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A case study of a long-term glioblastoma survivor with unmethylated MGMT and hypermutated genotype.

ABSTRACT: Effective treatments that extend survival of malignant brain tumor glioblastoma (GBM) have not changed in more than a decade; however, there exists a minority patient group (<5%) whose survival is longer than 3 yr. We herein present a case report of a long-term surviving 51-yr-old female diagnosed with a MGMT unmethylated GBM. The patient was progression-free for 23 mo. Fresh primary and recurrent tumor samples were collected and processed for patient-derived model development. Whole-genome sequencing (WGS) was performed concurrently with additional standard of care diagnostics. WGS revealed a hypermutated genotype in the germline tissue and in both the primary and recurrent tumor samples. Specific to the matched tumors, an average of 30 cancer driver genes were mutated. Noteworthy was the identification of a nonsynonymous mutation in the POLE gene. As a possible instigator of the hypermutational genotype observed in the tumors, we identified nonsynonymous germline mutations within the mismatch repair genes, MLH1 and PMS2 Mutations within these genes are often indicative of the pan-cancer phenotype known as Lynch syndrome; however, their pathogenicity remains unreported. We performed a drug screen of 165 compounds, which identified one compound, YM155, an experimental survivin inhibitor, that showed effectivity to the patient-derived cell lines of both tumors. Treatment selection based on a patient's genome to individualize treatment for GBM patients could potentially be useful in the clinic. This is a promising avenue for further translational research, with larger databases and integrated platforms to increase the efficiency of analyzing and interpreting the individual genomic data of GBM.

SUBMITTER: Jue TR

PROVIDER: S-EPMC6549560 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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Project description:Abstract Glioblastoma (GBM) is the most common and aggressive primary brain cancer. Current standard-of-care includes surgery, radiation and treatment with temozolomide (TMZ), however nearly all tumors recur and the prognosis for recurrent GBM is dismal. Resistance to TMZ is correlated with expression of the DNA repair enzyme O6-methylguanine-DNA-methyltransferase (MGMT), which is highly expressed in a majority of GBM tumors. Dianhydrogalactitol (VAL-083) is a first-in-class bi-functional DNA-targeting agent that exhibited activity against GBM in NCI-sponsored clinical trials both as a single agent and in combination with radiotherapy. VAL-083 readily crosses the blood-brain barrier and accumulates in brain tumor tissue. We have demonstrated that VAL-083 targets N7-Guanine and rapidly induces interstrand DNA cross-links, leading to DNA double-strand breaks, S/G2 cell-cycle arrest and cell death in GBM cell lines and GBM cancer stem cells (CSCs) in vitro. This unique N7-guanine targeting mechanism not only circumvents MGMT-mediated chemo-resistance but also maintains cytotoxic activity in cancer cells deficient in mismatch repair (MMR). These data suggest VAL-083 may offer a superior chemotherapeutic alternative in the treatment of MGMT-unmethylated or MMR deficient GBM. Here, we provide an update of ongoing clinical trials with VAL-083 in MGMT-unmethylated GBM: i) a single-arm, biomarker-driven, Phase II study to determine if VAL-083 treatment of MGMT-unmethylated adult GBM patients at first recurrence/progression, prior to bevacizumab improves survival compared to historical lomustine control (clinicaltrials.gov identifier: NCT02717962); ii) a single-arm, biomarker-driven, Phase II study to confirm the tolerability and efficacy of VAL-083 in combination with radiotherapy in newly diagnosed MGMT-unmethylated GBM patients (clinicaltrials.gov identifier: NCT03050736). The results of these studies may support a new treatment paradigm in for the treatment of MGMT-unmethylated GBM.

Project description:Abstract Glioblastoma (GBM) is the most common and aggressive primary brain cancer. Current standard-of-care includes surgery followed by concurrent therapy with radiation and temozolomide (TMZ) and maintenance TMZ. Almost all GBM patients experience recurrent/progressive disease, and median survival after recurrence is 3–9 months. Effective therapies for recurrent GBM (rGBM) are lacking, representing a significant unmet medical need. Unmethylated promoter for O6-methylguanine-DNA-methyltransferase (MGMT) is a validated biomarker for TMZ-resistance and is correlated with a poor prognosis. Second-line treatment with the anti-angiogenic agent bevacizumab (BEV) has not improved survival, and 5-year survival is less than 3%. VAL-083 is a bi-functional DNA-targeting agent rapidly inducing interstrand cross-links at N7-guanine, leading to DNA double-strand breaks and cell-death. VAL-083s cytotoxicity is independent of MGMT status, and VAL-083 overcomes TMZ-resistance in GBM cell lines, GBM cancer stem cells, and in vivo GBM models. We completed a 3 + 3 dose-escalation trial of VAL-083 in TMZ- and BEV-refractory rGBM. 40mg/m2/day given on days 1,2,3 of a 21-day cycle was generally well-tolerated, and this dose was selected for further clinical evaluation in Phase 2 trials. The trial described here is an ongoing single-arm, biomarker-driven Phase 2 trial in MGMT-unmethylated BEV-naïve adult rGBM. In this trial, 48 patients will receive VAL-083 40mg/m2/day on days 1,2,3 of a 21-day cycle. Tumor response will be assessed by MRI approximately every 42 days, per RANO criteria. The primary objective of this study is to determine if VAL-083 improves median overall survival (mOS) for MGMT-unmethylated rGBM patients compared to a historical mOS of 7.1 months for such patients treated with lomustine (EORTC26101). Secondary efficacy endpoints include progression-free survival (PFS), overall response rate (ORR), duration of response (DOR), and quality-of-life (QOL) evaluation using the MD Anderson Symptom Inventory-Brain Tumor Module (MDASI-BT) self-reporting tool. Enrollment and safety data update will be provided at the meeting. Clinicaltrials.gov identifier: NCT02717962.

Project description:Abstract Glioblastoma (GBM) is the most common and aggressive primary brain cancer. Current standard-of-care includes surgery followed by chemo-radiation and temozolomide. An unmethylated promoter for O6-methylguanine-DNA-methyltransferase (MGMT) is a validated biomarker for temozolomide-resistance and is strongly correlated with poor outcomes. Unmethylated MGMT represents the majority of newly diagnosed GBM tumors. VAL-083 is a first-in-class bi-functional DNA-targeting agent that has shown activity against GBM in NCI-sponsored clinical trials both as single agent and in combination with radiotherapy. VAL-083 induces interstrand cross-links at N7-guanine, leading to DNA double-strand breaks and cell-death. VAL-083s unique mechanism-of-action circumvents MGMT-mediated chemoresistance, and it has demonstrated cytotoxicity in MGMT-unmethylated GBM cell-lines, cancer stem cells (CSCs) and in vivo models. Furthermore, VAL-083 acts as a radiosensitizer in GBM CSCs and non-CSCs. We completed a dose-escalation trial of VAL-083 in recurrent GBM, and a generally well-tolerated dosing regimen was selected for further clinical development. The present trial is an ongoing open-label, biomarker-driven, Phase 1/2 study to evaluate the tolerability and efficacy of VAL-083 in combination with radiotherapy in newly diagnosed MGMT-unmethylated GBM patients. A treatment regimen, consisting of a 6-week induction period of VAL-083 and concurrent radiation (2 Gy daily, 5 days/week) followed by up to 24 weeks of maintenance therapy with single-agent VAL-083, is being evaluated. The study is being conducted in two parts: 1) a dose-escalation part (20, 30, and 40mg/m2/day IV infusion on days 1,2,3 of a 21-day cycle) in up to 10 patients; 2) an expansion part in up to 20 additional patients at the determined well-tolerated dose. Tumor response will be assessed by MRI, according to RANO criteria. Efficacy endpoints include progression-free survival (PFS) and overall survival (OS). Additional endpoints include safety evaluations and pharmacokinetic assessments of plasma and CSF samples. Enrollment and safety data update will be provided at the meeting. Clinicaltrials.gov identifier: NCT03050736.

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A case study of a long-term glioblastoma survivor with unmethylated MGMT and hypermutated genotype.

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