was 1.7 months (95% CI, 1.4 to 1.8 months). The most common grade 3 or greater adverse events related to treatment were lipase elevation (n = 7 10.8%), fatigue (n = 4 6.2%), hyperglycemia (n = 3 4.6%), and elevated ALT (n = 3 4.6%).
Buparlisib had minimal single-agent efficacy in patients with PI3K-activated recurrent glioblastoma. Although buparlisib achieved significant brain penetration, the lack of clinical efficacy was explained by incomplete blockade of the PI3K pathway in tumor tissue. Integrative results suggest that additional study of PI3K inhibitors that achieve more-complete pathway inhibition may still be warranted.
Vandetanib, a tyrosine kinase inhibitor of KDR (VEGFR2), EGFR, and RET, may enhance sensitivity to chemotherapy and radiation. We conducted a randomized, noncomparative, phase II study of radiation ...(RT) and temozolomide with or without vandetanib in patients with newly diagnosed glioblastoma (GBM).
We planned to randomize a total of 114 newly diagnosed GBM patients in a ratio of 2:1 to standard RT and temozolomide with (76 patients) or without (38 patients) vandetanib 100 mg daily. Patients with age ≥ 18 years, Karnofsky performance status (KPS) ≥ 60, and not on enzyme-inducing antiepileptics were eligible. Primary endpoint was median overall survival (OS) from the date of randomization. Secondary endpoints included median progression-free survival (PFS), 12-month PFS, and safety. Correlative studies included pharmacokinetics as well as tissue and serum biomarker analysis.
The study was terminated early for futility based on the results of an interim analysis. We enrolled 106 patients (36 in the RT/temozolomide arm and 70 in the vandetanib/RT/temozolomide arm). Median OS was 15.9 months 95% confidence interval (CI), 11.0-22.5 months in the RT/temozolomide arm and 16.6 months (95% CI, 14.9-20.1 months) in the vandetanib/RT/temozolomide (log-rank P = 0.75).
The addition of vandetanib at a dose of 100 mg daily to standard chemoradiation in patients with newly diagnosed GBM or gliosarcoma was associated with potential pharmacodynamic biomarker changes and was reasonably well tolerated. However, the regimen did not significantly prolong OS compared with the parallel control arm, leading to early termination of the study.
OBJECTIVE:A subset of meningiomas recur after surgery and radiation therapy, but no medical therapy for recurrent meningioma has proven effective.
METHODS:Pasireotide LAR is a long-acting ...somatostatin analog that may inhibit meningioma growth. This was a phase II trial in patients with histologically confirmed recurrent or progressive meningioma designed to evaluate whether pasireotide LAR prolongs progression-free survival at 6 months (PFS6). Patients were stratified by histology (atypical World Health Organization grade 2 and malignant grade 3 meningiomas in cohort A and benign grade 3 in cohort B).
RESULTS:Eighteen patients were accrued in cohort A and 16 in cohort B. Cohort A had median age 59 years, median Karnofsky performance status 80, 17 (94%) had previous radiation therapy, and 11 (61%) showed high octreotide uptake. Cohort B had median age 52 years, median Karnofsky performance status 90, 11 (69%) had previous radiation therapy, and 12 (75%) showed high octreotide uptake. There were no radiographic responses to pasireotide LAR therapy in either cohort. Twelve patients (67%) in cohort A and 13 (81%) in cohort B achieved stable disease. In cohort A, PFS6 was 17% and median PFS 15 weeks (95% confidence interval8–20). In cohort B, PFS6 was 50% and median PFS 26 weeks (12–43). Treatment was well tolerated. Octreotide uptake and insulin-like growth factor–1 levels did not predict outcome. Expression of somatostatin receptor 3 predicted favorable PFS and overall survival.
CONCLUSIONS:Pasireotide LAR has limited activity in recurrent meningiomas. The finding that somatostatin receptor 3 is associated with favorable outcomes warrants further investigation.
CLASSIFICATION OF EVIDENCE:This study provides Class IV evidence that in patients with recurrent or progressive meningioma, pasireotide LAR does not significantly increase the proportion of patients with PFS at 6 months.
Bevacizumab is FDA-approved for patients with recurrent GBM. However, the median duration of response is only 4 months. Potential mechanisms of resistance include upregulated FGF signaling and ...increased PDGF-mediated pericyte coverage. Nintedanib is an oral, small-molecule tyrosine kinase inhibitor of PDGFR α/β, FGFR 1-3, and VEGFR 1-3 that may overcome resistance to anti-VEGF therapy. This was a two-stage phase II trial in adults with first or second recurrence of GBM, stratified by prior bevacizumab therapy (ClinicalTrials.gov number NCT01380782; 1199.94). The primary endpoint was PFS6 in the bevacizumab-naive arm (Arm A) and PFS3 in the post-bevacizumab arm (Arm B). Up to 10 anaplastic glioma (AG) patients were accrued to each arm in exploratory cohorts. Twenty-two patients enrolled in Arm A and 14 in Arm B. Arm A included 12 GBMs (55 %), 13 patients with one prior regimen (59 %), and median age 54 years (range 28–75). Arm B included 10 GBMs (71 %), one patient with one prior regimen (7 %), and median age 52 years (range 32–70). Median KPS overall was 90 (range 60–100). There were no responses. In Arm A (GBM only), PFS6 was 0 %, median PFS 28 days (95 % CI 27–83), and median OS 6.9 months (3.7–8.1). In Arm B (GBM only), PFS3 was 0 %, median PFS 28 days (22–28), and median OS 2.6 months (1.0–6.9). Among AG patients in each arm, PFS6 was 0 %. Treatment was well tolerated. In conclusion, nintedanib is not active against recurrent high-grade glioma, regardless of prior bevacizumab therapy.
Neoantigens, which are derived from tumour-specific protein-coding mutations, are exempt from central tolerance, can generate robust immune responses
and can function as bona fide antigens that ...facilitate tumour rejection
. Here we demonstrate that a strategy that uses multi-epitope, personalized neoantigen vaccination, which has previously been tested in patients with high-risk melanoma
, is feasible for tumours such as glioblastoma, which typically have a relatively low mutation load
and an immunologically 'cold' tumour microenvironment
. We used personalized neoantigen-targeting vaccines to immunize patients newly diagnosed with glioblastoma following surgical resection and conventional radiotherapy in a phase I/Ib study. Patients who did not receive dexamethasone-a highly potent corticosteroid that is frequently prescribed to treat cerebral oedema in patients with glioblastoma-generated circulating polyfunctional neoantigen-specific CD4
and CD8
T cell responses that were enriched in a memory phenotype and showed an increase in the number of tumour-infiltrating T cells. Using single-cell T cell receptor analysis, we provide evidence that neoantigen-specific T cells from the peripheral blood can migrate into an intracranial glioblastoma tumour. Neoantigen-targeting vaccines thus have the potential to favourably alter the immune milieu of glioblastoma.
VEGF is upregulated in glioblastoma and may contribute to immunosuppression. We performed a phase II study of pembrolizumab alone or with bevacizumab in recurrent glioblastoma.
Eighty ...bevacizumab-naïve patients with recurrent glioblastoma were randomized to pembrolizumab with bevacizumab (cohort A,
= 50) or pembrolizumab monotherapy (cohort B,
= 30). The primary endpoint was 6-month progression-free survival (PFS-6). Assessed biomarkers included evaluation of tumor programmed death-ligand 1 expression, tumor-infiltrating lymphocyte density, immune activation gene expression signature, and plasma cytokines. The neurologic assessment in neuro-oncology (NANO) scale was used to prospectively assess neurologic function.
Pembrolizumab alone or with bevacizumab was well tolerated but of limited benefit. For cohort A, PFS-6 was 26.0% 95% confidence interval (CI), 16.3-41.5, median overall survival (OS) was 8.8 months (95% CI, 7.7-14.2), objective response rate (ORR) was 20%, and median duration of response was 48 weeks. For cohort B, PFS-6 was 6.7% (95% CI, 1.7-25.4), median OS was 10.3 months (95% CI, 8.5-12.5), and ORR was 0%. Tumor immune markers were not associated with OS, but worsened OS correlated with baseline dexamethasone use and increased posttherapy plasma VEGF (cohort A) and mutant
, unmethylated
, and increased baseline PlGF and sVEGFR1 levels (cohort B). The NANO scale contributed to overall outcome assessment.
Pembrolizumab was ineffective as monotherapy and with bevacizumab for recurrent glioblastoma. The infrequent radiographic responses to combinatorial therapy were durable. Tumor immune biomarkers did not predict outcome. Baseline dexamethasone use and tumor MGMT warrant further study as potential biomarkers in glioblastoma immunotherapy trials.
Abstract
Background
Programmed death ligand 1 (PD-L1) contributes to tumor immunosuppression and is upregulated in aggressive meningiomas. We performed a phase II study of nivolumab, a programmed ...death 1 (PD-1) blocking antibody among patients with grade ≥2 meningioma that recurred after surgery and radiation therapy.
Methods
Twenty-five patients received nivolumab (240 mg biweekly) until progression, voluntary withdrawal, unacceptable toxicity, or death. Tumor mutational burden (TMB) and quantification of tumor-infiltrating lymphocytes (TIL) were evaluated as potential immunocorrelative biomarkers. Change in neurologic function was prospectively assessed using the Neurologic Assessment in Neuro-Oncology (NANO) scale.
Results
Enrolled patients had multiple recurrences including ≥3 prior surgeries and ≥2 prior courses of radiation in 60% and 72%, respectively. Nivolumab was well tolerated with no unexpected adverse events. Six-month progression-free survival (PFS-6) rate was 42.4% (95% CI: 22.8, 60.7) and the median OS was 30.9 months (95% CI: 17.6, NA). One patient achieved radiographic response (ongoing at 4.5 years). TMB was >10/Mb in 2 of 15 profiled tumors (13.3%). Baseline TIL density was low but increased posttreatment in 3 patients including both patients with elevated TMB. Most patients who achieved PFS-6 maintained neurologic function prior to progression as assessed by NANO.
Conclusion
Nivolumab was well tolerated but failed to improve PFS-6, although a subset of patients appeared to derive benefit. Low levels of TMB and TIL density were typically observed. NANO assessment of neurologic function contributed to outcome assessment. Future studies may consider rationally designed combinatorial regimens.
The Individualized Screening Trial of Innovative Glioblastoma Therapy (INSIGhT) is a phase II platform trial that uses response adaptive randomization and genomic profiling to efficiently identify ...novel therapies for phase III testing. Three initial experimental arms (abemaciclib a cyclin-dependent kinase CDK4/6 inhibitor, neratinib an epidermal growth factor receptor EGFR/human epidermal growth factor receptor 2 inhibitor, and CC-115 a deoxyribonucleic acid-dependent protein kinase/mammalian target of rapamycin inhibitor) were simultaneously evaluated against a common control arm. We report the results for each arm and examine the feasibility and conduct of the adaptive platform design.
Patients with newly diagnosed O
-methylguanine-DNA methyltransferase-unmethylated glioblastoma were eligible if they had tumor genotyping to identify prespecified biomarker subpopulations of dominant glioblastoma signaling pathways (EGFR, phosphatidylinositol 3-kinase, and CDK). Initial random assignment was 1:1:1:1 between control (radiation therapy and temozolomide) and the experimental arms. Subsequent Bayesian adaptive randomization was incorporated on the basis of biomarker-specific progression-free survival (PFS) data. The primary end point was overall survival (OS), and one-sided
values are reported. The trial is registered with ClinicalTrials.gov (identifier: NCT02977780).
Two hundred thirty-seven patients were treated (71 control; 73 abemaciclib; 81 neratinib; 12 CC-115) in years 2017-2021. Abemaciclib and neratinib were well tolerated, but CC-115 was associated with ≥ grade 3 treatment-related toxicity in 58% of patients. PFS was significantly longer with abemaciclib (hazard ratio HR, 0.72; 95% CI, 0.49 to 1.06; one-sided
= .046) and neratinib (HR, 0.72; 95% CI, 0.50 to 1.02; one-sided
= .033) relative to the control arm but there was no PFS benefit with CC-115 (one-sided
= .523). None of the experimental therapies demonstrated a significant OS benefit (
> .05).
The INSIGhT design enabled efficient simultaneous testing of three experimental agents using a shared control arm and adaptive randomization. Two investigational arms had superior PFS compared with the control arm, but none demonstrated an OS benefit. The INSIGhT design may promote improved and more efficient therapeutic discovery in glioblastoma. New arms have been added to the trial.
Panobinostat is a histone deacetylase inhibitor with antineoplastic and antiangiogenic effects in glioma that may work synergistically with bevacizumab. We conducted a multicenter phase II trial of ...panobinostat combined with bevacizumab in patients with recurrent high-grade glioma (HGG).
Patients with recurrent HGG were treated with oral panobinostat 30 mg 3 times per week, every other week, in combination with bevacizumab 10 mg/kg every other week. The primary endpoint was a 6-month progression-fee survival (PFS6) rate for participants with recurrent glioblastoma (GBM). Patients with recurrent anaplastic glioma (AG) were evaluated as an exploratory arm of the study.
At interim analysis, the GBM arm did not meet criteria for continued accrual, and the GBM arm was closed. A total of 24 patients with GBM were accrued prior to closure. The PFS6 rate was 30.4% (95%, CI 12.4%-50.7%), median PFS was 5 months (range, 3-9 months), and median overall survival (OS) was 9 months (range, 6-19 months). Accrual in the AG arm continued to completion, and a total of 15 patients were enrolled. The PFS6 rate was 46.7% (range, 21%-73%), median PFS was 7 months (range, 2-10 months), and median OS was 17 months (range, 5 months-27 months).
This phase II study of panobinostat and bevacizumab in participants with recurrent GBM did not meet criteria for continued accrual, and the GBM cohort of the study was closed. Although it was reasonably well tolerated, the addition of panobinostat to bevacizumab did not significantly improve PFS6 compared with historical controls of bevacizumab monotherapy in either cohort.
Although antiangiogenic therapy for high-grade glioma (HGG) is promising, responses are not durable. Correlative clinical studies suggest that the SDF-1α/CXCR4 axis may mediate resistance to VEGFR ...inhibition. Preclinical data have demonstrated that plerixafor (a reversible CXCR4 inhibitor) could inhibit glioma progression after anti-VEGF pathway inhibition. We conducted a phase I study to determine the safety of plerixafor and bevacizumab in recurrent HGG.
Part 1 enrolled 23 patients with a 3 × 3 dose escalation design to a maximum planned dose of plerixafor 320 μg/kg subcutaneously on days 1 to 21 and bevacizumab 10 mg/kg intravenously on days 1 and 15 of each 28-day cycle. Cerebrospinal fluid (CSF) and plasma samples were obtained for pharmacokinetic analyses. Plasma and cellular biomarkers were evaluated before and after treatment. Part 2 enrolled 3 patients and was a surgical study to determine plerixafor's penetration in tumor tissue.
In Part 1, no dose-limiting toxicities were seen at the maximum planned dose of plerixafor + bevacizumab. Treatment was well tolerated. After plerixafor 320 μg/kg treatment, the average CSF drug concentration was 26.8 ± 19.6 ng/mL. Plerixafor concentration in resected tumor tissue from patients pretreated with plerixafor was 10 to 12 μg/g. Circulating biomarker data indicated that plerixafor + bevacizumab induces rapid and persistent increases in plasma SDF-1α and placental growth factor. Progression-free survival correlated with pretreatment plasma soluble mesenchymal-epithelial transition receptor and sVEGFR1, and overall survival with the change during treatment in CD34
progenitor/stem cells and CD8 T cells.
Plerixafor + bevacizumab was well tolerated in HGG patients. Plerixafor distributed to both the CSF and brain tumor tissue, and treatment was associated with biomarker changes consistent with VEGF and CXCR4 inhibition.
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