Targeting the IL4 receptor with MDNA55 in patients with recurrent glioblastoma: Results of a phase IIb trial

BACKGROUND

MDNA55 is an interleukin 4 receptor (IL4R)-targeting toxin in development for recurrent GBM, a universally fatal disease. IL4R is overexpressed in GBM as well as cells of the tumor microenvironment. High expression of IL4R is associated with poor clinical outcomes.

METHODS

MDNA55-05 is an open-label, single-arm phase IIb study of MDNA55 in recurrent GBM (rGBM) patients with an aggressive form of GBM (de novo GBM, IDH wild-type, and nonresectable at recurrence) on their 1st or 2nd recurrence. MDNA55 was administered intratumorally as a single dose treatment (dose range of 18 to 240 ug) using convection-enhanced delivery (CED) with up to 4 stereo-tactically placed catheters. It was co-infused with a contrast agent (Gd-DTPA, Magnevist®) to assess distribution in and around the tumor margins. The flow rate of each catheter did not exceed 10μL/min to ensure that the infusion duration did not exceed 48 h. The primary endpoint was mOS, with secondary endpoints determining the effects of IL4R status on mOS and PFS.

RESULTS

MDNA55 showed an acceptable safety profile at doses up to 240 μg. In all evaluable patients (n = 44) mOS was 11.64 months (80% one-sided CI 8.62, 15.02) and OS-12 was 46%. A subgroup (n = 32) consisting of IL4R High and IL4R Low patients treated with high-dose MDNA55 (>180 ug) showed the best benefit with mOS of 15 months, OS-12 of 55%. Based on mRANO criteria, tumor control was observed in 81% (26/32), including those patients who exhibited pseudo-progression (15/26).

CONCLUSIONS

MDNA55 demonstrated tumor control and promising survival and may benefit rGBM patients when treated at high-dose irrespective of IL4R expression level.Trial Registration: Clinicaltrials.gov NCT02858895.

Elimination of Radiation-Induced Senescence in the Brain Tumor Microenvironment Attenuates Glioblastoma Recurrence

Glioblastomas (GBM) are routinely treated with ionizing radiation (IR) but inevitably recur and develop therapy resistance. During treatment, the tissue surrounding tumors is also irradiated. IR potently induces senescence, and senescent stromal cells can promote the growth of neighboring tumor cells by secreting factors that create a senescence-associated secretory phenotype (SASP). Here, we carried out transcriptomic and tumorigenicity analyses in irradiated mouse brains to elucidate how radiotherapy-induced senescence of non-neoplastic brain cells promotes tumor growth. Following cranial irradiation, widespread senescence in the brain occurred, with the astrocytic population being particularly susceptible. Irradiated brains showed an altered transcriptomic profile characterized by upregulation of CDKN1A (p21), a key enforcer of senescence, and several SASP factors, including HGF, the ligand of the receptor tyrosine kinase (RTK) Met. Preirradiation of mouse brains increased Met-driven growth and invasiveness of orthotopically implanted glioma cells. Importantly, irradiated p21^-/- mouse brains did not exhibit senescence and consequently failed to promote tumor growth. Senescent astrocytes secreted HGF to activate Met in glioma cells and to promote their migration and invasion in vitro, which could be blocked by HGF-neutralizing antibodies or the Met inhibitor crizotinib. Crizotinib also slowed the growth of glioma cells implanted in preirradiated brains. Treatment with the senolytic drug ABT-263 (navitoclax) selectively killed senescent astrocytes in vivo, significantly attenuating growth of glioma cells implanted in preirradiated brains. These results indicate that SASP factors in the irradiated tumor microenvironment drive GBM growth via RTK activation, underscoring the potential utility of adjuvant senolytic therapy for preventing GBM recurrence after radiotherapy. SIGNIFICANCE: This study uncovers mechanisms by which radiotherapy can promote GBM recurrence by inducing senescence in non-neoplastic brain cells, suggesting that senolytic therapy can blunt recurrent GBM growth and aggressiveness.

Modified RANO, Immunotherapy RANO, and Standard RANO Response to Convection-Enhanced Delivery of IL4R-Targeted Immunotoxin MDNA55 in Recurrent Glioblastoma

PURPOSE

The current study compared the standard response assessment in neuro-oncology (RANO), immunotherapy RANO (iRANO), and modified RANO (mRANO) criteria as well as quantified the association between progression-free (PFS) and overall survival (OS) in an immunotherapy trial in recurrent glioblastoma (rGBM).

PATIENTS AND METHODS

A total of 47 patients with rGBM were enrolled in a prospective phase II convection-enhanced delivery of an IL4R-targeted immunotoxin (MDNA55-05, NCT02858895). Bidirectional tumor measurements were created by local sites and centrally by an independent radiologic faculty, then standard RANO, iRANO, and mRANO criteria were applied.

RESULTS

A total of 41 of 47 patients (mean age 56 ± 11.7) were evaluable for response. PFS was significantly shorter using standard RANO compared with iRANO (log-rank, P < 0.0001; HR = 0.3) and mRANO (P < 0.0001; HR = 0.3). In patients who died and had confirmed progression on standard RANO, no correlation was observed between PFS and OS (local, P = 0.47; central, P = 0.34). Using iRANO, a weak association was observed between confirmed PFS and OS via local site measurements (P = 0.017), but not central measurements (P = 0.18). A total of 24 of 41 patients (59%) were censored using iRANO and because they lacked confirmation of progression 3 months after initial progression. A strong correlation was observed between mRANO PFS and OS for both local (R2 = 0.66, P < 0.0001) and centrally determined reads (R2 = 0.57, P = 0.0007).

CONCLUSIONS

No correlation between radiographic PFS and OS was observed for standard RANO or iRANO, but a correlation was observed between PFS and OS using the mRANO criteria. Also, the iRANO criteria was difficult to implement due to need to confirm progression 3 months after initial progression, censoring more than half the patients.

Assessing the impact of coordinated COVID-19 exit strategies across Europe

As rates of new coronavirus disease 2019 (COVID-19) cases decline across Europe owing to nonpharmaceutical interventions such as social distancing policies and lockdown measures, countries require guidance on how to ease restrictions while minimizing the risk of resurgent outbreaks. We use mobility and case data to quantify how coordinated exit strategies could delay continental resurgence and limit community transmission of COVID-19. We find that a resurgent continental epidemic could occur as many as 5 weeks earlier when well-connected countries with stringent existing interventions end their interventions prematurely. Further, we find that appropriate coordination can greatly improve the likelihood of eliminating community transmission throughout Europe. In particular, synchronizing intermittent lockdowns across Europe means that half as many lockdown periods would be required to end continent-wide community transmission.

ATIM-30. COMBATING RECURRENT GLIOBLASTOMA WITH MDNA55, AN INTERLEUKIN-4 RECEPTOR TARGETED IMMUNOTHERAPY, THROUGH MRI-GUIDED CONVECTIVE DELIVERY

MDNA55, an IL4R-directed toxin, is being studied in a Phase 2b trial in recurrent GBM (rGBM) patients at first or second relapse. MDNA55 is co-infused with Gadolinium-based contrast agent and delivered as a single intratumoral infusion using Convection Enhanced Delivery (CED). Primary endpoint is median Overall Survival (mOS) and secondary endpoint is objective response rate (ORR) assessed by mRANO-based criteria incorporating advanced imaging modalities. Enrollment is complete (n=46). Current safety data show similar profile to previous MDNA55 trials with no systemic toxicities or drug related deaths. Current mOS in subjects treated with low doses of MDNA55 (median 63µg; n=21) is 11.8 months. When stratified by IL4R expression, a biomarker for more aggressive GBM, IL4R+ve subjects (mOS 15.2 months; n=8) show a survival advantage of 7 months compared to IL4R-ve subjects (mOS 8.1 months; n=10). Updated survival and response outcomes including subjects receiving the high dose (median 180µg; n=25) and stratification by IL4R expression will be reported. Review of serial imaging within 90 days following MDNA55 treatment demonstrated tumor shrinkage or stabilization from baseline in 19/42 evaluable subjects (disease control rate of 45%). To account for initial pseudo-progression in some subjects, tumor response was also assessed from nadir: 83% (35/42) showed disease control. Multi-parametric MRI biomarkers including relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) measurements demonstrated distinct imaging phenotypes among different disease states (pseudo-progression vs true-progression, pseudo-response vs true-response) and improved response staging. This trial is advancing neurosurgical methods for CED, potential of IL4R expression as a biomarker to select GBM patients most likely to benefit from MDNA55 treatment, and optimal use of multi-parametric MRI as an adjunct to clinical decision making. The improved survival and disease control seen after only a single infusion of MDNA55, especially in IL4R+ve subjects, may provide promising clinical benefit for rGBM patients.

Radiation-Induced DNA Damage Cooperates with Heterozygosity of TP53 and PTEN to Generate High-Grade Gliomas

Glioblastomas are lethal brain tumors that are treated with conventional radiation (X-rays and gamma rays) or particle radiation (protons and carbon ions). Paradoxically, radiation is also a risk factor for GBM development, raising the possibility that radiotherapy of brain tumors could promote tumor recurrence or trigger secondary gliomas. In this study, we determined whether tumor suppressor losses commonly displayed by patients with GBM confer susceptibility to radiation-induced glioma. Mice with Nestin-Cre-driven deletions of Trp53 and Pten alleles were intracranially irradiated with X-rays or charged particles of increasing atomic number and linear energy transfer (LET). Mice with loss of one allele each of Trp53 and Pten did not develop spontaneous gliomas, but were highly susceptible to radiation-induced gliomagenesis. Tumor development frequency after exposure to high-LET particle radiation was significantly higher compared with X-rays, in accordance with the irreparability of DNA double-strand breaks (DSB) induced by high-LET radiation. All resultant gliomas, regardless of radiation quality, presented histopathologic features of grade IV lesions and harbored populations of cancer stem-like cells with tumor-propagating properties. Furthermore, all tumors displayed concomitant loss of heterozygosity of Trp53 and Pten along with frequent amplification of the Met receptor tyrosine kinase, which conferred a stem cell phenotype to tumor cells. Our results demonstrate that radiation-induced DSBs cooperate with preexisting tumor suppressor losses to generate high-grade gliomas. Moreover, our mouse model can be used for studies on radiation-induced development of GBM and therapeutic strategies. SIGNIFICANCE: This study uncovers mechanisms by which ionizing radiation, especially particle radiation, promote GBM development or recurrence.

A Systematic Analysis of 2 Monoisocentric Techniques for the Treatment of Multiple Brain Metastases

BACKGROUND

In this treatment planning study, we compare the plan quality and delivery parameters for the treatment of multiple brain metastases using 2 monoisocentric techniques: the Multiple Metastases Element from Brainlab and the RapidArc volumetric-modulated arc therapy from Varian Medical Systems.

METHODS

Eight patients who were treated in our institution for multiple metastases (3-7 lesions) were replanned with Multiple Metastases Element using noncoplanar dynamic conformal arcs. The same patients were replanned with the RapidArc technique in Eclipse using 4 noncoplanar arcs. Both techniques were designed using a single isocenter. Plan quality metrics (conformity index, homogeneity index, gradient index, and R50%), monitor unit, and the planning time were recorded. Comparison of the Multiple Metastases Element and RapidArc plans was performed using Shapiro-Wilk test, paired Student t test, and Wilcoxon signed rank test.

RESULTS

A paired Wilcoxon signed rank test between Multiple Metastases Element and RapidArc showed comparable plan quality metrics and dose to brain. Mean ± standard deviation values of conformity index were 1.8 ± 0.7 and 1.7 ± 0.6, homogeneity index were 1.3 ± 0.1 and 1.3 ± 0.1, gradient index were 5.0 ± 1.8 and 5.1 ± 1.9, and R50% were 4.9 ± 1.8 and 5.0 ± 1.9 for Multiple Metastases Element and RapidArc plans, respectively. Mean brain dose was 2.3 and 2.7 Gy for Multiple Metastases Element and RapidArc plans, respectively. The mean value of monitor units in Multiple Metastases Element plan was 7286 ± 1065, which is significantly lower than the RapidArc monitor units of 9966 ± 1533 ( P < .05).

CONCLUSION

For the planning of multiple brain lesions to be treated with stereotactic radiosurgery, Multiple Metastases Element planning software produced equivalent conformity, homogeneity, dose falloff, and brain V12 Gy but required significantly lower monitor units, when compared to RapidArc plans.

VB-111: a novel anti-vascular therapeutic for glioblastoma multiforme

Glioblastoma multiforme (GBM) is among the most highly vascularized of solid tumors, contributing to the infiltrative nature of the disease, and conferring poor outcome. Due to the critical dependency of GBM on growth of new endothelial vasculature, we evaluated the preclinical activity of a novel adenoviral gene therapy that targets the endothelium within newly formed blood vessels for apoptosis. VB-111, currently in phase II clinical trials, consists of a non-replicating Adenovirus 5 (El deleted) carrying a proapoptotic human Fas-chimera (transgene) under the control of a modified murine promoter (PPE-1-3×) which specifically targets endothelial cells within the tumor vasculature. Here we report that a single intravenous dose of 2.5 × 10(11) or 1 × 10(11) VPs was sufficient to extend survival in nude rats bearing U87MG-luc2 or nude mice bearing U251-luc, respectively. Bioluminescence imaging of nude rats showed that VB-111 effectively inhibited tumor growth within four weeks of treatment. This was confirmed in a select group of animals by MRI. In our mouse model we observed that 3 of 10 nude mice treated with VB-111 completely lost U251 luciferase signal and were considered long term survivors. To assess the antiangiogenic effects of VB-111, we evaluated the tumor-associated microvaculature by CD31, a common marker of neovascularization, and found a significant decrease in the microvessel density by IHC. We further assessed the neovasculature by confocal microscopy and found that VB-111 inhibits vascular density in two separate mouse models bearing U251-RFP xenografts. Collectively, this study supports the clinical development of VB-111 as a treatment for GBM.

Cyclic sciatica from extrapelvic endometriosis affecting the sciatic nerve

Sciatic (catamenial) radiculopathy, waxing and waning with the menstrual cycle, is an uncommon condition typically caused by pelvic endometriosis affecting the lumbosacral plexus or proximal sciatic nerve. The authors describe a woman with catamenial sciatica caused by endometriosis affecting the sciatic nerve trunk in the upper thigh. Symptomatic with leg pain for 5 years, this patient developed gluteal atrophy and sensory loss and decreased strength in the L-5 dermatomyotome, a distribution confirmed by electromyography. Magnetic resonance imaging suggested thickening of the sciatic nerve at and distal to the sciatic notch. At operation the nerve showed extrinsic and intrinsic abnormality, proven to be endometriosis. Her symptoms improved, and she began gonadotropin-releasing hormone agonist therapy for further suppression. This very unusual case shows that endometriosis can affect the sciatic nerve over a range of territory inside and outside the pelvis, and that surgery must be appropriately directed to avoid negative exploration. Surgical decompression achieves good relief of symptoms, and medical therapy also allows sustained suppression of this disease.

Endoscopic, image-guided, transnasal instillation of (32)P for recurrent infrachiasmatic cystic craniopharyngioma

INTRODUCTION

The neurovascular and anatomic relationships surrounding craniopharyngiomas, and their tending to recur despite any method of primary treatment, has characterized this tumor as an exigent and frustrating clinical entity. Various strategies have been developed to deal with recurrences which include radical re-resection, stereotactic or localized radiotherapy, cyst fenestration, marsupialization or stent placement, and intracavitary therapies such as bleomycin or radionucleotides.

CASE REPORT

We present a case where the patient had previously experienced a transsphenoidal resection followed by a pterional, microsurgical resection of her craniopharyngioma at an outside hospital. The second recurrence was cystic, and confined to the sella. We elected to proceed with a minimally invasive, transnasal endoscopic approach for the instillation of phosphorus 32 radionucleotide into the cyst. There were no complications, and the patient was discharged home on postoperative day one. At six months, there was no progression of the cyst.

CONCLUSION

While intracystic adionucleotide therapies have been utilized for primary and secondary treatment of craniopharyngioma, to our knowledge, this is the first report of the delivery of this therapy by an endoscopic transsphenoidal route.