3D volume growth rate evaluation in the EORTC-BTG-1320 clinical trial for recurrent WHO grade 2 and 3 meningiomas

BACKGROUND

We previously reported that tumor 3D volume growth rate (3DVGR) classification could help in the assessment of drug activity in patients with meningioma using three main classes and a total of five subclasses: class 1: decrease; 2: stabilization or severe slowdown; 3: progression. The EORTC-BTG-1320 clinical trial was a randomized phase II trial evaluating the efficacy of trabectedin for recurrent WHO 2 or 3 meningioma. Our objective was to evaluate the discriminative value of 3DVGR classification in the EORTC-BTG-1320.

METHODS

All patients with at least one available MRI before trial inclusion were included. 3D volume was evaluated on consecutive MRI until progression. 2D imaging response was centrally assessed by MRI modified Macdonald criteria. Clinical benefit was defined as neurological or functional status improvement or steroid decrease or discontinuation.

RESULTS

Sixteen patients with a median age of 58.5 years were included. Best 3DVGR classes were: 1, 2A, 3A and 3B in 2 (16.7%), 4 (33.3%), 2 (16.7%) and 4 (33.3%) patients, respectively. All patients with progression-free survival longer than 6 months had best 3DVGR class 1 or 2. 3DVGR classes 1 and 2 (combined) had a median overall survival of 34.7 months versus 7.2 months for class 3 (p=0.061). All class 1 patients (2/2), 75% of class 2 patients (3/4) and only 10% of class 3 patients (1/10) had clinical benefit.

CONCLUSIONS

Tumor 3DVGR classification may be helpful to identify early signals of treatment activity in meningioma clinical trials.

P14.09 BORTEM-17: A Phase IB/II Single-Arm, Control Non-Randomized, Multicentre, Open Label Clinical Trial for Recurrent Glioblastoma with unmethylated MGMT promoter (NCT03643549)

BACKGROUND

Glioblastoma (GBM) is the most malignant primary brain tumor in adults where median survival in unselected patients is approximately 10 months. There is no standard treatment for patients who progress on temozolomide and patients are best treated within investigational clinical protocols. Patients harbouring tumours with functional O⁶ methylguanine DNA methyltransferase (MGMT) DNA repair enzyme have particularly poor prognosis with median overall survival of 12.7 months, compared to 21.7 months for patients with hypermethylated MGMT promoter. The pre-clinical studies have shown that Bortezomib depletes the MGMT enzyme, restoring the tumour ´s susceptibility to Temozolomide, if the chemotherapy is administered in the precise schedule when the MGMT enzyme is depleted. Additionally, Bortezomib shows an antitumour effect by blocking autophagy flux. Based on the promising pre-clinical results, a non-randomized, open label phase IB/II clinical trial was designed. The primary endpoints include assessment of safety of Bortezomib administered with Temozolomide for phase IB and median progression free survival, overall survival as well as progression free rate at 6 months.

MATERIAL AND METHODS

Recurrent glioblastoma patients with unmethylated MGMT promotor, progressing at least 12 weeks after completion of postoperative radiotherapy, with adequate organ function, performance status Karnofsky 70 or better and radiologically measurable lesions are screened for study inclusion. The experimental treatment consists of Bortezomib 1.3mg/m² administered IV on days 1, 4, 7, during each 4-week chemotherapy cycle with per oral Temozolomide at 200mg/m² 5 days/week every 4 weeks starting on day 3. Study group will be compared to historical controls on conventional management. The sample size was calculated to 63 patients, ten of them were included in the phase IB.

RESULTS

The phase IB of the trial was completed in 2019 and the combination of Temozolomide and Bortezomib was shown to be safe and well tolerated. Until April 2021 a total number of 23 patients were included into the trial. The patients are treated at 4 different referral university hospitals in Norway. A clinical treatment benefit with both radiological tumor volume response and stable disease were observed. The patient inclusion in the trial is delayed due COVID-19. The majority of observed side effects are mild or moderate. The grade 3 or 4 adverse effects included thrombocytopenia, ataxia, muscle weakness, delirium and hyperglycemia. Patients that progressed under the treatment received another line of therapy according to the institutional practice.

CONCLUSION

A combination of Bortezomib and Temozolomide administered in a defined time sequence to achieve sensitization of glioblastoma to alkylating agent is safe and feasible and may represent a novel treatment option for patients with this devastating disease.

P14.65 Survival in a consecutive series of 467 glioblastoma patients: impact of prognostic factors and recurrent treatment at two independent institutions

BACKGROUND

Glioblastoma (GBM) is an aggressive primary brain tumor with median overall survival (OS) of less than one year in unselected adult patients. There is no standard therapy at recurrence. We aimed to evaluate OS in a consecutive series of GBM patients from Norway’s two largest regional health authorities, compare the effect of physicians’ choice of antineoplastic treatment upon recurrence and identify prognostic and predictive factors.

MATERIAL AND METHODS

Clinicopathological data from n=467 patients with histologically confirmed GBM diagnosed and treated at Haukeland and Oslo university hospitals from January 2015 to December 2017 was retrospectively collected. Data included tumor location, methylation status of the methylguanine-DNA methyltransferase (MGMT) promoter and mutation of the isocitrate dehydrogenase (IDH) genes, patient age and sex, extent of tumor resection at primary diagnosis, and treatment at first, second and third tumor recurrences. Cox-proportional hazards regression with pairwise analyses adjusted for multiple testing with Scheffé’s post-hoc test were used to adjust effect of multiple risk factors on mortality.

RESULTS

Median OS was 12.1 months and 21.4 % and 6.8 % of patients were alive at 2 and 5 years, respectively. Treatment at recurrence varied between institutions but did not impact OS (p=0.201). Median time to progression was 8.2 months. Age, MGMT promoter methylation, tumor location and extent of tumor resection were all independent prognostic factors for OS. Patients receiving radiotherapy to 60 Gray with concomitant and adjuvant temozolomide at primary diagnosis had best outcome with median OS of 16.1 months and 9.3% were alive at 5 years. At first recurrence patients eligible for gammaknife/stereotactic radiosurgery (GK/SRS) or surgery, alone or combined with chemotherapy, had superior survival compared to chemotherapy alone (p<0.0001 and p=0.014, respectively). On Scheffé’s post-hoc analyses only GK/SRS was superior to chemotherapy (p=0.01). At second and third recurrence none of the antineoplastic strategies came across as superior or inferior to each other using Cox. On Scheffé’s post-hoc analyses chemotherapy alone and combined with bevacizumab were superior at second recurrence (p=0.008 and p=0.042, respectively) and chemotherapy combined with bevacizumab was superior at third recurrence (p=0.043), compared to no antineoplastic treatment. Our retrospective study is limited by small sample sizes and heterogeneous treatment groups, especially at second and third recurrences, as well as patient selection.

CONCLUSION

Recurrence treatment differed between the two institutions but there was no difference in OS. Our findings underline the lack of standard therapy upon GBM recurrence and the urgent need for novel therapeutic strategies.

PL3.2 Trabectedin for recurrent WHO grade II or III meningioma: a randomized phase II study of the EORTC Brain Tumor Group (EORTC-1320-BTG)

BACKGROUND

EORTC-1320-BTG investigated the activity, safety and quality of life of therapy with the tetrahydroisoquinoline alkaloid trabectedin (Yondelis®) in patients with recurrent higher-grade meningiomas. Trabectedin was originally derived from the Caribbean sea squirt, Ecteinascidia turbinata, and currently is manufactured by total synthesis.

METHODS

Adult patients with histological diagnosis of WHO grade II or III meningioma and radiologically documented progression after maximal feasible surgery and radiotherapy were randomly assigned in a 2:1 ratio to receive intravenous trabectedin (1.5 mg/m2every three weeks) or local standard of care (LOC). The primary endpoint was progression-free survival (PFS).

RESULTS

Within 22.1 months, we randomized a total of 90 patients (n=29 in LOC arm, n=61 in trabectedin arm) in 35 institutions and nine countries. In the LOC arm, the following treatments were administered: hydroxyurea (n=11), bevacizumab (n=9), none (n=4), chemotherapy (n=3), somatostatin analogue (n=1), combined chemotherapy and somatostatin analogue (n=1). With 71 PFS events, median PFS was 4.17 months in the LOC and 2.43 months in the trabectedin arm (hazard ratio [HR] for progression, 1.42; 80% CI, 1.00–2.03; p=0.204) with a PFS-6 rate of 29.1% (95% CI, 11.9%-48.8%) in the LOC and 21.1% (95% CI, 11.3%-32.9%) in the trabectedin arm. Median OS was 10.61 months in the LOC and 11.37 months in the trabectedin arm (HR for death, 0.98; 95% CI, 0.54–1.76; p=0.94).Grade 3 to 5 adverse events occurred in 44.4% (18.5% related, 4 serious adverse events, 0 lethal events) of the patients in the LOC and 59% (32.8% related, 57 serious adverse events and 2 toxic deaths) of patient in the trabectedin arm.

CONCLUSIONS

In this first prospective randomized trial performed in recurrent grade II or III meningioma, trabectedin did not improve PFS and OS and was associated with significantly higher toxicity as compared to LOC treatment. The data collected in this study may serve as benchmark for future clinical trials in this setting.

Are melanomas averse to cerebellum? Cerebellar metastases in a surgical series

OBJECTIVES

To study the propensity of different cancers to metastasize to the cerebrum and cerebellum, and to study overall survival (OS) and prognostic factors for patients after surgical resection for cerebellar metastases.

MATERIALS AND METHODS

From a prospectively collected tumor database, all patients that underwent a craniotomy for intracranial metastases between 2003 and 2011 at Oslo University Hospital were included.

RESULTS

One hundred and forty patients underwent resection for cerebellar metastases. Most common primary tumor sites were lung, colon/rectum, and breast in 45%, 19%, and 14%, respectively. None were prostate cancers. Melanoma metastases were significantly underrepresented, and colorectal cancer metastases significantly overrepresented in cerebellum, compared to the overall proportion of cerebellar/supratentorial metastases surgically resected (P < 0.05). Thirty-day post-operative mortality rate was 4.3%. Median OS was 7.7 months (95% CI 6.0-9.5 months) irrespective of post-operative adjuvant therapy. Median OS was 51.8, 8.4, and 3.4 months, respectively, for recursive partitioning analysis class 1(n = 11), 2 (n = 78) and 3 (n = 34). Significant negative prognostic factors were age ≥65 years, Karnofsky performance score (KPS) <70, extracranial metastases and uncontrolled systemic disease.

CONCLUSIONS

Melanoma metastases were significantly underrepresented in cerebellum, whereas colorectal cancer metastases were significantly overrepresented. Surgical mortality and OS after surgical treatment of cerebellar metastases were similar to the results of supratentorial metastases.

Molecular cytogenetic analysis of a gliosarcoma with osseous metaplasia

Gliosarcoma, a rare glioblastoma variant, is composed of a glial and a mesenchymal component. Though the mesenchymal portion most commonly resembles a fibrosarcoma, other differentiation patterns have been observed. We present the first genomic characterisation (karyotyping followed by FISH and array comparative genomic hybridisation analysis) of a gliosarcoma with osseous metaplasia. In addition to chromosomal changes often found in gliomas (+7, -10, -13, and -22), the tumour cells also harboured a hitherto unknown t(3;21)(q13∼21;q21∼22).