Signature-guided treatment of GBM with neddylation inhibitor pevonedistat

PROJECT SUMMARY – PROJECT 3 The ubiquitin/proteasome system maintains intracellular homeostasis via degradation of unwanted proteins. Neddylation is a specific pathway within the ubiquitin/proteasome system that is overactive in glioblastoma (GBM), and whose upregulation has been associated with glioma progression and worse survival. Pevonedistat

is a first-in-class small-molecule neddylation inhibitor shown to impact protein degradation and inhibit growth of GBM cells in culture and orthotopic xenografts. Pevonedistat is in clinical trials and available through NCI’s Cancer Therapy Evaluation Program (CTEP). Because the molecular heterogeneity within and across GBM

patients obscures therapeutic targets and obfuscates signals of efficacy in clinical trials, we propose the use of molecular “signatures of vulnerability” to targeted agents in subsets of models, and to use these signatures to guide patient enrollment in early-stage clinical trials. Our preliminary data revealed molecular determinants of

synergy against PTEN-deleted (PTENdel) and PTEN-mutated (PTENmt) GBM from combining pevonedistat with a TOP2A inhibitor, etoposide. We hypothesize that a specific “synergy signature” can be used to identify patients likely to respond to pevonedistat + etoposide and propose a signature-guided clinical trial to achieve synergy in

patients with recurrent GBM (rGBM). We propose the following Aims: Aim 1. Discover and validate the mechanism underlying the antitumor synergy of pevonedistat + TOP2Ais in GBM. We will use GBM patient-derived xenograft (PDX) explant cultures and orthotopic tumors to pursue this aim and will validate the

predictive performance of the “synergy signature” in patient tumor samples from the proposed clinical trial in Aim 3. Aim 2. Validate a “signature of vulnerability” to pevonedistat alone in GBM. We will use GBM PDX cultures and orthotopic models to refine and test the predictive accuracy of a “signature of vulnerability” to

pevonedistat for future clinical trials. Aim 3. Determine the safety of pevonedistat + etoposide in “synergy signature” rGBM patients in a phase I clinical trial. We will enroll patients with “synergy signature” GBM to a phase I study of pevonedistat + etoposide to determine the maximum tolerated dose/recommended phase II

dose of the combination therapy; obtain preliminary response data; define the neuropharmacokinetic (nPK) of pevonedistat using intracerebral microdialysis; and evaluate the neuropharmacodynamics (nPD) of pevonedistat using a window of opportunity design in subsets of study participants. This project relies on support

from Core A for nPK analysis, Core B for exome and RNA Seq and bioinformatics, and the Admin Core for coordination and integration with Projects 1 and 2 for data sharing and comparison of signatures of vulnerability to OV-αCD47-G1 and tasquinimod. If successful, our project will advance drug development in the setting of a

heretofore recalcitrant tumor by linking molecular subsets of GBM with both drug discovery/development and patient recruitment for highest likelihood of conveying precision medicine into the care stream.