Dataset Information

Convection-Enhanced Delivery of Enhancer of Zeste Homolog-2 (EZH2) Inhibitor for the Treatment of Diffuse Intrinsic Pontine Glioma.

ABSTRACT:

Background

Diffuse intrinsic pontine glioma (DIPG) is a fatal childhood brain tumor and the majority of patients die within 2 yr after initial diagnosis. Factors that contribute to the dismal prognosis of these patients include the infiltrative nature and anatomic location in an eloquent area of the brain, which precludes total surgical resection, and the presence of the blood-brain barrier (BBB), which reduces the distribution of systemically administered agents. Convection-enhanced delivery (CED) is a direct infusion technique to deliver therapeutic agents into a target site in the brain and able to deliver a high concentration drug to the infusion site without systemic toxicities.

Objective

To assess the efficacy of enhancer of zeste homolog-2 (EZH2) inhibitor by CED against human DIPG xenograft models.

Methods

The concentration of EZH2 inhibitor (EPZ-6438) in the brainstem tumor was evaluated by liquid chromatography-mass spectrometry (LC/MS). We treated mice-bearing human DIPG xenografts with EPZ-6438 using systemic (intraperitoneal) or CED administration. Intracranial tumor growth was monitored by bioluminescence image, and the therapeutic response was evaluated by animal survival.

Results

LC/MS analysis showed that the concentration of EPZ-6438 in the brainstem tumor was 3.74% of serum concentration after systemic administration. CED of EPZ-6438 suppressed tumor growth and significantly extended animal survival when compared to systemic administration of EPZ-6438 (P = .0475).

Conclusion

Our results indicate that CED of an EZH2 inhibitor is a promising strategy to bypass the BBB and to increase the efficacy of an EZH2 inhibitor for the treatment of DIPG.

SUBMITTER: Sasaki T

PROVIDER: S-EPMC7666886 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Abstract INTRODUCTION While the safety and efficacy of convection-enhanced delivery (CED) have been studied in patients receiving single dose drug infusions, agents for oncologic therapy require repeated or chronic infusions to maintain therapeutic concentrations. Repeat/chronic CED infusions have rarely been described for oncologic purposes. We report on the safety and experience in a group of pediatric patients who received sequential CED into the brainstem for the treatment of diffuse intrinsic pontine glioma (DIPG). METHODS Patients were enrolled in a phase I single center clinical trial using 124I-8H9 monoclonal antibody (124I-Omburtamab, Y-mAbs Therapeutics) administered by CED (NCT01502917). Retrospective chart review was used to assess demographic data, CED infusion data, and post-operative neurologic and surgical outcomes. MRI scans were analyzed using iPlan® Flow software (Brainlab AG, Munich, Germany) for volumetric measurements. Target and catheter coordinates as well as radial, depth, and absolute error in MRI space were calculated with the Clearpoint imaging software (Clearpoint®, MRI Interventions Inc. Irvine, USA). RESULTS Seven patients underwent two or more sequential CED infusions. No patients experienced deficits Clinical Terminology Criteria for Adverse Events (CTCAE) grade 3 or greater. One patient had persistent grade 2 cranial nerve deficit after a second infusion. No patients experienced hemorrhage or stroke post-operatively. There was a statistically significant decrease in radial error (p= 0.005) and absolute tip error (p=0.008) for infusion two compared to the initial infusion. Sequential infusions did not result in significantly different distribution capacity between the first and second infusion (Vd:Vi ratio: 2.66 ± 0.35 versus 2.42 ± 0.75; p=0.45). CONCLUSIONS This series demonstrates the ability to safely perform sequential CED infusions into the pediatric brainstem. Past treatments did not negatively influence the procedural work flow, technical application of the targeting interface, or distribution capacity. This limited experience provides a foundation for using repeat CED for oncologic purposes.

Project description:BackgroundDiffuse intrinsic pontine glioma is one of the deadliest central nervous system tumours of childhood, with a median overall survival of less than 12 months. Convection-enhanced delivery has been proposed as a means to efficiently deliver therapeutic agents directly into the brainstem while minimising systemic exposure and associated toxic effects. We did this study to evaluate the safety of convection-enhanced delivery of a radioimmunotherapy agent targeting the glioma-associated B7-H3 antigen in children with diffuse intrinsic pontine glioma.MethodsWe did a phase 1, single-arm, single-centre, dose-escalation study at the Memorial Sloan Kettering Cancer Center (New York, NY, USA). Eligible patients were aged 3-21 years and had diffuse intrinsic pontine glioma as diagnosed by consensus of a multidisciplinary paediatric neuro-oncology team; a Lansky (patients <16 years of age) or Karnofsky (patients ≥16 years) performance score of at least 50 at study entry; a minimum weight of 8 kg; and had completed external beam radiation therapy (54·0-59·4 Gy at 1·8 Gy per fraction over 30-33 fractions) at least 4 weeks but no more than 14 weeks before enrolment. Seven dose-escalation cohorts were planned based on standard 3 + 3 rules: patients received a single infusion of 9·25, 18·5, 27·75, 37, 92·5, 120·25, or 148 MBq, respectively, at a concentration of about 37 MBq/mL by convection-enhanced delivery of the radiolabelled antibody [124I]-8H9. The primary endpoint was identification of the maximum tolerated dose. The analysis of the primary endpoint was done in the per-protocol population (patients who received the full planned dose of treatment), and all patients who received any dose of study treatment were included in the safety analysis. This study is registered with ClinicalTrials.gov, number NCT01502917, and is ongoing with an expanded cohort.FindingsFrom April 5, 2012, to Oct 8, 2016, 28 children were enrolled and treated in the trial, of whom 25 were evaluable for the primary endpoint. The maximum tolerated dose was not reached as no dose-limiting toxicities were observed. One (4%) of 28 patients had treatment-related transient grade 3 hemiparesis and one (4%) had grade 3 skin infection. No treatment-related grade 4 adverse events or deaths occurred. Estimated volumes of distribution (Vd) were linearly dependent on volumes of infusion (Vi) and ranged from 1·5 to 20·1 cm3, with a mean Vd/Vi ratio of 3·4 (SD 1·2). The mean lesion absorbed dose was 0·39 Gy/MBq 124I (SD 0·20). Systemic exposure was negligible, with an average lesion-to-whole body ratio of radiation absorbed dose higher than 1200.InterpretationConvection-enhanced delivery in the brainstem of children with diffuse intrinsic pontine glioma who have previously received radiation therapy seems to be a rational and safe therapeutic strategy. PET-based dosimetry of the radiolabelled antibody [124I]-8H9 validated the principle of using convection-enhanced delivery in the brain to achieve high intra-lesional dosing with negligible systemic exposure. This therapeutic strategy warrants further development for children with diffuse intrinsic pontine glioma.FundingNational Institutes of Health, The Dana Foundation, The Cure Starts Now, Solving Kids' Cancer, The Lyla Nsouli Foundation, Cookies for Kids' Cancer, The Cristian Rivera Foundation, Battle for a Cure, Cole Foundation, Meryl & Charles Witmer Charitable Foundation, Tuesdays with Mitch Charitable Foundation, and Memorial Sloan Kettering Cancer Center.