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Study Design: Retrospective, single institution, multisurgeon case control series. Objective: To determine whether there are differences in reoperation rates or outcomes for patients undergoing 2-level posterolateral fusion (PLF) augmented by a transforaminal lumbar interbody fusion (TLIF) at only one of the levels or at both. Methods: A total of 416 patients were identified who underwent 2-level PLF with a TLIF at either one of those levels (n = 183) or at both (n = 233) with greater than 1-year follow-up. Demographic, surgical, radiographic, and clinical data was reviewed for each patient. These included age, sex, race, body mass index, smoking status, Charleston Comorbidity Index, operative time, estimated blood loss, length of stay, and patient-reported outcome measures. Results: Each cohort underwent 24 reoperations. Although the number of overall reoperations was not significantly different ( P > .05), among the reoperation types, there were significantly more reoperations for adjacent segment disease in the 2-level group compared to the 1-level group (19 vs 12, P = .04). There was no difference in reoperation for pseudarthrosis between the groups ( P > .05). Although both groups experienced significant improvements in Oswestry Disability Index ( P < .001) and Short Form–12 health questionnaire ( P < .001), there were no differences between improvements for 1- versus 2-level cohorts. Conclusions: For patients undergoing 2-level PLF in the setting of a TLIF, using a TLIF at one versus both levels does not seem to influence reoperation rates or outcomes. However, reoperation rates for adjacent segment disease are increased in the setting of a 2-level PLF augmented by a 2-level TLIF.

Background: Multiple myeloma (MM) is a heterogeneous disease with varying survival outcomes depending on the presence of certain genetic abnormalities. Common abnormalities include trisomies, translocations involving the chromosome 14, and amplifications or deletions of chromosomes 1, 13, and 17. t(11;14), occurring in 15% of patients with myeloma, had been considered a standard risk abnormality, but recent data suggest inferior outcome. This is important as new therapeutic options such as the BCL-2 inhibitor venetoclax has been shown to be particularly effective in t(11;14) patients. Methods: This was a multicenter study to identify the outcomes of patients with t(11;14), using a retrospectively assembled cohort. Patients with MM diagnosed between 2005 and 2015 with t(11;14) identified on FISH performed within six months of diagnosis, and with treatment details available and if alive, a minimum of 12 months of follow up, were enrolled. Results: The current analysis includes 1216 patients; median age of 62.56 years; 58.7% male. The median follow-up from diagnosis for the entire cohort was 51.9 months; 69.1% of the patients were alive at the last follow up. ISS stage distribution included: Stage I (35.7%), Stage II (34.0%) and Stage III (15.1%), data was missing for the rest. The distribution of concurrent FISH abnormalities included: trisomies (3.5%), del 13q (13.3%), 1q amp (8.8%), and del 17p or monosomy 17 (5.8%). Initial regimen included: 27.2% had an immunomodulatory (IMiD), 45.9% had a proteasome inhibitor (PI), 17.7% had both, and 9.0% had no novel agent. The drug classes by line of therapy are shown in Table 1. An early stem cell transplant (defined as within 12 months of start of first line treatment) was used in 49.4% of patients. The median time to next treatment (TTNT) after starting initial treatment was 26.6 (95% CI: 23.9 to 29.2) months. The median overall survival (OS) from diagnosis for the entire cohort was 95.1 (95% CI: 85.9 to 105.9) months; 4-year estimates for those diagnosed from January 2005 to December 2009, and from January 2010 to December 2014 were 77.5% and 78.6%, respectively. The median OS for those with any one high risk FISH lesion (del 17p/ 1q amp) was 67.5 (55.2, 97.1) versus 101.7 (89.7, 107.3) months. Patients with early SCT (within 12 months of diagnosis) had better OS: 108.3 (103.8, 133.0) vs. 69.8 (61.5, 80.3) months. Conclusion: Patients with t(11;14) without high risk FISH abnormalities have an excellent survival. Patients receiving a PI + IMiD combination and those receiving autologous SCT as part of initial therapy had best survival. Though numbers are limited, patients in the later lines receiving newer drugs such as venetoclax and daratumumab had high response rates and durable responses. Disclosures Kumar: Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Takeda: Research Funding. Bittrich:Celgene: Other: Travel Funding, Research Funding; Else Kröner Fresenius Foundation: Research Funding; Otsuka Pharmaceuticals Europe: Other: N/A; SANOFI Aventis: Membership on an entity's Board of Directors or advisory committees, N/A, Research Funding; University Hospital Wuerzburg: Employment; Bristol Myers Squibb: Research Funding; Pfizer: Other: Travel Funding; AMGEN: Other: Travel Funding; JAZZ Pharmaceuticals: Other: Travel Funding; Wilhelm Sander Foundation: Research Funding; German Research Foundation (DFG): Other: N/A; University of Würzburg: Other: N/A. Goldschmidt:Mundipharma: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnology: Membership on an entity's Board of Directors or advisory committees; John-Hopkins University: Research Funding; Dietmar-Hopp-Stiftung: Research Funding; Janssen: Consultancy, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MSD: Research Funding; Molecular Partners: Research Funding; John-Hopkins University: Research Funding; Amgen: Consultancy, Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Chugai: Honoraria, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Reece:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Otsuka: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; BMS: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Merck: Research Funding. Mateos:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmamar: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Adaptive: Honoraria; EDO: Membership on an entity's Board of Directors or advisory committees. Ludwig:Celgene: Speakers Bureau; Amgen: Research Funding, Speakers Bureau; Takeda: Research Funding, Speakers Bureau; PharmaMar: Consultancy; Janssen: Speakers Bureau; BMS: Speakers Bureau. Mangiacavalli:celgene: Consultancy; Amgen: Consultancy; Janssen cilag: Consultancy. Dimopoulos:Sanofi Oncology: Research Funding. Kastritis:Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Takeda: Honoraria; Pfizer: Honoraria; Prothena: Honoraria; Genesis: Honoraria. Yee:Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Karyopharm: Consultancy; Adaptive: Consultancy. Raje:Amgen Inc.: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene Corporation: Consultancy; Takeda: Consultancy; Janssen: Consultancy; Merck: Consultancy. Rosta:Cornerstone Research Group: Employment. Haltner:Cornerstone Research Group: Employment. Cameron:Cornerstone Research Group: Employment, Equity Ownership. Durie:Amgen, Celgene, Johnson & Johnson, and Takeda: Consultancy.

Purpose: Multiple myeloma (MM) is a plasma cell (PC) malignancy with an increasing incidence in the US. Epidemiological studies demonstrate a 2-3 fold higher incidence of the pre-malignant monoclonal gammopathy of undetermined significance (MGUS) and MM with a ~4-year younger age of onset among African Americans (AA) compared to European Americans (EAs) (Fonseca, Leukemia, 2017). With equal access to care, AAs have better overall survival compared to EAs (Waxman, Blood, 2010). This disparity may be explained by ancestral-associated genetic predisposition of AAs to development of monoclonal gammopathies and to specific acquired, cytogenetically-defined subtypes. Using calculated genetic ancestry data, we have previously identified a higher prevalence of IgH translocations t(11;14), t(14;16) and t(14;20) in individuals with >80% African ancestry (Baughn, BCJ, 2018). Since SNP rs9344 encoding the CCND1 870G>A polymorphism has been reported in association with increased risk of t(11;14) (Weinhold, Nature Genetics, 2013), we investigated whether rs9344 correlates with African ancestry and with t(11;14) in our cohort of patients with plasma cell dyscrasias. Methods: We studied 898 patients with monoclonal gammopathies who had undergone uniform testing to identify MM-specific cytogenetic abnormalities. DNA from bone marrow samples was genotyped on the Precision Medicine Research Array and biogeographical ancestry was assessed using the Geographic Population Structure Origins tool (Elhaik, Nat Commun, 2014). Plasma cell proliferative disorder FISH of immunoglobulin (cIg)-stained positive plasma cells was performed as described (Baughn, BCJ, 2018). Individuals were divided into three ancestral groups: 1. EAs (<0.1% African ancestry and <30% Asian ancestry); 2. AAs (> 80% African ancestry); and 3. Other. Chi-squared test was used to determine the overall comparison between the 3 ancestral groups and also between ancestral groups 1 vs 2, and 2 vs 3 using pairwise comparison. All tests were two-sided with alpha level set at 0.05 for overall statistical significance. Pairwise comparison was considered statistically significant when p<0.025 based on Bonferroni method for multiple comparisons. Results: We identify increased risk of development of either a t(11;14), t(14;16) or t(14;20) in AAs (48.8%) compared to EAs (33.6%) (p-value=0.0051). To explore the genetic basis of increased t(11;14) specifically (37.4% AAs vs. 27.3% p-value=0.049), we evaluated the frequency of the G risk allele of rs9344 in relation to African ancestry. The frequency of the G risk allele was higher in AAs (0.81) compared to EAs (0.59) (p-value <0.0001) and also higher in t(11;14) cases (0.73) compared to non-t(11;14) controls (0.58) (p-value <0.0001). A multivariate model identified only rs9344 as significantly associated with t(11;14) after adjusting for age, gender and race group suggesting that it plays a role in the development of t(11;14) (p-value <0.001 for GG, p-value=0.005 for AG). To test if these results are replicable, we studied the MMRF CoMMpass cohort. This cohort includes individuals with newly diagnosed MM along with self-report race information and translocation data from long insert whole genome sequencing. Although t(11;14) was not enriched in self-reported Black individuals from this cohort (17.5% Black vs. 20.4% White, p-value=0.47), there was association between the rs9344 and self-reported Black race (p-value <0.0001) and with the presence of t(11;14) when the t(11;14) was analyzed by long insert whole genome sequencing (p-value=0.0001). Conclusions: To our knowledge, this study includes the largest group of African individuals with an abnormal plasma cell clone along with uniformly collected FISH, genotyping and ancestry data. We have identified in this diverse population the association of the CCND1 870G>A polymorphism (rs9344) with African ancestry and with t(11;14) suggesting that it plays a role in the development of t(11;14) plasma cell dyscrasias. Disclosures Elhaik: DNA Diagnostics Center: Consultancy. Baird:DNA Diagnostics Center: Employment. Cerhan:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; NanoString: Research Funding. Bergsagel:Celgene: Consultancy; Ionis Pharmaceuticals: Consultancy; Janssen Pharmaceuticals: Consultancy. Dispenzieri:Alnylam: Research Funding; Akcea: Consultancy; Intellia: Consultancy; Janssen: Consultancy; Pfizer: Research Funding; Takeda: Research Funding; Celgene: Research Funding. Kumar:Janssen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Takeda: Research Funding.

Background: Early data from anti-CD19 chimeric antigen receptor (CAR) T-cell trials suggest that concurrent infection can lead to poor outcomes. 1,2 The relationship between CAR T-cell mediated inflammatory responses and infections is not well-established. With CAR T-cell therapies more readily available, practitioners must identify which patient, disease and CAR T-cell specific parameters are associated with an increased risk of infection to optimize outcomes. We provide a comprehensive analysis of infection risk within the first 30 days after CAR T-cell infusion across multiple types of CAR T-cell trials targeting distinct antigens. Methods: This was a single-center, retrospective study conducted at the National Cancer Institute analyzing infectious complications in subjects who underwent CAR T-cell therapy on one of four phase I clinical trials, targeting CD19, CD22, B-cell maturation antigen (BCMA) or disialoganglioside (GD2) from 2012 though 2018. Baseline characteristics are in Table 1. The primary objective was to establish the incidence of infections between initiation of lymphodepleting (LD) chemotherapy through day 30 after CAR T-cell infusion. The secondary objective was to identify risk factors for infection. Patients were censored at relapse and/or initiation of alternative therapy, including treatment for relapse or consolidative hematopoietic stem cell transplantation (HSCT). Univariate screening methods were used to identify parameters associated with increased risk of infection Results: Amongst 144 subjects, 52 (36.1%) received anti-CD19 CAR T-cells (CAR-T); 53 (36.8%) received anti-CD22 CAR-T, 26 (18.1%) received anti-BCMA CAR-T; and 13 (9%) received anti-GD2 CAR-T. The median age was 18 years (range: 4 to 66). Sixty-one (42.4%) had undergone at least one prior allogeneic hematopoietic stem cell transplant (HSCT) and 24 (16.7%) had at least one prior autologous HSCT. Sixty-eight (47.2%) had a history of a recent infection within 100 days of initiation of LD chemotherapy, of which 17 were a major chronic infection and 9 were considered severe. Fifty-eight (40.3%) subjects experienced a total of 103 infections from initiation of LD chemotherapy through day 30 post CAR T-cell infusion, with the median time to first infection being 6 days post-CAR infusion. Twenty-eight (19.4%) subjects had more than 1 infection; 20 (13.9%) subjects had C. difficile infection. The 103 infections consisted of 47 (45.6%) distinct episodes of focal bacterial infections (e.g., sinusitis, pneumonia, urinary tract infection), 25 (24.2%) episodes of bacteremia, 22 (21.4%) viral infections, and 9 (8.7%) invasive fungal infections. Fourteen infections (13.6%) occurred between initiation of LD chemotherapy and day 0 (prior to CAR T-cell infusion). Fever and neutropenia, without a source, was documented as a distinct entity in 85 patients (59.0%). Using univariate statistical screening methods, we identified 4 parameters that were individually associated with an increased risk of infection: increasing number of prior therapies (p=0.0034), prior history of recent infection within the past 100 days (p=0.0064), age > 18 (p =0.028), or enrollment on the CD22 CAR trial (p=0.0028). Eliminating the trial, since that is not generalizable, and combining these into a multivariable logistic regression model identified age > 18, prior history of infection and prior lines of therapies jointly associated with an increased risk of infection. Using these parameters, a predictive model was developed, which, when applied to the data set used to develop the model, can correctly predict 69 of 86 patients without an infection (80.3%; CI: 70.3-88.0%) as well as 32 of 58 patients with an infection (55.2%; 95% CI: 41.5- 68.3%). Conclusion: In this retrospective analysis, we provide the largest experience to date analyzing infection in the setting of CAR T-cell therapy across multiple CAR constructs. Our study demonstrates that adult age, prior history of infection, increased number of prior therapies and enrollment on a particular CAR T-cell trial, in this case the CD22 CAR-T trial, may lead to a higher risk of infection than in those without these risk factors. Further investigations are underway to evaluate clinical outcomes with infection which occur in the peri CAR T-cell setting and potential strategies to minimize infection risk. Generalizability of this model will be tested in an independent data set. Disclosures Lee: Kite, a Gilead Company: Research Funding; Harpoon Therapeutics: Consultancy; Juno Therapeutics: Other: External Advisory Board; ACI Clinical on behalf of Celgene:: Other: Independent Central Quality Review Committee. Mackall:Obsidian: Research Funding; Lyell: Consultancy, Equity Ownership, Other: Founder, Research Funding; Nektar: Other: Scientific Advisory Board; PACT: Other: Scientific Advisory Board; Bryologyx: Other: Scientific Advisory Board; Vor: Other: Scientific Advisory Board; Roche: Other: Scientific Advisory Board; Adaptimmune LLC: Other: Scientific Advisory Board; Glaxo-Smith-Kline: Other: Scientific Advisory Board; Allogene: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Apricity Health: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Unum Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Kochenderfer:Kite and Celgene: Research Funding; Bluebird and CRISPR Therapeutics: Other: received royalties on licensing of his inventions. OffLabel Disclosure: Conditioning chemotherapy for CAR T-cell therapy; this is a retrospective study that used different lymphodepletion regimens.

Abstract Central nervous system hemangioblastoma (CNS HGB) is a rare neoplasm. Sporadic and von-Hippel Lindau (VHL)-associated forms exist. Predicting tumor growth is difficult, making the indication for intervention challenging. A retrospective analysis of consecutive, neurosurgically managed CNS HGB at Mayo Clinic spanning 1988–2018 was performed to clarify their characteristics. 117 sporadic and 67 VHL HGBs were reviewed. 9 sporadic lesions (8 cases) and 80 VHL lesions (35 cases) had tumor size data at ≥4 follow-up time-points beyond 1 year. The median follow-up was 8.0 years. No statistical difference existed between sporadic and VHL lesions regarding growth speed or growth latency (period of time without growth). Symptomatic lesions showed faster growth than asymptomatic lesions (2.79 vs 0.59 cm3/month, p=0.005). Solid and cystic portions often showed different growth patterns in cases harboring both (66.7%). Cyst growth was faster than solid portions (1.22 vs 1.05cm3/month, p=0.009) and growth latency was longer in the latter (15.2 vs 18.5%, p=0.25). Lesions’ growth were classified as linear (7), exponential (49), cubic (regressed to cubic function curve, 7), saltatory (19) and no-growth (7) patterns. Growth latency often existed in growing lesions (27-out-of-64 linear/exponential/cubic lesions, 57.8%), being average 8.3% of follow-up time. Contrarily, although saltatory lesions grew slower than exponential lesions (p=0.03), their overall growth speed was comparable to linear/cubic lesions (0.67cm3/month), and 9-out-of-19 showed growth surges at their ends. Growth speed at each follow-up roughly depended on the tumor size in cubic regression (R2=0.52). However, whereas total 18/821 time-point lesions showed rapid growth (≥1cm3/m, 2.2%), relatively small lesions (≤2cm3) also occasionally showed rapid growth (5/687, 0.73%). Not all large (>5cm3) lesions grew rapidly (8/62, 12.9%). These results revealed while symptomatic/large/cystic lesions tend to grow more rapidly, HGB behavior is difficult to predict, which stresses the importance of careful follow-up.

Abstract BACKGROUND High-grade gliomas (HGGs) of the brainstem represent a rarer subtype of central nervous system tumors compared to their supratentorial counterpart. Predictors of survival and patterns of care have not yet been established on a national, multi-institutional scale. METHODS The National Cancer Database was queried for adult cases surgically diagnosed with brainstem high-grade glioma. An array of patient demographics, comorbidities, tumor characteristics and treatment parameters were captured. Predictors of survival were investigated using multivariable Cox proportional hazards regression analysis adjusting for age, insurance status, Charlson comorbidity score, tumor grade, tumor size and type of treatment. RESULTS A total of 422 patients (median 51 years, 60% males) were analyzed. Two hundred eighty one received postoperative radiation with chemotherapy (66.6%), thirty-nine had radiation alone (9.2%), while the remaining had no adjuvant treatment (24.2%). Median radiation dosage was 54Gy. Overall median survival was 9.8 months (95% CI 8.8–12). Survival was significantly longer (p< .001) in the chemotherapy+radiation group (median: 14.2 months, 95% CI 11.7–17.1) compared to radiation alone (median: 5.7 months, 95% CI 3.7–12) and no adjuvant treatment (median:1.8 months, 95% CI 1.4–4). In multivariable analysis, increasing age (HR 1.87, 95% CI 1.47–2.37, p< .001) was associated with worse survival, whereas radiation with chemotherapy (HR 0.67, 95% CI 0.46–0.98, p=0.038) were associated with lower hazards of death compared to radiation alone. In subgroup analysis, the effect of adjuvant chemotherapy with radiation remained significant for grade IV (HR 0.46, 95% CI 0.28–0.76, p=0.003), but not for grade III tumors (HR 0.87, 95% CI 0.48–1.58, p=0.65). CONCLUSION Findings of the present analysis demonstrate the effectiveness of radiation with chemotherapy for adult patients with high-grade brainstem gliomas, particularly grade IV. Further research should aim on identifying specific patient profiles and molecular subgroups that are more likely to benefit from multimodality therapy.

Abstract Glioblastoma (GBM) is a common deadly malignant brain cancer of the central nervous system (CNS), with a median survival of 12–15 months. Scientific advancements are lacking in developing effective therapies for both primary GBM, as well as secondary GBMs, that typically originate as malignant transformation of lower-grade isocitrate dehydrogenase (IDH) 1-mutant tumors. The unique metabolomic profile of IDH1-mutant tumors may present opportunities to develop biomarker signatures of therapeutic efficacy. Microdialysis is an extracellular fluid sampling collection technique utilizing a perfused semipermeable catheter to permit diffusion of molecules between brain interstitium and the perfusate. We hypothesized that microdialysis may identify a metabolomics-based biomarker response to therapy in IDH1-mutant tumors. To test this hypothesis, orthotopic xenografts were generated from two patient-derived GBM lines harboring mutations in IDH1. Perfusates were collected from intra-cranial tumors in aythmic nude mice sampled at baseline and 72h post treatment with temozolomide, an oral alkylating agent used to treat IDH1-mutant gliomas, compared with vehicle treatment, and TMZ-treated non-tumor bearing animals. Perfusates were analyzed via unsupervised metabolomic profiling using both gas and liquid chromatography-mass spectrometry (GC/LC-MS). Tumor specific metabolites such as carnitine and pyruvic acid were detected in microdialysate from tumor bearing mice compared to non-tumor bearing mice. Microdialysis is a feasible technology to identify metabolomics-based biomarker in IDH1-mutant PDX. This work is complemented by parallel analysis of non-IDH1-mutant and TMZ resistant xenografts to yield predictive in vivo tissue biomarkers of drug responsiveness translatable to clinical practice.

Abstract BACKGROUND Despite best current therapies, median survival for glioblastoma remains little more than a year. There remains an urgent need for improved treatment strategies. Current therapies, including radiation and temozolomide, are known to induce senescence in tumor cells. Advances in aging research have identified drugs with “senolytic” properties to kill senescent cells. This work tests the hypothesis that induction of senescence pathways following radiation can provide a window of opportunity to eliminate residual glioblastoma cells using drugs that block senescent cell-associated pathways (SCAPs). METHODS Human glioblastoma cells were radiated with 10, 15, or 20 Gy and maintained in culture for 3 to 4 weeks to facilitate maturation of a senescent phenotype. Given existence of multiple SCAPs, we evaluated the IC50 for several senolytic candidates including Dasatinib, Quercetin, Fisetin, AMG-232, Onalespib, A1331852, and Navitoclax in radiated vs non-radiated cells. RESULTS Among these, the Bcl-XL inhibitors A1331852 and Navitoclax both selectively killed multiple lines of radiated, senescent tumor cells at lower concentrations as compared to unirradiated, non-senescent tumor cells. Across multiple GBM cell line, the average IC50 for senescent cells was 12.88 nM (95%CI= 9.068–18.58 nM), as compared to the IC50 of non-senescent cells of 103.2 nM (95%CI= 74.24–143.9 nM; p< 0.005). Such differential sensitivity to Bcl-XL inhibition after radiation was not observed in the non-GBM control cells evaluated to date. CONCLUSION Our findings suggest that blocking the anti-apoptotic pathway Bcl-XL in GBM cells rendered at least transiently senescent following radiation may provide an avenue to selectively ablate residual glioblastoma cells following radiation. Our data provide proof of principle that senolytic therapy may represent a previously untapped window of opportunity to increase extent of tumor ablation following completion of standard cytotoxic therapies.

Abstract OBJECTIVE The K16ApoE peptide enhances delivery of multiple agents across the blood-brain barrier (BBB). Transgenic mouse models are central to elucidating the underlying pathophysiology of Alzheimer’s Disease (AD) and provide a system for evaluating novel therapeutic strategies. PET imaging plays a central clinical role in diagnosing human cases of AD but has had variable performance in mouse models. We investigated the role of K16ApoE to enhance delivery of a radiolabeled PET imaging tracer, 11C-PiB and assess whether this corresponds to improved PET sensitivity in APP/PS1 transgenic mice. METHODS Brain-delivery of 11C-PiB was accomplished by successive injections of K16ApoE and 11C-PiB. Distribution of 11C-PiB to the brain and heart was quantified via dynamic PET/CT imaging and digital autoradiography. RESULTS K16ApoE increased the brain uptake of 11C-PiB in both wild-type (WT) and APP/PS1 mice. Administration of K16ApoE increased the PET standard uptake value of 11C-PiB at 5 minutes in WT mice from 1.132 to 2.963 (p=0.006) and in APP/PS1 mice from 0.842 to 3.268 (p=0.016). Enhancement peaked at 5 minutes. Binding was reversible with similarly increased kinetics in both WT and APP/PS1 mice. The absolute values were higher in APP/PS1 mice suggesting increased retention. The increased retention in APP/PS1 mice was consistent with specific binding to A-beta plaques as unlabeled PiB reduced 11C-PiB signal retention. CONCLUSION K16ApoE mediates enhancement of 11C-PiB signal in APP/PS1 mice brains with increased PET sensitivity. There is increased uptake kinetics in both WT and APP/PS1 mice with specific A-beta plaque binding in the latter. This enhanced delivery of the PET tracer has implications for development and testing of new hypotheses and the efficacy of novel therapeutic paradigms. K16ApoE has potential for improving delivery of several agents across the BBB. This has implication for delivery of diagnostic and therapeutic agents for neurodegenerative and neuro-oncologic diseases.

Disease monitoring in nonalcoholic steatohepatitis (NASH) is limited by absence of noninvasive biomarkers of disease regression or progression. We aimed to examine the role of multiparametric three‐dimensional magnetic resonance elastography (3D‐MRE) and magnetic resonance imaging proton density fat fraction (MRI‐PDFF) in the detection of NASH regression after interventions. This is a single‐center prospective clinical trial of 40 patients who underwent bariatric surgery. Imaging and liver biopsies were obtained at baseline and 1 year after surgery. The imaging protocol consisted of multifrequency 3D‐MRE to determine the shear stiffness at 60 Hz and damping ratio at 40 Hz, and MRI‐PDFF to measure the fat fraction. A logistic regression model including these three parameters was previously found to correlate with NASH. We assessed the model performance in the detection of NASH resolution after surgery by comparing the image‐predicted change in NAFLD activity score (delta NAS) to the histologic changes. A total of 38 patients (median age 43, 87% female, 30 of 38 with NAS ≥ 1, and 13 of 38 with NASH) had complete data at 1 year. The NAS decreased in all subjects with NAS ≥ 1 at index biopsy, and NASH resolved in all 13. There was a strong correlation between the predicted delta NAS by imaging and the delta NAS by histology (r = 0.73, P < 0.001). The strength of correlation between histology and the predicted delta NAS using single conventional parameters, such as the fat fraction by MRI‐PDFF or shear stiffness at 60 Hz by MRE, was r = 0.69 (P < 0.001) and r = 0.43 (P = 0.009), respectively. Conclusion: Multiparametric 3D‐MRE and MRI‐PDFF can detect histologic changes of NASH resolution after bariatric surgery. Studies in a nonbariatric setting are needed to confirm the performance as a composite noninvasive biomarker for longitudinal NASH monitoring.