Recurrent Central Nervous System Tumors Research Articles

OH2 oncolytic virus: A novel approach to glioblastoma intervention through direct targeting of tumor cells and augmentation of anti-tumor immune responses

Glioblastoma (GBM), the deadliest central nervous system cancer, presents a poor prognosis and scant therapeutic options. Our research spotlights OH2, an oncolytic viral therapy derived from herpes simplex virus 2 (HSV-2), which demonstrates substantial antitumor activity and favorable tolerance in GBM. The extraordinary efficacy of OH2 emanates from its unique mechanisms: it selectively targets tumor cells replication, powerfully induces cytotoxic DNA damage stress, and kindles anti-tumor immune responses. Through single-cell RNA sequencing analysis, we discovered that OH2 not only curtails the proliferation of cancer cells and tumor-associated macrophages (TAM)-M2 but also bolsters the infiltration of macrophages, CD4+ and CD8+ T cells. Further investigation into molecular characteristics affecting OH2 sensitivity revealed potential influencers such as TTN, HMCN2 or IRS4 mutations, CDKN2A/B deletion and IDO1 amplification. This study marks the first demonstration of an HSV-2 derived OV's effectiveness against GBM. Significantly, these discoveries have driven the initiation of a phase I/II clinical trial (ClinicalTrials.gov: NCT05235074). This trial is designed to explore the potential of OH2 as a therapeutic option for patients with recurrent central nervous system tumors following surgical intervention.

A phase 2 study of sirolimus in combination with metronomic chemotherapy (CHOAnome) in children with recurrent and/or refractory solid and CNS tumors.

10024 Background: Multiple low-dose, anti-angiogenic (metronomic) chemotherapy regimens have demonstrated activity in pediatric solid and central nervous system (CNS) tumors. The mTOR pathway is activated in many human cancers and provides an attractive therapeutic target. We previously conducted a phase 1 trial establishing the dose (2 mg/m2), safety and tolerability of sirolimus in combination with metronomic chemotherapy. In the current study, we conducted a prospective, multi-institutional phase 2 trial to determine the objective response rate (ORR) in pediatric patients with recurrent and/or refractory (R/R) solid and CNS tumors treated with this regimen (NCT02574728); herein we report the results of the CNS tumor stratum. Methods: Patients aged 12 months to 30 years with R/R CNS tumors of all world health organization (WHO) grades were eligible. After completion of the trial’s first stage, patients with diffuse intrinsic pontine glioma (DIPG) were excluded due to lack of efficacy. Patients were required to have measurable disease and no known curative therapeutic options. Treatment consisted of continuous sirolimus (2 mg/m2/dose PO daily), celecoxib (100 mg PO BID), and oral etoposide (50 mg/m2/day; max dose: 100 mg) alternating every 21 days with oral cyclophosphamide (2.5 mg/kg/day; max dose: 100 mg) in 42-day cycles. Sirolimus was dose-adjusted to maintain a serum trough concentration of 10-15 ng/ml. Response was determined using a modified Response Assessment in Neuro-Oncology (RANO) criteria. Enrollment proceeded using a Fleming’s two-stage design based on best overall response (BOR), which required two objective disease status determinations. Results: Twenty-two CNS tumor patients were enrolled; 20/22 were evaluable for response. Median age was 11.2 years (range: 5.9 – 18.1); 6 (30%) were female. Diagnoses included DIPG (N = 5), medulloblastoma (N = 3), high-grade (HG) glioma (N = 5), HG/malignant neuroepithelial tumor (N = 3) and one each of diffuse midline glioma, atypical teratoid/rhabdoid tumor (ATRT), choroid plexus carcinoma, and pineoblastoma. Median number of cycles was 2 (range: 1-6). Best response after any cycle was partial response (PR) in 4 [medulloblastoma (N = 3); pineoblastoma (N = 1)], stable disease (SD) in 4, and progressive disease (PD) in 12 for an ORR of 20%; all patients with DIPG had PD at or before their first disease evaluation. BOR was PR in 3 (15%), SD in 2 (10%), PD in 14 (70%), and unknown in 1 (5%). Four patients had SD or response for ≥ 6 months [medulloblastoma (n = 1), pineoblastoma (N = 1), and HG glioma (N = 2)]. Conclusions: The combination of sirolimus with metronomic chemotherapy showed activity in pediatric patients with some R/R CNS tumors, producing objective responses in medulloblastoma and pineoblastoma. Patients with DIPG did not benefit from this regimen and should be offered alternative treatments. Clinical trial information: NCT02574728 .

ВЫСОКОДОЗНАЯ ХИМИОТЕРАПИЯ С АУТОЛОГИЧНОЙ ТРАНСПЛАНТАЦИЕЙ ГЕМОПОЭТИЧЕСКИХ СТВОЛОВЫХ КЛЕТОК ПРИ РЕЦИДИВАХ ОПУХОЛЕЙ ЦНС: АКТУАЛЬНЫЕ ВОПРОСЫ И ЭФФЕКТИВНОСТЬ

Intensification of antitumor treatment using high-dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation (aHSCT) has been an effective option for many years in a number of nosological forms of central nervous system (CNS) tumors in children as the first-choice therapy. However, its benefits in relapsing forms of the disease are not obvious, which has led to ongoing discussions. Studies on the comparative efficacy of HDCT in recurrent CNS tumors are few. The heterogeneity of the studied patient cohorts should be noted additionally, which in its turn does not allow reaching a consensus on indications for its use. The Article represents current bibliographical data on the use of HDCT with aHSCT in pediatric patients with relapses of various nosological forms of CNS tumors in terms of its possible effectiveness and toxicity.

GEN-13 PAIRED MUTATIONAL ANALYSIS IN SECONDARY NERVOUS SYSTEM LYMPHOMA AND PCNSL SYSTEMIC RELAPSE REVEALS DRIVER MUTATION CANDIDATES IN THE CENTRAL NERVOUS SYSTEM

Abstract Primary central nervous system lymphoma (PCNSL) is an aggressive extranodal non-Hodgkin lymphoma confined to the brain, eyes, and the spinal cord. The mechanism of central nervous system (CNS) tropism in PCNSL has not been fully elucidated. Diffuse large B cell lymphomas (DLBCLs) occasionally present with distant recurrence, which can involve inside and outside the CNS. Secondary central nervous system lymphomas (SCNSLs) are CNS relapse of systemic lymphoma. PCNSLs also rarely present with systemic relapse. We have previously reported in our study of whole exome sequencing that PCNSLs harbor frequent mutations in genes of B cell receptor pathway members and aberrant somatic hypermutation (aSHM) target genes. Although several genetic alterations were identified as more frequent in PCNSLs compared with systemic lymphomas, specific genetic alterations which serve as the driver for CNS tropism in PCNSLs has not been identified. In order to search for mutations which might serve as driver mutations in the CNS, we have performed targeted sequencing in paired samples from patients with recurrent lymphomas, either SCNSLs or PCNSL systemic relapses, using Ion Torrent multiplex PCR. Mutational profiles were compared between the primary and recurrent tumor. Six cases (four SCNSL cases and two PCNSL systemic relapse cases) were analyzed. Of note, in the SCNSL cases, several de novo mutations were enriched only among the recurrent CNS tumors. Among these mutations, BTG2 mutations were observed in 3/4 (75%), and B2M and KLHL14 mutations were observed in 2/4 (50%) cases. In the two PCNSL systemic relapse cases, KMT2D mutations were enriched only in the recurrent systemic tumors. It is suggested that these de novo mutations in the recurrent CNS tumors might serve as driver mutations in the CNS. Further analysis in larger cohorts, and functional studies are required in order to validate these findings.

Pulsed Reduced Dose Rate (PRDR) Intensity Modulated Radiotherapy for Recurrent Primary Central Nervous System Malignancies: Dosimetric and Clinical Results

<h3>Purpose/Objective(s)</h3> Pulsed reduced dose rate (PRDR) intensity-modulated radiotherapy (IMRT) is a reirradiation approach that may reduce the risk of toxicities in the setting of prior radiotherapy (RT) for recurrent central nervous system (CNS) malignancies. However, toxicities and cumulative doses (in EQD2) to CNS structures are not uniformly reported. We shared our institutional outcomes of PRDR and reported cumulative doses for CNS organs-at-risk (OARs) <h3>Materials/Methods</h3> Consecutive patients diagnosed with recurrent primary CNS tumors treated with PRDR from April 2017 to September 2021 were evaluated. Data collected included number of prior interventions, diagnosis, tumor grade, RT dose and fractionation, cumulative OAR doses, progression-free survival (PFS), overall survival (OS), and adverse events. A systematic review of literature was also performed, and results were compared to this study. <h3>Results</h3> Eighteen patients met inclusion criteria (11 WHO grade 4 glioma, 6 grade 3 glioma, and 1 grade 2 glioma). All patients had at least 1 surgery (range 1-4) and 2 systemic therapy regimens (range 2-6) before PRDR. The median dose for the first course of RT was 59.4 Gy (range: 50-75 Gy) in 33 fractions and the median time from the initial RT to PRDR was 35.6 months (range: 7.0-122.0 months). The median PRDR dose was 45 Gy (range: 36-59.4 Gy) in 25 fractions; the median cumulative EQD2 dose was 107.6 Gy (93.1-132.5 Gy). The median target volume was 134.9 cc (range: 17.9-696.6 cc). The median cumulative EQD2 Dmax values for the brain and brainstem were 111.4 Gy (range: 82.4-175.2 Gy), and 85.4 Gy (range: 14.8-111.6 Gy). At a median follow-up of 6.2 months, grade 2+ treatment-related toxicities were seen in 12 (66.7%) patients. Symptomatic radiation necrosis occurred in 3 (16.7%) patients, the median EQD2 brain Dmax for these patients was 115.9 Gy (110.4-156.7 Gy). In addition, two patients had grade 3 toxicity (fatigue and hearing impairment); no Grade 4+ toxicities were observed. The median PFS and OS after PRDR were 6.3 months (95% Cl: 0.9-11.6 months) and 8.6 months (95% Cl: 4.9-12.3 months), respectively. The systematic review analyzed 5 peer-reviewed studies reporting outcomes for reirradiation with PRDR for 188 patients. The median PRDR dose was 50 Gy (range: 22-60 Gy) in 25 fractions with a median cumulative dose of 110.3 Gy to a median tumor volume of 369.1 cc. At a median follow-up of 8.7 months, the total number of grade 3+ toxicities was 24, but time-dependent analyses were not uniformly reported. <h3>Conclusion</h3> This study supports PRDR reirradiation as a feasible and appropriate strategy for recurrent primary CNS tumors where other options have been exhausted. Despite high cumulative EQD2 to the OARs, the risk of developing high-grade toxicities remains acceptable; the median cumulative brain EQD2 dose for developing necrosis is 115.9 Gy.

A CASE OF LOMUSTINE-INDUCED PNEUMONITIS

A CASE OF LOMUSTINE-INDUCED PNEUMONITIS

IMMU-09. Interim analysis from BrainChild-03: Seattle Children’s Locoregional B7-H3 CAR T Cell Trial for Children with Recurrent Central Nervous System Tumors and DIPG

Abstract BrainChild-03 is a phase 1 clinical trial delivering repeated locoregional 2nd generation B7-H3 CAR T cells with 4-1BB co-stimulation to children with central nervous system (CNS) tumors without lymphodepleting chemotherapy. The primary endpoints are feasibility and safety, with secondary endpoints of disease response and correlatives of CAR T cell activity. There are 3 arms: (A) – weekly delivery into the tumor cavity, (B) – weekly delivery into the lateral ventricle for metastatic disease, (C) – biweekly delivery into the lateral ventricle for diffuse intrinsic pontine glioma (DIPG). In total, 23/24 (96%) enrolled patients have had successful CAR T manufacturing. 16/24 patients are evaluable and have received a total of 141 intracranial CAR T cell doses. Unevaluable patients include 5 never treated and 3 who progressed prior to receiving the minimum doses to become evaluable. The most common adverse events have been headache (16/16, 100%), nausea/vomiting (12/16, 75%), and fever (10/16, 63%). There has been 1 DLT for an intratumoral hemorrhage and no cytokine release syndrome (CRS). 7 evaluable patients with DIPG (Arm C) have received a cumulative 50 infusions. 5/7 DIPG patients enrolled after progression and have a median survival of 246.5 days post-initial CAR T cell infusion, with 4/5 still alive. The 2 DIPG patients enrolled prior to progression had radiographic improvement, including 1 with improvement of a cranial nerve 6 palsy who self-withdrew from protocol therapy after 18 infusions over 12 months and 1 still on protocol therapy after 11 infusions over 6 months. DIPG patients have had increased CSF levels of proinflammatory mediators (e.g. CXCL10, CCL2, IFNg, GM-CSF, IL-12) without systemic cytokine changes. 5/7 DIPG patients had detectable CAR T cells in their CSF post-infusion. Ultimately, the preliminary experience suggests locoregional delivery of B7-H3 CAR T cells may be feasible and tolerable in children with CNS tumors, including DIPG.

LGG-42. Thromboembolic toxicity observed with concurrent trametinib and lenalidomide therapy

INTRODUCTION: Event-free survival of pediatric low-grade glioma (pLGG) is poor, and patients often require multiple treatment strategies. The hallmark of pLGGs are genetic aberrations of the mitogen-activated protein kinase pathway, which lead to constitutive pathway activation. MEK and RAF inhibitors target this pathway and are efficacious in early phase trials in recurrent pLGGs. However, not all patients respond to monotherapy, and many experience progression after completion of therapy. Evaluating combination therapies that may enhance efficacy or prolong disease stabilization is warranted. Lenalidomide is an immunomodulatory agent with an anti-tumor effect demonstrated in phase 1 trials in recurrent pediatric central nervous system (CNS) tumors. OBJECTIVE: To describe our institutional experience using concurrent trametinib and lenalidomide in the treatment of primary pediatric central and peripheral nervous system (PNS) tumors. METHODS: Retrospective review of patients’ medical records. RESULTS: Four patients with locally recurrent primary CNS or PNS tumors, three with WHO grade II pilomyxoid astrocytomas and one with a plexiform neurofibroma, were treated with trametinib and lenalidomide concurrently. Two patients developed severe thromboembolic events. One patient was treated with combination therapy for seven months until trametinib and lenalidomide were held after urgent ventriculoperitoneal shunt revision. Shortly following shunt revision, he experienced near-complete vision loss. MRI of the brain demonstrated a left posterior watershed territory hypoxic-ischemic injury. In a second patient, after four months of combination therapy, surveillance echocardiogram showed an incidental finding of severe biventricular dysfunction with a left ventricular ejection fraction (LVEF) of 17.7% and two mural thrombi in the left ventricular apex. She started losartan and enoxaparin and discontinued trametinib and lenalidomide. Her LVEF normalized four months later, and the mural thrombi resolved. CONCLUSIONS: Given the severe thromboembolic events experienced by these patients treated with concomitant trametinib and lenalidomide, this combination requires further investigation, and we urge caution if used concurrently.

Abstract P162: Phase 1 trial of selinexor in children and adolescents with recurrent/refractory solid and CNS tumors (ADVL1414): A Children’s Oncology Group Phase 1 Consortium trial

Abstract Introduction: Selinexor is a first-in-class, central nervous system (CNS) penetrant, oral inhibitor of exportin 1 (XPO1), the sole nuclear exporter of many key tumor suppressors. Selinexor is FDA-approved for refractory multiple myeloma and DLBCL and has been evaluated in a phase 1 trial in children with leukemia. We report a phase 1 trial of selinexor in children and adolescents with recurrent CNS and solid tumors, including lymphoma (NCT02323880). Methods: A rolling-six design was used to evaluate selinexor (10 or 25 mg tablets) administered twice or once weekly during a 28-day cycle. Dose determination was based on protocol-defined dose limiting toxicity (DLT) using CTCAEv4 during cycle 1. First dose pharmacokinetics (PK) were performed. Results: 43 subjects were enrolled (17 males); median (range) age was 15 (6-20) years. 27 (63%) had CNS tumors, most commonly high-grade glioma (n=12); 16 (37%) had extracranial solid tumors. 42 were evaluable for DLT. At the starting dose (35 mg/m2/dose, twice weekly), no DLTs were observed in 6 subjects, however, 2 subjects had unexpected late myelosuppression delaying initiation of cycle 2. The dosing schedule was amended to twice weekly for 3 weeks followed by a 1 week break. 12 subjects received 35 mg/m2/dose; 4 experienced DLTs [grade 3 fatigue (n=2), grade 3 thrombocytopenia (n=1), or grade 3 ALT increase (n=1)]. The dose was de-escalated to 20 mg/m2/dose, 3 weeks on, 1 week off. 12 subjects enrolled; 3 experienced a DLT [grade 3 increased AST/ALT, acute reversible neurologic changes, or neutropenia (each n=1)]. At the 20 mg/m2 (n=12) and 35 mg/m2 (n=19) dose levels, respectively, the mean ± SD Cmax (ng/ml) was 324±116 and 535±174, and AUC (hr•ng/ml) was 3092 ± 842 and 5156 ± 1227. This was comparable to PK in adults receiving 35 and 50 mg/m2. Based on a desire to achieve a higher Cmax and avoid breaks in schedule, and emerging evidence for similar effectiveness with decreased toxicity in adults receiving continuous once weekly dosing, we evaluated a dosing schedule with once weekly dosing for all 4 weeks of each cycle. At the initial dose level (45 mg/m2 weekly), 2 of 6 subjects had DLTs [prolonged grade 2 thrombocytopenia or grade 3 seizure in a primary CNS tumor patient]. Six subjects received 35 mg/m2/dose once weekly; 1 DLT [grade 3 thrombocytopenia] was observed. Non-dose-limiting toxicity (Grade ≥2 occurring in &amp;gt;10% of subjects during cycle 1) included lymphopenia, leukopenia, neutropenia, thrombocytopenia, anorexia, fatigue, hypophosphatemia, nausea, and vomiting. Subjects received a median (range) of 1 (1-9) cycle; 13 received 2-3 cycles, and 6 received 5-9 cycles. Conclusions: Selinexor-related toxicities were primarily hematological and gastrointestinal. The maximum tolerated dose (MTD) of selinexor in children and adolescents with recurrent solid and CNS tumors is 20 mg/m2/dose twice weekly for 3 weeks followed by one week off. On a continuous once weekly schedule, the MTD and recommended phase 2 starting dose of selinexor is 35 mg/m2/dose. Citation Format: Adam L. Green, Charles G. Minard, Xiaowei Liu, Joel M. Reid, Kerice Pinkney, Stephan Voss, Marvin D. Nelson, Elizabeth Fox, Brenda J. Weigel, Julia Glade Bender. Phase 1 trial of selinexor in children and adolescents with recurrent/refractory solid and CNS tumors (ADVL1414): A Children’s Oncology Group Phase 1 Consortium trial [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P162.

Pulsed Reduced-Dose Rate Re-Irradiation With Intensity Modulated Radiation Therapy (IMRT) for Recurrent Primary Central Nervous System Malignancies

Pulsed Reduced-Dose Rate (PRDR) Re-irradiation with Intensity Modulated Radiation Therapy (IMRT) for recurrent primary Central Nervous System (CNS) malignancies was previously reported to be a feasible and well tolerated treatment option. We report our IMRT PRDR outcomes and toxicities for 55 patients with KPS ≥ 70 treated at our institution.We did a retrospective review of our database of 55 patients with recurrent primary CNS tumors treated at our institution treated with PRDR IMRT. Data collected included demographic information, initial diagnosis, prior surgery, radiation, and chemotherapy, toxicities for each treatment, PRDR IMRT plans, dates of progression, and date of death when available.The mean age of our patient population at diagnosis was 40.2 years. 31 patients were male and 24 patients were female. The initial diagnosis was WHO grade IV in 16 patients, 12 grade III, 21 Grade II, 1 Grade I glioma, and 5 patients had other primary CNS malignancies. All patients had at least 1 surgery (range 1-5) followed by initial radiation. The mean number of salvage treatments undergone by our cohort before PRDR IMRT was 2.83 treatments. The mean dose of prior radiation therapy was 57.75 Gy (Range 50.4 Gy to 75 Gy). Mean Karnofsky Performance Status (KPS) at PRDR IMRT was 80. 14 patients had an updated pathologic diagnosis before PRDR; 6 of those had grade III gliomas and 8 had grade IV. The average time from the first radiation treatment to the PRDR was 68.6 months. The dose of PRDR given ranged from 50.4 Gy to 60 Gy at 1.8-2 Gy/fraction (Median 54 Gy in 30 fractions, with one exception of a patient who stopped early). The mean progression free survival (PFS) after PRDR IMRT was 5.59 months. The median PFS was 4.8 months. Overall Survival (OS) from the time of initiation of PRDR was 10.98 months. The treatment was well tolerated with 86.6% of adverse events being grade 1-2. There were 3 grade 3 adverse events and 3 grade 4 side effects all attributed to concurrent chemotherapy. There was no radiation necrosis reported after PRDR IMRT.We report a large institutional series of patients who were treated with PRDR IMRT for recurrent primary CNS malignancies. Our series shows the feasibility, safety and efficacy of PRDR IMRT for re-irradiation for recurrent primary CNS malignancies in our heavily pretreated population with a good performance status. This warrants further prospective studies of PRDR IMRT in a randomized setting.A. Halima: None. S.T. Chao: Honoraria; Varian Medical Systems, Zeiss, AbbVie. Consultant; AbbVie. J.H. Suh: Consultant; Philips, Novocure. Met to discuss current indications for TTF; Novocure. Met during 1 day retreat to discuss future of radiation oncology; Philips. Scientific advisory board; Neutron Therapeutics. J.S. Yu: None. T.A. Chan: None. S.S. Kilic: None. D. Peereboom: None. G. Stevens: None. Y. Rauf: None. E.S. Murphy: None.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

The pivotal role of sampling recurrent tumors in the precision care of patients with tumors of the central nervous system

Effective management of brain and spine tumors relies on a multidisciplinary approach encompassing surgery, radiation, and systemic therapy. In the era of personalized oncology, the latter is complemented by various molecularly targeting agents. Precise identification of cellular targets for these drugs requires comprehensive profiling of the cancer genome coupled with an efficient analytic pipeline, leading to an informed decision on drug selection, prognosis, and confirmation of the original pathological diagnosis. Acquisition of optimal tumor tissue for such analysis is paramount and often presents logistical challenges in neurosurgery. Here, we describe the experience and results of the Personalized OncoGenomics (POG) program with a focus on tumors of the central nervous system (CNS). Patients with recurrent CNS tumors were consented and enrolled into the POG program prior to accrual of tumor and matched blood followed by whole-genome and transcriptome sequencing and processing through the POG bioinformatic pipeline. Sixteen patients were enrolled into POG. In each case, POG analyses identified genomic drivers including novel oncogenic fusions, aberrant pathways, and putative therapeutic targets. POG has highlighted that personalized oncology is truly a multidisciplinary field, one in which neurosurgeons must play a vital role if these programs are to succeed and benefit our patients.

Pediatric Phase I Trial and Pharmacokinetic Study of Trebananib in Relapsed Solid Tumors, Including Primary Tumors of the Central Nervous System ADVL1115: A Children's Oncology Group Phase I Consortium Report.

Purpose: Trebananib is a first-in-class antiangiogenic peptibody (peptide-Fc fusion protein) that inhibits Angiopoietin 1 and 2. A pediatric phase 1 trial was performed to define trebananib dose-limiting toxicities (DLT), recommended phase 2 dose (RP2D), and pharmacokinetics (PK).Experimental Design: Trebananib was administered by weekly infusion. Three dose levels (10, 15, or 30 mg/kg/dose) were evaluated using a rolling-six design. Part 2 evaluated a cohort of subjects with primary central nervous system (CNS) tumors. Pharmacokinetic sampling and analysis of peripheral blood biomarkers was performed during the first 4 weeks. Response was evaluated after 8 weeks. Correlative studies included angiogenic protein expression and DCE-MRI.Results: Thirty-seven subjects were enrolled (31 evaluable for toxicity) with median age 12 years (range, 2 to 21). Two of 19 evaluable non-CNS subjects developed DLT at the 30 mg/kg dose level, including venous thrombosis and pleural effusion. In the CNS cohort, 3/12 subjects developed DLT, including decreased platelet count, transient ischemic attack, and cerebral edema with headache and hydrocephalus. Other grade 3 or 4 toxicities included lymphopenia (n = 4), anemia, thrombocytopenia, neutropenia, vomiting, and hypertension (n = 1 each). Response included stable disease in 7 subjects, no partial or complete responses. Two subjects continued study treatment with prolonged stable disease for 18 cycles (neuroblastoma) and 26 cycles (anaplastic astrocytoma). Pharmacokinetics appeared linear over 3 dose levels. Correlative studies demonstrated increased PlGF and sVCAM-1, but no change in endoglin or perfusion by DCE-MRI.Conclusions: Trebananib was well tolerated in pediatric patients with recurrent or refractory solid or CNS tumors. RP2D is 30 mg/kg. Clin Cancer Res; 23(20); 6062-9. ©2017 AACR.

Intensity modulated radiation therapy with pulsed reduced dose rate as a reirradiation strategy for recurrent central nervous system tumors: An institutional series and literature review

BackgroundPulsed reduced dose rate (PRDR) is a reirradiation technique that potentially overcomes volume and dose limitations in the setting of previous radiation therapy for recurrent central nervous system (CNS) tumors. Intensity modulated radiation therapy (IMRT) has not yet been reported as a PRDR delivery technique. We reviewed our IMRT PRDR outcomes and toxicity and reviewed the literature of available PRDR series for CNS reirradiation. Methods and materialsA total of 24 patients with recurrent brain tumors received PRDR reirradiation between August 2012 and December 2014. Twenty-two patients were planned with IMRT. Linear accelerators delivered an effective dose rate of 0.0667 Gy/minute. Data collected included number of prior interventions, diagnosis, tumor grade, radiation therapy dose and fractionation, normal tissue dose, radiation therapy planning parameters, time to progression, overall survival, and adverse events. ResultsThe median time to PRDR from completion of initial radiation therapy was 47.8 months (range, 11-389.1 months). The median PRDR dose was 54 Gy (range, 38-60 Gy). The mean planning target volume was 369.1 ± 177.9 cm3. The median progression-free survival and 6-month progression-free survival after PRDR treatment was 3.1 months and 31%, respectively. The median overall survival and 6-month overall survival after PRDR treatment was 8.7 months and 71%, respectively. Fifty percent of patients had ≥4 chemotherapy regimens before PRDR. Toxicity was similar to initial treatment, including no cases of radiation necrosis. ConclusionIMRT PRDR reirradiation is a feasible and appropriate treatment strategy for large volume recurrent CNS tumors resulting in acceptable overall survival with reasonable toxicity in our patients who were heavily pretreated. Prospective studies are necessary to determine the optimal timing of PRDR reirradiation, the role of concurrent systemic agents, and the ideal patient population who would receive the maximal benefit from this treatment approach. SummaryIntensity modulated radiation therapy (IMRT) has not yet been reported as a pulsed reduced dose rate (PRDR) delivery technique for recurrent brain tumors and may allow for safe and comprehensive reirradiation for large volume tumors. We reviewed our IMRT PRDR outcomes and toxicity and reviewed the literature of available PRDR series for recurrent central nervous system tumors. We conclude that IMRT PRDR reirradiation is a feasible and appropriate treatment strategy for large volume recurrent brain tumors resulting in acceptable overall survival with reasonable toxicity in our patients who were heavily pretreated.

Pembrolizumab: first experience with recurrent primary central nervous system (CNS) tumors.

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 4mg; range 2-8, and in children 1.5mg, 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 2.6months in adults and 3.2months 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.

IMCT-01PEMBROLIZUMAB: FIRST EXPERIENCE WITH RECURRENT PRIMARY CENTRAL NERVOUS SYSTEM (CNS) TUMORS

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.

SP-01 * PEER-TO-PEER SUPPORT: A NEW WAY TO ASSIST CAREGIVERS

The UCSF Neuro-Oncology Clinic provides treatment recommendations and care for patients with newly-diagnosed and recurrent central nervous system tumors. Due to the nature of the illness, the caregiver of the patient often has the responsibility of managing the patient's health, in addition to attending to their daily needs. Significant life changes may occur for the caregiver. The impetus of implementing the Neuro-Oncology Caregiver-to-Caregiver Peer Support Program was these observed stresses. Numerous studies have shown how peer support between patients has improved the patients' quality of life. Extrapolating this for caregivers, goals of the program include: reduction of anxiety and isolation, allowing for the exchange of navigational information and coping strategies, improving emotional support, indirectly improving the quality of life of the patient by improving the support network of the caregiver, and improving patient and caregiver satisfaction of clinic services. The peer support program allows caregivers to talk with experienced caregivers of brain tumor patients without exchanging medical advice. These experienced caregivers are formally trained by UCSF staff as peer volunteers in topics concerning confidentiality, peer support skills, and caregiver resources. Intake of peer support requests and matching is conducted by a staff member. The mode of communication is primarily over the phone, which can benefit those that do not have time to meet in person or for those that live a far distance from the clinic or peer support volunteer. The desire to obtain peer support is high. However, available time to participate is minimal due to caregiver burden, resulting in 12 matches to date. This is a novel program and collection of data will be administered at year 2 from implementation, using tools such as questionnaires, and pre- and post-surveys for both the volunteers and the caregivers seeking support.

Bevacizumab (BVZ)‐associated toxicities in children with recurrent central nervous system tumors treated with BVZ and irinotecan (CPT‐11)

The incidence and spectrum of acute toxicities related to the use of bevacizumab (BVZ)-containing regimens in children are largely unknown. This report describes the adverse events in a recently completed large phase 2 trial of BVZ plus irinotecan (CPT-11) in children with recurrent central nervous system tumors. Pediatric Brain Tumor Consortium trial-022 evaluated the efficacy and toxicity of BVZ (10 mg/kg administered intravenously) as a single agent for 2 doses given 2 weeks apart and then combined with CPT-11 every 2 weeks (1 course = 4 weeks) in children with recurrent central nervous system tumors. Children were treated until they experienced progressive disease, unacceptable toxicity or completed up to a maximum of 2 years of therapy. Toxicities were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0. Patients who received at least 1 dose of BVZ were included for toxicity assessment. Between October 2006 and June 2010, 92 patients evaluable for toxicity were enrolled and received 687 treatment courses. The most common toxicities attributable to BVZ included grade I-III hypertension (38% of patients), grade I-III fatigue (30%), grade I-II epistaxis (24%), and grade I-IV proteinuria (22%). Twenty-two patients (24%) stopped therapy due to toxicity. The combination of BVZ and CPT-11 was fairly well-tolerated, and most severe BVZ-related toxicities were rare, self-limiting, and manageable.

A phase I clinical trial of veliparib and temozolomide in children with recurrent central nervous system tumors: A Pediatric Brain Tumor Consortium report.

2036 Background: A phase I trial of veliparib (ABT-888), an oral poly(ADP-ribose) polymerase (PARP) inhibitor, and temozolomide (TMZ) was conducted in children with recurrent brain tumors to: 1) estimate the maximum tolerated doses (MTD) or recommended phase II doses (RP2D) of veliparib and TMZ using the Continual Reassessment Method; 2) describe the toxicities of this regimen; and 3) evaluate plasma pharmacokinetics (PK) and peripheral blood mononuclear cell (PBMC) PARP inhibition after veliparib treatment. Methods: TMZ was given once daily and veliparib twice daily for 5 days, every 28 days. Five veliparib/TMZ dose levels were studied: 20/180; 15/180; 15/150; 20/135; and 25/135 mg/m2/dose, respectively. Baseline and serial veliparib PK samples were obtained on days 1 and 4. PBMC poly(ADP-ribose) (PAR) levels were also measured using an ELISA assay. A total of 12 subjects were enrolled at the RP2D. Results: Thirty-one patients (29 evaluable) with a median age of 7.0 years (range 1.3-19.8) were enrolled. Dose-limiting toxicities (DLT) included grade 4 neutropenia and thrombocytopenia at the 20/180 and 15/180 mg/m2/dose levels. Based on the toxicity profile, PKs and PBMC PAR results, the RP2D were veliparib, 25 mg/m2 BID, and TMZ, 135 mg/m2/day, for 5 days every 28 days. No objective responses were observed, although 4 subjects had SD &gt; 6 months duration, including one patient each with glioblastoma multiforme, anaplastic ependymoma, pilocytic astrocytoma, and optic pathway glioma. At the veliparib RP2D, the PK parameters included: Cmax, 1.2 ± 0.7 µM; AUC0-12 hr, 1.53 ± 0.61 µg•hr/mL; and Cl/F, 173 ± ml/min/m2. PARP inhibition was observed in PBMC but did not correlate with veliparib dose levels. Conclusions: The combination of veliparib and TMZ was well tolerated in children with recurrent CNS tumors. Veliparib PK parameters at RP2D are similar to those in adults. PBMC PARP inhibition did not correlate with veliparib dose levels, perhaps due to the smaller number of patients at each dose level and the technical limitations of specimen collection/processing and the ELISA assay. A phase II trial of veliparib/TMZ in children with recurrent primary brain tumors is planned. Clinical trial information: NCT00946335.

A phase II prospective study of sequential myeloablative chemotherapy with hematopoietic stem cell rescue for the treatment of selected high risk and recurrent central nervous system tumors

High risk/recurrent CNS tumors have a poor prognosis. We studied tandem high dose chemotherapy (HDC) with hematopoietic progenitor stem cell rescues (HPCR) as potentially curative therapy. Twenty-four patients (mean age 6.8 years) were enrolled, 19 underwent HDC/HPCR. Diagnoses were medulloblastoma (n = 9), germ cell tumor (n = 4), high grade astrocytoma (n = 2), supratentorial PNET (n = 1), pineoblastoma (n = 2), or papillary meningioma (n = 1). Cytoreduction regimen #1 consisted of carboplatin (500 mg/m(2)) x 3 days, etoposide (250 mg/m(2)) x 3 days, and thiotepa (300 mg/m(2)) x 3 days. Patients without progression or excessive toxicity (n = 11), received regimen #2 with melphalan (60 mg/m(2)) x 3 days and cyclophosphamide (1,500 mg/m(2)) x 4 days. Projected overall/event-free survival for the 19 patients was 51/37% and 34/28% at 1 and 5 years, respectively. Toxicity was significant with six treatment related deaths including four with veno-occlusive disease. This regimen of sequential HDC/HPCR in high risk/recurrent CNS tumor patients is not feasible due to toxicity.