Aldape, Kenneth

1 The full, final text of this abstract will be available at abstract.asco.org at 7:30 AM (EDT) on Sunday, June, 2, 2013, and in the Annual Meeting Proceedings online supplement to the June 20, 2013, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Sunday edition of ASCO Daily News.

LBA2010 Background: RTOG 0825 evaluated the addition of BEV to standard CRT in the treatment of GBM and included molecular stratification that assessed the degree of mesenchymal (MES) gene enrichment. We investigated the ability of the MES signature to predict response to BEV. Methods: Sufficient FFPE tissue for molecular analysis was available for 650 registered, eligible patients. TaqMan PCR was performed prospectively using the molecular stratifier on all patients and an expanded 43 member MES set on 234 cases. A subset of specimens was subjected to whole genome expression profiling (GEP). Predictive models were evaluated for their ability to predict survival (overall, OS, and progression-free, PFS) in the training cohort of the BEV arm after adjusting for prognostic factors and treatment arm. Unsupervised clustering of GEP data was used to identify molecular subsets and gene set enrichment analysis (GSEA) performed to evaluate for MES enrichment. Results: We observed a significant association between increasing MES signature and worse PFS and OS in the BEV arm (p=0.036 and p=0.032, respectively). Based on the association between high MES expression and poor outcome in the BEV arm, we sought to optimize a predictor using an expanded set of MES genes. Unbiased gene selection from a total of 43 genes followed by radial basis machine modeling identified a 10-gene predictor of outcome in the BEV arm (p<0.001/HR 4.04 for OS and p<0.001/HR 2.21 for PFS). To further support the association of MES enrichment and poor outcome in the BEV arm, we performed GEP. Unsupervised clustering identified a subtype of tumors with MES enrichment associated with the 10-gene predictor survival probability (p=0.0124, t-test). Ongoing studies will determine the extent to which this represents a predictive marker for BEV. Conclusions: We developed a 10-gene predictor specific to BEV treatment and suitable for FFPE that may serve to identify subsets of patients with newly diagnosed GBM who benefit from BEV. Supported by RTOG grant U10 CA21661, CCOP grant U10 CA37422, and Brain SPORE P50 CA127001 from the NCI and Genentech. Clinical trial information: NCT00884741.

1 Background: Chemoradiation (CRT) with temozolomide (TMZ/RT→TMZ) is the standard of care for newly diagnosed GBM. This trial determined if the addition of Bev to standard CRT improves survival (OS) or progression-free survival (PFS) in newly diagnosed GBM. Methods: This phase III trial was conducted by the RTOG, NCCTG, and ECOG. Neurologically stable pts > 18 yrs with KPS ≥ 60, and > 1cm3 tumor tissue block, were randomized to Arm 1: standard CRT + placebo or Arm 2: standard CRT plus Bev (10 mg/kg iv q 2wks). Experimental treatment began at wk 4 of radiation then thru 6-12 cycles of maintenance chemotherapy. Protocol specified co-primary endpoints were OS and PFS, with significance levels of .023 and .002, respectively. At progression, treatment was unblinded and pts allowed to crossover or continue Bev. Symptom, QOL and neurocognitive (NCF) testing was performed in the majority of pts. Secondary analyses evaluated impact of MGMT methylation (meth) and prognostic 9 gene signature status. Results: From 978 registered pts, 637 were randomized. Inadequate tissue (n=105) and blood on imaging (n=40) were key reasons for non-randomization. No difference was found between arms for OS (median 16.1 vs. 15.7 mo, p = 0.11). PFS was extended for Arm 2 (7.3 vs. 10.7 mo, p = 0.004). Pts with MGMT meth had superior OS (23.2 vs. 14.3 mo, p < 0.001) and PFS (14.1 vs. 8.2 mo, p < 0.001). Neither the 9 gene signature nor MGMT predicted selective benefit for Bev treatment, but best prognosis pts (MGMT meth, favorable 9-gene), had a worse survival trend with Bev (15.7 vs 25 mo p = 0.08). To date, 128 pts were unblinded on Arm 1 (salvage Bev in 86) and 87 pts on Arm 2 (continued Bev in 39). Increased grade ≥ 3 toxicity was seen with Bev, mostly neutropenia, hypertension, and DVT/PE. Conclusions: The addition of Bev for newly diagnosed GBM did not improve OS, did improve PFS but did not reach the significance criterion. MGMT and 9 gene profile did not identify selective benefit, but risk subset results suggested strongly against the upfront use of Bev in the best prognosis pts. Full interpretation of the PFS results incorporating symptom burden, QOL, and NCF is ongoing. Support: NCI U10 CA 21661, U10 CA37422, and Genentech. Clinical trial information: NCT00884741.

Abstract Background: Glioblastomas (GBMs) are aggressive primary brain tumors with high levels of genomic heterogeneity impacting prognosis and treatment response. A recurrent in-frame deletion within the extracellular domain of the epidermal growth factor receptor (EGFR variant III, or vIII) is found in a substantial fraction of GBMs. Methods: The Radiation Therapy Oncology Group (RTOG) 0525 trial of temozolomide dosing in newly-diagnosed GBM enrolled 1174 patients. Of these, 494 eligible GBMs were analyzed for EGFRvIII expression by RT-PCR. The Kaplan-Meier method was used to compare the progression free survival (PFS) and overall survival (OS) of GBMs expressing EGFRvIII with those not expressing EGFRvIII. Results: 142 of 494 tested GBMs (29%) had expressed EGFRvIII. There were no significant differences in PFS or OS between patients whose tumors did (494) or did not (631) undergo EGFRvIII expression analysis. EGFRvIII expression was significantly associated with age (p=0.005), Karnofsky performance status (p=0.02), and RTOG recursive partitioning analysis (RPA) class (p=0.005). EGFRvIII expression analyzed in the entire study population did not reveal an association with PFS or OS. In a univariate subgroup analysis of patients treated on the standard-of-care arm of RTOG-0525, EGFRvIII expression was was significantly associated with worse PFS (HR=1.43, 95% CI: [1.05, 1.96], p=0.025), and worse OS (HR 1.45, 95% CI:[1.03, 2.05], p=0.032). However, in multivariate models, when adjusted for RPA class and MGMT methylation status, EGFRvIII was not an independent predictor of either PFS or OS. Conclusion: For GBMs treated with standard-of-care therapy in RTOG-0525, EGFRvIII expression was associated with worse PFS and OS. However, well-established stratification metrics such as age, KPS, and RPA override this prognostic association, suggesting that trials of therapeutic modalities directed against EGFRvIII should utilize these standard prognostic variables when survival is being analyzed or compared. Project Support: This project was supported by RTOG grant U10 CA21661, and CCOP grant U10 CA37422 from the National Cancer Institute (NCI) and Schering-Plough Corporation. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A110. Citation Format: Daniel P. Cahill, Asha George, Mark R. Gilbert, Arnab Chakravarti, Roger Stupp, Monika Hegi, Paul Brown, Kurt A. Jaeckle, Benjamin Corn, Erik P. Sulman, Luis Souhami, Maria Werner-Wasik, Bethany M. Anderson, Minesh Mehta, Kenneth D. Aldape. EGFRvIII expression is associated with shorter progression-free and overall survival in glioblastoma patients treated with standard-of-care temozolomide and radiation: A report from the RTOG-0525 trial. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A110.

Targeting a kinase common to both the EGFR and TNFα signaling pathways may prevent drug resistance in glioblastoma.

Abstract Major discoveries in the biology of nervous system tumors have raised the question of how non‐histological data such as molecular information can be incorporated into the next W orld H ealth O rganization ( WHO ) classification of central nervous system tumors. To address this question, a meeting of neuropathologists with expertise in molecular diagnosis was held in H aarlem, the N etherlands, under the sponsorship of the I nternational S ociety of N europathology ( ISN ). Prior to the meeting, participants solicited input from clinical colleagues in diverse neuro‐oncological specialties. The present “white paper” catalogs the recommendations of the meeting, at which a consensus was reached that incorporation of molecular information into the next WHO classification should follow a set of provided “ ISN ‐ H aarlem” guidelines. Salient recommendations include that (i) diagnostic entities should be defined as narrowly as possible to optimize interobserver reproducibility, clinicopathological predictions and therapeutic planning; (ii) diagnoses should be “layered” with histologic classification, WHO grade and molecular information listed below an “integrated diagnosis”; (iii) determinations should be made for each tumor entity as to whether molecular information is required, suggested or not needed for its definition; (iv) some pediatric entities should be separated from their adult counterparts; (v) input for guiding decisions regarding tumor classification should be solicited from experts in complementary disciplines of neuro‐oncology; and (iv) entity‐specific molecular testing and reporting formats should be followed in diagnostic reports. It is hoped that these guidelines will facilitate the forthcoming update of the fourth edition of the WHO classification of central nervous system tumors.