Citations

Glioblastoma (GBM) is a devastating cancer with a dismal prognosis. Current treatment includes temozolomide (TMZ), which is more effective in about 50% of GBMs that have O 6 - methylguanine DNA methyltransferase ( MGMT ) promoter methylation. MGMT is a DNA repair protein that reverses TMZ-induced DNA damage. EGFR is a prime oncogene in GBM. Here, we report that EGFR inhibition induced the down-regulation of MGMT in GBM cells, revealing a previously unidentified link between EGFR signaling and response to TMZ. EGFR inhibition led to activation of two transcription factors, activator protein-1 (AP-1), which repressed MGMT transcription, and nuclear factor κB (NF-κB), which up-regulated MGMT transcription. EGFR inhibition also induced AP-1–mediated transcription of miR-616. miR-616 inhibited both MGMT translation and NF-κB activation. Thus, the overall effect of EGFR inhibition was down-regulation of MGMT expression. In addition, we provided an explanation for the prior failure of clinical trials that used concomitant EGFR tyrosine kinase inhibitors (TKIs) and TMZ. TMZ up-regulated MGMT, and concomitant treatment with EGFR TKIs and TMZ failed to down-regulate MGMT. However, pretreatment with EGFR TKIs followed by TMZ efficiently down-regulated MGMT and enhanced TMZ sensitivity in experimental models. Posttreatment tumor tissues from two clinical trials were used to validate these findings. We demonstrated that EGFR inhibitors induced down-regulation of MGMT in posttreatment resected tumor tissues from patients with GBM and the failure of EGFR inhibition to down-regulate MGMT if TMZ was used concomitantly. These data support using EGFR TKIs before TMZ treatment as a therapeutic approach in MGMT unmethylated GBM.

Abstract Glioblastoma is highly vascularized with increased perfusion and prognosis remains dismal, despite improved diagnosis and aggressive multimodal treatment. The current standard of care is maximal surgical resection when feasible, followed by adjuvant radiation with concurrent chemotherapy, temozolomide. However, treatment resistance and tumor recurrence pose a considerable challenge for stratifying patients for optimal treatment planning. Current radiological assessment of glioblastoma therapy response predominantly relies on morphological measures; that may not accurately capture early microscopic changes or therapeutic efficacy. We have developed and validated an advanced imaging method, Arterial Spin Labeling (ASL) MRI that enable noninvasive spatial assessment of the entire tumor. ASL-MRI uses water within the blood as an endogenous tracer and measures perfusion without the need for exogenous gadolinium-based contrast agent. The objective of this study was to investigate ASL measured quantitative perfusion after surgery to predict survival in glioblastoma patients undergoing the standard of care chemoradiation treatment. In this prospective, IRB-approved study, twenty-three adults with glioblastoma participated for longitudinal MRI. Progression-free survival (PFS) and overall survival (OS) were recorded for each patient. A baseline MRI scan was performed prior to chemoradiation treatment and after surgery utilizing a 3D ASL sequence. All structural images were co-registered to T1 post-contrast images. Tumor regions of interest (ROIs) such as enhancing tumor (ET), tumor core, whole tumor, and necrosis were manually segmented. Cerebral blood flow maps were calculated and mean perfusion values (MPV) within ET ROIs were extracted. Scatter plot of MPV and Kaplan-Meier graphs were generated using GraphPad Prism. Based on median survival of 420 days, patients were categorized into short (≤420 days) or long (>420 days) survival. A threshold ASL measured perfusion value of 30 mL/100g/min distinguished survival groups; hyper-perfusion correlated with shorter OS, while hypo-perfusion linked to longer OS. The mean±SD of PFS and OS for patients with shorter survival were 119±42 days and 230±117 days respectively, while for longer survival were 624±285 and 726±210 days respectively, and the values were statistically different (P<0.001for both). Kaplan-Meier curves showed significant OS and PFS differences (p<0.015, Hazard Ratio=3.056). Our data indicate that ASL measured baseline perfusion, after surgery and before chemoradiation treatment can benefit in predicting survival and treatment stratification in glioblastoma patients. ASL measured perfusion can be performed during radiation treatment and could provide valuable information that can be incorporated into emerging treatment strategies such as adaptive radiation. Citation Format: Durga Udayakumar, Limin Zhou, Marco Pinho, Yiming Wang, Ben Wagner, Michael Youssef, Joseph Maldjian, Ananth Madhuranthakam. Noninvasive magnetic resonance imaging measured quantitative perfusion as predictive and prognostic biomarker in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7163.

Abstract GBM AGILE(NCT03970447) is a phase 2/3 Bayesian adaptive registration platform trial testing multiple therapies against a common control. Paxalisib, a PI3K/mTOR inhibitor, is the 3rd arm in the trial to conclude evaluation. METHODS Paxalisib was open to patients with newly diagnosed unmethylated (NDU) and recurrent (RD) glioblastoma, with three possible signatures: NDU, RD, and All(NDU+RD). Arm enrollment occurred Dec2020 through May2022. Control patients were enrolled from study initiation (July2019) and were treated with temozolomide(NDU) or lomustine(RD). GBM AGILE investigational arms have 1 or 2 stages, with adaptive randomization in stage 1 and fixed randomization if arms continue to stage 2. Efficacy is based on OS hazard ratio(HR) of Arm/Control. Efficacy goal is final Bayesian probability ≥ 98% for HR<1.00 in combined Stages. An Arm continues to Stage 2 if Bayesian predictive power (PP) ≥ 0.8. An Arm stops accruing in Stage 1 if it reaches maximal sample size(N) or does not meet a minimum efficacy threshold (PP<0.25 for all signatures when N>50). Clinical cut-off is 12 months after accrual stops. The maximum N for paxalisib was approximately 150(Stage 1) and 50(Stage 2). RESULTS After paxalisib reached >150 patients in Stage 1, accrual stopped [Paxalisib/control N 54/75(NDU), 100/188(RD)]. Neither PP thresholds for moving to Stage 2 nor stopping for minimum efficacy were met. Following an unplanned public disclosure that the arm did not continue to stage 2, clinical cut-off for final analysis (planned May2023) was updated to public disclosure date (August2022). At final analysis mean HRs were 0.89(NDU), 1.25(RD), 1.05(All), probabilities of HR<1.00 of 0.72(NDU), 0.076(RD), 0.398(All). Model estimated median OS paxalisib/control (months) were 14.77/13.84(NDU) and 8.58/10.06(RD). CONCLUSION Paxalisib did not show survival benefit over cumulative control in final primary analysis; additional secondary analyses are being considered. GBM AGILE continues to rapidly and efficiently assess therapies in ND and RD glioblastoma.

Objectives The aim of this study was to study the prevalence of exocrine pancreas insufficiency (EPI) at a population level and the subsequent risk of pancreatic ductal adenocarcinoma (PDAC). Materials and Methods Using TriNetX (a database of over 79 million US residents), we included patients ≥18 years with EPI (identified via ICD-10 codes) and continuous follow-up from 2016–2022. Patients with prior pancreas resection and PDAC before an EPI diagnosis were excluded. The primary outcome was EPI prevalence. Secondary outcomes included imaging utilization, PDAC risk, and pancreatic enzyme replacement therapy (PERT) utilization. We performed 1:1 propensity score matching (PSM) of patients with EPI versus patients without an EPI diagnosis. Results The population prevalence of EPI was 0.8% (n = 24,080) with a mean age of 55.6 years. After PSM, PDAC risk among patients with EPI was twice as high compared with patients without EPI (aHR, 1.97; 95% CI, 1.66–2.36). This risk persisted even after excluding patients with a history of acute or chronic pancreatitis (adjusted odds ratio, 4.25; 95% CI, 2.99–6.04). Only 58% (n = 13, 390) of patients with EPI received PERT. No difference was observed in PDAC risk between patients with EPI on PERT and those not on PERT (aHR, 1.10; 95% CI, 0.95–1.26; P = 0.17). Conclusions Despite a low prevalence, patients with EPI may have a higher risk of PDAC, and majority with EPI were not on PERT. PERT did not impact incident PDAC risk after an EPI diagnosis.

Abstract Background Homelessness is an important public health issue with a prevalence around 4.2% in the United States. Homelessness has been associated with lack of access to healthcare services, poor quality of care, and negative health outcomes. However, there is limited data on clinical outcomes among homeless individuals with Crohn’s disease (CD). Aims In this study, we examine inpatient outcomes including endoscopy utilization, surgical treatment, and post-operative complications among homeless patients with CD. Methods The Healthcare Utilization Project (HCUP) State Inpatient Databases from New York, Arizona, Massachusetts and Florida for 2013 and 2014 were used to identify adults ≥18 years admitted with CD identified by International Classification of Diseases, Ninth Revision codes. Homeless patients were then identified, and propensity score matched using a one-to-ten greedy nearest-neighbor approach to non-homeless patients to balance the distribution of baseline covariates. Differences in outcomes including endoscopy utilization, surgical treatment and post-operative complications were reported as odds ratios (ORs) and 95% confidence intervals (CI). Results A total of 70,457 CD hospitalizations were identified, of which 469 (0.6%) were associated with homelessness. We matched 440 homeless patients with 4,400 housed patients with CD. Homeless individuals had a higher proportion of males (p=0.002), tended to be older (p=0.035), and had more comorbidities than non-homeless individuals. There was no difference in mortality between non-homeless and homeless patients (OR 1.6, 95% CI 0.72-3.57). Endoscopy utilization was comparable between non-homeless and homeless patients with CD including gastroscopy (OR 0.71, 95% CI 0.40-1.18), colonoscopy (OR 0.80, 95% CI 0.31-1.69), and sigmoidoscopy (OR 0.37, 95% CI 0.02-1.74) [Figure 1]. Surgical treatment was also comparable, except for lower rates of bowel resection among homeless patients (OR 0.55, 95% CI: 0.29-0.93). The two groups also had similar rates of post-operative complications including pulmonary, cardiovascular, gastrointestinal, and infectious complications (Figure 1). Conclusions Homeless patients with CD have comparable endoscopy utilization and surgical treatment as non-homeless patients, except for lower bowel resection rates. Postoperative complications are also similar between the two groups. Future studies are needed to better understand the impact of homelessness on health outcomes and healthcare service utilization among patients with CD. Figure 1. Endoscopy utilization, surgical treatment, and post-operative complications among homeless and non-homeless individuals using 1:10 propensity matching Funding Agencies None