Mechanisms of EGFR Resistance in Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Despite numerous efforts to target epidermal growth factor receptor (EGFR), commonly dysregulated in GBM, approaches directed against EGFR have not achieved the same degree of success as seen in other tumor types, particularly as compared to non-small cell lung cancer (NSCLC). EGFR alterations in glioblastoma lie primarily in the extracellular domain, unlike the kinase domain alterations seen in NSCLC. Small molecule inhibitors are difficult to develop for the extracellular domain. Monoclonal antibodies can be developed to target the extracellular domain but must contend with the blood brain barrier (BBB). We review the role of EGFR in GBM, the history of trialed treatments, and the potential paths forward to target the pathway that may have greater success

Advances in Radiotherapy for Glioblastoma

External beam radiotherapy (RT) has long played a crucial role in the treatment of glioblastoma. Over the past several decades, significant advances in RT treatment and image-guidance technology have led to enormous improvements in the ability to optimize definitive and salvage treatments. This review highlights several of the latest developments and controversies related to RT, including the treatment of elderly patients, who continue to be a fragile and vulnerable population; potential salvage options for recurrent disease including reirradiation with chemotherapy; the latest imaging techniques allowing for more accurate and precise delineation of treatment volumes to maximize the therapeutic ratio of conformal RT; the ongoing preclinical and clinical data regarding the combination of immunotherapy with RT; and the increasing evidence of cancer stem-cell niches in the subventricular zone which may provide a potential target for local therapies. Finally, continued development on many fronts have allowed for modestly improved outcomes while at the same time limiting toxicity

Magnetic Resonance Spectroscopy, Positron Emission Tomography and Radiogenomics—Relevance to Glioma

Advances in metabolic imaging techniques have allowed for more precise characterization of gliomas, particularly as it relates to tumor recurrence or pseudoprogression. Furthermore, the emerging field of radiogenomics where radiographic features are systemically correlated with molecular markers has the potential to achieve the holy grail of neuro-oncologic neuro-radiology, namely molecular diagnosis without requiring tissue specimens. In this section, we will review the utility of metabolic imaging and discuss the current state of the art related to the radiogenomics of glioblastoma

Diffusion Weighted/Tensor Imaging, Functional MRI and Perfusion Weighted Imaging in Glioblastoma—Foundations and Future

In this article, we review the basics of diffusion tensor imaging and functional MRI, their current utility in preoperative neurosurgical mapping, and their limitations. We also discuss potential future applications, including implementation of resting state functional MRI. We then discuss perfusion and diffusion-weighted imaging and their application in advanced neuro-oncologic practice. We explain how these modalities can be helpful in guiding surgical biopsies and differentiating recurrent tumor from treatment related changes

ACTR-71. FULL ENROLLMENT RESULTS FROM THE PHASE 1/2, MULTICENTER, OPEN-LABEL STUDY OF MARIZOMIB (MRZ) ± BEVACIZUMAB (BEV) IN RECURRENT WHO GRADE IV MALIGNANT GLIOMA (GLIOBLASTOMA, RGBM)

Abstract MRZ – an irreversible, brain-penetrant, pan-proteasome inhibitor with anti-glioma preclinical activity – was evaluated in BEV-naïve rGBM patients. METHODS Phase 1 (P1) MRZ+BEV, 3 + 3 MRZ dose-escalation (N=6, 3, 3 at 0.55, 0.7, 0.8 mg/m2) followed by dose-expansion (N=24, 0.8 mg/m2). Phase 2 (P2) MRZ monotherapy (N=30, 0.8 mg/m2). Treatments (IV, 28-day (D) cycles): MRZ (10min infusion) D1, 8, 15; BEV (10 mg/kg) D1, 15. Tumor response (RANO criteria) every other cycle; MRZ and BEV PK, and proteasome inhibition in blood evaluated in P1. RESULTS as of 14Apr2017: P1 mean age 55 yrs, 64% male, mean treatment duration 5.3 cycles, 1 patient active; P2 56 yrs, 57% male, 2.5 cycles, 6 patients active. One DLT (fatigue) in P1 at 0.55 mg/m2, no other DLTs. P1 treatment-related AEs (TRAEs Grade ≥3 in ≥2 patients): hypertension, headache, confusional state, fatigue, hallucination, proteinuria; three Grade 4 SAEs (appendicitis perforated, depressed level of consciousness, not-related; blindness, BEV-related), three Grade 5 SAEs (2 PD, not-related; intracranial hemorrhage, BEV-related). P2 TRAEs (Grade ≥3 in ≥2 patients): fatigue, hallucination, lethargy; one Grade 4 SAE (hallucination). P1 overall response (≥PR) 44% (16/36) including 1 CR, 15 PR; overall survival (OS) at 6/9/12 months (mos) 75/60/39%, median 9.4mos; OS 68/45/15% (median 7.2mos) in unmethylated MGMT (uMGMT, N=22), 78/78/67% (median not reached) in methylated MGMT (N=10). In P2: 1 PR, 6 SD; 4 patients (3 SD, 1 PR) ongoing at 5–10 cycles. P1 patients experiencing ≥1 CNS-related AEs (any grade: ataxia/balance disorder/dizziness/dysarthria/fall/gait disturbance/hallucination) have increased OS (83/74/45%, median 11.4mos, N=23) versus patients without these AEs (59/34/25%, median 6.3mos, N=13). CONCLUSIONS MRZ monotherapy and MRZ+BEV active in rGBM overall and in uMGMT. Possible therapeutic improvement in patients experiencing CNS AEs will be explored in ongoing P2 MRZ+BEV extension allowing intra-patient MRZ dose-escalation if no CNS AE in first cycle (0.8 mg/m2)

ACTR-71. FULL ENROLLMENT RESULTS FROM THE PHASE 1/2, MULTICENTER, OPEN-LABEL STUDY OF MARIZOMIB (MRZ) ± BEVACIZUMAB (BEV) IN RECURRENT WHO GRADE IV MALIGNANT GLIOMA (GLIOBLASTOMA, RGBM)

Abstract MRZ – an irreversible, brain-penetrant, pan-proteasome inhibitor with anti-glioma preclinical activity – was evaluated in BEV-naïve rGBM patients. METHODS Phase 1 (P1) MRZ+BEV, 3 + 3 MRZ dose-escalation (N=6, 3, 3 at 0.55, 0.7, 0.8 mg/m2) followed by dose-expansion (N=24, 0.8 mg/m2). Phase 2 (P2) MRZ monotherapy (N=30, 0.8 mg/m2). Treatments (IV, 28-day (D) cycles): MRZ (10min infusion) D1, 8, 15; BEV (10 mg/kg) D1, 15. Tumor response (RANO criteria) every other cycle; MRZ and BEV PK, and proteasome inhibition in blood evaluated in P1. RESULTS as of 14Apr2017: P1 mean age 55 yrs, 64% male, mean treatment duration 5.3 cycles, 1 patient active; P2 56 yrs, 57% male, 2.5 cycles, 6 patients active. One DLT (fatigue) in P1 at 0.55 mg/m2, no other DLTs. P1 treatment-related AEs (TRAEs Grade ≥3 in ≥2 patients): hypertension, headache, confusional state, fatigue, hallucination, proteinuria; three Grade 4 SAEs (appendicitis perforated, depressed level of consciousness, not-related; blindness, BEV-related), three Grade 5 SAEs (2 PD, not-related; intracranial hemorrhage, BEV-related). P2 TRAEs (Grade ≥3 in ≥2 patients): fatigue, hallucination, lethargy; one Grade 4 SAE (hallucination). P1 overall response (≥PR) 44% (16/36) including 1 CR, 15 PR; overall survival (OS) at 6/9/12 months (mos) 75/60/39%, median 9.4mos; OS 68/45/15% (median 7.2mos) in unmethylated MGMT (uMGMT, N=22), 78/78/67% (median not reached) in methylated MGMT (N=10). In P2: 1 PR, 6 SD; 4 patients (3 SD, 1 PR) ongoing at 5–10 cycles. P1 patients experiencing ≥1 CNS-related AEs (any grade: ataxia/balance disorder/dizziness/dysarthria/fall/gait disturbance/hallucination) have increased OS (83/74/45%, median 11.4mos, N=23) versus patients without these AEs (59/34/25%, median 6.3mos, N=13). CONCLUSIONS MRZ monotherapy and MRZ+BEV active in rGBM overall and in uMGMT. Possible therapeutic improvement in patients experiencing CNS AEs will be explored in ongoing P2 MRZ+BEV extension allowing intra-patient MRZ dose-escalation if no CNS AE in first cycle (0.8 mg/m2)

Marizomib alone or in combination with bevacizumab in patients with recurrent glioblastoma: Phase I/II clinical trial data.

Background: This phase I/II trial in patients with recurrent glioblastoma (GBM) evaluates the safety and preliminary efficacy of marizomib, an irreversible pan-proteasome inhibitor that crosses the blood-brain barrier. Methods: Part A assessed the safety and efficacy of marizomib monotherapy. In Part B, escalating doses of marizomib (0.5-0.8 mg/m Results: In Part A, 30 patients received marizomib monotherapy. The most common AEs were fatigue (66.7%), headache (46.7%), hallucination (43.3%), and insomnia (43.3%). One patient (3.3%) achieved a partial response. In Part B, the recommended phase II dose of marizomib was 0.8 mg/m Conclusions: The safety profile of marizomib as monotherapy and in combination with bevacizumab was consistent with previous observations that marizomib crosses the blood-brain barrier. Preliminary efficacy did not demonstrate a meaningful benefit of the addition of marizomib to bevacizumab for the treatment of recurrent GBM

Axicabtagene Ciloleucel in Patients Ineligible for ZUMA-1 Because of CNS Involvement and/or HIV: A Multicenter Experience

Secondary central nervous system lymphoma (SCNSL) is associated with poor prognosis and new therapeutic approaches are needed. The pivotal trial that led to US Food and Drug Administration (FDA) approval of axicabtagene ciloleucel excluded patients with SCNSL and human immunodeficiency virus. In this multi-institutional retrospective study, 14 SCNSL patients treated with axicabtagene ciloleucel, 3 of whom had human immunodeficiency virus, experienced rates of severe neurotoxicity and complete response of 32% and 58%, respectively. This is similar to rates observed in the pivotal ZUMA-1 trial that led to the approval of axi-cel at median follow-up of 5.9 months. Chimeric antigen receptor T-cell therapy is potentially a life-saving therapy for SCNSL patients and should not be withheld