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Intestinal innate lymphoid cells (ILCs) contribute to the protective immunity and homeostasis of the gut, and the microbiota are critically involved in shaping ILC function. However, the role of the gut microbiota in regulating ILC development and maintenance still remains elusive. Here, we identified opposing effects on ILCs by two Helicobacter species, Helicobacter apodemus and Helicobacter typhlonius , isolated from immunocompromised mice. We demonstrated that the introduction of both Helicobacter species activated ILCs and induced gut inflammation; however, these Helicobacter species negatively regulated RORγt + group 3 ILCs (ILC3s), especially T-bet + ILC3s, and diminished their proliferative capacity. Thus, these findings underscore a previously unknown dichotomous regulation of ILC3s by Helicobacter species, and may serve as a model for further investigations to elucidate the host–microbe interactions that critically sustain the maintenance of intestinal ILC3s.

Abstract Background - The phenotype and biological role of monocytes in B-cell non-Hodgkin lymphoma (NHL) is not fully understood, however, an increased absolute monocyte count in the peripheral blood of lymphoma patients is associated with a poor prognosis. We have previously reported that monocytes from patients with relapsed B-cell NHL displayed an immunosuppressive CD14+HLA-DRlow/- phenotype that correlated with a poor prognosis. However, the underlying mechanism by which CD14+HLA-DRlow/- monocytes develop in patients with B-cell NHL is unknown. The goal of this study was to determine whether cytokines are responsible for the increased number and phenotype of CD14+HLA-DRlow/-monocytes present in lymphoma patients. Methods – Whole blood from patients with newly diagnosed, untreated B-cell NHL (n=20) and healthy donors (n=20) was stained with a panel of antibodies and analyzed by 10-color flow cytometry. Cytokine levels in serum and culture supernatants were measured by Luminex and ELISA, respectively. Polarization of monocytes from healthy donors was performed by incubating CD14+ cells with specific cytokines or supernatants from B-cell NHL cell lines for 24 hours. Activation and proliferation of CD4+T cells cocultured with IL-10-pretreated monocytes were measured by flow cytometry. Results – By flow cytometry, we observed that the absolute number of peripheral monocytes was increased in newly-diagnosed lymphoma patients compared to healthy donors. A significant proportion of these monocytes displayed an immunosuppressive CD14+HLA-DRlow/- phenotype and the numbers of CD14+HLA-DRlow/- cells were significantly higher in lymphoma patients than in healthy donors. To identify the underlying mechanism by which CD14+HLA-DRlow/- monocytes develop thereby leading to increased numbers of CD14+HLA-DRlow/- monocytes in B-cell NHL, we tested a panel of cytokines and found that IL-10 played a key role in the process. Firstly, treatment of monocytes with IL-10 in vitro resulted in the generation of CD14+HLA-DRlow/- cells. Second, monocytes co-cultured with IL-10 producing lymphoma B-cells, or treated with supernatants from lymphoma cell cultures, developed a CD14+HLA-DRlow/- phenotype. Thirdly, IL-10 levels were increased in the serum of DLBCL (p<0.0001) and FL patients (p=0.010) compared to healthy controls, and serum IL-10 levels correlated with increased numbers of peripheral monocytes (p=0.02). Finally, IL-10-pretreated CD14+HLA-DRlow/- monocytes were significantly immunosuppressive and inhibited the proliferation and activation of CD4+T cells in co-culture assays. Conclusions- Taken together, our results suggest that IL-10 signaling contributes to the increased numbers of CD14+HLA-DRlow/- monocytes in B-cell NHL. Strategies to inhibit IL-10 production may therefore have therapeutic potential in B-cell NHL. Disclosures No relevant conflicts of interest to declare.

Background: Multiple myeloma (MM) is common among the elderly, with 35% of patients (pts) diagnosed being aged ≥75 years (y). With increasing overall life expectancy, the incidence and prevalence of newly diagnosed and previously treated MM patients ≥80 y is expected to increase over time. Because elderly pts are often excluded from clinical trials, data focused on their treatment patterns and clinical outcomes are lacking. The Connect® MM Registry (NCT01081028) is a large, US, multicenter, prospective observational cohort study of pts with newly diagnosed MM (NDMM) designed to examine real-world diagnostic patterns, treatment patterns, clinical outcomes, and health-related quality of life patient-reported outcomes. This analysis reviews treatment patterns and outcomes in elderly pts from the Connect MM Registry. Methods: Pts enrolled in the Connect MM registry at 250 community, academic, and government sites were included in this analysis. Eligible pts were adults aged ≥18 y with symptomatic MM diagnosed ≤2 months before enrollment, as defined by International Myeloma Working Group criteria; no exclusion criteria were applied. For this analysis, pts were categorized into 4 age groups: <65, 65 to 74, 75 to 84, and ≥85 y. Pts were followed from time of enrollment to the earliest of disease progression (or death), loss to follow-up, or data cutoff date of February 7, 2019. Descriptive statistics were used for baseline characteristics and treatment regimens. Survival outcomes were analyzed using Cox regression. Time to progression (TTP) analysis excluded causes of death not related to MM. Results: Of 3011 pts enrolled (median age 67 y), 132 (4%) were aged ≥85 y, and 615 (20%) were aged 75-84 y at baseline. More pts aged ≥85 y had poor prognostic factors such as ISS stage III disease and reduced hemoglobin (<10 g/dL or >2 g/dL <LLN) compared with other age groups, although no notable differences between creatinine and calcium levels were observed across age groups (Table). A lower proportion of elderly pts (75-84 and ≥85 y) received triplet regimens as frontline therapy. More elderly pts received a single novel agent, whereas use of 2 novel agents was more common in younger pts (Table). The most common frontline regimens among elderly pts were bortezomib (V) + dexamethasone (D), followed by lenalidomide (R) + D, whereas those among younger pts included RVD, followed by VD and CyBorD (Table). No pt aged ≥85 y, and 4% of pts aged 75-84 y received high-dose chemotherapy and autologous stem cell transplant (vs 61% in the <65 y and 37% in the 65-74 y age group). The most common maintenance therapy was RD in pts ≥85 y (although the use was low) and R alone in other age groups (Table). In the ≥85 y group, 27%, 10%, and 4% of pts entered 2L, 3L, and 4L treatments respectively, vs 43%, 23%, and 13% in the <65 y group. Progression-free survival was significantly shorter in the ≥85 y age group vs the 75-84 y age group (P=0.003), 65-74 y age group (P<0.001), and <65 y age group (P<0.001; Fig.1). TTP was significantly shorter in the ≥85 y group vs the <65 y group (P=0.020); however, TTP was similar among the 65-74 y, 75-84 y, and ≥85 y cohorts (Fig. 2). Overall survival was significantly shorter in the ≥85 y group vs the 75-84 y, 65-74 y, and <65 y groups (all P<0.001; Fig. 3). The mortality rate was lowest (46%) during first-line treatment (1L) in pts aged ≥85 y (mainly attributed to MM progression) and increased in 2L and 3L (47% and 54%, respectively); a similar trend was observed in the younger age groups. The main cause of death was MM progression (29% in the ≥85 y vs 16% in the <65 y group). Other notable causes of death in the ≥85 y group included cardiac failure (5% vs 2% in <65 y group) and pneumonia (5% vs 1% in <65 y group). Conclusions: In this analysis, elderly pts received similar types of frontline and maintenance regimens as younger pts, although proportions varied with decreased use of triplet regimens with age. Considering similarities in TTP across the 65-74 y, 75-84 y, and ≥85 y cohorts, these real-world data support active treatment and aggressive supportive care of elderly symptomatic pts, including with novel agents. Additionally, further clinical studies specific to elderly patients with MM should be explored. Disclosures Lee: Amgen: Consultancy, Research Funding; GlaxoSmithKline plc: Research Funding; Sanofi: Consultancy; Daiichi Sankyo: Research Funding; Celgene: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Janssen: Consultancy, Research Funding. Ailawadhi:Janssen: Consultancy, Research Funding; Takeda: Consultancy; Pharmacyclics: Research Funding; Amgen: Consultancy, Research Funding; Celgene: Consultancy; Cellectar: Research Funding. Gasparetto:Celgene: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; Janssen: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; BMS: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed . Jagannath:AbbVie: Consultancy; Merck & Co.: Consultancy; Bristol-Myers Squibb: Consultancy; Karyopharm Therapeutics: Consultancy; Celgene Corporation: Consultancy; Janssen Pharmaceuticals: Consultancy. Rifkin:Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Durie:Amgen, Celgene, Johnson & Johnson, and Takeda: Consultancy. Narang:Celgene: Speakers Bureau. Terebelo:Celgene: Honoraria; Jannsen: Speakers Bureau; Newland Medical Asociates: Employment. Toomey:Celgene: Consultancy. Hardin:Celgene: Membership on an entity's Board of Directors or advisory committees. Wagner:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; American Cancer Society: Other: Section editor, Cancer journal. Omel:Celgene, Takeda, Janssen: Other: Patient Advisory Committees. Srinivasan:Celgene: Employment, Equity Ownership. Liu:TechData: Consultancy. Dhalla:Celgene: Employment. Agarwal:Celgene Corporation: Employment, Equity Ownership. Abonour:BMS: Consultancy; Celgene: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Janssen: Consultancy, Research Funding.

Background: MM clinical trials often have stringent eligibility criteria that limit the enrollment of patients (pts) reflective of the general patient population (Shah, Clin Lymphoma Myeloma Leuk 2017). The Connect® MM Registry, a prospective observational study of pts with newly diagnosed MM (NDMM) in the US, provided the opportunity to examine differences between pts with MM who were identified as RCT-eligible vs -ineligible, to observe the generalizability of clinical trial results to real-world clinical settings. Differences in baseline characteristics, treatment, clinical outcomes, and HRQoL were examined in RCT-eligible and -ineligible pts from this registry, which represents an unselected, broad real-world population. Methods: Pts with NDMM were enrolled at 250 community, academic, and government sites. Eligible pts were ≥18 y of age with symptomatic MM diagnosed ≤2 months preenrollment per the International Myeloma Working Group (IMWG) criteria. For this analysis, pts were considered ineligible for RCT per the following key exclusion criteria previously described: absolute neutrophil count ≤1.5 × 109/L, platelet count ≤75 × 109/L, creatinine >2.5 mg/dL, AST/ALT >3 times the ULN, peripheral neuropathy grade >2; ECOG PS 3/4; history of myelodysplastic syndromes/other hematologic malignancies, or solid tumors (Shah 2017). Sites administered pt HRQoL questionnaires and provided clinical data at baseline and quarterly during follow-up until death or study discontinuation. Differences in HRQoL at baseline, changes from baseline to 1 and 2 years, and survival outcomes, adjusted for covariates via propensity score, were compared between RCT-eligible/-ineligible pts. Results: Of the 3011 pts enrolled, 2873 pts met the CRAB (hyperCalcemia, Renal failure, Anemia, and Bone disease) criteria per IMWG at enrollment. Of these, 1622 (56.5%) were identified as RCT-eligible and 1251 (43.5%) as RCT-ineligible (data cut-off February 7, 2019). Both groups were similar in median age, sex, race, and ethnicity distribution, although the RCT-ineligible group had more pts aged ≥75 y (26.3% vs 23.2%) and more pts with ECOG PS 3/4 (6.2% vs none). Overall, 34.5% of RCT-ineligible pts received a transplant vs 42.8% of RCT-eligible pts. More RCT-ineligible pts had ISS stage III disease (39.4% vs 19.8%), elevated calcium (≥11.5 mg/dL; 12.7% vs 6.8%), elevated creatinine (>2.0 mg/dL; 40.3% vs 6.5%), and low hemoglobin (<10 g/dL or >2 g/dL <LLN; 60.8% vs 40.3%). Use of triplet treatment (54.2% vs 56.2%) and alkylator (24.9% vs 20.1%) was similar between the RCT-ineligible/-eligible groups. Lenalidomide + bortezomib + dexamethasone (RVd) was the most common initial therapy, and R was the most common maintenance therapy in both groups, but fewer RCT-ineligible pts received RVd as initial therapy (23.9% vs 31.0%) and R as first maintenance regimen (18.1% vs 22.7%). Absolute baseline HRQoL scores were significantly higher, indicating better HRQoL, in RCT-eligible (115.9) vs -ineligible (111.5) pts on the Functional Assessment of Cancer Therapy-Multiple Myeloma (FACT-MM) Total score (P=0.007), FACT-MM Trial Outcome Index (74.3 vs 70.3, P=0.002), and FACT-MM Subscale (37.3 vs 35.5, P=0.003). Scores were similar for EuroQol-5D Overall Index (0.73 vs 0.72, P=0.5) and Brief Pain Inventory (3.42 vs 3.43, P=0.9). Both RCT-eligible and -ineligible pts showed significant improvement in HRQoL from baseline at years 1 and 2, although the magnitude of improvement was similar between both groups (Fig. 1a and b). RCT-ineligible pts showed significantly shorter median PFS and OS vs RCT-eligible pts (Fig. 2 & 3, respectively). Conclusions: The CONNECT MM registry provided the opportunity to examine key differences between RCT-eligible and -ineligible pts. By applying common RCT eligibility criteria, a substantial proportion of MM pts (43.5%) in this real-world population may have been ineligible to participate in a RCT. RCT-ineligible pts had advanced disease, poor performance status, and poor laboratory parameters at baseline vs RCT-eligible pts, which could affect PFS and OS. These findings enhance our understanding of HRQoL among MM pts, which at present, is largely based on RCT participants. A similar magnitude of HRQoL improvement in both groups at 1 and 2 years suggests the need to evaluate RCT eligibility criteria in MM to help broaden enrollment and maximize external validity. Disclosures Wagner: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; American Cancer Society: Other: Section editor, Cancer journal. Toomey:Celgene: Consultancy. Ailawadhi:Takeda: Consultancy; Amgen: Consultancy, Research Funding; Celgene: Consultancy; Cellectar: Research Funding; Janssen: Consultancy, Research Funding; Pharmacyclics: Research Funding. Jagannath:Merck & Co.: Consultancy; Bristol-Myers Squibb: Consultancy; AbbVie: Consultancy; Celgene Corporation: Consultancy; Janssen Pharmaceuticals: Consultancy; Karyopharm Therapeutics: Consultancy. Gasparetto:Janssen: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; BMS: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; Celgene: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed . Durie:Amgen, Celgene, Johnson & Johnson, and Takeda: Consultancy. Narang:Celgene: Speakers Bureau. Rifkin:Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Terebelo:Celgene: Honoraria; Jannsen: Speakers Bureau; Newland Medical Asociates: Employment. Omel:Celgene, Takeda, Janssen: Other: Patient Advisory Committees. Hardin:Celgene: Membership on an entity's Board of Directors or advisory committees. Lee:Janssen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Daiichi Sankyo: Research Funding; Celgene: Consultancy, Research Funding; Sanofi: Consultancy; GlaxoSmithKline plc: Research Funding; Amgen: Consultancy, Research Funding. Srinivasan:Celgene: Employment, Equity Ownership. Liu:TechData: Consultancy. Dhalla:Celgene: Employment. Catamero:Celgene: Employment, Equity Ownership. Abonour:BMS: Consultancy; Takeda: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding.

Background: Despite treatment advances, multiple myeloma (MM) remains a condition with high unmet medical need as patients (pts) relapse and become resistant to therapy. MM pts experience a range of serious disease-related symptoms and side effects impacting their functioning and health-related quality of life (HRQL). The median overall survival (OS) has improved with the advent of new treatments in the last two decades, however, the impact of newer combination treatments on pt quality of life remains unknown (Beckner, N et al. Cancer Res. 2011;183:25; Bharat, N et al. J Clin Oncol 2019;37:15(suppl):8039). Venetoclax is a novel, orally bioavailable small molecule inhibitor of BCL-2 activity in MM. In the Phase 3 double-blind, randomized clinical trial (M14-031, BELLINI) progression free survival (PFS) was studied in relapsed/refractory (RR) MM pts receiving venetoclax or placebo in combination with bortezomib and dexamethasone. In addition, patient-reported outcomes (PRO) data focused on physical functioning, pain, and fatigue from BELLINI were evaluated to better understand the overall impact on pt HRQL of adding venetoclax to bortezomib and dexamethasone-based doublet therapy. Methods: The BELLINI Phase 3 study (NCT01794520) enrolled patients ≥18 y old with R/R MM who had received 1-3 prior lines of therapy. The study met its primary endpoint of PFS (HR 0.63, 95% CI=0.44-0.89) but higher risk of death (HR 2.027, 95% CI=1.04-3.95) was observed in the treatment arm compared with placebo, although the OS data are not yet mature (Kumar, S et al. EHA Library. Jun 16 2019;273254:LB2601). The secondary HRQL endpoints included in this study were pain severity, fatigue, physical functioning (PF), and global health status, which were measured using the Brief Pain Inventory-Short Form (BPI-SF), PROMIS Fatigue Short Form surveys, and the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). Change from baseline to day 1 of each cycle visit (up to 25 cycles or last treatment visit) was assessed for each measure in both the treatment and placebo groups. Summary analyses compared mean and median scores between arms at each cycle. The treatment effect was evaluated in a mixed effect model controlling for the patient's baseline score, total visits (or cycles of treatment), age (<65 or ≥65), prior therapy lines, and prior proteasome inhibitor exposure. The model also included an interaction term examining treatment by visits. Results: The intention-to-treat (ITT) dataset included 194 pts (median age: 66y; 53% with 2 or 3 prior lines of therapy) in the treatment group and 97 pts (median age: 65y; 55% with 2 or 3 prior lines of therapy) in the placebo group (2:1 randomization). There was no clear evidence for an independent effect of treatment on PF (P=0.522). Pain scores across multiple measures showed a similar trend, with a statistically non-significant improvement of unadjusted average "Worst Pain" scores for the venetoclax group (P=0.289; Figure B). Non-inferiority in pain results were replicated by the pain subscale of the QLQ-30 (P=0.778), the BPI pain severity index (P=0.418), and the related BPI pain interference subscale score (P=0.603). Fatigue scores likewise demonstrated no significant differences between treatment arms whether using PROMIS Cancer Fatigue t-scores (P=0.442), raw scores (P=0.568), or the 3-item QLQ-C30 subscale (P=0.959), although there was a positive trend across cycle summary scores for the treatment group compared with the placebo group. Unadjusted QLQ-C30 PF subscale scores showed declines from baseline that were generally worse in the placebo group across 25 treatment cycles, although differences were smaller and non-significant in the adjusted model (Figure A). Conclusions: Comparable HRQL in pain severity, fatigue, and PF was observed in RRMM pts receiving venetoclax in combination with bortezomib and dexamethasone compared to pts receiving bortezomib and dexamethasone. The summary scores showed outcomes that were comparable or slightly improved for those randomized to the venetoclax combination. Results of concurrent measures of the same or associated concepts reinforced confidence in these results. Additional analyses of subgroups are ongoing (eg, t(11;14), BCL-2 expression status) and may provide further insights surrounding HRQL in these populations. Figure Disclosures Gasparetto: BMS: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; Celgene: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; Janssen: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed . Popat:Takeda: Honoraria, Other: travel, accommodations, expenses; GSK: Consultancy, Honoraria; Celgene Corporation: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel, accommodations, expenses; Janssen: Honoraria, Other: travel support to meetings; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees. Kumar:Celgene: Consultancy, Research Funding; Takeda: Research Funding; Janssen: Consultancy, Research Funding. Cavo:celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; AbbVie: Consultancy, 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, Speakers Bureau; amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; novartis: Honoraria; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. de la Rubia:Janssen: Consultancy; AbbVie: Consultancy; Celgene: Consultancy; Amgen: Consultancy; Takeda: Consultancy. Hungria:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Salwender:Sanofi: Honoraria, Other: Travel or accommodations; Amgen: Honoraria, Other: Travel or accommodations; Janssen Cilag: Honoraria, Other: Travel or accommodations; AbbVie: Honoraria; Bristol-Myers Squibb: Honoraria, Other: Travel or accommodations; Celgene: Honoraria, Other: Travel or accommodations; Takeda: Honoraria, Other: Travel or accommodations. Suzuki:Ono: Research Funding; BMS: Honoraria, Research Funding; Takeda: Honoraria; Janssen: Honoraria; Celgene: Honoraria. Maciel:Amgen: Other: funding for travel, teaching, participation in advisory boards; Janssen: Other: funding for travel, teaching, participation in advisory boards. Moreau:Takeda: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Harrison:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: investigator on studies, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Jia:AbbVie: Employment, Other: Stock/stock options. Karve:AbbVie: Employment, Other: stock/stock options. Ma:Genentech: Employment, Other: stock options; AbbVie: Other: Alliance Partner. Devine:Genentech: Employment, Other: stock options; AbbVie: Other: Alliance Partner. Benjamin:AbbVie: Employment, Other: stock/stock options.

Abstract Diffuse midline gliomas harboring the H3K27M mutation, previously known as diffuse intrinsic pontine gliomas (DIPG), are rare and aggressive pediatric brain tumors without cure. One of the major challenge sin DIPG treatment is the effective delivery of therapeutic agents across the blood-brain barrier (BBB) to the tumor and surrounding infiltrating cells. Therefore, strategies that enhance drug delivery to the brain are of great interest. Convection-enhanced delivery (CED) is a technique that bypasses the BBB and increases drug distribution by applying hydraulic pressure to deliver compounds directly and evenly into a target region. However, knowledge in CED pharmacology and convective kinetics is still lacking. In an effort to characterize the feasibility, safety, and distribution in the brain based on molecular size of the delivered agent, we performed infusions of FITC-dextran (range 3,000 Da–150,000 Da) comparing CED and osmotic pump-based delivery into the brainstem of rodents. We calculated the area and volume of distribution (Vd) of the FITC-dextran throughout the brain. Our data showed that the Vd decreased exponentially with increased molecular weight of the FITC-dextran. Interestingly, the Vdcan maintain linearity at lower molecular weights. Maximal cross-sectional area and craniocaudal extension of fluorescence also decreased when lowering the infusate size. In addition, we developed a patient-derived DIPG orthotopic xenograft model and performed an image-guided CED cannula installation in the tumor bed. Using 3D bioluminescence imaging and computed tomography, we determined the tumor volume and the positioning of the cannula in the bulk tumor. The summation of these results supports CED as a promising technique for treating DIPG tumors. A better understanding of how drugs distribute by convection will allow us to optimize treatment regimens and, ultimately, offers hope to patients and families with this devastating disease.

Abstract BACKGROUND Diffuse midline gliomas harboring the H3K27M mutation, previously known as diffuse intrinsic pontine gliomas (DIPG), are rare and aggressive pediatric brain tumors. Over 100 clinical trials with different chemotherapeutics have failed to show any therapeutic benefit. One reason for failure is likely due to poor delivery of these agents to the brainstem. Convection-enhanced delivery (CED) is an emerging delivery technique used to directly inject the agent of interest into the brainstem under pressure. While there is evidence that this may be an effective delivery method, little work has been done to understand the optimal physical properties of these drugs. We sought characterize volume of distribution in the brain based on molecular size of the agent delivered via CED. METHODS Sprague- Dawley rats underwent a single injection of FITC-dextran (3,000 Da, 10,000 Da, 20,000 Da, 70,000 Da, 150,000 Da) via CED into the pons. Post-injection, animals were sacrificed and their brains harvested. Fluorescent microscopy imaging was used to calculate the volume of distribution of the FITC-dextran throughout the brain. RESULTS The volume of distribution (Vd) decreased exponentially according to a two-phase delay (r2= 0.94) as the molecular size of the FITC-dextran increased. The highest mean Vd (107.87mm3) was at a molecular weight of 3,000 Da, and lowest mean Vd (26.48 mm3) was at a molecular weight of 150,000 Da. ANOVA analysis was statistically significant (p= 0.0017). CONCLUSIONS As the molecular size of the FITC-dextran increased, the volume of distribution within the brain following a single injection via CED into the pons decreased. A better understanding of how drugs distribute by convection will allow us to optimize treatment regimens for DIPG tumors.

Abstract BACKGROUND Diffuse intrinsic pontine gliomas (DIPG), known today as diffuse midline gliomas with the H3K27M mutation, are inoperable and aggressive brain tumors found predominantly in children. Despite extensive research no treatment or cure has been elucidated. Studies in 2012 showed that the majority of DIPG tumors have the H3K27M mutation, but the development of novel therapeutics has been hindered by lack of good laboratory models. Although patient derived cell lines with the H3K27M mutation have increased, the development of good murine xenografts are lagging, requiring extensive time and money. Previous studies have shown that the chicken embryo Chorioallantoic Membrane (CAM) model is an affordable and time-efficient method of studying tumor biology and response to treatment. We sought to develop this in H3K27M tumors to bridge the gap between in vitro—in vivo studies. METHODS Three patient-derived H3K27M cell lines were cultured and implanted on the chick embryo CAM on day 9 post-fertilization. Tumors underwent multiple drug treatment with 0.5uM or 2.0uM Alisertib (days 11, 13, 15) or a single targeted radiation treatment at 2 Grey (day 13). Tumor volume was assessed via ultrasound on day 16. The tumor specimens were harvested and analyzed by immunohistochemistry. RESULTS Patient-derived DIPG cells implanted on the CAM maintain their molecular characteristics and form tumors on the surface of the CAM as evidenced by H&E and H3K27M status. Statistically significant differences in volume were found in three H3K27M DIPG lines in Alisertib treated tumors compared to the control (p< 0.001, p< 0.001, p= 0.005). Statistically significant differences in tumor volume were found when treating two DIPG lines with targeted radiation therapy compared to controls (p= 0.01, p= 0.02). CONCLUSIONS These results validated the CAM assay as a reliable xenograft model for studying DIPG tumor biology and determining efficacy of drug and radiation treatment.

Diffuse intrinsic pontine glioma (DIPG), otherwise known as diffuse midline glioma with H3K27M mutation, is a devastating brainstem glioma without a cure. Efforts are currently underway to better optimize molecular diagnoses through biological sampling, which today remains largely limited to surgical biopsy sampling. Surgical intervention is not without its risks, and therefore a preference remains for a less invasive modality that can provide biological information about the tumor. There is emerging evidence to suggest that a liquid biopsy, targeting biofluids such as CSF and blood plasma, presents an attractive alternative for brain tumors in general. In this update, the authors provide a summary of the progress made to date regarding the use of liquid biopsy to diagnose and monitor DIPG, and they also propose future development and applications of this technique moving forward, given its unique histone biology.