Activity of a first-in-class oral HIF2-alpha inhibitor, PT2385, in patients with first recurrence of glioblastoma.

INTRODUCTION: Hypoxia inducible factor 2-alpha (HIF2α) mediates cellular responses to hypoxia and is over-expressed in glioblastoma (GBM). PT2385 is an oral HIF2α inhibitor with in vivo activity against GBM. METHODS: A two-stage single-arm open-label phase II study of adults with GBM at first recurrence following chemoradiation with measurable disease was conducted through the Adult Brain Tumor Consortium. PT2385 was administered at the phase II dose (800 mg b.i.d.). The primary outcome was objective radiographic response (ORR = complete response + partial response, CR + PR); secondary outcomes were safety, overall survival (OS), and progression free survival (PFS). Exploratory objectives included pharmacokinetics (day 15 Cmin), pharmacodynamics (erythropoietin, vascular endothelial growth factor), and pH-weighted amine- chemical exchange saturation transfer (CEST) MRI to quantify tumor acidity at baseline and explore associations with drug response. Stage 1 enrolled 24 patients with early stoppage for ≤ 1 ORR. RESULTS: Of the 24 enrolled patients, median age was 62.1 (38.7-76.7) years, median KPS 80, MGMT promoter was methylated in 46% of tumors. PT2385 was well tolerated. Grade ≥ 3 drug-related adverse events were hypoxia (n = 2), hyponatremia (2), lymphopenia (1), anemia (1), and hyperglycemia (1). No objective radiographic responses were observed; median PFS was 1.8 months (95% CI 1.6-2.5) and OS was 7.7 months (95% CI 4.9-12.6). Drug exposure varied widely and did not differ by corticosteroid use (p = 0.12), antiepileptics (p = 0.09), or sex (p = 0.37). Patients with high systemic exposure had significantly longer PFS (6.7 vs 1.8 months, p = 0.009). Baseline acidity by pH-weighted CEST MRI correlated significantly with treatment duration (R2 = 0.49, p = 0.017). Non-enhancing infiltrative disease with high acidity gave rise to recurrence. CONCLUSIONS: PT2385 monotherapy had limited activity in first recurrent GBM. Drug exposure was variable. Signals of activity were observed in GBM patients with high systemic exposure and acidic lesions on CEST imaging. A second-generation HIF2α inhibitor is being studied.

Routine use of low-dose glucarpidase following high-dose methotrexate in adult patients with CNS lymphoma: an open-label, multi-center phase I study.

BACKGROUND: High-dose methotrexate (HD-MTX) has broad use in the treatment of central nervous system (CNS) malignancies but confers significant toxicity without inpatient hydration and monitoring. Glucarpidase is a bacterial recombinant enzyme dosed at 50 units (u)/kg, resulting in rapid systemic MTX clearance. The aim of this study was to demonstrate feasibility of low-dose glucarpidase to facilitate MTX clearance in patients with CNS lymphoma (CNSL). METHODS: Eight CNSL patients received HD-MTX 3 or 6 g/m2 and glucarpidase 2000 or 1000u 24 h later. Treatments repeated every 2 weeks up to 8 cycles. RESULTS: Fifty-five treatments were administered. Glucarpidase 2000u yielded > 95% reduction in plasma MTX within 15 min following 33/34 doses (97.1%) and glucarpidase 1000u yielded > 95% reduction following 15/20 doses (75%). Anti-glucarpidase antibodies developed in 4 patients and were associated with MTX rebound. In CSF, glucarpidase was not detected and MTX levels remained cytotoxic after 1 (3299.5 nmol/L, n = 8) and 6 h (1254.7 nmol/L, n = 7). Treatment was safe and well-tolerated. Radiographic responses in 6 of 8 patients (75%) were as expected following MTX-based therapy. CONCLUSIONS: This study demonstrates feasibility of planned-use low-dose glucarpidase for MTX clearance and supports the hypothesis that glucarpidase does not impact MTX efficacy in the CNS. CLINICAL TRIAL REGISTRATION: NCT03684980 (Registration date 26/09/2018).

Phase 1b trial of an ibrutinib-based combination therapy in recurrent/refractory CNS lymphoma.

Ibrutinib is a first-in-class inhibitor of Bruton tyrosine kinase (BTK) and has shown single-agent activity in recurrent/refractory central nervous system (CNS) lymphoma. Clinical responses are often transient or incomplete, suggesting a need for a combination therapy approach. We conducted a phase 1b clinical trial to explore the sequential combination of ibrutinib (560 or 840 mg daily dosing) with high-dose methotrexate (HD-MTX) and rituximab in patients with CNS lymphoma (CNSL). HD-MTX was given at 3.5 g/m2 every 2 weeks for a total of 8 doses (4 cycles; 1 cycle = 28 days). Ibrutinib was held on days of HD-MTX infusion and resumed 5 days after HD-MTX infusion or after HD-MTX clearance. Single-agent daily ibrutinib was administered continuously after completion of induction therapy until disease progression, intolerable toxicity, or death. We also explored next-generation sequencing of circulating tumor DNA (ctDNA) in cerebrospinal fluid (CSF) before and during treatment. The combination of ibrutinib, HD-MTX, and rituximab was tolerated with an acceptable safety profile (no grade 5 events, 3 grade 4 events). No dose-limiting toxicity was observed. Eleven of 15 patients proceeded to maintenance ibrutinib after completing 4 cycles of the ibrutinib/HD-MTX/rituximab combination. Clinical responses occurred in 12 of 15 patients (80%). Sustained tumor responses were associated with clearance of ctDNA from the CSF. This trial was registered at www.clinicaltrials.gov as #NCT02315326.

The consistency of neuropathological diagnoses in patients undergoing surgery for suspected recurrence of glioblastoma.

PURPOSE: Clinical factors and neuro-imaging in patients with glioblastoma who appear to progress following standard chemoradiation are unable to reliably distinguish tumor progression from pseudo-progression. As a result, surgery is commonly recommended to establish a final diagnosis. However, studies evaluating the pathologists' agreement on pathologic diagnoses in this setting have not been previously evaluated. METHODS: A hypothetical clinical history coupled with images of histological sections from 13 patients with glioblastoma who underwent diagnostic surgery for suspected early recurrence were sent to 101 pathologists from 50 NCI-designated Cancer Centers. Pathologists were asked to provide a final diagnosis (active tumor, treatment effect, or unable to classify) and to report on percent active tumor, treatment effect, and degree of cellularity and degree of mitotic activity. RESULTS: Forty-eight pathologists (48%) from 30 centers responded. In three cases > 75% of pathologists diagnosed active tumor. In two cases > 75% diagnosed treatment effect. However, in the remaining eight cases the disparity in diagnoses was striking (maximum agreement on final diagnosis ranged from 36 to 68%). Overall, only marginal agreement was observed in the overall assessment of disease status [kappa score 0.228 (95% CI 0.22-0.24)]. CONCLUSIONS: Confidence in any clinical diagnostic assay requires that very similar results are obtained from identical specimens evaluated by sophisticated clinicians and institutions. The findings of this study illustrate that the diagnostic agreement between different cases of repeat resection for suspected recurrent glioblastoma can be variable. This raises concerns as pathological diagnoses are critical in directing standard and experimental care in this setting.

The effect of regadenoson on the integrity of the human blood-brain barrier, a pilot study.

Regadenoson is an FDA approved adenosine receptor agonist which increases blood-brain barrier (BBB) permeability in rodents. Regadenoson is used clinically for pharmacologic cardiac stress testing using SPECT or CT imaging agents that do not cross an intact BBB. This study was conducted to determine if standard doses of regadenoson transiently disrupt the human BBB allowing higher concentrations of systemically administered imaging agents to enter the brain. Patients without known intracranial disease undergoing clinically indicated pharmacologic cardiac stress tests were eligible for this study. They received regadenoson (0.4 mg) followed by brain imaging with either 99mTc-sestamibi for SPECT or visipaque for CT imaging. Pre- and post-regadenoson penetration of imaging agents into brain were quantified [SPECT: radioactive counts, CT: Hounsfield units (HU)] and compared using a matched-pairs t-test. Twelve patients (33% male, median 60 yo) were accrued: 7 SPECT and 5 CT. No significant differences were noted in pre- and post-regadenoson values using mean radionuclide counts (726 vs. 757) or HU (29 vs. 30). While animal studies have demonstrated that regadenoson transiently increases the permeability of the BBB to dextran and temozolomide, we were unable to document changes in the penetration of contrast agents in humans with intact BBB using the FDA approved doses of regadenoson for cardiac evaluation. Further studies are needed exploring alternate regadenoson dosing, schedules, and studies in patients with brain tumors; as transiently disrupting the BBB to improve drug entry into the brain is critical to improving the care of patients with CNS malignancies.

Serial changes in lymphocyte subsets in patients with newly diagnosed high grade astrocytomas treated with standard radiation and temozolomide.

The immune system plays a significant role in cancer prevention and outcome. In high grade astrocytomas (HGA), severe lymphopenia is associated with shortened survival due to tumor progression. This study was performed to quantify serial changes in lymphocyte subsets in HGA following standard radiation (RT) and temozolomide (TMZ). Adults (KPS >60, HIV negative) with newly diagnosed HGA scheduled to receive concurrent RT and TMZ and adjuvant TMZ were eligible. Blood was collected before beginning concurrent RT/TMZ and at weeks 6, 10, 18, and 26, and 3 months after completing adjuvant TMZ. Lymphocyte subsets were analyzed by flow cytometry. Twenty patients (70% glioblastoma, median age 53, 50% male, 80% Caucasian) who enrolled from January 2014 to August 2014 were followed until April 2016. Baseline dexamethasone dose was 0.5 mg/day and 15% had absolute lymphocyte counts (ALC) <1000 cells/mm3 before starting RT/TMZ. However, 75% developed lymphopenia with ALC <1000 cells/mm3 after completion of RT/TMZ. NK cells, B cells and all T lymphocytes subsets dropped significantly after concurrent RT/TMZ and remained depressed for the 48 weeks of observation. The CD4+/CD8+ ratio was not affected significantly during follow-up. Severe lymphopenia involving all subsets occurred early in treatment and remained present for nearly 1 year. To our knowledge, this is the first report of serial trends in lymphocyte subsets following standard RT and TMZ for HGA.

Lymphopenia and its association with survival in patients with locally advanced cervical cancer.

OBJECTIVE: To evaluate the association between lymphopenia and survival in women with cervical cancer treated with primary chemoradiation. METHODS: A single institution, retrospective analysis of patients with stage IB2-IVA cervical cancer who received upfront chemoradiation from 1998 to 2013 was performed. Complete blood counts from pre-treatment to 36 months post-treatment were analyzed. Lymphopenia and known prognostic factors were evaluated for an association with progression-free (PFS) and overall survival (OS). RESULTS: Seventy-one patients met study criteria for whom 47 (66%) had a documented total lymphocyte count (TLC) two months after initiating chemoradiation. FIGO stage distribution was 6% Stage I, 46% Stage II, 45% Stage III and 3% Stage IV. Pre-treatment TLC was abnormal (<1000 cells/mm3) in 15% of patients. The mean reduction in TLC was 70% two months after initiating chemoradiation. Severe post-treatment lymphopenia (TLC <500 cells/mm3) was observed in 53% of patients; they experienced inferior median OS (21.2 vs. 45.0 months, P=0.03) and similar 25th percentile PFS (6.3 vs. 7.7 months, P=0.06) compared to patients without severe lymphopenia. Multivariate analysis demonstrated pre-treatment TLC ≥1000 cells/mm3 and post-treatment TLC >500 cells/mm3 had a 77% (HR: 0.23; 95% CI 0.05-1.03; P=0.053) and 58% decrease in hazards of death (HR: 0.42; 95%CI 0.12-1.46; P=0.17) respectively. CONCLUSION: More than half of cervical cancer patients treated with chemoradiation experienced severe and prolonged lymphopenia. Although statistical significance was not reached, the findings suggest that pre- and post-treatment lymphopenia may be associated with decreased survival. Further research is warranted, given that lymphopenia could be a reversible prognostic factor.

Caring for Patients with Newly Diagnosed High-Grade Gliomas.

Novel diagnostic and therapeutic information has had a major impact on the care of patients with high-grade gliomas. These advances and discoveries are highlighted using case-based discussions to focus attention on the important diagnostic and treatment decisions that commonly arise during the care of patients with newly diagnosed glioblastoma, anaplastic astrocytoma, and anaplastic oligodendroglioma.

Magnetic resonance imaging findings in patients presenting with (sub)acute cerebellar ataxia.

INTRODUCTION: Acute or subacute cerebellar inflammation is mainly caused by postinfectious, toxic, neoplastic, vascular, or idiopathic processes and can result in cerebellar ataxia. Previous magnetic resonance (MR) studies in single patients who developed acute or subacute ataxia showed varying imaging features. METHODS: Eighteen patients presenting with acute and subacute onset of ataxia were included in this study. Cases of chronic-progressive/hereditary and noncerebellar causes (ischemia, multiple sclerosis lesions, metastasis, bleedings) were excluded. MR imaging findings were then matched with the clinical history of the patient. RESULTS: An underlying etiology for ataxic symptoms were found in 14/18 patients (postinfectious/infectious, paraneoplastic, autoimmune, drug-induced). In two of five patients without MR imaging findings and three of eight patients with minimal imaging features (cerebellar atrophy, slight signal alterations, and small areas of restricted diffusion), adverse clinical outcomes were documented. Of the five patients with prominent MR findings (cerebellar swelling, contrast enhancement, or broad signal abnormalities), two were lost to follow-up and two showed long-term sequelae. CONCLUSION: No correlation was found between the presence of initial MRI findings in subacute or acute ataxia patients and their long-term clinical outcome. MR imaging was more flagrantly positive in cases due to encephalitis.

A multicenter, phase 1, Adult Brain Tumor Consortium trial of oral terameprocol for patients with recurrent high-grade glioma (GATOR).

Recurrent high-grade gliomas (rHGGs) have a dismal prognosis, where the maximum tolerated dose (MTD) of IV terameprocol (5 days/month), a transcriptional inhibitor of specificity protein 1 (Sp1)-regulated proteins, is 1,700 mg/day with median area under the plasma concentration-time curve (AUC) of 31.3 µg∗h/mL. Given potentially increased efficacy with sustained systemic exposure and challenging logistics of daily IV therapy, here we investigate oral terameprocol for rHGGs in a multicenter, phase 1 trial (GATOR). Using a 3 + 3 dose-escalation design, we enroll 20 patients, with median age 60 years (range 31-80), 70% male, and median one relapse (range 1-3). Fasting patients tolerate 1,200 mg/day (n = 3), 2,400 mg/day (n = 6), 3,600 mg/day (n = 3), and 6,000 mg/day (n = 2) oral doses without major toxicities. However, increased dosage does not lead to increased systemic exposure, including in fed state (6,000 mg/day, n = 4), with maximal AUC <5 µg∗h/mL. These findings warrant trials investigating approaches that provide sustained systemic levels of transcription inhibitors to exploit their therapeutic potential. This study was registered at ClinicalTrials.gov (NCT02575794).

Clinical, histological, and molecular features of gliomas in adults with neurofibromatosis type 1.

BACKGROUND: People with NF1 have an increased prevalence of central nervous system malignancy. However, little is known about the clinical course or pathologic features of NF1-associated gliomas in adults, limiting clinical care and research. METHODS: Adults (≥18 years) with NF1 and histologically confirmed non-optic pathway gliomas (non-OPGs) at Johns Hopkins Hospital, Memorial Sloan Kettering Cancer Center, and Washington University presenting between 1990 and 2020 were identified. Retrospective data were collated, and pathology was reviewed centrally. RESULTS: Forty-five patients, comprising 23 females (51%), met eligibility criteria, with a median of age 37 (18-68 years) and performance status of 80% (30%-100%). Tissue was available for 35 patients. Diagnoses included infiltrating (low-grade) astrocytoma (9), glioblastoma (7), high-grade astrocytoma with piloid features (4), pilocytic astrocytoma (4), high-grade astrocytoma (3), WHO diagnosis not reached (4) and one each of gliosarcoma, ganglioglioma, embryonal tumor, and diffuse midline glioma. Seventy-one percent of tumors were midline and underwent biopsy only. All 27 tumors evaluated were IDH1-wild-type, independent of histology. In the 10 cases with molecular testing, the most common genetic variants were NF1, EGFR, ATRX, CDKN2A/B, TP53, TERT, and MSH2/3 mutation. While the treatments provided varied, the median overall survival was 24 months [2-267 months] across all ages, and 38.5 [18-109] months in individuals with grade 1-2 gliomas. CONCLUSIONS: Non-OPGs in adults with NF1, including low-grade tumors, often have an aggressive clinical course, indicating a need to better understand the pathobiology of these NF1-associated gliomas.

Clinical trial of proton craniospinal irradiation for leptomeningeal metastases.

BACKGROUND: Leptomeningeal metastases (LM) are associated with limited survival and treatment options. While involved-field radiotherapy is effective for local palliation, it lacks durability. We evaluated the toxicities of proton craniospinal irradiation (CSI), a treatment encompassing the entire central nervous system (CNS) compartment, for patients with LM from solid tumors. METHODS: We enrolled patients with LM to receive hypofractionated proton CSI in this phase I prospective trial. The primary endpoint was to describe treatment-related toxicity, with dose-limiting toxicity (DLT) defined as any radiation-related grade 3 non-hematologic toxicity or grade 4 hematologic toxicity according to the Common Terminology Criteria for Adverse Events that occurred during or within 4 weeks of completion of proton CSI. Secondary endpoints included CNS progression-free survival (PFS) and overall survival (OS). RESULTS: We enrolled 24 patients between June 2018 and April 2019. Their median follow-up was 11 months. Twenty patients were evaluable for protocol treatment-related toxicities and 21 for CNS PFS and OS. Two patients in the dose expansion cohort experienced DLTs consisted of grade 4 lymphopenia, grade 4 thrombocytopenia, and/or grade 3 fatigue. All DLTs resolved without medical intervention. The median CNS PFS was 7 months (95% CI: 5-13) and the median OS was 8 months (95% CI: 6 to not reached). Four patients (19%) were progression-free in the CNS for more than 12 months. CONCLUSION: Hypofractionated proton CSI using proton therapy is a safe treatment for patients with LM from solid tumors. We saw durable disease control in some patients.

Preclinical and first-in-human-brain-cancer applications of [18F]poly (ADP-ribose) polymerase inhibitor PET/MR.

BACKGROUND: We report preclinical and first-in-human-brain-cancer data using a targeted poly (ADP-ribose) polymerase 1 (PARP1) binding PET tracer, [18F]PARPi, as a diagnostic tool to differentiate between brain cancers and treatment-related changes. METHODS: We applied a glioma model in p53-deficient nestin/tv-a mice, which were injected with [18F]PARPi and then sacrificed 1 h post-injection for brain examination. We also prospectively enrolled patients with brain cancers to undergo dynamic [18F]PARPi acquisition on a dedicated positron emission tomography/magnetic resonance (PET/MR) scanner. Lesion diagnosis was established by pathology when available or by Response Assessment in Neuro-Oncology (RANO) or RANO-BM response criteria. Resected tissue also underwent PARPi-FL staining and PARP1 immunohistochemistry. RESULTS: In a preclinical mouse model, we illustrated that [18F]PARPi crossed the blood-brain barrier and specifically bound to PARP1 overexpressed in cancer cell nuclei. In humans, we demonstrated high [18F]PARPi uptake on PET/MR in active brain cancers and low uptake in treatment-related changes independent of blood-brain barrier disruption. Immunohistochemistry results confirmed higher PARP1 expression in cancerous than in noncancerous tissue. Specificity was also corroborated by blocking fluorescent tracer uptake with an excess unlabeled PARP inhibitor in patient cancer biospecimen. CONCLUSIONS: Although larger studies are necessary to confirm and further explore this tracer, we describe the promising performance of [18F]PARPi as a diagnostic tool to evaluate patients with brain cancers and possible treatment-related changes.

Genomic Correlates of Disease Progression and Treatment Response in Prospectively Characterized Gliomas.

PURPOSE: The genomic landscape of gliomas has been characterized and now contributes to disease classification, yet the relationship between molecular profile and disease progression and treatment response remain poorly understood.Experimental Design: We integrated prospective clinical sequencing of 1,004 primary and recurrent tumors from 923 glioma patients with clinical and treatment phenotypes. RESULTS: Thirteen percent of glioma patients harbored a pathogenic germline variant, including a subset associated with heritable genetic syndromes and variants mediating DNA repair dysfunctions (29% of the total) that were associated with somatic biallelic inactivation and mechanism-specific somatic phenotypes. In astrocytomas, genomic alterations in effectors of cell-cycle progression correlated with aggressive disease independent of IDH mutation status, arose preferentially in enhancing tumors (44% vs. 8%, P < 0.001), were associated with rapid disease progression following tumor recurrence (HR = 2.6, P = 0.02), and likely preceded the acquisition of alkylating therapy-associated somatic hypermutation. Thirty-two percent of patients harbored a potentially therapeutically actionable lesion, of whom 11% received targeted therapies. In BRAF-mutant gliomas, response to agents targeting the RAF/MEK/ERK signaling axis was influenced by the type of mutation, its clonality, and its cellular and genomic context. CONCLUSIONS: These data reveal genomic correlates of disease progression and treatment response in diverse types of glioma and highlight the potential utility of incorporating genomic information into the clinical decision-making for patients with glioma.

Systemic depletion of lymphocytes following focal radiation to the brain in a murine model.

Severe radiation-related lymphopenia is common and associated with decreased survival in patients with several solid tumors. As the mechanisms underlying systemic lymphopenia are poorly understood, we developed an animal model to study the effects of brain radiation on lymphocytes and cytokines. C57 BL/6 and BALB/c mice received focal brain irradiation (4 Gy x 10 fractions or 2 Gy x 30 fractions). Weekly total lymphocyte counts (TLC), lymphocyte subsets and cytokines in blood and lymph nodes were measured. Non-irradiated lymph nodes were collected and examined before, during, and after radiation. We found that systemic TLC decreased rapidly irrespective of mouse strain or radiation schedule. 4 Gy x 10 resulted in a 42% and 75% & 70% and 49% TLC reduction in C57 BL/6 and BALB/c mice respectively. 2 Gy x 30 caused a 70% / 49% decrease in TLC in C57 BL/6 and BALB/c. Similar trends were seen for total T cells, CD4+, regulatory T and CD8+ cells. Changes in lymph node architecture and cellular composition correlated with the development of systemic lymphopenia. Three weeks after radiation, TLC returned to 60-80% of baseline, preceded by increased IL-7 levels in the lymph nodes. Focal brain radiation in mice results in significant systemic lymphodepletion.

Immune Control Despite Protracted Lymphopenia After Chemoradiation in an Elite Controller.

Elite controllers are human immunodeficiency virus-1-positive individuals capable of sustaining undetectable viral loads without treatment. We present the case of an elite controller diagnosed with extensive stage small cell lung cancer who maintained a viral load of <20 copies/mL despite the development of severe treatment-related lymphopenia.

Clinical Management of Seizures in Patients With Low-Grade Glioma.

Seizures, transient disruptions of normal brain electrical activity, are common for patients with low-grade glioma (LGG) and significantly affect quality of life. Up to 75% of patients with a LGG will have seizures in the course of their disease (compared with 1%-2% of the general population). Depending on the type of abnormal electrical activity, the functional implications of seizure can impact any domain, including mental status, sensation or strength. In most cases, either the seizure or the medications used to treat the seizure may contribute to cognitive and psychosocial difficulties of various degrees of severity. Hence, effective management of seizures is a major priority for patients with LGG. Evidence-based guidelines suggest that levetiracetam is the best first-line agent for treatment of seizures in this population due to both its efficacy and tolerability. An important consideration in the field of neuro-oncology is that levetiracetam has very few drug interactions. Unfortunately, approximately one-third of patients with LGG have refractory epilepsy where additional agents such as valproic acid, or lacosamide, lamotrigine and nonpharmacologic therapies such as diet-based interventions, epilepsy surgery, and devices are considered.