Surgical Management of Craniospinal Axis Solitary Fibrous Tumors: A Single-Institution Case Series and Comprehensive Review of the Literature

BACKGROUND AND OBJECTIVES

Meningeal solitary fibrous tumors (SFTs) comprise 0.4% of primary central nervous system neoplasms and carry metastatic potential. Disease course and optimal management are largely unknown, and there is currently no literature rigorously describing neurological outcomes in surgically managed SFTs. We present one of the largest craniospinal SFT series, analyze patient outcomes, and extensively review the associated literature.

METHODS

All surgically managed SFTs at our institution between January 2005 and March 2023 were retrospectively reviewed. Patient demographics, tumor and radiographic features, treatment, and clinical outcomes were collected. Neurological function was quantified using Frankel grade and Neurologic Assessment in Neuro-Oncology scores. Descriptive statistics, multivariate analysis, log-rank test, and Kaplan-Meier survival analysis were performed.

RESULTS

Twenty-one patients satisfied inclusion criteria. Tumor locations included 15 supratentorial, three infratentorial, and three spinal. All patients underwent surgical resection, and 16 (76.2%) underwent radiation. Six (28.6%) patients had tumor recurrence, and three (14.3%) developed metastasis. Younger age and higher postoperative Frankel grade were significantly associated with increased overall survival (OS) ( P = .011, P = .002, respectively). All patients symptomatically improved or stabilized after surgery, and Neurologic Assessment in Neuro-Oncology score ( P = .001) and functional status significantly improved postoperatively (Karnofsky Performance Status: 65.2 ± 25.2 vs 91.4 ± 13.5, P = .001). Sex, adjuvant radiation, and extent of resection were not significantly associated with OS.

CONCLUSION

SFT of the central nervous system is a rare entity with a variable clinical course. Surgical resection was associated with improved postoperative functional and neurological status. Higher postoperative neurological function was significantly associated with OS. Further studies are warranted to validate a standardized treatment algorithm and investigate the efficacy of adjuvant radiation in SFT.

Pharmacological ascorbate improves the response to platinum-based chemotherapy in advanced stage non-small cell lung cancer

PURPOSE

Platinum-based chemotherapy with or without immunotherapy is the mainstay of treatment for advanced stage non-small cell lung cancer (NSCLC) lacking a molecular driver alteration. Pre-clinical studies have reported that pharmacological ascorbate (P-AscH-) enhances NSCLC response to platinum-based therapy. We conducted a phase II clinical trial combining P-AscH- with carboplatin-paclitaxel chemotherapy.

EXPERIMENTAL DESIGN

Chemotherapy naïve advanced stage NSCLC patients received 75 g ascorbate twice per week intravenously with carboplatin and paclitaxel every three weeks for four cycles. The primary endpoint was to improve tumor response per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 compared to the historical control of 20%. The trial was conducted as an optimal Simon's two-stage design. Blood samples were collected for exploratory analyses.

RESULTS

The study enrolled 38 patients and met its primary endpoint with an objective response rate of 34.2% (p = 0.03). All were confirmed partial responses (cPR). The disease control rate was 84.2% (stable disease + cPR). Median progression-free and overall survival were 5.7 months and 12.8 months, respectively. Treatment-related adverse events (TRAE) included one grade 5 (neutropenic fever) and five grade 4 events (cytopenias). Cytokine and chemokine data suggest that the combination elicits an immune response. Immunophenotyping of peripheral blood mononuclear cells demonstrated an increase in effector CD8 T-cells in patients with a progression-free survival (PFS) ≥ 6 months.

CONCLUSIONS

The addition of P-AscH- to platinum-based chemotherapy improved tumor response in advanced stage NSCLC. P-AscH- appears to alter the host immune response and needs further investigation as a potential adjuvant to immunotherapy.

Abstract CT164: Pharmacological ascorbate enhances platinum-based chemotherapy responses in metastatic non-small cell lung cancer (NSCLC): A phase II clinical trial

PURPOSE: First line treatment with platinum-based chemotherapy with or without immunotherapy improves survival in metastatic non-small cell lung cancer (NSCLC). Preclinical studies suggest that pharmacological ascorbate (P-AscH-) enhances tumor response to platinum therapy. Hence, we conducted a single-arm phase II study to evaluate the efficacy of P-AscH- in combination with platinum-doublet chemotherapy in patients with advanced stage NSCLC (NCT02420314). METHODS: Chemotherapy naïve advanced stage NSCLC patients with an ECOG PS of 0-2 were enrolled to receive 4-cycles of carboplatin (AUC 6) and paclitaxel (200 mg/m2) every 3 weeks (wks). Ascorbate (75 g) infusions were given twice a wk for 12-wks. The primary endpoint was to assess tumor objective response per RECIST v1.1. The trial was conducted as an optimal Simon two-stage design. After initial therapy, patients could receive maintenance or consolidation treatment. Secondary endpoints were to evaluate tolerability, progression-free survival (PFS) and overall survival (OS). Serum cytokines and chemokines were measured at baseline, C2d1, and C4d21± 7d. RESULTS: Forty subjects were enrolled. The study met its primary endpoint with 38 efficacy evaluable subjects. The objective response rate was 34.2%. All were confirmed partial responses (cPR). Disease control rate was 84.2% (stable disease + cPR). Median duration of follow up was 11.7 months (mo), mPFS was 5.7 mo (95% CI:4.2-6.7), and mOS was 12.5 mo (95% CI:7.5-21.4). Treatment-related adverse events (TRAE) included one grade 5 (neutropenic fever) and five grade 4 (cytopenia) events. These events were not attributed to P-AscH-. Common (≥5%) grade 3 TRAE included transient hypertension (27.5%), lymphopenia (22.5%), fatigue (7.5%), anemia (7.5%) and hypokalemia (5%). Cytokine and chemokines data suggest that protocol regimen elicited an immune response with multiple distinct cytokine signatures. Immunophenotyping of peripheral blood mononuclear cells (n=7) demonstrated a mean fold increase in effector CD8 T cells of 4.9 in patients with PFS ≥ 6 mo compare to 1.6 in patients with PFS < 6 mo. Assessments of serum iron profile and somatic alterations in KRAS, KEAP1, NFE2L2 and STK11 genes are underway. CONCLUSIONS: This phase II trial met the primary objective of improving the tumor response rate in advanced stage NSCLC by adding P-AscH- to platinum-based chemotherapy. P-AscH- appears to alter the host immune response. These promising findings warrant further investigation.

Citation Format: Muhammad Furqan, Taher Abu-Hejleh, Kellie L. Bodeker, Laura M. Pietrok, Stacey M. Hartwig, Mikaela M. Tremblay, Micaela G. Fosdick, Jon Houtman, Steven Varga, Casey F. Pulliam, Michael Petronek, Melissa A. Fath, Sarah L. Mott, Aaron D. Bossler, Andrew M. Bellizzi, Jun Zhang, Hariharasudan Mani, Varun Monga, Brian J. Smith, Joseph Cullen, Brett A. Wagner, Garry R. Buettner, John M. Buatti, Douglas R. Spitz, Bryan G. Allen. Pharmacological ascorbate enhances platinum-based chemotherapy responses in metastatic non-small cell lung cancer (NSCLC): A phase II clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT164.

Pharmacologic ascorbate enhances the therapeutic index of ATM-inhibitor based chemoradiation for colorectal cancer

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Background: Ataxia telangectasia mutated protein (ATM) is one of the key sensors of DNA damage and specific inhibitors of ATM are potent radiosensitizers. However, their clinical utility with radiation (RT) is limited because they lack tissue specificity and increase normal tissue injury. Pharmacologic (high dose) ascorbate (P-AscH-) selectively increases oxidative stress in tumors while functioning as a donor antioxidant and reducing RT damage in normal tissues. We hypothesized that P-AscH- could enhance the therapeutic index of ATM-inhibitor based chemoradiation (CRT) for colorectal cancer (CRC) by simultaneously enhancing efficacy and reducing RT bowel injury. Methods: Human HCT116, SW480, and HT29 and murine CT26 and MC38 CRC models were used. Clonogenic survival was assessed following single-fraction RT (2-8 Gy) +/- P-AscH- (5 pM/cell) +/- veliparib (PARP), VE821 (ATR), or KU60019 (ATM). Catalase expression was induced using HCT116 cells expressing a doxycycline inducible catalase transgene. DNA double strand breaks (DSBs) were quantified using neutral comet assays 0-24 hours post RT. Cell cycle phases were assessed using flow cytometry. ATM and pATM localization were assessed using IF. Jejunal toxicity was assessed using IHC in fixed tissues following single fraction (10 Gy) whole abdominal RT in c57blj/6 mice. Tumor growth delay was assessed following RT (5 Gy x 3) +/- drug treatment in unilateral flank tumors. Results: Veliparib, VE821, and KU60019 were potent radiosensitizers in HCT116, SW480, HT29, MC38, and CT26 CRC tumor models and P-AscH- further reduced clonogenic survival with DRIs in all lines except for HT29. In contrast, P-AscH- enhanced survival of cultured HUVEC and FHs-74 cells exposed to RT. Enhanced cell kill with P-AscH- is H202 mediated as it is completely attenuated by inducible catalase expression. P-AscH- significantly increased the number of DNA DSBs in tumors after RT in vitro. Despite the increase in DNA DSBs, P-AscH-significantly decreased nuclear localization of activated P-ATM after RT and significantly decreased the fraction of cells in G2/M phases of the cell cycle. In vivo, RT + P-AscH- + KU60019 induced more tumor growth delay/clearance than all other combinations in unilateral MC38 or HCT116 flank tumors. Finally, P-AscH- significantly reduced loss of jejunal crypt cell density, epithelial architecture, and markers of lipid and protein oxidation following whole abdominal RT. Conclusions: P-AscH- selectively enhances the efficacy of ATM-based CRT in CRC tumor models while simultaneously decreasing RT-mediated small bowel toxicity. In tumors, P-AscH- enhances DNA DSBs by stimulating an H202 flux and prevents activation of DNA repair pathways and cell cycle checkpoints by inhibiting RT-induced activation of ATM. Selective radioprotectors like P-AscH- could facilitate the clinical translation ATM inhibitors as radiosensitizers.

BIMG-07. PHARMACOLOGICAL ASCORBATE ENHANCES RADIATION AND TEMOZOLOMIDE EFFECTIVENESS IN GLIOBLASTOMA BY A MECHANISM MEDIATED BY REDOX ACTIVE IRON

Pharmacological ascorbate (P-AscH^-; high dose intravenous infusions of vitamin C generating milli-molar plasma concentrations) has re-emerged as an anti-cancer therapy. Phase 1 clinical trials combining P-AscH^- with chemotherapy and ionizing radiation demonstrate safety and promising clinical outcomes in a variety of malignancies. In a first-in-human trial, subjects with newly diagnosed glioblastoma (GBM) and undetectable MGMT promoter methylation were treated with P-AscH^-, ionizing radiation, and temozolomide. Results demonstrate median progression-free survival (PFS) of 10 months and median overall survival (OS) of 23 months, comparing favorably to historical GBM patients expressing MGMT. P-AscH^-‘s anti-cancer mechanism is dependent upon the presence of redox active labile iron. In the presence of redox active iron, the formation of hydrogen peroxide, which causes oxidative stress and eventual cell death, selectively forms in cancer cells. Treatment with P-AscH^- increased cancer cells’ labile iron pool, further enhancing sensitivity to P-AscH^-. We investigated the capability of MR imaging (T₂* relaxation time) to measure the redox active iron and predict response to P-AscH^-. T₂* relaxation time is influenced by in-field inhomogeneities, such as redox active paramagnetic iron. The active phase 2 trial evaluating P-AscH^-, radiation, and temozolomide for GBM, obtains T₂* imaging prior to (baseline) and immediately after ascorbate infusion (NCT02344355). A preliminary analysis of the baseline scan for the first 15 subjects suggests those with faster GBM T₂* relaxation times (≤ 58 ms) have more redox active labile iron pools as well as an improved median PFS (11.4 months) compared to those with slower T₂* relaxation times (> 58 ms; median PFS of 8.5 months). Pre-clinical studies evaluating the effectiveness of iron nano-particle supplementation in GBM animal models are on-going. (Supported by P01 CA217797, R01 CA169046, U01 CA140206, T32 CA078586, P30 CA086862, as well as the Gateway for Cancer Research grant G-17–1500.)

Genome-wide methylation analysis in long-term survivors of glioblastoma (GBM)

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Background: Identification of tumor characteristics that may be associated with survival in patients with glioblastoma (GBM) has been largely characterized by IDH mutations and MGMT promoter methylation status. However, these genetic changes and other currently available data are not sufficient to explain the longevity experienced by a subset of long-term survivors (LTS) - patients surviving longer than 3 years past diagnosis. Methods: The study identified GBM patients established and treated at University of Iowa Holden Comprehensive Cancer Center from 2007-2017 whose disease recurred after initial resection. Patients were categorized LTS if they survived > = 3 years beyond initial definitive resection; short-term survivors (STS) if less than 3 years. Pathologic specimens at initial and repeat resection underwent genome wide methylation analysis using the Infinium EPIC microarray system. Data were analyzed to identify genes that exhibited differentially methylated CpG regions. Results: Resection specimens from GBM survivors were compared to those of STS. A total of 29 samples were analyzed and compared (15 LTS and 14 STS samples). Multidimensional scaling plots identified significant differences in genomic constitution between LTS and STS specimens. Granular analysis yielded 89 differentially methylated regions significantly associated with long-term survival (adjusted p < 0.05). PTPRN2 (p = 0.000376), PTPN11 (p = 1.38E-05), and PAX6 (p = 0.000671) were found to exhibit numerous differentially methylated CpG sites between MGMT-methylated vs. unmethylated specimens. Further notable, higher levels of differentially methylated CpG shores and open-seas regions on chromosome 12 were associated with long-term survival (p = 1.89E-08). Conclusions: Our study identified multiple significant epigenetic differences that, functionally or consequentially, may be associated with extended survival in GBM patients. The implication that CpG shores, rather than islands, are associated with long-term survival raises further intriguing questions regarding the depth of epigenetic complexity in this disease. More immediately, the surprising association of multiple protein phosphatases with LTS in our study may hint at the class’ previously unspecified, yet integral, role in delaying disease progression and identify new, novel avenues for therapy.