Daniel, J.

Abstract Despite recent advances in cancer therapy, options for central nervous system metastasis (CM) remain limited and patient outcomes are dismal. The lack of tumor models that reflect the heterogeneity and complexity of human CM tumors is a barrier to understanding the underlying biology and to developing novel therapies. Here, we report the development and characterization of 39 patient derived xenograft (PDX) models of CM tumors with histological subtypes representing the disease spectrum. The PDX models successfully grew both in the flank and brains of mice, and retained their histology regardless of the site of implantation. Brain metastasis also formed in 5/12 models after intra-cardiac injection. Multi-omic analysis of the PDX tumor and the patient-matched CM tumor showed that PDXs largely retained the molecular profiles of the tumor from which they were derived, including the retention of aberrations in key driver genes and signaling pathways. PDXs differed primarily from the ungrafted patient tumors by a downregulation in immunity-related pathways, which was expected due to the use of an immuno-compromised host, arguing for the validity of using the flank as a site of implantation. Integrated analysis of mutations and gene expression changes in CM revealed an upregulation of neuronal signaling and DNA damage response, and downregulation of calcium signaling and inflammation. We also assessed the clonal evolution of the PDX from the original patient CM by tracing variant allele frequencies in copy number neutral regions. We found that the PDX tumors were heterogeneous and comprised of multiple tumor clones that were either unique or in common with the original tumor, and displayed evidence of clonal expansion. Two PDXs that underwent phylogeny assessment showed evidence of minor clone expansion. One such PDX was a tumor from a Her2+ breast cancer (CM13), which largely did not molecularly resemble its matched patient tumor but was confirmed to have some shared expressed variants. The PDX was nearly copy number neutral, which included loss of the Her2 amplicon, and had few mutations compared with its parent tumor. Most noteworthy, is that CM13 displayed unique molecular patterns, aggressive growth and was highly metastatic in vivo. From the flank, it led to multiple metastases, including micrometastasis in the brain. This suggests that minor clone takeover may confer tumor aggressiveness and potentiate brain metastasis. The large and diverse repertoire of PDXs developed and characterized in this study provides a new set of tools that will help deepen our understanding of CM and improve preclinical testing for CM therapies. Our data also show that expansion of minor clones could confer aggressive tumor behavior and may be important in tumor evolution in PDX models and human cancers. Citation Format: Ben Yi Tew, Christophe Legendre, Tim Triche, Gerald C. Gooden, Kyle N. Johnson, Rae Anne Martinez, Emanuel F. Petricoin, Mariaelena Pierobon, Joyce O'Shaughnessy, Cindy Osborne, Mark A. Schroeder, Daniel J. Ma, Mark Bernstein, Jann N. Sarkaria, Steven A. Toms, Bodour Salhia. Development and characterization of patient derived xenografts from central nervous system metastasis reveal minor clone expansion linked with aggressive tumor behavior [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 991.

Abstract Controversy exists surrounding whether heterogeneous disruption of the blood–brain barrier (BBB), as seen in glioblastoma (GBM), leads to adequate drug delivery sufficient for efficacy in GBM. This question is especially important when using potent, targeted agents that have a poor penetration across an intact BBB. Efficacy of the murine double minute-2 (MDM2) inhibitor SAR405838 was tested in patient-derived xenograft (PDX) models of GBM. In vitro efficacy of SAR405838 was evaluated in PDX models with varying MDM2 expression and those with high (GBM108) and low (GBM102) expression were evaluated for flank and orthotopic efficacy. BBB permeability, evaluated using TexasRed-3 kDa dextran, was significantly increased in GBM108 through VEGFA overexpression. Drug delivery, MRI, and orthotopic survival were compared between BBB-intact (GBM108-vector) and BBB-disrupted (GBM108-VEGFA) models. MDM2-amplified PDX lines with high MDM2 expression were sensitive to SAR405838 in comparison with MDM2 control lines in both in vitro and heterotopic models. In contrast with profound efficacy observed in flank xenografts, SAR405838 was ineffective in orthotopic tumors. Although both GBM108-vector and GBM108-VEGFA readily imaged on MRI following gadolinium contrast administration, GBM108-VEGFA tumors had a significantly enhanced drug and gadolinium accumulation, as determined by MALDI-MSI. Enhanced drug delivery in GBM108-VEGFA translated into a marked improvement in orthotopic efficacy. This study clearly shows that limited drug distribution across a partially intact BBB may limit the efficacy of targeted agents in GBM. Brain penetration of targeted agents is a critical consideration in any precision medicine strategy for GBM. Mol Cancer Ther; 17(9); 1893–901. ©2018 AACR.

Objectives/HypothesisSarcomatoid carcinoma is a rare variant of squamous cell carcinoma of the head and neck. No consensus exists on its management. Our aim was to present our outcomes.Study DesignRetrospective study. Median follow‐up 45 months.MethodsThere were 38 patients with pathologically confirmed sarcomatoid carcinoma of the larynx treated at the Mayo Clinic from 1990 to 2014. Statistical analysis of overall survival (OS), progression‐free survival (PFS), and local control (LC) were conducted using the Kaplan‐Meier method.ResultsThe majority of patients were elderly males (92%) with a smoking history (74%) presenting with early‐stage disease (71%). Surgery alone was the primary treatment in 27 patients (71%). Nine patients (25%) were treated with adjuvant radiation due to initial stage or high‐risk pathologic features. Median radiation dose to the primary/surgical bed was 65 Gy (range, 60.3–75.0 Gy). A total of 15 patients (39%) had tumor recurrence, majority being local (n = 12). Sixty percent (n = 9) had multiple local recurrences. Five‐year OS, PFS, and LC were 63%, 46%, and 72%, respectively. Subgroup analysis by stage I versus higher stages (II–IV) showed an OS of 80% versus 43% (P = .030), PFS of 65% versus 18% (P = .003), and LC of 84% versus 57% (P = .039).ConclusionsSarcomatoid carcinoma of the larynx is rare, and frequently presents at an early stage in older men with history of smoking. Based on our outcomes and patterns of failure, it appears early‐stage tumors are treated appropriately with single‐modality therapy, whereas more advanced tumors require multimodality therapy. Validation in a larger cohort is warranted.Level of Evidence4. Laryngoscope, 128:373–377, 2018

Abstract Clinical data indicate that certain regions within glioblastoma (GBM) have a relatively intact blood-brain barrier (BBB), but controversy surrounds whether associated heterogeneous delivery may limit efficacy for otherwise highly active drugs with poor brain distribution. In this study, the efficacy of molecularly targeted therapies was compared in relevant GBM patient-derived xenograft (PDX) models grown either as heterotopic or orthotopic tumors. The impact of further disrupting BBB integrity in non-responsive orthotopic tumors was evaluated by over-expressing vascular endothelial growth factor (VEGF) and measuring drug distribution by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). The brain:plasma ratio for five targeted agents was determined by LC-MSMS and treatment efficacy was evaluated in target-relevant GBM PDX lines: erlotinib (brain:plasma = 0.02 ± 0.02; efficacy tested in GBM6), palbociclib (brain:plasma = 0.06; efficacy tested in GBM22), AZD1775 (brain:plasma = 0.05; efficacy tested in GBM22), SAR405838 (brain:plasma = 0.01 ± 0.003; efficacy tested in GBM108), and AZD4547 (brain:plasma = 0.045 ± 0.02; efficacy tested in GBM150). Each of these drugs was effective in relevant GBM PDX flank tumor models with a 27% to 218% prolongation in the median time to exceed their pre-specified endpoint compared to placebo treatment (p≤0.02 for each drug). In contrast, none of these drugs were effective in prolonging survival in the same target-relevant orthotopic tumor models (-6% to 8% extension in median survival; p>0.05 for each drug). Consistent with partial and heterogeneous disruption of the BBB, MALDI-MSI of erlotinib, AZD1775 or SAR405838 distribution within orthotopic tumors demonstrated highly heterogeneous drug levels with large regions within each tumor approaching the low drug levels observed within surrounding normal brain. To further evaluate whether heterogenous drug distribution in orthotopic tumors could account for poor treatment efficacy, GBM108 was transduced with lentiviral constructs encoding for VEGF or empty vector (EV). While both GBM108-sublines were readily detectable with gadolinium-enhanced magnetic resonance imaging (MRI), the GBM108-VEGF tumors had a significantly more disrupted BBB, as evidenced by a more uniform and intense distribution of a brain-impenetrant TexasRed-dextran vascular marker. Similarly, the distribution of SAR405838, measured by MALDI-MSI, was markedly higher and more uniform in the GBM108-VEGF tumors when compared to the GBM108-EV tumors. Enhanced delivery of SAR405838 into orthotopic GBM108-VEGF models translated into a marked enhancement in treatment efficacy in comparison to GBM108-EV with a median survival prolongation of 37 vs. 4 days, respectively (p=0.0055). Collectively, these data highlight the importance of testing novel therapeutic agents in orthotopic tumor models and suggest that limited brain penetration for many molecules may significantly limit their efficacy in brain tumors that have a partially intact BBB. In the face of continued failure to develop effective targeted agents for GBM, these in vivo results highlight the importance of re-evaluating the dogma in neuro-oncology that the BBB is fully disrupted in GBM and, therefore, drug delivery across the BBB is not a major factor limiting treatment efficacy. Citation Format: Jann N. Sarkaria, David Calligaris, Daniel Ma, Karen Parrish, Ann C. Mladek, Janice Laramy, Minjee Kim, Shuangling Zhang, Mark Schroeder, Brett L. Carlson, Katrina Bakken, Aaron Johnson, Nathalie Agar, William Elmquist. The critical importance of the blood-brain barrier in modulating the response to otherwise highly effective targeted therapies in patient-derived orthotopic glioblastoma xenografts. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B25.

Purpose: To report the outcomes of patients with favorable risk oropharyngeal cancer that underwent adjuvant radiation therapy with omission of the primary site from the clinical target volume (CTV). Material/Methods: A retrospective study of 40 patients treated with transoral surgery (TOS) followed by neck only radiation using intensity modulated radiation therapy (IMRT) with exclusion of the primary site. For all patients, a CTV of the primary surgical bed was contoured to obtain the estimated incidental dose to the primary site. Results: Median follow-up was 51 months (range, 13-155 months). The median radiation therapy (RT) dose to the neck was 6000 cGy (range, 5400-6400 cGy). The mean incidental dose to the primary tonsillar site was 4320 cGy (SD ± 480 cGy) and to the primary base of tongue site was 4060 cGy (SD ± 420 cGy). There were no local failures and only 1 regional failure, resulting in 97.5% locoregional control rate at 4 years. Two patients developed distant metastases, without evidence of locoregional recurrence, for a 4-year overall survival rate of 97%. Conclusions: Our analysis suggests that mucosal sparing RT after TOS in favorable risk oropharyngeal cancer patients may provide comparable oncologic and improved functional outcomes compared to conventional treatment in selected patients.

ObjectivesTo examine outcomes of selective neck dissection (SND) in patients with human papillomavirus (HPV)‐related oropharyngeal squamous cell carcinoma (OPSCC) who present with clinical neck disease.Study DesignMulti‐institutional retrospective review.MethodsTwo institutional databases of patients with HPV‐related OPSCC were reviewed to identify patients with clinical (c) N1‐N3 neck disease who underwent SND ± adjuvant therapy.ResultsThree hundred and twenty‐four patients were identified with a median follow‐up of 49 months (range 3–199 months). All patients underwent transoral resection of the primary tumor and SND, including levels II–IV and ± levels I or V, with resection of additional nonlymphatic tissue (extended SND) as indicated by extent of disease, including the spinal accessory nerve (7%), the internal jugular vein (13%), and the sternocleidomastoid muscle (8%). Two hundred and seventy (83%) patients underwent adjuvant radiation. There were 13 (4%) regional recurrences and 19 (6%) distant recurrences. Regional control following salvage was 98%. On univariable analysis, absence of radiation was associated with regional recurrence (odds ratio [OR] 9.2, 95% confidence interval [CI] 2.9–29.4). On multivariable analysis, adjuvant radiation was associated with improved disease‐free survival (DFS) (OR 0.27, 95% CI 0.14–0.53) but lost significance for overall (OS) and disease‐specific survival (DSS) (P > 0.05). Five‐year Kaplan‐Meier estimates for OS, DSS, and DFS were 88% (95% CI 84%–92%), 93% (95% CI 89%–96%), and 83% (95% CI 78%–87%), respectively.ConclusionIn HPV‐related OPSCC presenting with clinical neck disease, a SND ± additional tissue resection and adjuvant therapy, when indicated, provides excellent long‐term regional control. Omission of radiotherapy increases the risk of regional recurrence, although it may not significantly impact OS or DSS. It appears unnecessary to routinely perform a comprehensive neck dissection.Level of Evidence4. Laryngoscope, 127:623–630, 2017