Dose-intensified Temozolomide Research Articles

Anlotinib in combination with dose-intense temozolomide for the recurrent or progressive glioblastoma after STUPP regimen.

e14014 Background: Nearly all patients (pts) with glioblastoma (GBM) will suffered relapse or disease progression after resection and adjuvant radiotherapy and temozolomide (TMZ). Anlotinib is a new multikinase inhibitors (MKI) blocking angiogenesis and tumor cell proliferation simultaneously and a prospective phase II study was performed to explore the potency of the combination anlotinib and TMZ for pts with relapse or progression GBM. Here, we reports the preliminary results of this study. Methods: This is a prospective, single-arm, open label, phase II study (NCT04547855). Eligible pts were diagnosed with histologically confirmed glioblastoma and experienced relapse or progression for the first time from surgery (including biopsy, partial resection and total resection) and radiotherapy-TMZ therapy (STUPP regimen). Other criteria included 18 to 75 years age, Karnofsky performance status (KPS) ≥ 60% and adequate organ function. The primary endpoint was progression free survival at 6 months (6m-PFS). All pts received orally TMZ (150 mg/m2) from D1-D7 every 2 weeks and anlotinib (12mg, QD) from D1-D14 every 3 weeks until disease progression or unacceptable toxicities. Results: From July 2020 to November 2021, 25 pts were enrolled. The median age was 49 (rang: 23, 62) and the median KPS was 80 (range: 60, 100). Most pts had poor prognostic factors that 17 pts (70.8%) had unmethylated MGMT promoter and 22 pts (91.6%) were IDH wild-type, which 24 pts detected IDH and MGMT status. At the data cutoff date on January 2022, the 6m-PFS was 25.2% and the median PFS was 4.2 months (95% CI, 3.4-5.0m). The median OS reached 9.1 months (95% CI, 8.1-10.2). Tumor response was assessed for all pts. 7 pts achieved partial response and the objective response rate was 28%. 10 pts had stable disease and the disease control rate was 68%. The most common grade 3 or worse adverse events (AEs) was lympyhopenia (48.0%), which may be caused by TMZ. No death was attributed to AEs. Conclusions: Combination of anlotinib and dose-intense temozolomide was tolerable in the treatment of recurrent or progressive glioblastoma. Preliminary results indicated that the efficacy was promising for those miserable pts with worse prognosis factors. Further investigation was ongoing. Clinical trial information: NCT04547855.

CBIO-16. DOSE INTENSIFIED TEMOZOLOMIDE IMPROVES INFILTRATION OF CD70 CAR T CELLS INTO THE GBM TUMOR MICROENVIRONMENT

Abstract CD70 CAR T cells developed by our group have anti-tumor efficacy in syngeneic murine GBM model and are currently being developed for first-in-human testing. The objective of this study was to evaluate the impact of temozolomide (TMZ) in various dosing strategies on the expansion, persistence and function of the CD70 CAR T cells after infusion. C57BL/6 mice underwent intracranial implantation of KR-158 overexpressing CD70 tumor cells. Tumor bearing animals were treated with standard dose (SD) (50 mg/kg x 5 days), metronomic dose (MD) (25mg/kg x 10 days), or dose intensified (DI) (75mg/kg x 5 days) of TMZ, followed by 10×106 CAR T cells infusion. Peripheral blood was collected to monitor the persistence of CAR T cells in the systemic blood circulation. Six weeks post treatments, spleens and tumors were collected and CAR T cells abundance and function were measured. TMZ preconditioning resulted in the expected lymphopenia in animals by generation of dose dependent lymphopenia. Circulating CD70 CAR T cells peaked in the systemic blood 2 weeks after infusion (3-fold, p< 0.0001). Markers of T cell exhaustion including PD-1 and TOX expression on CAR T cells were not different between the three TMZ treatment groups compared to control. Six weeks post treatment, CD70 CAR T cells were found to be highly infiltrated within the tumor microenvironment in the DI TMZ group compared to the other groups (4-fold,p < 0.0001). Tumor infiltrating CD70 CAR T cells in the DI TMZ group did not have an increase in PD-1 and TOX expression which was seen in the MD and SD TMZ groups. DI TMZ preconditioning results in greater CD70 CAR T cell trafficking to the tumor without T cell exhaustion compared to lower doses of TMZ. The affects of TMZ on the immune microenvironment to enhance CAR T cell regimens warrants further study.

A phase 1b randomised, placebo-controlled trial of nabiximols cannabinoid oromucosal spray with temozolomide in patients with recurrent glioblastoma

BackgroundPreclinical data suggest some cannabinoids may exert antitumour effects against glioblastoma (GBM). Safety and preliminary efficacy of nabiximols oromucosal cannabinoid spray plus dose-intense temozolomide (DIT) was evaluated in patients with first recurrence of GBM.MethodsPart 1 was open-label and Part 2 was randomised, double-blind, and placebo-controlled. Both required individualised dose escalation. Patients received nabiximols (Part 1, n = 6; Part 2, n = 12) or placebo (Part 2 only, n = 9); maximum of 12 sprays/day with DIT for up to 12 months. Safety, efficacy, and temozolomide (TMZ) pharmacokinetics (PK) were monitored.ResultsThe most common treatment-emergent adverse events (TEAEs; both parts) were vomiting, dizziness, fatigue, nausea and headache. Most patients experienced TEAEs that were grade 2 or 3 (CTCAE). In Part 2, 33% of both nabiximols- and placebo-treated patients were progression-free at 6 months. Survival at 1 year was 83% for nabiximols- and 44% for placebo-treated patients (p = 0.042), although two patients died within the first 40 days of enrolment in the placebo arm. There were no apparent effects of nabiximols on TMZ PK.ConclusionsWith personalised dosing, nabiximols had acceptable safety and tolerability with no drug–drug interaction identified. The observed survival differences support further exploration in an adequately powered randomised controlled trial.Clinical trial registrationClinicalTrials.gov: Part 1– NCT01812603; Part 2– NCT01812616.

CTIM-29. CRUCIAL APPLICATION OF SINGLE CELL GENE EXPRESSION FOR MONITORING CHANGES IN GLIOBLASTOMA PATIENTS WITH SUSTAINED RADIOGRAPHIC RESPONSE TO CMV pp65-LAMP RNA-PULSED DENDRITIC CELL-BASED VACCINES

Abstract BACKGROUND The application of single cell sequencing as a novel immune monitoring platform can be used to identify the molecular mechanisms of immune response to dendritic cell- based vaccines, trace the cell types and states involved, and uncover novel biomarkers for immunotherapy. We applied single-cell RNA Seq analysis of longitudinal peripheral blood mononuclear cells (PBMCs) in patients with newly-diagnosed GBM enrolled on the ATTAC II clinical trial (FDA IND BB-16530; Clinicaltrials.gov # NCT02465268) who experienced a sustained radiographic response to autologous CMV pp65-LAMP RNA-pulsed DC vaccines plus GM-CSF and tetanus-diphtheria booster administered during adjuvant cycles of dose-intensified temozolomide. METHODS We constructed 5’ gene expression libraries and T cell receptor enriched libraries for 10x Genomics single-cell 5’ and VDJ sequencing, generated from PBMCs collected prior to and during patient immunization using dendritic cells loaded with messenger ribonucleic acid encoding the human cytomegalovirus (CMV) matrix protein pp65 conjugated with the lysosomal associated membrane protein (LAMP) sequence. RESULTS Overall, we sequenced a total of 189,808 single-cell transcriptomes from 5 patients. We leveraged these transcriptome-wide features to distinguish 15 peripheral immune cell subtypes in tested PBMCs. Analysis revealed dynamic changes in immune cell subsets over the course of first three vaccines, including increases in cytotoxic CD8 T cells, CD4 T cells, and NK cell subsets. Increased markers of T cell activation were observed during vaccination. Surprisingly, we observed a very high-level frequency of natural killer T (NKT) cells in the patient with a complete durable response compared to other patients. After three DC vaccines, the level of NKT cells in PBMC of this patient increased up to 10%. CONCLUSIONS These results emphasize the importance of subset specific profiling to achieve higher resolution in monitoring immune responses compared with bulk expression profiling in patients receiving immunotherapeutic treatment.

Association of peripheral blood CD4+ T-cell depletion under temozolomide with inferior survival of patients with IDH wildtype glioblastoma.

2548 Background: Standard first line chemoirradiation with temozolomide is associated with distinctive peripheral blood immune cell profiles in IDH wildtype glioblastoma. Whether such profiles at recurrence are associated with survival has not been studied in detail. Methods: Peripheral blood mononuclear cells of 21 healthy donors and of 91 patients with IDH wildtype glioblastoma were analyzed by flow cytometry at 1st recurrence. Patients received either (i) standard chemoirradiation with temozolomide (TMZ) followed by dose-intensified TMZ at first recurrence within the phase II trial DIRECTOR (N = 52) or (ii) hypofractionated radiotherapy with or without bevacizumab (N = 39) followed by investigators’ choice within the phase II trial ARTE. Patients were classified based on unsupervised analyses of PBMC profiles at 1st recurrence. Associations with survival were explored in multivariate Cox models controlling for established prognostic and predictive factors. Results: At 1st recurrence, two patient clusters were identified in the DIRECTOR cohort which differed in CD4+ T-cell fractions, but not with respect to CD8+ T-cells, CD4+;CD25+;FoxP3+ regulatory T-cells, B-cells or monocytes. The composition of CD4+, CD8+ or regulatory T-cell fractions was similar in both clusters. All control samples clustered with the CD4high cluster. Patients in both clusters did not differ by established prognostic factors, including age, O6-methylguanine-DNA-methyl-transferase ( MGMT) gene promoter methylation, tumor volume, Karfnosky performance score or steroid use. Progression-free survival was similar (CD4high vs CD4low 2.1 vs 2.4 months, p = 0.19), whereas post-recurrence overall survival was longer among the CD4high cluster (12.7 vs 8.7 months, p = 0.004). At 2nd recurrence after dose-intensified TMZ re-challenge, monocyte fractions increased, whereas memory CD4+ T-cell fractions decreased. Higher memory CD4+ fractions were associated with longer overall survival at 2nd recurrence (p = 0.004). The reported associations were retained in multivariate Cox models controlling for established prognostic factors. In the ARTE cohort, CD4+ T cell fractions at 1st recurrence did not differ compared to diagnosis (p = 0.91) and there were no associations with bevacizumab (p = 0.28) or survival (p = 0.74), supporting that the effects observed in the DIRECTOR cohort were driven by TMZ. Conclusions: We conclude that TMZ-associated memory CD4+ T-cell depletion may have deteriorating effects on the survival of glioblastoma patients.

ATIM-15. SUSTAINED COMPLETE RADIOGRAPHIC RESPONSE AND PROLONGED SYSTEMIC IMMUNE ACTIVATION IN A PATIENT WITH MGMT UNMETHYLATED MIDLINE GLIOBLASTOMA RECEIVING CMV pp65-LAMP RNA-PULSED DENDRITIC CELL VACCINES

Abstract BACKGROUND We initiated a Phase 2, randomized, placebo-controlled, clinical trial evaluating the efficacy of autologous CMV pp65-LAMP RNA pulsed dendritic cell vaccines mixed with GM-CSF and administered during cycles of adjuvant dose-intensified temozolomide (ATTAC II, NCT02465268). STUDY OBJECTIVE A patient with partially resected GBM experienced a sustained complete radiographic response after receiving five DC vaccines. Peripheral blood responses were characterized to examine possible immunologic biomarkers concordant with a sustained clinical response. METHODS Patients with newly diagnosed glioblastoma undergoing surgical resection are eligible and randomized 2:1 to DC vaccine arms vs placebo (PBMCs in saline). DC vaccines consist of CMV pp65 RNA conjugated either to the full-length lysosomal associated membrane protein (LAMP) or to the short LAMP signal sequence. Patients undergo leukapheresis for DC generation prior to standard chemoradiation and receive cycle 1 of dose-intensified temozolomide (100 mg/m^2 x 21 days) before first three biweekly intradermal DC vaccines admixed with GM-CSF. Subsequent DC vaccines (total of 10) are given monthly with each diTMZ cycle with an intradermal tetanus-diphtheria booster given 6-24hrs before the third, fifth, seventh, and ninth DC vaccines. PBMCs and serum are collected for immune monitoring. RESULTS A 58-year old white male with partially-resected, MGMT-unmethlyated, p53 mutant, H3.3 mutant, midline glioblastoma was enrolled on the ATTAC II study and experienced a complete radiographic response after the fifth DC vaccine that has been sustained > 10 months. Immune monitoring by Elispot, cytokine array, and single-cell RNA sequencing have revealed significant expansion of CMV pp65-specific immune responses, increased circulating IFNg, and marked systemic expansion of cytotoxic T cells and iNKT cells during vaccination. These responses were sustained through cycles of diTMZ despite profound lymphopenia. CONCLUSIONS CMV pp65-LAMP RNA-pulsed DC vaccination was associated with profound immunologic and clinical response in a patient with MGMT unmethylated midline glioblastoma.

Enhanced Copper-Temozolomide Interactions by Protein for Chemotherapy against Glioblastoma Multiforme.

Current treatment of recurrent glioblastoma multiforme (GBM) demands dose-intense temozolomide (TMZ), a prodrug of 5-(3-methyltriazen-1-yl) imidazole-4-carboxamide (MTIC), based on the spontaneous hydrolysis of TMZ at basic pH. However, how to control the activity of MTIC remains unknown, which poses a particular challenge to search a reliable MTIC receptor. We reported that copper, for the first time, is found to recognize and bind MTIC in the process of TMZ degradation, which means copper can play an important role in enhancing the bioavailability of MTIC derived from TMZ. Using apoferritin as a model copper-bound protein, we studied the copper-TMZ interaction in protein and observed efficient MTIC immobilization with high binding efficiency (up to 92.9% based on original TMZ) and capacity (up to 185 MTIC moieties per protein). The system was stable against both alkaline and acidic pH and could be activated by glutathione to liberate MTIC, which paves a way to deliver a DNA-alkylating agent for both TMZ-sensitive and TMZ-resistant GBM chemotherapy. Our study provides a new insight for understanding the potential relationship between the special GBM microenvironment (specific copper accumulation) and the therapeutic effect of TMZ.

OS1.6 Peripheral blood immune profiles at first recurrence of IDH wild type glioblastoma after standard chemoradiotherapy predict overall survival: secondary analyses of the phase II DIRECTOR trial

Abstract BACKGROUND Isocitrate dehydrogenase (IDH) wildtype glioblastoma is associated with distinctive peripheral blood immune cell profiles that evolve under first line chemoirradiation with temozolomide. Whether peripheral blood immune cell profiles at recurrence are associated with survival of IDH wildtype glioblastoma has not been studied in detail. PATIENTS AND METHODS Peripheral blood mononuclear cells (PBMC) of 21 healthy donors and of 52 clinically well-annotated patients with IDH wildtype glioblastoma were analyzed by 11-color flow cytometry at 1st recurrence after standard chemoirradiation with temozolomide and at 2nd recurrence after dose-intensified temozolomide re-challenge. Patients were treated within the randomized phase II trial DIRECTOR, which explored the efficacy of dose-intensified temozolomide at first recurrence of glioblastoma. Patients were classified based on unsupervised analyses of PBMC profiles at 1stand 2ndrecurrence. Associations with survival were explored in multivariate Cox models controlling for established prognostic and predictive factors. RESULTS At 1strecurrence, two patient clusters were identified which differed in CD4+ T-cell fractions, but not with respect to CD8+ T-cells, CD4+;CD25+;FoxP3+ regulatory T-cells, B-cells or monocytes. The composition of CD4+, CD8+ or regulatory T-cell fractions was similar in both clusters. All control samples clustered with the CD4high cluster. Patients in both clusters did not differ by established prognostic factors, including age, O6-methylguanine-DNA-methyl-transferase (MGMT) gene promoter methylation, tumor volume, Karfnosky performance score or steroid use. Progression-free survival was similar (CD4high vsCD4low 2.1 vs 2.4 months, p=0.19), whereas post-recurrence overall survival was longer among the CD4highcluster (12.7 vs 8.7 months, p= 0.004). At 2nd recurrence, monocyte fractions increased, whereas memory CD4+ T-cell fractions decreased. Unsupervised segregation of patients by CD4+ subpopulations yielded two clusters characterized by the abundance of memory T-cell fractions and higher memory CD4+ fractions were associated with longer overall survival at 2nd recurrence (p=0.004). The reported prognostic associations were retained in multivariate Cox models controlling for established prognostic factors. CONCLUSION We conclude that temozolomide-associated memory CD4+ T-cell depletion may have deteriorating effects on the survival of glioblastoma patients.

P14.112 Long-term application of TTFields in glioblastoma: a multiple-case study

Abstract BACKGROUND Tumor treating fields (TTFields) is an antimitotic cancer therapy that utilizes low-intensity, intermediate-frequency alternating electrical fields to treat glioblastoma (GBM). Increased compliance with TTFields is independently prognostic for improved survival and was correlated with significantly improved overall and progression-free survival versus temozolomide (TMZ) alone. We present two exemplary cases of primary GBM treated with TTFields on long-term and adjuvant chemotherapy to explore treatment adherence, feasibility and safety issues. MATERIAL AND METHODS We present case details of two patients from our comprehensive cancer center, both of whom have primary GBM and are long-term TTFields users. One patient began TTFields at first diagnosis whilst the other had already survived to two years at the time of TTFields commencement. Their histories and disease status under continuous, ongoing TTFields therapy with concomitant, extended chemotherapy are explored. RESULTS Patient A is a 52-year-old male with IDH1-wildtype, MGMT promoter-methylated GBM. He began TTFields 24 months after initial diagnosis. Before starting TTFields, he had two resections, one owing to early locoregional progression, and had underwent standard, dual radiochemotherapy and started adjuvant TMZ. He has now completed 931 days of treatment with an average daily usage of 82% and has survived 55 months from first diagnosis. Since beginning TTFields, he has undergone a further two resections and another radiotherapy course. His chemotherapy regime has been modified several times, from standard-dose to dose-intensified TMZ, then later switched to lomustine and irinotecan-containing protocols. Patient B is a 68-year-old male, also with IDH1-wildtype, MGMT promoter-methylated GBM. He began TTFields six months after first diagnosis and after one tumor resection, concomitant radiochemotherapy and initiation of long-term TMZ therapy. He has now undergone 636 days of TTFields treatment with an average daily usage of 74%. In addition, 28 cycles of TMZ have been completed. CONCLUSION During a mean treatment duration of 784 days and alongside extended-course adjuvant chemotherapy, TTFields was well tolerated. Both patients are alive and still receiving treatment. Compliance has remained within the target range. Significant adverse events or treatment interruptions have not occurred. The patients have remained symptomatically stable and their quality of life has been maintained.

Abstract 4705: Single cell derived 3D organoids recapitulate the tumorigenic features of glioblastoma

Abstract In recent years, three-dimensional (3D) models of human brain derived from pluripotent embryonic and iPS cells have emerged as brain organoids, providing established models for brain development and genetic engineering. However, tumor organoids derived from adult glioblastoma multiforme (GBM) patients were seldomly formed. WHO grade IV GBM is a devastating locally invasive brain cancer with a median survival of 14.6 months. Standard of care for GBM includes surgical resection followed by radiotherapy plus concomitant and maintenance temozolomide (TMZ). Resistance to TMZ develops rapidly and neither dose-intensified TMZ nor anti-angiogenic approaches could improve survival. Genomic, transcriptomic and epigenetic profiling allowed classifying adult GBM into three groups: isocitrate dehydrogenase (IDH)-mutant (mut), 1p/19q co-deleted oligodendroglial GBM with best prognosis; IDH-mut, 1p/19q non-co-deleted astrocytic GBM with intermediate outcome; and IDH wild-type (WT) GBM with poor prognosis. Preclinical models that reflect these GBM profiles and heterogeneity are urgently needed to examine new therapies. Patient derived orthotopic xenografts (PDOXs) are thought to better mimic the GBM environment. Genetically engineered mouse models (GEMMs) make gliomas in mice with competent immune systems, but are laborious and expensive requiring compound genetics to mimic human GBM. Here, we describe a 3D serum-free organoid system in low-adherence plates derived from primary and sphere cultures that supports the long-term growth and expansion of GBM organoids for several months. We generated organoids from GBM with IDH-WT or IDH-Mut, EGFR amplification, +7q/-10q genotype, PTEN mutation, and EGFRvIII expression. GBM organoids are comprised of a heterogenous cell populations, thus mimicking the original tumor. GBM organoids could be generated from a single cell, therefore allowing to track intratumor heterogeneity. GBM organoids could be utilized for investigating aspects of GBM biology such as 3D cellular self-renewal showing expression of stem cell and differentiation targets, 3D cell cycle regulation including synchronized growth and phase cycling, 3D cell metabolism including intracellular adenosine triphosphate (ATP) level and protein synthesis rate, 3D cell invasiveness validated with IHC assays, and for evaluation of drug effects in the context of IDH, PI3K and EGFR aberrations. We have demonstrated that GBM sphere cells exhibit a solid growth pattern when implanted orthotopically into the mouse PDOXs. Since GBM organoids form tighter cell-cell contact, oxygen and nutrient gradients, we implanted GBM organoids in mouse orthotopic xenografts to demonstrate their tumor growth and invasive phenotypes. This human GBM organoid platform allows for novel preclinical therapeutic approaches to be assessed and provides personalized therapeutic options for individual GBM patients. Citation Format: Michelle Chadwick, Rachael Mfon, Kelly Jara, Shabbar Danish, Robert Aiken, Hatem E. Sabaawy. Single cell derived 3D organoids recapitulate the tumorigenic features of glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4705.

Temozolomide lymphodepletion enhances CAR abundance and correlates with antitumor efficacy against established glioblastoma

ABSTRACTAdoptive transfer of T cells expressing chimeric antigen receptors (CARs) is an effective immunotherapy for B-cell malignancies but has failed in some solid tumors clinically. Intracerebral tumors may pose challenges that are even more significant. In order to devise a treatment strategy for patients with glioblastoma (GBM), we evaluated CARs as a monotherapy in a murine model of GBM. CARs exhibited poor expansion and survival in circulation and failed to treat syngeneic and orthotopic gliomas. We hypothesized that CAR engraftment would benefit from host lymphodepletion prior to immunotherapy and that this might be achievable by using temozolomide (TMZ), which is standard treatment for these patients and has lymphopenia as its major side effect. We modelled standard of care temozolomide (TMZSD) and dose-intensified TMZ (TMZDI) in our murine model. Both regimens are clinically approved and provide similar efficacy. Only TMZDI pretreatment prompted dramatic CAR proliferation and enhanced persistence in circulation compared to treatment with CARs alone or TMZSD + CARs. Bioluminescent imaging revealed that TMZDI + CARs induced complete regression of 21-day established brain tumors, which correlated with CAR abundance in circulation. Accordingly, TMZDI + CARs significantly prolonged survival and led to long-term survivors. These findings are highly consequential, as it suggests that GBM patients may require TMZDI as first line chemotherapy prior to systemic CAR infusion to promote CAR engraftment and antitumor efficacy. On this basis, we have initiated a phase I trial in patients with newly diagnosed GBM incorporating TMZDI as a preconditioning regimen prior to CAR immunotherapy (NCT02664363).

A two-part safety and exploratory efficacy randomized double-blind, placebo-controlled study of a 1:1 ratio of the cannabinoids cannabidiol and delta-9-tetrahydrocannabinol (CBD:THC) plus dose-intense temozolomide in patients with recurrent glioblastoma multiforme (GBM).

2046 Background: Several plant-derived cannabinoids have shown efficacy in animal models of GBM, particularly when co-administered with temozolomide, a commonly-used treatment in both primary and recurrent disease. Methods: We conducted a two-part study in patients with recurrent GBM following standard chemo-radiotherapy treatment as described by Stupp et al. In Part 1 of the study, 6 patients were treated to an MTD of 1:1 CBD:THC oro-mucosal spray, as an adjunct to dose-intense temozolomide (DIT), to assess the safety of the combination. Part 2 was a double blind, randomized, placebo-controlled study in a planned 20 patients receiving either their individualized dose of 1:1 CBD:THC or placebo plus DIT. The primary endpoint was tolerability of 1:1 CBD:THC plus temozolomide. Results: There were no Grade 3 or 4 toxicities in Part 1 of the study. In Part 2, 12 patients were randomized to CBD:THC and 9 to placebo. Mean age was 58 years in both treatment groups, but there were more males in the placebo group (5 of 12 and 8 of 9, respectively). Baseline median Karnofsky score was 90 in both groups and median time from diagnosis of recurrence to start of treatment (day 1) was similar (3.6 and 3.0 weeks in the CBD:THC and placebo group, respectively). The median number of days of dosing with CBD:THC or placebo was similar (155 days [range: 50-356] and 134 days [range: 13-359]). Median survival in the placebo group was 369 days, and > 550 days in the CBD:THC treatment group (NS) and 1 year survival was 83% and 56% in the CBD:THC and placebo groups, respectively (p = 0.042). PFS6 was 42% in the CBD:THC group and 33% in the placebo group (NS). Overall, the commonest treatment related toxicities were dizziness (in 11/18 patients) and nausea (in 7/18 patients). Results of biomarker analyses are awaited. Conclusions: This randomized study provides preliminary evidence that 1:1 CBD:THC offers some efficacy in patients with recurrent GBM when used as an adjunct to dose-intense temozolomide and confirms the safety and feasibility of individualized dosing. Clinical trial information: NCT01812603.

Highlights of This Issue

Salt-inducible kinase 2 (SIK2) is overexpressed in 30% of ovarian cancers and regulates centrosome splitting, mitotic progression, and activation of PI3K. A small-molecule inhibitor of SIK2 (ARN-3236) blocks the activity of SIK2 kinase, inhibits growth of ovarian cancer cell lines, and enhances sensitivity to paclitaxel in cell culture and in xenografts. ARN-3236 produces nuclear-centrosome dissociation, inhibits centrosome splitting, blocks mitotic progression, induces polyploidy, reduces AKT/survivin signaling, and triggers apoptotic cell death. Thus, ARN-3236 appears to be a drug with promise for enhancing primary treatment of ovarian cancers.Mameri and colleagues report that cytidine deaminase (CDA) expression is downregulated in about 60% of tumors, mostly due to DNA methylation. Immunohistochemistry assessments of CDA expression status defined two new subgroups of tumors: CDA-deficient tumors and CDA-proficient tumors. CDA-deficient tumor cells, but not CDA-proficient tumor cells, present a marked susceptibility to aminoflavone, indicating that CDA expression status could be used to guide anticancer therapy. These results constitute a proof-of-concept that CDA deficiency may turn out to be a new predictive marker of susceptibility to antitumor drugs, thus opening up new possibilities for treating cancer.Patients with glioblastoma (GBM) have a median survival of <15 months despite surgical resection, high-dose radiation and chemotherapy with temozolomide (TMZ). Cytomegalovirus (CMV) proteins are expressed in over 90% of sampled GBM and expression is restricted to glioma cells not surrounding normal brain tissue. Batich and colleagues targeted the CMV antigen pp65 using dendritic cells (DCs) in combination with dose-intensified temozolomide (TMZ) and evaluated patient antitumor immune responses and survival. Despite increases in regulatory T cells after TMZ, patients treated with pp65-DCs showed increased pp65 immunity and long-term survival extending beyond predicted rates. Randomized studies on the prevention of generated regulatory T cells in the context of TMZ treatment and CMV targeting are under way.The lncRNA PVT1 is an important oncogene in human tumors; however, the mechanisms underlying the PVT1 functions remain elusive. Xu and colleagues demonstrate a reciprocal link between PVT1 and FOXM1 in gastric cancer (GC). PVT1 binds to the FOXM1 protein and enhances its stability, fulfills its functions in a FOXM1-mediated manner. Moreover, FOXM1 binds directly to and constitutively transactivates the PVT1 promoter. The authors report a novel mechanism by which transcript-induced lncRNA facilitate mRNA function by stabilizing a transcript-coding protein posttranscriptionally. PVT1 expression may be a useful biomarker for GC prognosis, and the PVT1-FOXM1 loop could be a therapeutic target.

Prognosis in glioblastoma: insight gained from recent prospective trials

Gittleman et al . report on the creation and independent validation of a nomogram estimating the survival of patients with glioblastoma multiforme (GBM) following chemoradiation therapy (CRT) (1). The nomogram was developed using three statistical approaches (cox proportional hazards regression, random survival forests, and RPA) from available data points of patients accrued to Radiation Therapy Oncology Group (RTOG) 0525, a clinical trial evaluating the benefit of dose-intensified temozolomide (TMZ) in patients with newly diagnosed GBM (2). The algorithm was validated in an independent population of patients who completed therapy on the RTOG 0825 clinical trial (2,3), which asked if the addition of bevacizumab to standard therapy for GBM improved survival. Neither of these randomized trials demonstrated a statistically significant difference in their primary endpoint (survival), so the inclusion of all patients in both cohorts is valid. The resultant nomogram provides an individualized tool for predicting 6, 12, and 24-month survival in patients with newly diagnosed GBM based on age, sex, performance status, extent of surgical resection, and O6-methylguanine-DNA-methyltransferaase (MGMT) methylation status.

Complete resection of contrast-enhancing tumor volume is associated with improved survival in recurrent glioblastoma-results from the DIRECTOR trial.

The role of reoperation for recurrent glioblastoma (GBM) remains unclear. Prospective studies are lacking. Here, we studied the association of clinical outcome with extent of resection upon surgery for recurrent GBM in the patient cohort of DIRECTOR, a prospective randomized multicenter trial comparing 2 dose-intensified temozolomide regimens at recurrence of GBM. We analyzed prospectively collected clinical and imaging data from the DIRECTOR cohort (N = 105). Volumetric analysis was performed on gadolinium contrast-enhanced MRI as well as fluid attenuated inversion recovery/T2 MRI and correlated with PFS after initial progression (PFS2) and post-recurrence survival (PRS). Quality of life was monitored by the EORTC QLQ-C30 and QLQ-BN20 questionnaires at 8-week intervals. Seventy-one patients received surgery at first recurrence. Prognostic factors, including age, MGMT promoter methylation, and Karnofsky performance score, were balanced between patients with and without reoperation. Outcome in patients with versus without surgery at recurrence was similar for PFS2 (2.0 mo vs 1.9 mo, P = .360) and PRS (11.4 mo vs 9.8 mo, P = .633). Among reoperated patients, post-surgery imaging was available in 59 cases. In these patients, complete resection of contrast-enhancing tumor (N = 40) versus residual detection of contrast enhancement (N = 19) was associated with improved PRS (12.9 mo [95% CI: 11.5-18.2] vs 6.5 mo [95% CI: 3.6-9.9], P < .001) and better quality of life. Incomplete tumor resection was associated with inferior PRS compared with patients who did not undergo surgery (6.5 vs 9.8 mo, P = .052). Quality of life was similar in these 2 groups. Surgery at first recurrence of GBM improves outcome if complete resection of contrast-enhancing tumor is achieved.

428P - ‘Low-Dose Metronomic Temozolomide’ in Recurrent Tmz-Refractory Glioblastoma Patients: a Retrospective Analysis of National Data in Korea

ABSTRACT Aim: The aim of this retrospective study is to evaluate the efficacy and safety of metronomic temozolomide (TMZ) treatment in 125 Korean patients with recurrent TMZ-refractory glioblastoma from national data in Korea. Methods: In Korea, KFDA (Korean Ministry of Food and Drug Administration) off-label use of anticancer drug has to approve its use in advance from HIRA (Health Insurance Review & Assessment Service in Republic of Korea), and report a one-year outcome data to HIRA. The KFDA approved dosage of temozolomide is TMZ 150 to 200 mg/m2 × 5 days in a 28-day cycle, while ‘low dose metronomic temozolomide’ is KFDA unapproved dosage, continuous dose-intense TMZ 50 mg/m2/day. We reviewed a total 125 patients' national clinical data retrospectively, which is reported to the efficacy and toxicity of ‘low-dose metronomic temozolomide’ in recurrent TMZ-refractory glioblastoma, as KFDA unapproved use in Korea. Results: A total 125 patients (male 58.4%, female 41.6%, mean 50 ± 12 yrs, range 13-75yrs) in 13 hospitals received ‘low-dose metronomic temozolomide’ during Mar. 2009 to Sep. 2013 in Korea. The 6-month PFS rate was 19.2% (95% CI: 12.2 ∼ 26.1). Complete response (CR) rate was 6.5%, and the average period of this state was 32.9+ months. Partial response (PR) rate was 4.3%, A progression free survival (PFS) time was 2.1 months. Median overall survival time was 7.5 months. Only 1 patient has a grade 3+ thrombocytopenia. Total 100 patients stopped the medication. Among them, the 95 patients were due to disease progression and the 5 patients were due to toxicities Conclusions: The results of this study show ‘Low-dose metronomic temozolomide’ also might be option for recurrent TMZ-refractory glioblastoma. And it can be necessary for some recurrent Korean GBM patients to receive KFDA unapproved low dosage. Disclosure: All authors have declared no conflicts of interest.

Phase I trial of hydroxychloroquine with dose-intense temozolomide in patients with advanced solid tumors and melanoma

Blocking autophagy with hydroxychloroquine (HCQ) augments cell death associated with alkylating chemotherapy in preclinical models. This phase I study evaluated the maximum tolerated dose (MTD), safety, preliminary activity, pharmacokinetics, and pharmacodynamics of HCQ in combination with dose-intense temozolomide (TMZ) in patients with advanced solid malignancies. Forty patients (73% metastatic melanoma) were treated with oral HCQ 200 to 1200 mg daily with dose-intense oral TMZ 150 mg/m2 daily for 7/14 d. This combination was well tolerated with no recurrent dose-limiting toxicities observed. An MTD was not reached for HCQ and the recommended phase II dose was HCQ 600 mg twice daily combined with dose-intense TMZ. Common toxicities included grade 2 fatigue (55%), anorexia (28%), nausea (48%), constipation (20%), and diarrhea (20%). Partial responses and stable disease were observed in 3/22 (14%) and 6/22 (27%) patients with metastatic melanoma. In the final dose cohort 2/6 patients with refractory BRAF wild-type melanoma had a near complete response, and prolonged stable disease, respectively. A significant accumulation in autophagic vacuoles (AV) in peripheral blood mononuclear cells was observed in response to combined therapy. Population pharmacokinetics (PK) modeling, individual PK simulations, and PK-pharmacodynamics (PD) analysis identified a threshold HCQ peak concentration that predicts therapy-associated AV accumulation. This study indicates that the combination of high-dose HCQ and dose-intense TMZ is safe and tolerable, and is associated with autophagy modulation in patients. Prolonged stable disease and responses suggest antitumor activity in melanoma patients, warranting further studies of this combination, or combinations of more potent autophagy inhibitors and chemotherapy in melanoma.

MGMT promoter methylation as a prognostic biomarker for benefit from dose-intensified temozolomide rechallenge in progressive glioblastoma: First results from the randomized phase II DIRECTOR trial.

2015 Background: Rechallenge with temozolomide (TMZ) at first progression of glioblastoma after radiotherapy with concomitant and maintenance temozolomide (TMZ/RT→TMZ) has been studied in retrospec...

Phase 2 study of dose-intense temozolomide in recurrent glioblastoma

Among patients with glioblastoma (GBM) who progress on standard temozolomide, the optimal therapy is unknown. Resistance to temozolomide is partially mediated by O(6)-methylguanine-DNA methyltransferase (MGMT). Because MGMT may be depleted by prolonged temozolomide administration, dose-intense schedules may overcome resistance. This was a multicenter, phase 2, single-arm study of temozolomide (75-100 mg/m(2)/day) for 21 days of each 28-day cycle. Patients had GBM in first recurrence after standard therapy. The primary end point was 6-month progression-free survival (PFS6). Fifty-eight participants were accrued, 3 of whom were ineligible for analysis; one withdrew before response assessment. There were 33 men (61%), with a median age of 57 years (range, 25-79 years) and a median Karnofsky performance score of 90 (range, 60-100). Of 47 patients with MGMT methylation results, 36 (65%) had methylated tumors. There were 7 (13%) partial responses, and PFS6 was only 11%. Response and PFS did not depend on MGMT status; MSH2, MLH1, or ERCC1 expression; the number of prior temozolomide cycles; or the time off temozolomide. Treatment was well tolerated, with limited grade 3 neutropenia (n = 2) or thrombocytopenia (n = 2). Dose-intense temozolomide on this schedule is safe in recurrent GBM. However, efficacy is marginal and predictive biomarkers are needed.

“One week on–one week off”: efficacy and side effects of dose-intensified temozolomide chemotherapy: experiences of a single center

To evaluate in a single center retrospectively the efficacy and tolerability of a weekly regimen, which alternates temozolomide (TMZ) in patients with recurrent or progressive high-grade glioma (HGG). From January 2005 until June 2011, 54 patients with recurrent or progressive HGG were treated with TMZ 150 mg/m²/day on days 1-7 and 15-21 of a 28-day cycle ("one week on-one week off" scheme; TMZ 7/14) with individual dose adjustment depending on toxicity. The majority of patients (n = 48, 89 %) was treated at first tumor recurrence or progression. All patients had received prior radiotherapy with or without concomitantly administered TMZ and, optionally, adjuvant chemotherapy. After initiation of TMZ 7/14, MRI was obtained every 8-12 weeks. Tumor response or progression was assessed according to Macdonald criteria. Blood examinations were performed weekly. Toxicity was evaluated according to Common Terminology Criteria for Adverse Events (CTCAE; version 3.0). A total of 434 treatment weeks with TMZ 7/14 were delivered. The median number of treatment weeks was 7 (range, 1-41 weeks). No grade 4 hematological toxicity and no opportunistic infections occurred. Patients with neutropenia were not observed. Two patients developed grade 3 and 4 patients grade 2 leukocytopenia. Thrombocytopenia grade 3 and grade 2 occurred in 4 patients and 6 patients, respectively. The progression-free survival (PFS) rate at 6 months was 43 %. Median PFS from treatment initiation was 18 weeks (95 % CI, 14-22 weeks) and median overall survival (OS) was 37 weeks (95 % CI, 31-42 weeks). The rates for PFS and OS at 1 year were 24 and 28 %, respectively. Our data suggest that treatment with TMZ 7/14 is safe and effective in patients with recurrent or progressive HGG.