Efficacy Of Temozolomide Research Articles

EXTH-79. A NOVEL ANTI-GALECTIN-3 ANTIBODY THERAPEUTIC SYNERGIZES WITH TEMOZOLOMIDE IN PRECLINICAL MODELS TO DIMINISH TUMOR GROWTH, DECREASE MIGRATION, AND PROLONG SURVIVAL

Abstract Glioblastoma (GBM) is the most aggressive, invasive, and malignant primary brain cancer whose standard of care for nearly 20 years has been surgical resection followed by radiotherapy and temozolomide (TMZ) treatment, resulting in a median survival of 15 months following diagnosis. Heterogenous tumor cell populations that evade resection and develop chemoradiation resistance highlight the need for novel therapies that can target both the migratory and proliferative nature of GBM cells. Galectin-3, a carbohydrate-binding protein overexpressed in the GBM parenchyma and stromal astrocytes, is a potent modulator of cell proliferation, migration, angiogenesis, T-cell inhibition, and M2 macrophage polarization, and is seen to increase following TMZ and radiation treatment. Heightened Galectin-3 expression levels correlate to lower survival in glioma patients, thus greatly underscoring the need for targeting Galectin-3 in conjunction with initial standard-of-care treatment. Here, we characterize the therapeutic effects of a brain-penetrant monoclonal anti-Galectin-3 antibody (Gal3 Ab) we have developed for its ability to inhibit GBM growth and migration in several in vitro assays and in vivo heterotopic and orthotopic mouse models. Our Gal3 Ab significantly decreases cell viability, neurosphere migration, and cell invasion in vitro in the presence of full length or truncated Gal3, whose expression and secretion in GBM cells is enhanced following short and long-term TMZ stimulation. We find that Galectin-3 directly binds to EGFR, amplified in ~40% of GBM patients, as well as its most commonly mutated form, EGFRvIII, and our Gal3 Ab can block these bindings, decrease EGFR activation, and alter EGFR localization. In vivo, our Gal3 Ab decreases tumor burden and improves survival in combination with temozolomide, compared to standard-of-care treatment alone in multiple cell-line models. Our pre-clinical studies highlight the potential for our novel Gal3 antibody to further improve TMZ efficacy and benefit GBM patients by diminishing tumor cell migration and slowing tumor growth.

EXTH-43. TARGETING THE DNA DAMAGE RESPONSE THROUGH COMBINATION MDM2 AND AKT INHIBITOR THERAPY IMPROVES TEMOZOLOMIDE EFFECTIVENESS IN CHEMO-RESISTANT GLIOBLASTOMA

Abstract Temozolomide remains the lone pharmacotherapeutic option for glioblastoma (GBM), yet the development of resistance to temozolomide has been a major challenge contributing to the persistent median < 2-year survival for patients after diagnosis. Tumor heterogeneity and induction of treatment response networks, such as the DNA damage response (DDR), are major contributors to temozolomide resistance in GBM. Targeting DDR treatment response networks, such as the MDM2/p53/p73 and PI3K/AKT/mTOR networks, with small-molecule inhibitors (SMIs) presents an opportunity to disrupt resistance mechanisms and enhance temozolomide efficacy. We utilized a triple drug combination of clinically relevant concentrations of the blood-brain-barrier penetrant SMIs of AKT (ipatasertib; GDC-0068) and MDM2 (idasanutlin; RG7388) with temozolomide to evaluate this targeted strategy using the recurrent, temozolomide-resistant, p53wt GBM10 xenoline. Proliferation studies demonstrated dose-related additive to synergistic inhibition of proliferation at clinically relevant concentrations of ipatasertib and idasanutlin. Further, IncuCyte live-cell imaging demonstrated dose-and time-related growth inhibition of these GBM cells and apoptosis marked by increased cleaved caspase 3 expression following the temozolomide+idasanutlin+ipatasertib triple combination treatment. Cells treated with temozolomide+idasanutlin+ipatasertib also displayed senescence phenotypes, with increased cell cycle arrest and elevated expression of SPiDER β-Gal expression and cell-cycle inhibitors such as p53 and p21. Experiments are in progress to determine the extent to which the effects of temozolomide+idasanutlin+ipatasertib combination therapy are dependent on p53 using siRNA knockdown of p53. In the present study, targeting the temzolomide-induced DNA damage response with idasanutlin+ipatasertib increased the effectiveness of temozolomide. These results indicate that this triple combination may be a promising approach to improving patient outcomes in temozolomide-resistant GBM.

Phase II study of everolimus and temozolomide as first-line treatment in metastatic high-grade gastroenteropancreatic neuroendocrine neoplasms

BackgroundThe optimal treatment for metastatic high-grade gastroenteropancreatic (GEP) neuroendocrine neoplasms when Ki-67 ≤55% is unknown. A prospective multi-centre phase 2 study was performed to evaluate the efficacy and safety of everolimus and temozolomide as first-line treatment for these patients.MethodsPatients received everolimus 10 mg daily continuously and temozolomide 150 mg/m2 for 7 days every 2 weeks. Endpoints included response, survival, safety and quality of life (QoL). Histopathological re-evaluation according to the 2019 WHO classification was performed.ResultsFor 37 eligible patients, the primary endpoint with 65% disease control rate (DCR) at 6 months (m) was reached. The response rate was 30%, the median progression-free survival (PFS) 10.2 months and the median overall survival (OS) 26.4 months. Considering 26 NET G3 patients, 6 months DCR was 77% vs. 22% among nine NEC patients (p = 0.006). PFS was superior for NET G3 vs. NEC (12.6 months vs. 3.4 months, Log-rank-test: p = 0.133, Breslow-test: p < 0.001). OS was significantly better for NET G3 (31.4 months vs. 7.8 months, p = 0.003). Grade 3 and 4 toxicities were reported in 43% and 38%. QoL remained stable during treatment.ConclusionEverolimus and temozolomide may be a treatment option for selected GEP-NET G3 patients including careful monitoring. Toxicity did not compromise QoL.Clinical trial registrationClinicalTrials.gov (NTC02248012).

Efficacy and safety of capecitabine and temozolomide (CAPTEM) in advanced gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NEN): a systematic review and meta-analysis

Efficacy and safety of capecitabine and temozolomide (CAPTEM) in advanced gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NEN): a systematic review and meta-analysis

5-lipoxygenase as a target to sensitize glioblastoma to temozolomide treatment via β-catenin-dependent pathway

ABSTRACT Sensitizing strategy is required to improve the clinical management of glioblastoma (GBM). 5-Lipoxygenase (Alox5) has been recently garnered attention due to its pro-carcinogenic roles in various cancers. This study demonstrates that Alox5 is overexpressed in GBM but not normal neuronal tissues. Alox5 depletion inhibits the growth of GBM cells, both in bulky and stem-like populations, and enhances the anti-cancer effects of temozolomide. The mechanism behind this involves a decrease in β-catenin level and activity upon Alox5 depletion. The inhibitory effects of Alox5 can be reversed by the addition of a Wnt agonist. Additionally, the study reveals that zileuton, an Alox5 inhibitor approved for asthma treatment, significantly improves the efficacy of temozolomide in mice without causing toxicity. Combination index analysis clearly demonstrates that zileuton and temozolomide act synergistically. These findings highlight the importance of Alox5 as a critical regulator of glioblastoma sensitivity and suggest the potential repurposing of zileuton for GBM treatment.

P10.06.B APPLYING TUMOR TREATING FIELDS (TTFIELDS) FOR ENHANCEMENT OF TEMOZOLOMIDE AND LOMUSTINE EFFICACY IN GLIOBLASTOMA CELL LINES

Abstract BACKGROUND Tumor Treating Fields (TTFields) are electric fields that disrupt cellular processes critical for cancer cell viability and tumor progression, ultimately leading to cell death. TTFields therapy concurrent with maintenance temozolomide (TMZ) is approved for treatment of newly-diagnosed glioblastoma (GBM). Recently, benefit was demonstrated in patients with O6-methylguanine DNA methyltransferase (MGMT) promoter methylation for the combination of TMZ with lomustine (CCNU). The addition of adjuvant TTFields to this treatment regimen further improved patient outcomes, leading to a CE mark. The current study aimed to elucidate the mechanism underlying the benefit of this treatment protocol by utilizing GBM cell lines with different MGMT expression status. MATERIAL AND METHODS Human GBM cell lines with different MGMT promoter methylation status [LN-18 (unmethylated MGMT promoter), U-118 MG (partially methylated MGMT promoter), and U-87 MG and LN-229 (methylated MGMT promoter)] were examined for MGMT expression levels. Next, the cells were treated with TTFields (intensity of 0.83 V/cm RMS; frequency of 200 kHz) using the inovitro system. Cell count and colony formation were employed to detect the effectiveness of TTFields concomitant with TMZ and/or CCNU. Western blot allowed the detection of expression levels of DNA repair proteins in control versus TTFields-treated cells. RESULTS The cell lines displayed comparable responses to TTFields and CCNU, while they differed in sensitivity to TMZ according to MGMT expression status. TTFields concomitant with TMZ displayed an additive effect, irrespective of MGMT expression levels. The effect of concomitant TTFields with CCNU was additive in MGMT-expressing cell lines, whereas it trended toward synergy in MGMT-non-expressing cell lines. Expression of proteins from the Fanconi Anemia (FA)-BRCA pathway for DNA repair was downregulated following TTFields application. TTFields concurrent with both TMZ and CCNU provided higher efficacy relative to TMZ plus CCNU or TTFields apart, with additivity in MGMT-expressing cell lines and a tendency toward synergy in MGMT-non-expressing cell lines. CONCLUSION The results support the clinical benefit demonstrated for concomitant TTFields with TMZ plus CCNU, showing that the efficacy of TMZ and CCNU may be enhanced by TTFields, with synergism seen for the latter case in cells not expressing MGMT. The BRCAness state induced by TTFields rationalizes this, as in the absence of MGMT DNA damage induced by CCNU requires the FA-BRCA pathway for repair.

P07.09.B A RANDOMIZED PHASE 2B STUDY OF SURVIVIN VACCINE SURVAXM PLUS ADJUVANT TEMOZOLOMIDE FOR NEWLY-DIAGNOSED GLIOBLASTOMA (SURVIVE)

Abstract BACKGROUND Newly-diagnosed glioblastoma (nGBM) has a dismal prognosis with a median overall survival (OS) of nearly 16 months. nGBM cells have high expression of tumor-associated survivin protein. Survivin, localized to the cell surface through presentation by MHC class I molecules, is recognized by antibodies and cytotoxic T-lymphocytes (CTLs). A Phase 2a trial (NCT02455557) showed that a 15-amino acid-peptide-conjugate vaccine (SurVaxM) stimulates the production of survivin-directed antibodies and anti-tumor CTL in nGBM patients, resulting in a median OS of 25.9 months. This Phase 2b randomized controlled trial (RCT) aims to further investigate the efficacy of SurVaxM and adjuvant temozolomide for nGBM. METHODS This multicenter, placebo-controlled, investigator- and patient-blinded, in-progress RCT randomizes nGBM patients receiving standard of care to either SurVaxM (arm A) or saline placebo (arm B) in a 3:2 ratio at 15 sites. Included patients have age ≥18 years, normal organ function, Karnofsky Performance Status (KPS) ≥70, surgical resection, residual MRI contrast enhancement of ≤1 cm3 within 72 hours of resection, and adjuvant temozolomide (TMZ) therapy. Patients with recurrent, multicentric, brainstem- or cerebellar-origin GBM are excluded, as well as patients on tumor-treating fields or other immunotherapies. All patients undergo 3 phases: (1) vaccine priming (VP) phase, starting within 4 weeks after completion of chemoradiation, where 4 doses of SurVaxM or Placebo are administered every 2 weeks; (2) adjuvant TMZ phase, started after ≥1 VP dose; and (3) vaccine maintenance phase, started 8 weeks after VP, with SurVaxM or placebo given every 8 weeks. TMZ phase overlaps with VP and VM phases. The primary endpoint is median OS. Assuming a 1-year survival rate of 75% in the SurVaxM arm, comparable to the median OS in early phase trials, and 60% in the control arm, the study will enroll 265 patients, 159 in arm A and 106 in arm B. A log-rank test stratified by KPS (70-80 and 90-100), MGMT status (methylated and unmethylated), and IDH status (mutant and wild-type) will be used for analysis. Secondary endpoints per study arm are survival at 15, 18, and 24 months, median progression-free survival, toxicity, and progression-free survival at 3, 6, and 12 months. A single sequential OS-driven interim analysis is planned when 50% of OS events (deaths) occur. The study is expected to take 35 months, with ongoing accrual. RESULTS 69 patients have been enrolled as of April 11, 2023. CONCLUSION Findings from this trial will demonstrate the safety and efficacy of survivin vaccine in GBM (Clinical trial information: NCT05163080).

P11.17.A TEMOZOLOMIDE ONLY FOR GBM MGMT PROMOTER METHYLATEDELDERLY PATIENTS IN REAL CLINICAL SET

Abstract BACKGROUND The course of glioblastoma (GBM) is worse in elderly and low KPS patients. The NORDIC and NOA08 clinical trials proved the non-inferiority of temozolomide (TMZ) treatment to radiotherapy alone for GBM MGMT promoter methylated (MGMT MET) elderly patients. TMZ alone is thus recommended in guidelines as first line of treatment for this group of patients. The data of real life efficacy of this treatment are sparse. MATERIAL AND METHODS We retrospectively evaluated the data of GBM MGMT MET patients, older than 65y that were treated in the Neuro-oncology unit at Sheba MC during 2012-2022. The treatment was adjuvant TMZ 200mg/m2/day 5 days q28 days. We compared treatment outcomes in our patients to the results of the NORDIC and NOA08 RCTs. RESULTS 36 patients were included in our analysis with stereotactic biopsy for diagnosis in 47% of them: 34 patients had GBM, 1 had WHO grade 3 Astrocytoma and in 1 patient the diagnosis was made by imaging (non diagnostic biopsy). Of this group, 25 were males and 11 females. The mean age was 76y (64-90) and 96% had KPS ≤ 60. Only one patient had IDH 1 mutation and in 9 cases IDH status was unknown. The interval from diagnosis to treatment was 2-19 weeks (median 6 weeks). The number of TMZ cycles was 1-12 (mean of 4 cycles after the exclusion of 11 patients who received less than 3 cycles). Median PFS/OS was 3 /7.5 months and 5/11 months respectively for the whole group and for patients that received ≥3 cycles. The 12/18/24 months survival rate was 33%/13%/8% respectively. 21 patients received second line treatment: 13 radiotherapy, 1 TMZ re-challenge and 7 Bevacizumab. Eight patients received a third line of treatment: 2 radiotherapy, 4 Bevacizumab, 1 Procarbazine and 1 TMZ. Grade 3-4 hematological toxicity was documented in 20% of the patients, with infections in 12.5% and bleeding in 4%. Fatigue was reported in 17% of the patients. CONCLUSION While our patients were older and with lower KPS than the patients in the RCTs the efficacy of TMZ only treatment was comparable with the clinical trials results with mOS of 11/11.9/8.3 month in Sheba/NOA08/Nordic patients, PFS of 5/8.4/NA in Sheba/NOA08/Nordic patients respectively. The main toxicity reported in all 3 data sets was hematological 20%/38%/12% in Sheba/NOA08/Nordic patients. We can conclude that TMZ only for GBM MGMT MET elderly patients in real clinical set is a valuable and safe first line treatment. &amp;lt;!--EndFragment--&amp;gt;

Effect of Concomitant and Adjuvant Temozolomide on Prognosis and Survival in Glioblastoma Multiforme

Objective: Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor in adults. The most common problem in the follow-up after GBM treatment is the lack of local control. This study aims to evaluate the efficacy and safety of Temozolomide (TMZ) in cases who received post-surgical radiotherapy and TMZ treatment in GBM compared to cases who received only radiotherapy treatment after surgery. Materials and Methods: The cases diagnosed with GBM were divided into two groups. The first group was divided into cases that received only radiotherapy after surgery, and the second group (combined treatment group) was divided into cases that received post-surgical radiotherapy and TMZ treatment. 28 cases who received radiotherapy and TMZ treatment after surgery and 26 cases who received only radiotherapy after surgery were included in the study. Local fractionated radiotherapy (60 Gy total dose: 2 Gyx5 days/week for 6 weeks) was applied to all cases. Only in the second group, 75 mg/m2/day 7 days/week orally, 200 mg/m2/day 5 days as monotherapy for 6 weeks, and six cycles of TMZ every 28 days were administered concomitantly. In addition to the effect of TMZ on prognosis and survival, the effects of age, gender, and resection size on progression-free survival (PSS) and overall survival (GSS) were evaluated in both groups. Results: There was no statistically significant benefit in terms of both PFS and OS in both groups for age and gender, a statistically significant benefit was found for resection size (total-subtotal). At the end of the study, PFS was 14 months in the combined treatment group and 6 months in the radiotherapy alone group (P&amp;lt;0.0001). OS was 16 months in the combined treatment group and 12.5 months in the radiotherapy alone group (P=0.0354). Conclusion: Combined (RT + TMZ) treatment after total surgical treatment was found to be more effective on prognosis and survival than radiotherapy alone.

Efficacy and safety of temozolomide in the treatment of aggressive pituitary neuroendocrine tumours in Spain.

Current guidelines recommend temozolomide as the first-line chemotherapy for aggressive pituitary neuroendocrine tumours. However, no clinical trials have been conducted to date and clinical experience is quite limited. We retrospectively analyzed 28 patients (9 women and 19 men), aged 46.6+16.9, with aggressive pituitary tumours (4 pituitary carcinomas and 24 aggressive adenomas) treated with temozolomide in 10 Spanish pituitary reference centres. Four patients had Cushing's disease, 9 prolactinomas and 15 clinically non-functioning pituitary tumours (seven silent corticotroph, three silent somatotroph, one silent lactotroph, one silent gondotroph and three null-cell tumours). Median size at diagnosis was 10.5 cm3 (IQR 4.7-22.5), with cavernous sinus invasion in 88% and no metastases. Pre-temozolomide treatment, these data were 5.2 cm3 (IQR 1.9-12.3), 89.3% and 14.3% (2 intracranial and 2 spinal metastases). All patients had undergone surgery (1-5 surgeries), 25 (89.3%) had received radiotherapy (7 of them reirradiated) and 13(46.4%) had received cabergoline. One patient interrupted temozolomide prematurely. The remaining 27 patients received a median of 13 cycles (range 3-66) of 5 days every 28 days, with a mean initial dose of 265 ± 73 mg when administered alone and of 133 ± 15 mg when co-administered with radiotherapy. Eight patients (29.6%) had a significant reduction (>30%) in tumour volume and 14 (51.9%) attained tumour stabilization. After a median follow-up of 29 months (IQR 10-55), 8 out of these 22 showed disease progression. A longer progression-free survival was found in the five patients who received concomitant radiotherapy. Seven patients (25%) died (all of them because of tumour progression or complications of treatments) at 77 months (IQR 42-136) after diagnosis and 29 months (IQR 16-55) after the first dose of temozolomide. Adverse effects occurred in 18 patients (14 mild and 4 moderate or severe). In conclusion, temozolomide is an effective medical treatment for aggressive pitNET and pituitary carcinomas but is sometimes followed by tumour progression. Co-administration with radiotherapy may increase progression-free survival.

EPIC-1042 as a potent PTRF/Cavin1-caveolin-1 interaction inhibitor to induce PARP1 autophagic degradation and suppress temozolomide efflux for glioblastoma.

Temozolomide (TMZ) treatment efficacy in glioblastoma is determined by various mechanisms such as TMZ efflux, autophagy, base excision repair (BER) pathway, and the level of O6-methylguanine-DNA methyltransferase (MGMT). Here, we reported a novel small-molecular inhibitor (SMI) EPIC-1042 (C20H28N6) with the potential to decrease TMZ efflux and promote PARP1 degradation via autolysosomes in the early stage. EPIC-1042 was obtained from receptor-based virtual screening. Co-immunoprecipitation and pull-down assays were applied to verify the blocking effect of EPIC-1042. Western blotting, co-immunoprecipitation, and immunofluorescence were used to elucidate the underlying mechanisms of EPIC-1042. In vivo experiments were performed to verify the efficacy of EPIC-1042 in sensitizing glioblastoma cells to TMZ. EPIC-1042 physically interrupted the interaction of PTRF/Cavin1 and caveolin-1, leading to reduced secretion of small extracellular vesicles (sEVs) to decrease TMZ efflux. It also induced PARP1 autophagic degradation via increased p62 expression that more p62 bound to PARP1 and specially promoted PARP1 translocation into autolysosomes for degradation in the early stage. Moreover, EPIC-1042 inhibited autophagy flux at last. The application of EPIC-1042 enhanced TMZ efficacy in glioblastoma in vivo. EPIC-1042 reinforced the effect of TMZ by preventing TMZ efflux, inducing PARP1 degradation via autolysosomes to perturb the BER pathway and recruitment of MGMT, and inhibiting autophagy flux in the later stage. Therefore, this study provided a novel therapeutic strategy using the combination of TMZ with EPIC-1042 for glioblastoma treatment.

Downregulation of MGMT expression by targeted editing of DNA methylation enhances temozolomide sensitivity in glioblastoma

Glioblastoma is the most common and aggressive primary tumor of the central nervous system with poor outcome. Current gold standard treatment is surgical resection followed by a combination of radio- and chemotherapy. Efficacy of temozolomide (TMZ), the primary chemotherapeutic agent, depends on the DNA methylation status of the O6-methylguanine DNA methyltransferase (MGMT), which has been identified as a prognostic biomarker in glioblastoma patients. Clinical studies revealed that glioblastoma patients with hypermethylated MGMT promoter have a better response to TMZ treatment and a significantly improved overall survival. In this study, we thus used the CRISPRoff genome editing tool to mediate targeted DNA methylation within the MGMT promoter region. The system carrying a CRISPR-deactivated Cas9 (dCas9) fused with a methyltransferase (Dnmt3A/3L) domain downregulated MGMT expression in TMZ-resistant human glioblastoma cell lines through targeted DNA methylation. The reduction of MGMT expression levels reversed TMZ resistance in TMZ-resistant glioblastoma cell lines resulting in TMZ induced dose-dependent cell death rates. In conclusion, we demonstrate targeted RNA-guided methylation of the MGMT promoter as a promising tool to overcome chemoresistance and improve the cytotoxic effect of TMZ in glioblastoma.

Specific KIR-HLA genotypes predict outcomes in refractory or relapsed primary central nervous system lymphoma

ABSTRACTIntroductionAn effective salvage regimen for the reinduction of remission is lacking for refractory or relapsed primary central nervous system lymphoma (r/r PCNSL). This study aimed to evaluate the efficacy and safety of cytarabine plus temozolomide in treating r/r PCNSL and to explore the associated prognostic factors.MethodsA single-center retrospective cohort study was conducted to assess the efficacy and safety of cytarabine and temozolomide (AT) in r/r PCNSL patients. KIR and HLA genotyping was performed on peripheral blood samples.ResultsThirty PCNSL patients receiving an AT regimen (cytarabine 3 g/m2 for 2 days combined with temozolomide 150 mg/m2 for 5 days) in our institution were analyzed. The median age was 65 years (range 25–79 years). A total of 43.4% of patients (13/30) achieved an overall response within a median follow-up of 16 months (95% confidence interval [CI]: 11–23 months). The median PFS and OS of the cohort were 1.5 months (95% CI: 1–4 months) and 19.5 months (95% CI: 11 months to not calculable), respectively. Patients harboring KIR3DL1/HLA-B genotypes predicting low affinity had a higher response rate (p = 0.042) and longer median PFS (3 months) than those with KIR3DL1/HLA-B genotypes predicting high affinity (1 month) (p = 0.0047). Cox regression analysis indicated that KIR/HLA-B genotypes were independently associated with PFS (p = 0.043). However, KIR/HLA-B genotypes had no impact on the OS of the cohort. The toxicity of AT treatment was mild and manageable.ConclusionThe AT regimen was well tolerated, and patients with specific KIR-HLA genotypes may benefit from this regimen.

Safety and Efficacy of Anlotinib Hydrochloride Plus Temozolomide in Patients with Recurrent Glioblastoma.

Glioblastoma (GBM) is a highly vascularized tumor with few treatment options after disease recurrence. Here, we report the efficacy and safety of anlotinib hydrochloride plus temozolomide in patients with recurrent GBM. Patients with first definite postsurgical progression of histologically confirmed GBM preceded by standard radiotherapy and temozolomide chemotherapy were eligible for inclusion. All patients received temozolomide (150-200 mg/m2, orally, every day (QD) d1-5/4 wk) and anlotinib (10 mg, orally, QD, d1-14/3 wk) until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed 6-month progression-free survival (PFS) rate by the Response Assessment in Neuro-Oncology (RANO) criteria. Twenty-one patients were enrolled between May 2020 and July 2021, with a median age of 55 (range 27-68) years old. According to the Response Assessment in Neuro-Oncology (RANO) criteria, tumor response occurred in 17 patients, of which 9 patients had a complete response, and the objective response rate was 81.0% [95% confidence interval (CI), 62.6-99.3]. The disease control rate was 95.2% (95% CI, 76.2-99.9), with three additional patients achieving a stable disease without tumor progression. The median PFS was 7.3 months (95% CI, 4.9-9.7), and the 6-month PFS rate was 61.9% (95% CI, 39.3-84.6). The median overall survival was 16.9 months (95% CI, 7.8-26.0). The most common adverse events were leukocytopenia (66.7%), thrombocytopenia (38.1%), and hypertriglyceridemia (38.1%). Five patients had nine grade 3 adverse events, with a 23.8% incidence rate. Two patients discontinued therapy due to ischemic stroke (grade 3) and wound dehiscence (grade 1), respectively. No grade 4 or treatment-related deaths occurred in this study. Anlotinib combined with temozolomide is efficacious and tolerated in patients with recurrent GBM.

Methadone Potentiates the Cytotoxicity of Temozolomide by Impairing Calcium Homeostasis and Dysregulation of PARP in Glioblastoma Cells.

Methadone is commonly used as an alternative to morphine in patients with pain associated with glioblastoma and other cancers. Although concomitant administration of methadone and cytostatics is relatively common, the effect of methadone on the efficacy of cytostatic drugs has not been well studied until recently. Moreover, the mechanism behind the effect of methadone on temozolomide efficacy has not been investigated in previous studies, or this effect has been automatically attributed to opioid receptors. Our findings indicate that methadone potentiates the effect of temozolomide on rat C6 glioblastoma cells and on human U251 and T98G glioblastoma cells and increases cell mortality by approximately 50% via a mechanism of action independent of opioid receptors. Our data suggest that methadone acts by affecting mitochondrial potential, the level of oxidative stress, intracellular Ca2+ concentration and possibly intracellular ATP levels. Significant effects were also observed on DNA integrity and on cleavage and expression of the DNA repair protein PARP-1. None of these effects were attributed to the activation of opioid receptors and Toll-like receptor 4. Our results provide an alternative perspective on the mechanism of action of methadone in combination with temozolomide and a potential strategy for the treatment of glioblastoma cell resistance to temozolomide.

Lysine methylation promotes NFAT5 activation and determines temozolomide efficacy in glioblastoma

Temozolomide (TMZ) therapy offers minimal clinical benefits in patients with glioblastoma multiforme (GBM) with high EGFR activity, underscoring the need for effective combination therapy. Here, we show that tonicity-responsive enhancer binding protein (NFAT5) lysine methylation, is a determinant of TMZ response. Mechanistically, EGFR activation induces phosphorylated EZH2 (Ser21) binding and triggers NFAT5 methylation at K668. Methylation prevents NFAT5 cytoplasm interaction with E3 ligase TRAF6, thus blocks NFAT5 lysosomal degradation and cytosol localization restriction, which was mediated by TRAF6 induced K63-linked ubiquitination, resulting in NFAT5 protein stabilization, nuclear accumulation and activation. Methylated NFAT5 leads to the upregulation of MGMT, a transcriptional target of NFAT5, which is responsible for unfavorable TMZ response. Inhibition of NFAT5 K668 methylation improved TMZ efficacy in orthotopic xenografts and patient-derived xenografts (PDX) models. Notably, NFAT5 K668 methylation levels are elevated in TMZ-refractory specimens and confer poor prognosis. Our findings suggest targeting NFAT5 methylation is a promising therapeutic strategy to improve TMZ response in tumors with EGFR activation.

Efficacy and safety of metformin plus low-dose temozolomide in patients with recurrent or refractory glioblastoma: a randomized, prospective, multicenter, double-blind, controlled, phase 2 trial (KNOG-1501 study)

PurposeGlioblastoma (GBM) has a poor prognosis after standard treatment. Recently, metformin has been shown to have an antitumor effect on glioma cells. We performed the first randomized prospective phase II clinical trial to investigate the clinical efficacy and safety of metformin in patients with recurrent or refractory GBM treated with low-dose temozolomide.MethodsIncluded patients were randomly assigned to a control group [placebo plus low-dose temozolomide (50 mg/m2, daily)] or an experimental group [metformin (1000 mg, 1500 mg, and 2000 mg per day during the 1st, 2nd, and 3rd week until disease progression, respectively) plus low-dose temozolomide]. The primary endpoint was progression-free survival (PFS). Secondary endpoints were overall survival (OS), disease control rate, overall response rate, health-related quality of life, and safety.ResultsAmong the 92 patients screened, 81 were randomly assigned to the control group (43 patients) or the experimental group (38 patients). Although the control group showed a longer median PFS, the difference between the two groups was not statistically significant (2.66 versus 2.3 months, p = 0.679). The median OS was 17.22 months (95% CI 12.19–21.68 months) in the experimental group and 7.69 months (95% CI 5.16–22.67 months) in the control group, showing no significant difference by the log-rank test (HR: 0.78; 95% CI 0.39–1.58; p = 0.473). The overall response rate and disease control rate were 9.3% and 46.5% in the control group and 5.3% and 47.4% in the experimental group, respectively.ConclusionsAlthough the metformin plus temozolomide regimen was well tolerated, it did not confer a clinical benefit in patients with recurrent or refractory GBM.Trial registration NCT03243851, registered August 4, 2017.

EPIC-0307-mediated selective disruption of PRADX-EZH2 interaction and enhancement of temozolomide sensitivity to glioblastoma via inhibiting DNA repair and MGMT.

Temozolomide (TMZ) treatment efficacy in glioblastoma (GBM) has been limited by resistance. The level of O-6-methylguanine-DNA methyltransferase (MGMT) and intrinsic DNA damage repair factors are important for the TMZ response in patients. Here, we reported a novel compound, called EPIC-0307, that increased TMZ sensitivity by inhibiting specific DNA damage repair proteins and MGMT expression. EPIC-0307 was derived by molecular docking screening. RNA immunoprecipitation (RIP), and chromatin immunoprecipitation by RNA (ChIRP) assays were used to verify the blocking effect. Chromatin immunoprecipitation (ChIP) and co-immunoprecipitation (Co-IP) assays were performed to explore the mechanism of EPIC-0307. A series of in vivo and in vitro experiments were designed to evaluate the efficacy of EPIC-0307 in sensitizing GBM cells to TMZ. EPIC-0307 selectively disrupted the binding of PRADX to EZH2 and upregulated the expression of P21 and PUMA, leading to cell cycle arrest and apoptosis in GBM cells. EPIC-0307 exhibited a synergistic inhibitory effect on GBM when combined with TMZ by downregulating TMZ-induced DNA damage repair responses and epigenetically silencing MGMT expression through modulating the recruitment of ATF3-pSTAT3-HDAC1 regulatory complex to the MGMT promoter. EPIC-0307 demonstrated significant efficacy in suppressing the tumorigenesis of GBM cells, restoring TMZ sensitivity. This study identified a potential small-molecule inhibitor (SMI) EPIC-0307 that selectively disrupted the PRADX-EZH2 interaction to upregulate expressions of tumor suppressor genes, thereby exerting its antitumor effects on GBM cells. EPIC-0307 treatment also increased the chemotherapeutic efficacy of TMZ by epigenetically downregulating DNA repair-associate genes and MGMT expression in GBM cells.

BORTEM-17: A phase IB/II single arm, multicentre study investigating the efficacy of sequential bortezomib and temozolomide in recurrent GBM with unmethylated MGMT promoter—The results of an interim analysis.

2019 Background: Glioblastoma (GBM) is the most frequent, lethal primary brain tumor in adults. Patients harboring tumors with functional O6 methylguanine DNA methyltransferase ( MGMT) DNA enzyme gain limited benefit from temozolomide therapy. As shown in preclinical studies, bortezomib depletes the MGMT enzyme, restoring the tumor ́s susceptibility to temozolomide, if administered in a precise schedule when the MGMT enzyme is depleted. We hypothesized that recurrent GBM patients with unmethylated MGMT promoter may obtain clinical benefit from sequential BTZ and TMZ treatment. Methods: BORTEM-17 is a multicenter, open label, single arm, non-randomized phase IB/II trial to investigate potential survival benefit for recurrent glioblastoma patients administered bortezomib 48hrs prior to temozolomide. Sample size is calculated to 63 patients, of whom 10 included in phase IB. The doses of bortezomib is 1.3mg/m2 intravenously days 1, 4, and 7 during 4-week cycle, and temozolomide 200mg/m2 days 5-7. The control group is a retrospective cohort of 467 patients treated at 2 referral hospitals in Norway from January 2015 to December 2017. For the survival analysis, the patients included in BORTEM-17 (n=44) were compared with MGMT unmethylated control, age matched patients (n=116). The pre-defined interim analysis was performed after inclusion of 15 patients and as more than 2 of 15 patients had clinical benefit, the study was continued. Results: Until January 2023, 44 patients with median age 55 years (range 25-69), 30 males and 14 females were treated. Median KPS was 90 (70-100) and median NANO score 1 (0-7). The interim analysis was performed after inclusion of 15 patients in the phase IB and II and clinical benefit was observed in 5 patients. Two of them had tumor volume reduction and three experienced stable disease. The study proceeded to the next step. No treatment related deaths were observed. The most common adverse effects included hematological toxicity, gastrointestinal symptoms, muscle weakness, lower back pain and fatigue. Patients that progressed during the BORTEM-17 trial and were fit for further therapy received treatment at their physician’s discretion. The preliminary data analysis after 44 of planned 63 patients were treated indicate prolonged median survival for BORTEM-17 patients 19.0 months vs 12.2 months of control MGMT unmethylated age matched patients. Median survival after recruitment is 5.5 months (1.0-23.8). Conclusions: The sequential BTZ+TMZ therapy is safe, feasible and effective as indicated by preliminary data when 70% of planned MGMT unmethylated patients have been included. Preliminary data indicate that the combination of BTZ and TMZ may offer an additional line of treatment with limited toxicity to the group of patients with particularly dismal prognosis. Clinical trial information: NCT03643549 .

The DRD2 antagonist haloperidol mediates autophagy-induced ferroptosis to increase temozolomide sensitivity by promoting endoplasmic reticulum stress in glioblastoma.

Temozolomide (TMZ) resistance remains a major obstacle in the treatment of glioblastoma (GBM). The combination of TMZ with another agent could offer an improved treatment option if it could overcome chemoresistance and prevent side effects. Here, we determined the critical drug that cause ferroptosis in GBM cells and elucidated the possible mechanism by which drug combination overcomes chemoresistance. Haloperidol/TMZ synergism was assessed in GBM cell lines with different DRD2 expression in vitro and in vivo. Inhibitors of ferroptosis, autophagy, endoplasmic reticulum stress and cAMP/PKA were used to validate the specific mechanisms by which haloperidol and TMZ induce ferroptosis in GBM cells. In the present work, we demonstrate that the dopamine D2 receptor (DRD2) level is increased by TMZ in a time-dependent manner and is inversely correlated with TMZ sensitivity in GBM. The DRD2 antagonist haloperidol (HP), a butylbenzene antipsychotic, markedly induces ferroptosis and effectively enhances TMZ efficacy in vivo and in vitro. Mechanistically, HP suppressed the effect of TMZ on cAMP by antagonizing DRD2 receptor activity, and the increases in cAMP/PKA triggered endoplasmic reticulum stress, which led to autophagy and ferroptosis. Furthermore, elevated autophagy mediates downregulation of FTH1 expression at the posttranslational level in an autophagy-dependent manner and ultimately leads to ferroptosis. Our results provide experimental evidence for repurposing HP as an effective adjunct therapy to inhibit adaptive TMZ resistance in order to enhance the efficacy of chemoradiotherapy in GBM, a strategy that may have broad prospects for clinical application.