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2036 Background: Glioblastoma (GBM) is one of the worst prognostic cancers and there is no effective treatment after failure of bevacizumab. Eribulin is a microtubule inhibitor used for the treatment of patients with metastatic breast cancer and liposarcoma. We previously reported that eribulin strongly inhibits the RNA-dependent RNA polymerase (RdRP) activity of TERT protein in cancer cells, and has a strong anti-tumor effect against GBM cells with TERT promoter mutation. In this study we aim to investigate the efficacy and safety of eribulin in patients with bevacizumab-resistant recurrent GBM. Methods: This is an open-label, multicenter, single-arm phase II trial. Eligible patients aged 20-75 years with bevacizumab-resistant recurrent GBM were enrolled from 2018-2020. Patients received eribulin 1.4 mg/m2 on days 1 and 8 of 21-day cycle until disease progression or intolerable toxicity was observed. The primary endpoint was one-year overall survival rate (1yOS%). The 35 patients are needed to achieve an 80% power at a one-sided alpha of 10%, under threshold 1yOS% of 10% and expected 1yOS% of 25%. Results: Thirty-seven patients aged 26-73 (median: 54) years were treated. Twenty-six of 37 (70.3%) patients were diagnosed as IDH-wildtype GBM, 4 (10.8%) were with IDH-mutant GBM and 7 (18.9%) were GBM, NOS. Thirty-four (91.9%) patients had a Karnofsky performance status of 70 or 80 at the registration. Thirty-one (83.8%) patients received additional treatments, including 28 (75.7%) bevacizumab, 11 (29.7%) re-irradiation and 3 (8.1%) resection after failure of eribulin. Among 37 subjects, 32 surgical specimens were analyzed for TERT promoter mutation and 15 for RdRP activity. 1yOS% was 29.7% [80% CI: 20.5 to 39.5 (p < 0.0001), 95% CI: 16.1 to 44.6]. Median OS was 9.0 months [95% CI: 6.2 to 11.0] and median progression-free survival was 1.5 months [95% CI: 1.4 to 1.7]. Neither TERT nor RdRP statuses was associated with prolonged OS. Among all the target lesions evaluated, two lesions decreased more than 50% in size and the patients survived more than one year, however no obvious PR was confirmed at the final evaluation. The disease control rate was 25.7% [95% CI: 12.5 to 43.3]. Common ≥ grade 2 AEs were neutropenia (70.3%), leukopenia (56.8%), lymphopenia (27.0%), elevation of γ-GTP (13.5%), elevation of ALT (10.8%), elevation of AST (8.1%), alopecia (8.1%). Treatment-related grade 3 or 4 AEs occurred in 59.5% of subjects. There were no AEs leading to death. Conclusions: Eribulin was safely applied for the patients with recurrent GBM. This phase II study met its primary endpoint of 1yOS%, although no obvious response was observed. Further investigation to reveal the biomarkers related to longer survival is underway. Clinical trial information: UMIN000030359.

Purpose Whereas whole-brain radiotherapy (WBRT) has been the standard treatment of brain metastases (BMs), stereotactic radiosurgery (SRS) is increasingly preferred to avoid cognitive dysfunction; however, it has not been clearly determined whether treatment with SRS is as effective as that with WBRT or WBRT plus SRS. We thus assessed the noninferiority of salvage SRS to WBRT in patients with BMs. Patients and Methods Patients age 20 to 79 years old with performance status scores of 0 to 2—and 3 if caused only by neurologic deficits—and with four or fewer surgically resected BMs with only one lesion > 3 cm in diameter were eligible. Patients were randomly assigned to WBRT or salvage SRS arms within 21 days of surgery. The primary end point was overall survival. A one-sided α of .05 was used. Results Between January 2006 and May 2014, 137 and 134 patients were enrolled in the WBRT and salvage SRS arms, respectively. Median overall survival was 15.6 months in both arms (hazard ratio, 1.05; 90% CI, 0.83 to 1.33; one-sided P for noninferiority = .027). Median intracranial progression-free survival of patients in the WBRT arm (10.4 months) was longer than that of patients in the salvage SRS arm (4.0 months). The proportions of patients whose Mini-Mental Status Examination and performance status scores that did not worsen at 12 months were similar in both arms; however, 16.4% of patients in the WBRT arm experienced grade 2 to 4 cognitive dysfunction after 91 days postenrollment, whereas only 7.7% of those in the SRS arm did ( P = .048). Conclusion Salvage SRS is noninferior to WBRT and can be established as a standard therapy for patients with four or fewer BMs.

2500 Background: Temozolomide (TMZ) is an oral alkylating agent that penetrates the blood-brain barrier with moderate toxicity, and has shown anti-tumor activity in primary central nervous system lymphoma (PCNSL) in single arm studies. Our goal was to determine whether the addition of concomitant and adjuvant TMZ chemotherapy to standard treatment of high-dose methotrexate (HD-MTX) and whole brain radiotherapy (WBRT) for PCNSL improves survival in a randomized controlled trial. Methods: We did an open-label, randomized phase III trial at 30 hospitals in Japan enrolling immunocompetent patients (pts) aged 20-70 years with histologically confirmed newly diagnosed PCNSL. Pts enrolled at step 1 registration received HD-MTX (MTX; 3.5 g/m2 at day 1, 15, 29). Pts who received at least 1 cycle of HD-MTX were randomly assigned (1:1) at step 2 registration to receive WBRT (30 Gy) ± 10 Gy boost (control arm: A) or WBRT ± boost with concomitant TMZ (75 mg/m2 daily) and adjuvant TMZ (150-200 mg/m2 daily for 5 days every 28 days) for two years after initiation of HD-MTX or until tumor progression (experimental arm: B). Randomization was adjusted by institution, PS (0-1 / 2-3), age (≤60/≥61 years), presence or absence of intraparenchymal tumor after HD-MTX. The primary endpoint was overall survival (OS). The planned sample size was 130 pts in total, to provide an 80% power to detect a 0.52 hazard ratio (65% vs 80% in 2y-OS) for arm B to A and a one-sided alpha of 5%. Results: Between September 29, 2014 and October 15, 2018, 134 pts were enrolled, of whom 122 were randomly assigned and analyzed; 62 to arm A and 60 to arm B. At the planned interim analysis, the 2-y OS was 86.8% (95% CI: 72.5-94.0) in arm A and 71.4% (56.0-82.2) in arm B. The hazard ratio was 2.18 (95% CI: 0.95 to 4.98) with predictive probability for showing the superiority of arm B at the final analysis was calculated to be 1.3%. The study was terminated due to futility. The 2-y progression-free survival was 60.6% (43.6-73.8) in arm A and 49.9% (34.4-63.5) in arm B with a hazard ratio of 1.54 (0.88 to 2.70). The most common grade 3 and 4 toxicities were lymphopenia, observed in 7 (11.5%) pts during WBRT in arm A, 18 (30%) pts during WBRT + concomitant TMZ and 18 (37.5%) pts during adjuvant TMZ in arm B. Conclusions: This study failed to demonstrate the benefit of the addition of TMZ to WBRT and adjuvant TMZ in newly diagnosed PCNSL. Possible biomarkers including methylation status of the MGMT promoter in the tumors will be analyzed. Clinical trial information: jRCTs031180207 .

2050 Background: The elderly patients with glioblastoma have an extremely poor prognosis. As they often have some degree of age-related vulnerability, it is especially important to minimize a risk of treatment-related adverse events by optimizing treatment intensity for this population. We conducted phaseⅡ clinical trial to investigate the efficacy of stratified monotherapy approach according to O6-methylguanine-DNA methyltransferase (MGMT) methylation status in elderly patients with glioblastoma. Methods: Patients aged 70 years or older with Karnofsky performance status (KPS) of at least 60 were eligible for this study. MGMT methylation status was quantitatively assessed by pyrosequencing based on the average methylation ratio of 16 CpG sites in the MGMT gene promoter. The patients with highly methylated MGMT promoter defined as an average methylation ratio with 30% or higher were treated with temozolomide (TMZ) monotherapy (standard 5/28 regimen), while the others with low or intermediate levels of MGMT promoter methylation were treated with radiation therapy (40Gy/15fr) alone. Results: Between April 2013 and December 2017, 70 patients were enrolled in this study. Median age was 78 years (70-91) and median KPS was 60 (60-100). Of 70 patients, 19 patients with highly methylated MGMT promoter received TMZ monotherapy, while the remaining 51 patients were treated with radiation therapy. Median progression-free survival (PFS) and median overall survival (OS) were 7.5 and 17.4 months in the TMZ group, respectively. Median PFS and median OS were 4.6 and 10.4 months in the radiotherapy group, respectively. Conclusions: For elderly glioblastoma patients with highly methylated MGMT promoter, TMZ monotherapy could be a treatment option. Clinical trial information: UMIN000012172.

2065 Background: The poor prognosis of glioblastoma (GBM; WHO grade IV) results from a high rate of disease recurrence and lack of effective treatment options. Depatuxizumab mafodotin (depatux-m, ABT-414) is comprised of an EGFR-directed antibody, depatuxizumab (depatux, ABT-806), conjugated to the microtubule toxin monomethyl auristatin F (MMAF, mafodotin). Once bounded with tumor cells, depatux-m is internalized and releases the cytotoxin, resulting in cell death. Here, we report safety, pharmacokinetic (PK) and efficacy in an ongoing phase 1/2 study of Japanese patients with/without EGFR-amplified recurrent GBM (rGBM). Methods: M13-714 (INTELLANCE-J, NCT02590263) is a non-randomized, phase 1/2 study in Japanese patients. Phase 1 assessed tolerability and PK where the dose escalation of depatux-m was from 0.5 to 1.25 mg/kg/Q2W at day 1 and 15 during 28-day cycle until progression disease (PD) or intolerable toxicity. Phase 2 assessed efficacy and safety of depatux-m in EGFR-amplified, rGBM and patients received 1.0 mg/kg of depatux-m on day 1 and 15 + 150 mg/m2 temozolomide (TMZ) on days 1-5 during each 28-day cycle until PD or intolerable toxicity. Results: As of 10 Jan 2019, 38 patients (WHO grade ≥3) were enrolled (9 in phase 1, 29 in phase 2). There was no dose limiting toxicity in phase 1. The recommended phase 2 dose was 1.25 mg/kg where the most common adverse events (AEs) were punctate keratitis in 21 patients (72%); lymphopenia in 14 patients (45%), thrombocytopenia in 13 patients (41%). Grade 3/4 AEs included thrombocytopenia and lymphopenia in 20 patients (69%). Ocular AEs were reported in 27 patients (93%) including punctate keratitis (72%). PK results (31 patients) in both phases were similar to those of non-Japanese result. Progression Free Survival (PFS) of 27 patients in phase 2 for 12 and 6 months were 8% and 27.5% respectively. The median PFS was 4 months. The overall survival (OS) for 24, 12 and 6 months were 28%, 62.5% and 93% respectively. The median OS was 15.5 months. Conclusions: Preliminary safety, PK and efficacy in Japanese patients with/without EGFR-amplified, rGBM suggests depatux-m was tolerated and showed encouraging anti-GBM effects. Clinical trial information: NCT02590263.

2000 Background: To establish whether personalized peptide vaccination (PPV) is clinically beneficial for human leukocyte antigen (HLA)-A24-positive glioblastoma multiforme (GBM) patients refractory to temozolomide (TMZ)-based therapy. Methods: From January 2012 to March 2016, 88 HLA-A24-positive GBM patients refractory to TMZ-based therapy from 20 Japanese hospitals were randomly assigned to receive PPV treatment (n = 58) or best supportive care (BSC) (n= 30) at a 2 to 1 ratio. Four peptides chosen from 12 peptide candidates based on pre-vaccination IgG levels specific to each peptide or 4 corresponding placebos were injected subcutaneously once weekly for 12 times at the first course followed by biweekly vaccinations until disease progression. The primary endpoint was overall survival (OS). Results: The primary endpoint was not met in this clinical trial. Unfavorable prognostic factors were performance status (PS) 3, higher plasma levels of pre-vaccination granulocyte macrophage-colony stimulating factor (GM-CFS), and PPV containing SART2-derived peptides. Therefore, 78 patients with PS of 0 to 2 (50 with PPV and 28 with BSC) were provided for the subgroup analysis. Among them, the median OS of 39 PPV patients (10.4 months, 95% CI, 7.8-12.0 months) who had either lower levels of GM-CSF ( < 0.9 pg/mL) or 4 peptide vaccinations that did not include SART2-derived peptides was significantly (p = 0.03) longer than that of the corresponding 19 BSC patients (6.8, 4.6-12.7). In contrast, the median OS of 10 PPV patients (4.1, 1.1-8.3) who had both higher levels of GM-CSF ( > 0.9 pg/mL) and 4 peptide vaccinations containing SART2-derived peptides was significantly (p = 0.01) shorter than that of the corresponding 9 BSC patients (not reached, 1.6-not reached). A single grade 3 adverse event was the only PPV-related adverse event of grade > 3 in this study. Conclusions: PPV monotherapy could be a new treatment modality for HLA-A24-positive GBM patients refractory to TMZ-based therapy, since this approach showed clinical benefit and safety under precision medicine-based pre-vaccination selection of appropriate patients. Clinical trial information: UMIN000006970.

2003Background: Whether salvage stereotactic radiosurgery (SRS) alone is effective for patients with brain metastases (BM) is not yet clarified, although clinical benefits such as better preservation of cognitive function and a shorter treatment period are reported with SRS compared to whole-brain radiation therapy (WBRT). We conducted a non-inferiority, randomized study of the effectiveness of salvage SRS for residual and recurrent tumors after surgical resection in comparison to tumor resection plus WBRT. Methods: Patients between 20-79 years with ECOG performance status (PS) 0-3 and ≤4 BM with only one lesion ≥3 cm in diameter having been surgically resected were eligible. Within 21 days after surgery, patients were randomized to WBRT or salvage SRS for residual and recurrent tumors. The primary end point was overall survival (OS) and the secondary end points were intracranial progression-free survival (IC-PFS), adverse events, and proportion of non-worsening in PS and Mini Mental Status Examination (M...