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Checkpoint inhibitor (CPI) therapy with anti-PD-1 antibodies has been associated with mixed outcomes in small cohorts of aggressive B-cell lymphoma patients following CAR T-cell therapy failure. To more definitively define CPI therapy efficacy in this population, we retrospectively evaluated clinical outcomes in a large cohort of 96 patients with aggressive B-cell lymphomas receiving CPI therapy after CAR-T failure across 15 U.S. academic centers. Most patients (53%) had DLBCL, were treated with axicabtagene ciloleucel (53%), relapsed early (≤180 days) after CAR-T (83%), and received pembrolizumab (49%) or nivolumab (43%). CPI therapy was associated with an overall response rate of 19% and a complete response rate of 10%. Median duration of response was 221 days. Median progression-free survival (PFS) and overall survival (OS) were 54 and 159 days, respectively. Outcomes to CPI therapy were significantly improved in patients with primary mediastinal B-cell lymphoma. PFS (128 versus 51 days) and OS (387 versus 131 days) were significantly longer in patients with late (>180 days) versus early (≤180 days) relapse after CAR-T. Grade ≥3 adverse events occurred in 19% of CPI-treated patients. Most patients (83%) died, commonly due to progressive disease. Only 5% had durable responses to CPI therapy. In the largest cohort of aggressive B-cell lymphoma patients treated with CPI therapy after CAR-T relapse, our results reveal poor outcomes, particularly among those relapsing early after CAR-T. In conclusion, CPI therapy is not an effective salvage strategy for most patients after CAR-T, where alternative approaches are needed to improve post-CAR-T outcomes.

New treatments are needed to address persistent unmet clinical needs for diffuse large B-cell lymphoma (DLBCL). Overexpression of transferrin receptor 1 (TFR1) is common across cancer and permits cell-surface targeting of specific therapies in preclinical and clinical studies of various solid tumors. Here, we developed novel nanocarrier delivery of chemotherapy via TFR1-mediated endocytosis, assessing this target for the first time in DLBCL. Analysis of published datasets showed novel association of increased TFR1 expression with high-risk DLBCL cases. Carbon–nitride dots (CND) are emerging nanoparticles with excellent in vivo stability and distribution and are adaptable to covalent conjugation with multiple substrates. In vitro, linking doxorubicin (Dox) and transferrin (TF) to CND (CND–Dox–TF, CDT) was 10–100 times more potent than Dox against DLBCL cell lines. Gain- and loss-of-function studies and fluorescent confocal microscopy confirmed dependence of these effects on TFR1-mediated endocytosis. In contrast with previous therapeutics directly linking Dox and TF, cytotoxicity of CDT resulted from nuclear entry by Dox, promoting double-stranded DNA breaks and apoptosis. CDT proved safe to administer in vivo, and when incorporated into standard frontline chemoimmunotherapy in place of Dox, it improved overall survival by controlling patient-derived xenograft tumors with greatly reduced host toxicities. Nanocarrier-mediated Dox delivery to cell-surface TFR1, therefore, warrants optimization as a potential new therapeutic option in DLBCL.Significance:Targeted nanoparticle delivery of doxorubicin chemotherapy via the TRF1 receptor presents a new opportunity against high-risk DLBCL tumors using potency and precision.

Supplemental Figures 1-9. Figure S1. Carbon-Nitride Dot Synthesis. Figure S2. Characterization of CND-Dox-TF. Figure S3. CND cytotoxicity. Figure S4. Cell surface TFR1 expression and receptor recycling. Figure S5. Rapid nuclear entry by Dox after CND-Dox-TF treatment in DLBCL. Figure S6. HEK293 is a model cell line for elucidating CND-Dox-TF mechanism. Figure S7. CND-Dox-TF working dose identified. Figure S8. CND-Dox-TF has improved toxicity profile compared to Dox. Figure S9. R-nanoCHOP treatment has favorable toxicity profile in non-malignant organs.

Chemotherapy remains the most widely used cancer treatment modality. Nanotechnology provides exciting opportunities to improve these drugs, transforming decades-old generic treatments into precise new medicines. We illustrate the potential of recent advances in nanotechnology-enhanced therapy focusing on diffuse large B-cell lymphoma (DLBCL); the most common hematologic malignancy.

New treatments are needed to address persistent unmet clinical needs for diffuse large B-cell lymphoma (DLBCL). Overexpression of transferrin receptor 1 (TFR1) is common across cancer and permits cell-surface targeting of specific therapies in preclinical and clinical studies of various solid tumors. Here, we developed novel nanocarrier delivery of chemotherapy via TFR1-mediated endocytosis, assessing this target for the first time in DLBCL. Analysis of published datasets showed novel association of increased TFR1 expression with high-risk DLBCL cases. Carbon–nitride dots (CND) are emerging nanoparticles with excellent in vivo stability and distribution and are adaptable to covalent conjugation with multiple substrates. In vitro, linking doxorubicin (Dox) and transferrin (TF) to CND (CND–Dox–TF, CDT) was 10–100 times more potent than Dox against DLBCL cell lines. Gain- and loss-of-function studies and fluorescent confocal microscopy confirmed dependence of these effects on TFR1-mediated endocytosis. In contrast with previous therapeutics directly linking Dox and TF, cytotoxicity of CDT resulted from nuclear entry by Dox, promoting double-stranded DNA breaks and apoptosis. CDT proved safe to administer in vivo, and when incorporated into standard frontline chemoimmunotherapy in place of Dox, it improved overall survival by controlling patient-derived xenograft tumors with greatly reduced host toxicities. Nanocarrier-mediated Dox delivery to cell-surface TFR1, therefore, warrants optimization as a potential new therapeutic option in DLBCL. Significance: Targeted nanoparticle delivery of doxorubicin chemotherapy via the TRF1 receptor presents a new opportunity against high-risk DLBCL tumors using potency and precision.

Colon extranodal marginal zone lymphoma (EMZL) is poorly characterized in the literature. We performed a retrospective review of patients with colon EMZL at our institution and from the Surveillance Epidemiology and End Results (SEER) database. Eight patients were identified in our institution with majority (88%) presenting with stage-I disease. Initial management included active surveillance, polypectomy followed by surveillance, and surgical resection followed by chemotherapy. One patient with concurrent prostate carcinoma received radiation to the rectum. Initial therapy led to complete remission in five out of six treated patients with four of them maintaining remission at 88 months. SEER database identified 361 patients with stage-I colon EMZL. Overall survival for this cohort was 73.9% at 10 years with no significant difference in outcomes between treatment groups. Our single institution experience and the SEER data analysis emphasize indolent nature of colon EMZL and need for non-aggressive therapeutic approaches.

Breast extranodal marginal zone lymphoma (EMZL) is a rare malignancy. We performed the largest published to date single-center retrospective analysis of 13 patients with breast EMZL focusing on clinical characteristics and treatment-related outcomes. The rarity of this disease at our center was concordant with the prevalence reported in the literature, with breast EMZL comprising 2% of 654 MZL cases. Most patients presented with stage I-II disease however four (30.8%) patients had stage IV disease mostly due to occult bone marrow (BM) involvement. Interestingly, EMZL was frequently non-FDG avid (66.7%) on staging PET/CT. With a median follow-up of 3.1 years (range 5 months to 10.2 years), the 3-year progression free survival was 68.7% (95%CI 30.2%-88.9%) and overall survival 80.2% (95%CI 40.3%-94.8%). No patient experienced higher-grade transformation. Herein we show that localized breast EMZL can be effectively treated with radiation therapy providing long term disease control.

Effector lymphocytes are multifunctional cells of the immune system that promote cytolysis of pathogen-infected cells and nascent tumors. Tumors must learn to evade effectors and employ a wide variety of mechanisms to do so. Bispecific Abs (BsAbs) are an emerging cancer immunotherapy approach seeking to re-engage either T effectors or NK cells with malignant cells. Possessing specificity for effector cells on one end and a tumor Ag on the other, these molecules work by attracting effectors to the target cell to build an immunologic synapse and induce tumor cell killing. The BsAb blinatumomab, for example, has specificity for the T cell–activating cell surface protein CD3 and the B cell Ag CD19. The only BsAb with regulatory approval currently, blinatumomab is used in the treatment of relapsed or refractory B cell acute lymphoblastic leukemia. Many additional BsAbs are in preclinical development, however, targeting many different tumor types. The variety of potential effector cells and cancer Ags, along with potential combination therapies, make BsAbs an active area of drug development. In this review, we discuss cancer recognition by the immune system and structural and mechanistic aspects of BsAbs. We summarize key steps in preclinical development and subsequent translation to medical practice. Future directions for BsAbs include combinations with a wide variety of both immunologic and nonimmunologic therapies. Defining their optimum clinical use is at early stages.

Background: Alterations in the RAS pathway have been linked to tumorigenesis, apoptosis, metabolism and angiogenesis. Mutations of KRAS in NSCLC are more frequent and better characterized, however, other family members such as HRAS remain under investigated and RAS remains a challenging therapeutic target. HRAS has been indirectly targeted with tipifarnib, a farnesyltransferase inhibitor rendering HRAS inactive in head and neck tumors. Here, we characterize the incidence, genomic landscape, and clinical context of HRAS alterations in NSCLC. Methods: A total of 29,767 NSCLC tumor samples underwent comprehensive molecular profiling at Caris Life Sciences. Analyses included next generation sequencing of DNA (592 Gene Panel, NextSeq, or whole exome sequencing, NovaSeq), RNA (NovaSeq, whole transcriptome sequencing, WTS) and immunohistochemistry. MAPK activation was assessed using the MPAS gene expression signature. Wilcoxon, Fisher’s exact, or Dunnett’s tests were used to determined statistical significance (displayed as p value without and q value with multi-comparison correction). Overall survival was calculated from date of tissue collection to last contact from insurance claims data and used for Kaplan-Meier analysis. Comparisons were conducted between HRAS mutated tumors and the entire NSCLC general cohort (GC). Results: HRAS mutations (Hm) were detected in 128 of 29767 NSCLC samples (0.4%) and were significantly enriched in older patients (median age, 71 vs. 69 years; q Conclusions: HRAS mutations are detectable but uncommon events in NSCLC and significantly enriched in squamous histology. HRAS mutations often occur with PIK3CA co-mutations and trended towards higher activation of MAPK pathway and MSI-H frequency. This warrants further investigation on possible clinical applications of HRAS pathway inhibitors and utility of immune checkpoint inhibitors for this subset of NSCLC. Citation Format: Asaad Trabolsi, Estelamari Rodriguez, Samuel Alexander Kareff, Michael Korn, Joanne Xiu, Stephen Liu, Philip walker, Patrick Ma, Hirva Mamdani, Jorge Nieva, Hossein Borghaei, Chadi Nabhan, Misako Nagasaka, Sonam puri, Gilberto Lopes. Molecular characteristics of HRAS mutated non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 48.

561 Background: The RAS pathway regulates tumorigenesis and cell proliferation. HRAS is a RAS family member that activates via farnesylation. Indirectly targeting mutant HRAS with tipifarnib, a farnesyltransferase inhibitor (FTI), recently demonstrated efficacy in head and neck tumors. We aimed to investigate the molecular characteristics and clinical outcomes of HRAS mutations (HRASmut) for any potential role as a prognostic and therapeutic biomarker in breast cancer (BC). Methods: A total of 14,013 BC tissue samples had molecular profiling, including next generation DNA (592 Gene Panel, NextSeq, or WES, NovaSeq) or RNA sequencing (NovaSeq, WTS), and immunohistochemistry analyses, at Caris Life Sciences. MAP kinase (MAPK) activation and likelihood of a tumor’s response to anti-PD1 therapy were evaluated via MAPK Pathway Activity Score (MAPS) and interferon (IFN) score, respectively. Wilcoxon, Fisher’s exact, or Dunnett’s tests were used to determine statistical significance. Overall survival (OS) was calculated from date of tissue collection to insurance claims last contact using the Kaplan-Meier method. HRAS mutations (HRASmut) were compared to the general BC cohort (GC). Results: HRASmut were significantly enriched in older patients (median 69 vs 60 yrs; q

3120 Background: The cell-surface transferrin receptor TFR1 imports iron-bound transferrin into cells via clathrin-mediated endocytosis. Tumors require constitutive iron import to drive proliferation, and several studies establish TFR1 as a target able to facilitate intracellular delivery of cytotoxic therapeutic molecules. Our own work previously revealed association between high expression of TFRC, the gene encoding TFR1, and high risk for poor outcome in diffuse large B-cell lymphoma (DLBCL). We showed therapetuic targeting of TFR1 in DLBCL results in significant anti-tumor benefit. Systematic analysis of TFRC expression as a prognostic marker across tumor types, however, has not been investigated. Methods: Tissue samples underwent comprehensive molecular profiling at Caris Life Sciences. Analyses included next generation sequencing of DNA (592 Gene Panel, NextSeq, or whole exome sequencing, NovaSeq), RNA (NovaSeq, whole transcriptome sequencing, WTS) and immunohistochemistry. Overall survival (OS) was calculated from date of tissue collection to last contact from insurance claims data and employed Kaplan-Meier analysis by Wilcoxon statistics, with p < 0.05 defined as significant. Results: Amongst 47 cancer types included, colorectal cancer (CRC) displayed the highest level of TFRC mRNA, followed by gastric cancer. In an all-tumor cohort (n = 93248), patients with higher TFRC expression (cutoff = median) had significantly worse OS (HR = 1.348, 95% CI [1.317-1.38], p < 0.00001). This was statistically significant in 23 individual tumor types. Drilling down further, TFRC adverse prognostic value was mainly driven by cohorts with larger number of samples in the database, including non-small cell lung cancer (n = 17309), CRC (n = 12860), breast cancer (n = 8632), ovarian carcinoma (n = 7998), uterine neoplasms (n = 6097), prostate adenocarcinoma (n = 3411), glioblastoma (n = 2821), gastric cancer (n = 1579), and others. Surprisingly, TFRC overexpression correlated with improved outcome in vulvar squamous cell carcinoma (VSCC, n = 297). TFRC was found to be most prognostic in prostate adenocarcinoma with median OS 1139 days in pts with high vs 3230 days in pts with low TFRC (HR = 2.556, 95% CI [2.213-2.951], p < 0.00001). Conclusions: Our study is the first to combine modern molecular profiling with a large cohort of clinical tissue samples to reveal a prognostic role for TFRC expression in a variety of solid tumor types. We found TFRC overexpression to be prognostic in a large proportion of histologies, though surprisingly association with improved OS in VSCC. Highest expression occured in CRC and gastric cancer, diseases with needs for new therapies. A number of TFR1-targeting therapeutics are currently at various stages of development, and warrant further investigation in disease cohorts identified from our study.

Diffuse large B-cell lymphoma (DLBCL) comprises a third of non-Hodgkin lymphoma (NHL), with incidence steadily rising in what is already the most common hematologic malignancy. The backbone of potentially curative frontline chemoimmunotherapy combinations like R-CHOP is doxorubicin (Dox), still considered the most active anti-lymphoma agent. Relapsed or refractory (rel/ref) disease after frontline treatment carries persistently poor prognosis, even with recent advances in immunotherapy. Development and implementation of new therapeutic strategies remain urgent priorities to address unmet clinical needs in both high-risk previously untreated and rel/ref patients. We have studied transferrin receptor (TFR1) expression as a marker of high-risk DLBCL revealing significantly worse outcomes following frontline therapy associated with high expression in diagnostic samples. TFR1 is therefore a rational target for treatments aimed specifically at high-risk DLBCL. We used third-generation carbon-nitride dot (CND) nanocarriers we have developed conjugated to Dox and holo-transferrin (TF) to develop a chemotherapeutic-nanocarrier (NanoDox) designed to deliver Dox to TFR1-expressing tumors while sparing non-malignant tissues. Dox's mechanism is primarily through nuclear DNA damage or induction of reactive oxygen species (ROS) H202. We treated DLBCL cell lines with NanoDox or Dox for 24-hours and observed induction of nuclear DNA damage marker γ-H2Ax at drastically lower doses (10 nM NanoDox vs. 100 nM Dox). Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay results yielded similar findings in BJAB cells, as observed under γ-H2Ax analysis, with TUNEL induction at significantly lower NanoDox concentrations. Treatment with NanoDox did not generate significant changes in ROS H202 when compared to Dox at 24-hours. Dox is known for a strong cytotoxic profile that extends past its terminal half-life of 24-36 hours. Therefore, we treated BJAB, Farage and DHL4 cells for 24-hours with a range of NanoDox and Dox doses, followed by washout and tracked cell viability for 6 additional days. We found as low as 10 nM NanoDox induced rapid and irreversible cytotoxicity, an effect only seen at much higher doses of Dox. These results combined with fluorescent confocal microscopy studies confirmed NanoDox works primarily through rapid nuclear Dox accumulation, causing DNA damage and apoptosis. Building on initial NanoDox dosing studies in NOD Scid Gamma (NSG) mice, we constructed R-nanoCHOP as an alternate to R-CHOP by replacing Dox with NanoDox at a working dose (WD) of 33.0 mg/kg. We next engrafted patient-derived xenograft (PDX) tumors derived from a previously untreated patient with germinal center B-cell (GCB) subtype DLBCL. We randomized NSG animals to two groups at tumor engraftment and treated with 21-day cycles of R-nanoCHOP (n=10) or R-CHOP (n=11). The treatments controlled tumor volume (TV) similarly, but R-nanoCHOP significantly improved overall survival associated with greatly reduced toxicities to host animals, which tolerated an average of 2 additional cycles of R-nanoCHOP. Studies with murine cells in vitro, including A20 B-cell lymphoma cells, confirmed these effects were not due to species differences, with human holo-TF alone and as part of NanoDox binding mouse and human TFR1 with equal affinity. This work establishes proof of principle in DLBCL for targeting TFR1, a specific marker of clinically high-risk disease. CND nanocarriers provide a flexible platform to exploit this, with our initial studies enhancing the safety profile of Dox, which remains the most active frontline DLBCL agent more than 50 years after it entered use. We are now optimizing NanoDox by substituting the holo-TF with an anti-TFR1 single chain variable fragment (scFv), decreasing size of the overall nanoconjugate by >50%. We believe dosing optimization from this change and additional optimizations to Dox delivery intracellularly will permit investigational new drug (IND) studies of absorption, distribution, metabolism and excretion (ADME). In sum, we provide compelling clinically relevant evidence for targeting TFR1 in DLBCL as a new therapeutic approach. Disclosures No relevant conflicts of interest to declare.

Diffuse large B-cell lymphoma (DLBCL), the most common hematologic malignancy, is an aggressive form of non-Hodgkin lymphoma. Approximately 60% of DLBCL patients achieve long-term disease-free survival from frontline R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone), but patients with relapsed or refractory disease have poor prognosis. Doxorubicin (Dox) remains the most active anti-lymphoma agent, but its use is limited by well-characterized toxicities, including potentially irreversible cardiac damage. Targeted and specific delivery of Dox to tumors to overcome these limitations has been an area of active research. Targeted delivery of Dox via the transferrin receptor (TFR1) has preclinical efficacy in solid malignancies but has yet to be explored in lymphoma. We have uncovered for the first time a significant association between TFR1 expression and poor prognosis in DLBCL. Carbon-nitride dots (CNDs) are third-generation nanocarriers with inherent photoluminescence, which are easily conjugated with a wide variety of substrates. We conjugated Dox and transferrin (TF), the ligand for TFR1, to CNDs to develop CND-Dox-TF (CDT). CDT is uniquely designed to enhance Dox delivery to TFR1-expressing DLBCL tumors while limiting effects on nonmalignant tissues. BJAB and Farage cell lines treated with CDT for 24 hours underwent apoptosis at a significantly lower concentration when compared to Dox (50 nM vs. 1000 nM). Overall, CDT was 1-2 Log10 more potent than Dox against DLBCL cell lines. Co-incubation with 250 uM of antagonist holo-transferrin significantly decreased BJAB and Farage sensitivity to CDT, confirming activity through TFR1. Confocal microscopy of BJAB cells incubated up to 24 hours with 250 nM Dox and 30 nM CDT reveled enhanced nuclear colocalization of Dox at a significantly lower concentration. Prior dose-finding experiments in non-tumor bearing mice identified a CDT safe working dose of 33.0 mg/kg containing 16% moles of Dox in comparison to Dox maximum-tolerated dose (MTD) 3.3 mg/kg. We engrafted 2 groups of 10 NSG mice with a Dox-sensitive high-TFR1 expressing patient-derived xenograft (PDX) tumor. Mice were dosed with CDT and Dox on day 0, 14, and 24. CDT demonstrated similar anti-lymphoma efficacy with reduced toxicity: CDT-treated mice displayed no significant decline in body weight, which is characteristic and was observed following each single-agent Dox treatment. Histology analyses revealed little to no obvious damage to CDT-treated nonmalignant tissues, including myocardium. With a working dose of CDT identified, we now have under way clinically relevant R-CHOP vs. R-nanoCHOP (CDT substituted for Dox) assessments in our PDX mouse model. Capitalizing on the unique design, we expect to observe improved anti-lymphoma efficacy, with decreased toxicities and an improvement in overall survival. In sum, we provide mechanistic insight for novel DLBCL nano-chemotherapy and illustrate preclinical efficacy for a promising new therapeutic approach. Citation Format: Artavazd Arumov, Piumi Y. Liyanage, Asaad Trabolsi, Evan R. Roberts, Braulio Ferreira, Daniel Bilbao, Roger M. LeBlanc, Jonathan H. Schatz. Cytotoxic mechanism of a novel transferrin receptor-targeting chemotherapeutic nanocarrier for use in diffuse large B-cell lymphoma [abstract]. In: Proceedings of the AACR Virtual Meeting: Advances in Malignant Lymphoma; 2020 Aug 17-19. Philadelphia (PA): AACR; Blood Cancer Discov 2020;1(3_Suppl):Abstract nr PO-48.

Background: BL is associated with a high risk of primary or secondary CNS involvement, warranting intrathecal (IT) and/or systemic therapy that penetrates the blood-brain barrier (BBB). The lower-intensity DA-EPOCH-R regimen has recently shown high survival rates in BL (Dunleavy, NEJM 2013), but it omits drugs traditionally used for CNS prophylaxis (like high-dose methotrexate [HDMTX]). The objective of this multi-institutional retrospective study was to examine treatments, risk factors, and CNS-related outcomes among patients (pts) with BL. Methods: We collected data from 26 US centers on adult BL pts diagnosed (dx) in 6/2009-6/2018. Using institutional expert pathology review and 2016 WHO criteria, we excluded other high-grade lymphomas (including BL-like/unclassifiable), or cases with inadequate clinicopathologic data. We studied factors associated with baseline CNS involvement (CNSinv) using logistic regression reporting odds ratios (OR). Progression-free (PFS), overall survival (OS), and cumulative incidence function of CNS recurrence (in a competing risk analysis) were examined in Cox or Fine-Gray models reporting hazard (HR) or subhazard ratios (SHR), respectively. All estimates report 95% confidence intervals (in square brackets). Results: Among 557 BL pts (median age, 47 years [yr], 24% women, 23% HIV+), 107 (19%) had CNSinv at dx, including 89 (16%) with leptomeningeal, and 15 (3%) with parenchymal CNS disease. In a multivariable model, factors significantly associated with CNSinv at dx included stage 3/4 (OR, 11.2 [1.47-85.9]), poor performance status (PS; OR, 2.12 [1.22-3.69]), ≥2 extranodal sites (OR, 3.77 [2.02-7.03]), or marrow involvement (OR, 2.44 [1.35-4.39]), whereas intestinal involvement conferred low risk of CNSinv (OR, 0.27 [0.11-0.65]). CNSinv at dx was not significantly associated with use of specific chemotherapy regimens (Fig. A,P=.75) or receipt of IT chemotherapy (91% vs 84%, P=.065). Pts with CNSinv were less likely to achieve a complete response (62% vs 76%, P=.005), had worse 3 yr PFS (47% vs 69%; P3x upper limit of normal [LDH>3x]; see Evens AM et al, ASH 2019 for further details). With median follow up of 3.6 yrs, 33 pts (6%) experienced a CNS recurrence (82% within 1 yr from dx; 79% purely in CNS, and 21% with concurrent systemic BL). The cumulative risk of CNS recurrence was 6% [4-8%] at 3y (Fig. D). Univariate significant predictors of CNS recurrence included baseline CNSinv, HIV+ status, stage 3/4, poor PS, LDH>3x, involvement of ≥2 extranodal sites, marrow, or testis. However, in a multivariate model only baseline CNSinv (SHR, 3.35 [1.53-7.31]) and poor PS (SHR, 2.24 [1.03-4.90]) retained significance. The 3 yr risk of CNS recurrence varied from 3% for pts with no risk factor, to 10% with one, and 17% with both factors (Fig. E). In addition, the risk of CNS recurrence differed according to chemotherapy regimen, and was significantly higher for pts treated with DA-EPOCH (12% at 3y [8-18%]; Fig. F) compared with CODOX-M/IVAC (4% [2-8%]) or hyperCVAD/MA (3% [1-6%]; SHR for DA-EPOCH vs. others, 3.50 [1.69-7.22]). All pts recurring after DA-EPOCH had received IT chemotherapy. Higher risk of CNS recurrence persisted with DA-EPOCH regardless of baseline CNSinv (Pinteraction=.70), poor PS (Pint=.14), or HIV status (Pint=.89). Baseline CNSinv was the strongest factor associated with CNS recurrence after DA-EPOCH (3 yr risk, 30% vs 8%, P Conclusions: In adult BL, baseline CNSinv and poor PS predicted subsequent CNS recurrence, an outcome that is associated with a dismal prognosis. Furthermore, treatment with DA-EPOCH was associated with a significantly increased risk of CNS recurrence in this real-world analysis. For BL pts with baseline CNSinv treated in routine clinical practice, regimens with highly BBB-penetrant drugs (e.g. CODOX-M/IVAC, hyperCVAD/MA) may be preferred. Studies should delineate ways to mitigate the risk of CNS recurrence with lower-intensity programs. Disclosures Evens: Seattle Genetics: Consultancy, Honoraria; Research to Practice: Honoraria; Verastem: Consultancy, Honoraria; Affimed: Consultancy, Honoraria; Pharmacyclics: Honoraria, Other: DMC; Bayer: Consultancy, Honoraria; Takeda: Research Funding; Merck: Research Funding. Smith:Incyte Corporation: Research Funding; Seattle Genetics: Research Funding; Portola Pharmaceuticals: Research Funding; Pharmacyclics: Research Funding; Acerta Pharma BV: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; Ignyta (spouse): Research Funding; Merck Sharp & Dohme Corp: Consultancy, Research Funding; Denovo Biopharma: Research Funding; Bristol-Myers Squibb (spouse): Research Funding; Ayala (spouse): Research Funding. Naik:Celgene: Other: Advisory board. Reddy:KITE Pharma: Consultancy; Abbvie: Consultancy; Genentech: Research Funding; BMS: Consultancy, Research Funding; Celgene: Consultancy. Farooq:Celgene: Honoraria; Kite Pharma: Research Funding. Epperla:Verastem Oncology: Speakers Bureau; Pharmacyclics: Honoraria. Khan:Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Janssen: Other: Educational Content/Symposium; Abbvie: Membership on an entity's Board of Directors or advisory committees; Bristol Myers: Other: Research Funds. Alderuccio:Puma Biotechnology: Other: Immediate family member; Agios: Other: Immediate family member; Inovio Pharmaceuticals: Other: Immediate family member; Targeted Oncology: Honoraria; OncLive: Consultancy; Foundation Medicine: Other: Immediate family member. Yazdy:Bayer: Honoraria; Genentech: Research Funding; Octapharma: Consultancy; Abbvie: Consultancy. Diefenbach:Bristol-Myers Squibb: Consultancy, Research Funding; Denovo: Research Funding; Genentech: Consultancy, Research Funding; Incyte: Research Funding; LAM Therapeutics: Research Funding; MEI: Research Funding; Merck: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Millenium/Takeda: Research Funding; Trillium: Research Funding. Karmali:Astrazeneca: Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution; Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau. Martin:Celgene: Consultancy; Teneobio: Consultancy; Karyopharm: Consultancy; Janssen: Consultancy; Sandoz: Consultancy; I-MAB: Consultancy. Magarelli:Tevan Oncology: Speakers Bureau. Kamdar:Seattle Genetics: Speakers Bureau; Pharmacyclics: Consultancy; AstraZeneca: Consultancy; Celgene: Consultancy; University of Colorado: Employment. Portell:Xencor: Research Funding; Roche/Genentech: Research Funding; Infinity: Research Funding; TG Therapeutics: Research Funding; AbbVie: Research Funding; Pharmacyclics: Consultancy; Janssen: Consultancy; Genentech: Consultancy, Research Funding; Amgen: Consultancy; Bayer: Consultancy; BeiGene: Consultancy, Research Funding; Kite: Consultancy, Research Funding; Acerta/AstraZeneca: Research Funding. Lossos:Janssen Scientific: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; NIH: Research Funding. Olszewski:Genentech: Research Funding; Adaptive Biotechnologies: Research Funding; TG Therapeutics: Research Funding; Spectrum Pharmaceuticals: Research Funding.

Doxorubicin (Dox) remains the most active drug against aggressive lymphomas, forming the backbone of multiple potentially curative frontline combination regimens. R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone), for example, cures diffuse large B-cell Lymphoma (DLBCL), the most common lymphoid malignancy in the United States, greater than 60% of the time. Patients with relapsed/refractory disease, however, have poor prognosis and require new options. Advances in nanotechnology provide new opportunities to widen therapeutic windows for existing drugs by enhancing delivery to tumor cells and limiting toxicities to non-malignant tissues. Carbon-Nitride Dots (CND) are novel nanocarriers we have developed that can be conjugated with a diverse range of molecules and have an established safe pharmacologic profile. Here, we sought CND-based enhancement of Dox's anti-lymphoma activities. We generated unconjugated CNDs (~3 nm) through a hydrothermal microwave synthesis, followed by carbodiimide cross-linking bioconjugation steps to covalently link Dox and/or transferrin (TF), the protein ligand for the transferrin receptor (TFR). Because TFR is expressed on the cell surface in a range of B-cell lymphomas including DLBCL, we aimed to increase Dox delivery to tumor cells and limit delivery to non-malignant tissues. We probed a cohort of DLBCL cell lines for TFR expression via western blot, followed by baseline viability assays. Unconjugated CNDs showed no toxicity in vitro, while conjugation to Dox alone resulted in potency similar to unconjugated Dox. CND-Dox-TF, however, was 1-2 Log10 more potent than Dox alone (LD50 1.2-48.5 nM vs. 205.5->1000 nM), consistent with enhanced activity due to the entry of the nanocarrier into the cells through the TF-TFR interaction. To create a functional model, we cloned the TFR1 gene into a GFP-lentiviral expression vector. We infected previously tested cell lines with TFR1, confirmed increased TFR expression via western blot, and exposed cells to CND nanocarriers. TFR1-infected cells showed selective disadvantage during CND-Dox-TF treatment compared to uninfected and empty-vector controls, while CND and CND-Dox controls showed no differential effect. After establishing CND-Dox-TF proof of principle in vitro, we next initiated testing in vivo, beginning with maximum-tolerated dose (MTD) finding experiments. We treated three groups of non-tumor-bearing NOD scid gamma (NSG) mice intravenously with a single dose of (1) CND, (2) CND-Dox, and (3) CND-Dox-TF. Maximum dosing of CND-Dox-TF based on solubility in 100 µL PBS was roughly 1:4 molar equivalent to Dox MTD (3.3 mg/kg). This dose of CND-Dox-TF caused decreased body weight to >20% loss from starting dosing and animals had to be sacrificed, with organ pathology pending. Molar equivalent dosing of CND and CND-Dox, however, resulted in no weight loss, demonstrating biologic activity of the TF moiety but unfortunately intolerable toxicity at this initial dose. We then reduced the CND-Dox-TF dose to 1:16 molar equivalent to Dox MTD and repeated dosing to three non-tumor-bearing animals. This resulted in decreased body weight of 10% from starting dose by day 11, followed by a rebound to normal body weight by day 17. This observed body weight fluctuation is similar to what is seen under a 0.75% of Dox MTD. With a dose of 33 mg/kg identified as the MTD of the CND-Dox-TF, we are now proceeding to anti-tumor efficacy experiments in four available PDX models of DLBCL (two each from previously untreated and relapsed/refractory patients). We will compare the MTD of Dox versus the MTD of CND-Dox-TF initially as single agents. We will then compare R-CHOP to "R-nanoCHOP" (replacement of Dox with the MTD of CND-Dox-TF). We hypothesize that both through the TF-TFR interaction and enhanced tumor permeability and retention that are known properties of CNDs, CND-Dox-TF treated mice will have improved anti-lymphoma responses. In sum, we show that a TF ligand conjugated to Dox via our CND nanocarrier significantly increases the anti-lymphoma efficacy of Dox on DLBCL cell lines. Importantly, we also show these novel nanocarrier therapeutic molecules are safe to administer in vivo, and we define MTD for studies moving forward. Proof of principle that CND nanotechnology enhances anti-lymphoma activity of Dox would open the door for many such approaches aimed at a variety of malignancies. Disclosures No relevant conflicts of interest to declare.

e14092 Background: Checkpoint inhibitors (blocking antibodies to PD-1, PD-L1, CTLA-4) have proven effective against several tumor types. While the response is impressive in some patients, we still don’t understand all the patient factors that determine resistance to this class of medication. Studies of host factors have identified composition of the gut microbiome at baseline as a positive predictor of ICI response. Proton pump inhibitors have been reported to interfere with gut microbiome composition. In this single center, retrospective study, we studied the effect of concomitant treatment of proton pump inhibitors on response to ICIs in patients with locally advanced and metastatic cancer. Methods: A retrospective cohort of Non-small cell lung cancer, renal cell carcinoma and Melanoma patients that were treated from January 2016 to May 2018 at the Mount Sinai Medical Center were included in this study. Demographics, prior systemic treatment, performance status, ICI agent, and use of PPI (with in 30 days prior to 30 days after the first dose of ICI administration) were collected. Primary objective of the study was progression free survival (PFS) by utilization of PPIs. PFS was calculated using the log-rank test and survival curve was generated using the Kaplan-Meier method. Information was collected from electronic medical records. Results: Of the 97 patients that met the study criteria, 63 patients had complete data and included in the analysis. 46 patients had Non-small cell lung cancer, 13 had melanoma and 4 renal cancer. Checkpoint inhibitors most commonly prescribed included: Pembrolizumab (29 patients : 46%), Nivolumab (22 patients:35%), Nivolumab + Ipilimumab (9:14 %). 25 patients were taking PPI upon initiation of ICI treatment. In addition, 26 patients received steroids with in 30 days of treatment initiation. There was no statistically significant difference in PFS between patients on PPIs and not on PPIs. The median PFS was 672 days (95% CI: 32, 1311) for PPI users and 341 days (95% CI: 123, 558) for non PPI users. P = 0.244. Conclusions: In this, single-center, retrospective study, we did not detect a significant difference in PFS between patients who used PPI at baseline and patients who did not. Limitations of this study mainly included retrospective analysis, a small sample size, single center population and heterogeneity in disease pathology. We did not collect information on other tumor and treatment related factors like PDL 1 expression, tumor mutation burden, use of antibiotics, and immunotherapy related adverse reactions.

e18838Background: Intracranial metastases occur in more than 50% of patients with small cell lung cancer (SCLC). Cranial irradiation (PCI) is effective in decreasing the incidence of cerebral metas...

Background Immune checkpoint inhibitors have become the first line therapy in melanoma treatment and their use is extending to other malignancies. However, we are still learning about immune side effects produced by these drugs and their severity especially in patients with history of inflammatory diseases. Case presentation We present two cases of metastatic melanoma treated with nivolumab and pembrolizumab (anti PD-1). Both patients developed acute interstitial nephritis during immune checkpoint therapy. We emphasize the causal association between immune checkpoint inhibitors and the nephritis. The timing of drug administration and appearance of nephritis is suggestive of a causal relation between the checkpoint inhibitor therapy and this adverse event. Conclusions Although uncommon, some side effects from checkpoint inhibitors can be severe and may need to be addressed with immunosuppression. Given the increasing frequency of immunotherapy use, awareness should be raised in regards to immune side effects and their appropriate management.