Citations

ABSTRACT Purpose Malignant rhabdoid tumor of the kidney (MRTK) is a rare, aggressive tumor seen in young children. The optimal timing of resection for locally advanced tumors is not well‐defined. The purpose of this study is to evaluate modern oncologic outcomes and the impact of surgical timing. Methods A multicenter retrospective review was performed by institutions participating in the Pediatric Surgical Oncology Research Collaborative. Children younger than 21 years old with MRTK diagnosed between 2000 and 2022 were included. Results Sixty‐nine patients were identified with MRTK and met the inclusion criteria. Median age of diagnosis was 10.1 months. Overall survival (OS) at 1, 5, and 10 years was 49%, 32%, and 19%, respectively. Patients with local Stage III disease who underwent upfront resection ( n = 18) compared to those who had delayed resection after NAT ( n = 15) had a similar OS, median OS greater than 60 months versus 14.6 months, respectively; p = 0.396. The surgical timing groups were balanced in terms of the presence of metastasis, length of follow‐up, and tumor characteristics. There was one occurrence of primary intraoperative tumor spill and two occurrences of organ injury in the upfront resection group compared to none in the delayed resection group. Conclusion MRTK carries a poor prognosis despite multimodal treatment. Histologic diagnosis may not be confirmed at presentation, and MRTK cannot be reliably distinguished from Wilms tumor on imaging alone. As overall survival is similar, the decision regarding surgical timing in locally advanced tumors should be individualized based on perceived resectability, balancing the risk of intraoperative complications against the possibility of tumor progression during neoadjuvant therapy.

ABSTRACT Introduction Children with hepatoblastoma (HB) and other solid tumors frequently undergo intraoperative blood transfusion (IBT) with unknown impact on oncologic outcomes and scant data to guide transfusion in this population. This study tested the hypothesis that IBT is associated with poorer survival in children with HB. Methods A multicenter retrospective observational study of patients aged <18 years with HB who underwent primary tumor resection, including liver transplantation, from 2010 to 2019 was performed at 19 institutions. The association of IBT with risk of recurrence and death were determined using propensity score reweighted (PSR) Cox proportional hazards regression analyses. Results There were 338 patients identified who met inclusion criteria and had sufficient data for inclusion. Of those, 257 (76%) received IBT, including 253 (98%) who received packed red blood cells (pRBC), 84 (33%) who received plasma, and 28 (11%) who received platelets. IBT was associated with higher pretreatment extent of disease ( p < 0.001), presence of annotation factors (+VPEFR: 50%, n = 129 vs. 37%, n = 30, p = 0.035), and complex resections (extended, meso‐, or total hepatectomy: 54%, n = 139 vs. 27%, n = 22, p < 0.001); these differences were mitigated after applying propensity score weighting. Patients who received IBT had greater postoperative hemoglobin (g/dL) (median 10 (I8–11) vs. 9 (8–10), p = 0.013) and required more postoperative plasma and platelet transfusions ( p < 0.05). Median follow‐up was 4.4 (2.0–8.3) years. Compared with non‐IBT patients, those with IBT had higher incidence of death (PSR HR 2.35, 95% CI 1.10–5.02). Recurrence did not significantly differ across groups (PSR HR = 0.82, 95% CI 0.45–1.48). Conclusion IBT was associated with greater hazard of death. Postoperative hemoglobin levels suggested that unnecessary transfusions occurred and a pRBC‐focused approach to IBT led to coagulopathy. Development of optimal transfusion strategies for HB are needed to minimize unnecessary transfusions.

ABSTRACTBackgroundRenal medullary carcinoma (RMC) is an aggressive tumor associated with sickle cell trait. Despite treatment advances for other rare renal tumors, RMC survival remains poor. We aimed to describe the contemporary management and survival of children and adults with RMC.ProcedureIn this multicenter retrospective cohort study, Pediatric Surgical Oncology Research Collaborative sites searched their databases for patients diagnosed with RMC (2000–2022). Descriptive statistics were calculated and survival analyses performed using Kaplan–Meier and Cox regression.ResultsThirty‐four patients with RMC were identified. Median age was 19 years (IQR: 15–28; range: 7–52). Most were male (24/34; 71%), Black (27/32; 84%), had sickle cell trait or disease (30/33; 91%), presented with metastatic disease (27/34; 79%), and were symptomatic at presentation (32/34; 94%). Median overall survival (OS) was 24 months from diagnosis (16 months for children, 28 months for adults, p = 0.6). Receipt of platinum‐based chemotherapy (23/34; 68%) was associated with significantly higher OS than other regimens (35 vs. 5 months, p < 0.001). Nephrectomy (24/34; 71%) was associated with significantly improved OS compared with non‐operative management (34 vs. 7 months, p = 0.001). Immunotherapy, targeted therapy, or radiation therapy were not associated with significant differences in OS, nor were age, sex, race, sickle cell status, SMARCB1/INI‐1, stage, nephrectomy approach, retroperitoneal lymph node dissection, gross residual disease, margins, or tumor size.ConclusionsRMC survival remains poor despite newer therapies. Nephrectomy and platinum‐based chemotherapy should be considered in locally advanced and metastatic disease. Coordinated international cooperative group studies are needed to meaningfully improve RMC survival.

AbstractBackgroundUndifferentiated embryonal sarcoma of the liver (UESL) is a rare tumor for which there are few evidence‐based guidelines. The aim of this study was to define current management strategies and outcomes for these patients using a multi‐institutional dataset curated by the Pediatric Surgical Oncology Research Collaborative.MethodsData were collected retrospectively for patients with UESL treated across 17 children's hospitals in North America from 1989 to 2019. Factors analyzed included patient and tumor characteristics, PRETEXT group, operative details, and neoadjuvant/adjuvant regimens. Event‐free and overall survival (EFS, OS) were the primary and secondary outcomes, respectively.ResultsSeventy‐eight patients were identified with a median age of 9.9 years [interquartile range [IQR): 7–12]. Twenty‐seven patients underwent resection at diagnosis, and 47 patients underwent delayed resection, including eight liver transplants. Neoadjuvant chemotherapy led to a median change in maximum tumor diameter of 1.6 cm [IQR: 0.0–4.4] and greater than 90% tumor necrosis in 79% of the patients undergoing delayed resection. R0 resections were accomplished in 63 patients (81%). Univariate analysis found that metastatic disease impacted OS, and completeness of resection impacted both EFS and OS, while multivariate analysis revealed that R0 resection was associated with decreased expected hazards of experiencing an event [hazard ratio (HR): 0.14, 95% confidence interval (CI): 0.04–0.6]. At a median follow‐up of 4 years [IQR: 2–8], the EFS was 70.0% [95% CI: 60%–82%] and OS was 83% [95% CI: 75%–93%].ConclusionComplete resection is associated with improved survival for patients with UESL. Neoadjuvant chemotherapy causes minimal radiographic response, but significant tumor necrosis.

Objective: The purpose of this study was to describe management and outcomes from a contemporary cohort of children with Wilms tumor complicated by inferior vena caval thrombus. Background: The largest series of these patients was published almost 2 decades ago. Since then, neoadjuvant chemotherapy has been commonly used to manage these patients, and outcomes have not been reported. Methods: Retrospective review of 19 North American centers between 2009 and 2019. Patient and disease characteristics, management, and outcomes were investigated and analyzed. Results: Of 124 patients, 81% had favorable histology (FH), and 52% were stage IV. IVC thrombus level was infrahepatic in 53 (43%), intrahepatic in 32 (26%), suprahepatic in 14 (11%), and cardiac in 24 (19%). Neoadjuvant chemotherapy using a 3-drug regimen was administered in 82% and postresection radiation in 90%. Thrombus level regression was 45% overall, with suprahepatic level showing the best response (62%). Cardiopulmonary bypass (CPB) was potentially avoided in 67%. The perioperative complication rate was significantly lower after neoadjuvant chemotherapy [(25%) vs upfront surgery (55%); P=0.005]. CPB was not associated with higher complications [CPB (50%) vs no CPB (27%); P=0.08]. Two-year event-free survival was 93% and overall survival was 96%, higher in FH cases (FH 98% vs unfavorable histology/anaplastic 82%; P=0.73). Neither incomplete resection nor viable thrombus cells affected event-free survival or overall survival. Conclusions: Multimodal therapy resulted in excellent outcomes, even with advanced-stage disease and cardiac extension. Neoadjuvant chemotherapy decreased the need for CPB to facilitate resection. Complete thrombectomy may not always be necessary.

AbstractWilms tumor (WT) is the most common renal malignancy in children. Children with favorable histology WT achieve survival rates of over 90%. Twelve percent of patients present with metastatic disease, most commonly to the lungs. The presence of a pleural effusion at the time of diagnosis of WT may be noted on staging imaging; however, minimal data exist regarding the significance and prognostic importance of this finding. The objectives of our study are to identify the incidence of pleural effusions in patients with WT, and to determine the potential impact on oncologic outcomes. A multi‐institutional retrospective review was performed from January 2009 to December 2019, including children with WT and a pleural effusion on diagnostic imaging treated at Pediatric Surgical Oncology Research Collaborative (PSORC) participating institutions. Of 1259 children with a new WT diagnosis, 94 (7.5%) had a pleural effusion. Patients with a pleural effusion were older than those without (median 4.3 vs 3.5 years; P = .004), and advanced stages were more common (local stage III 85.9% vs 51.9%; P < .0001). Only 14 patients underwent a thoracentesis for fluid evaluation; 3 had cytopathologic evidence of malignant cells. Event‐free and overall survival of all children with WT and pleural effusions was 86.2% and 91.5%, respectively. The rate and significance of malignant cells present in pleural fluid is unknown due to low incidence of cytopathologic analysis in our cohort; therefore, the presence of an effusion does not appear to necessitate a change in therapy. Excellent survival can be expected with current stage‐specific treatment regimens.

Abstract Inflammatory myofibroblastic tumor (IMT) is a mesenchymal neoplasm of intermediate malignancy. We describe the largest cohort of IMT patients to date, aiming to further characterize this rare, poorly understood tumor. This is a multi‐institutional review of IMT patients ≤39 years, from 2000 to 2018, at 18 hospitals in the Pediatric Surgical Oncology Research Collaborative. One hundred and eighty‐two patients were identified with median age of 11 years. Thirty‐three percent of tumors were thoracic in origin. Presenting signs/symptoms included pain (29%), respiratory symptoms (25%) and constitutional symptoms (20%). Median tumor size was 3.9 cm. Anaplastic lymphoma kinase (ALK) overexpression was identified in 53% of patients. Seven percent of patients had distant disease at diagnosis. Ninety‐one percent of patients underwent resection: 14% received neoadjuvant treatment and 22% adjuvant treatment. Twelve percent of patients received an ALK inhibitor. Sixty‐six percent of surgical patients had complete resection, with 20% positive microscopic margins and 14% gross residual disease. Approximately 40% had en bloc resection of involved organs. Median follow‐up time was 36 months. Overall 5‐year survival was 95% and 5‐year event‐free survival was 80%. Predictors of recurrence included respiratory symptoms, tumor size and distant disease. Gross or microscopic margins were not associated with recurrence, suggesting that aggressive attempts at resection may not be warranted.

10024 Background: Inflammatory myofibroblastic tumor (IMT) is a mesenchymal neoplasm of intermediate malignancy, predominantly seen in children and young adults. Given its rarity, data are limited. We describe the largest cohort of patients with IMT to date, with an aim to further characterize this poorly understood tumor. Methods: A multi-institutional review was performed at 18 North American hospitals participating in the Pediatric Surgical Oncology Research Collaborative to identify IMT patients ≤39 years, diagnosed from 2000-2018. Descriptive statistics are described as median and interquartile range. Multivariable analysis was used to identify predictors of event free survival (EFS). Results: 182 patients were identified with a median age of 11 years (5-17); 52% were female. 33% of tumors were thoracic, 26% abdominal/pelvic, 20% head/neck, and 14% genitourinary. Common presenting symptoms included pain (29%), respiratory symptoms (24%), weight loss (12%), and a palpable mass (10%). Median tumor size was 3.9 cm (1.9-6.5). Anaplastic lymphoma kinase (ALK) overexpression was identified via immunohistochemistry in 53% of patients tested. One third of patients had abnormal cytogenetics, with 12% of the entire cohort having an ALK mutation. 7% of patients had distant disease at diagnosis. 13% of patients received neoadjuvant therapy including chemotherapy (3%), ALK inhibitor (4%), radiation (0.5%), non-steroidal anti-inflammatories (NSAIDs) (7%), or steroids (2%). Of those who underwent resection with known margin status (n = 158), 66% had complete resection, 20% had microscopic positive margins, and 14% had gross residual disease. Just over 40% of patients had an en bloc resection of involved organs, most commonly lung (26%). 21% of patients received adjuvant therapy, including chemotherapy (3%), ALK inhibitor (9%), radiation (0.5%), NSAIDs (8%), or steroids (5%). 12% of all patients received an ALK inhibitor: 24% neoadjuvant, 62% adjuvant, and 14% without surgery. Median follow-up time was 36 months (14-69). Overall 5-year survival (OS) was 95% and 5-year EFS was 80%. Predictors of recurrence included respiratory symptoms, larger tumor size, or distant disease at diagnosis. Gender, race, age and primary site were not predictive of EFS. Likewise, there was no association of ALK overexpression or ALK mutation with EFS. The presence of gross or microscopic margins following resection was not associated with recurrence. Conclusions: IMT is a rare tumor with favorable OS. Five year recurrence rate was 20%. Presenting with respiratory symptoms, larger tumor size, or metastatic disease was associated with recurrence, while ALK positivity was not. Notably, a positive margin after resection was not associated with increased recurrence, indicating that aggressive attempts at surgical resection that would compromise form or function may not be warranted.

Background REGN1979 is an anti-CD20 x anti-CD3 bispecific IgG4 antibody (Ab) modified to reduce Fc binding. Engaging both targets results in CD20-specific, local T-cell activation and cytotoxicity, a mechanism of action distinct from standard anti-CD20 Abs. Dose escalation is complete and a recommended Ph 2 dose has been determined. We report Ph 1 safety and efficacy results of REGN1979 in patients (pts) with R/R B-NHL previously treated with anti-CD20 Abs, including pts with progressive disease after anti-CD19 CAR T-cell (CAR T) therapy. Methods Primary objectives are to determine safety, tolerability, and occurrence of dose limiting toxicities (DLTs). Other objectives are to assess antitumor activity, pharmacokinetics (PK), and pharmacodynamics. Eligible pts with R/R B-NHL must have received prior CD20-directed therapy. Treatment consists of 12 weekly intravenous doses of REGN1979 followed by every 2-week dosing for 12 doses (36 weeks total). Results As of June 3, 2019, 96 pts (diffuse large cell B-cell lymphoma [DLBCL] [n=53], follicular lymphoma [FL] grade [Gr] 1-3a [n=25], mantle cell lymphoma [n=6], marginal zone lymphoma [n=6], or other [FL Gr 3b, FL unknown, FL ungraded, or Waldenström macroglobulinemia ] [n=6]) were treated with REGN1979 0.03-320 mg and received a median of 9 doses (range 1-24). Pts had a median of 3 prior lines of therapy (range 1-11); 12 pts with prior CAR T therapy were included in the safety analysis of which 6 were included in the efficacy analysis. Twenty-four pts remain on treatment; 18 completed treatment; 54 discontinued early (35 due to progressive disease [PD]). No pts with B-NHL experienced a DLT. The most common treatment-emergent adverse events (AEs) were pyrexia (n=74), CRS (n=55), chills (n=49), infections and infestations (n=47), fatigue (n=36), increased C-reactive protein (n=32), and anemia (n=32). Seven pts experienced Gr 3 CRS. The severity of CRS symptoms declined through optimized pre-medication even with REGN1979 dose escalation. Most common Gr 3 or 4 AEs were anemia (n=19), decreased lymphocytes/lymphopenia (n=19), infections and infestations (n=18), decreased neutrophils/neutropenia (n=17), and hypophosphatemia/decreased blood phosphorus (n=16). No pts had seizures or grade 4/5 neurologic AEs. Gr 3 neurologic AEs included depressed level of consciousness (unrelated), somnolence, and syncope (n=1 each). Neurological events were transient and none required permanent treatment termination. Five pts discontinued due to AEs: Gr 3 hemolysis; Gr 3 fatigue; Gr 2 and Gr 3 pneumonia; and Gr 3 neck abscess (1 each). Eleven pts died on study: PD (n=6), gastric perforation (n=1), cardiac arrest (n=1), lung infection (n=1), multi-organ failure (n=1), pneumonia (n=1). The Table and Figure show efficacy and duration of response for R/R DLBCL by dose level. Pts who had opportunity for response assessment at Week 12 were included in the analysis of response. Emerging data suggest increasing efficacy with higher doses in R/R DLBCL, with 5 of 8 pts treated at 80/160/320 mg achieving CR; at these doses 2 of 3 pts achieved CR after failure of CAR T therapy. Data also suggest increasing efficacy with increasing doses in R/R FL, but maximum efficacy appears to be achieved at lower doses than in DLBCL; in pts with FL Gr 1-3a treated at ≥5 mg, the ORR was 93% (13/14), and the CR rate was 71.4% (10/14). REGN1979 concentrations in serum increased linearly with dose during the first five weeks. Elevated levels of serum cytokines were observed, mostly in week 1, and no correlation was observed with clinical efficacy. Immunohistological analysis of malignant lymph node tissue demonstrated that pts with high and low CD20 expression achieved clinical response. Relapse among responders was seen with either maintenance or loss of CD20 expression, suggesting antigen-dependent and independent disease escape mechanisms. Conclusions/Summary Tolerability of REGN1979 has been demonstrated at doses up to the final dose level of 320 mg weekly, with no observed DLTs in pts with B-NHL. No pts discontinued due to neurologic AE. Activity was observed broadly in heavily pretreated R/R B-NHL pts treated with REGN1979. With increasing dose, more resistant tumors such as R/R DLBCL are showing benefit, even in pts with prior CAR T therapy failure. Based on these efficacy findings, a global Ph 2 study is underway to evaluate REGN1979 monotherapy in R/R FL Gr 1-3a, R/R DLBCL, and other R/R B-NHL subtypes. Disclosures Bannerji: AbbVie, Inc: Consultancy, travel support; Gilead: Other: travel support; Gilead: Other: travel support; Pharmacyclics: Other: travel support; Merck: Other: travel support, Patents & Royalties: IP rights; AbbVie, Inc: Consultancy; Regeneron Pharmaceuticals, Inc.: Consultancy, Other: travel support, Research Funding; Regeneron Pharmaceuticals, Inc.: Consultancy, Other: travel support, Research Funding; Celgene: Consultancy; Celgene: Consultancy; Merck: Other: travel support, Patents & Royalties: IP rights; Pharmacyclics: Other: travel support. Allan:Acerta Pharma: Consultancy; Sunesis Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics LLC, an AbbVie company: Consultancy; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Consultancy; Verastem Oncology, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria. Arnason:Celgene/Juno: Consultancy; Regeneron Pharmaceuticals, Inc.: Consultancy. Brown:AstraZeneca: Consultancy; Acerta Pharma: Consultancy; Morphosys: Other: Data safety monitoring boards ; Sun Pharmaceuticals, Inc: Research Funding; Sun: Research Funding; Verastem: Consultancy, Research Funding; TG Therapeutics: Consultancy; Teva: Honoraria; Sunesis: Consultancy; Pharmacyclics: Consultancy; Pfizer: Consultancy; Janssen: Honoraria; Invectys: Other: other; Loxo: Consultancy, Research Funding; Novartis: Consultancy; Octapharma: Consultancy; Kite: Consultancy, Research Funding; Dynamo Therapeutics: Consultancy; Catapult Therapeutics: Consultancy; BeiGene: Consultancy; Gilead: Consultancy, Research Funding; Genentech/Roche: Consultancy. Advani:Kyowa Kirin Pharmaceutical Developments, Inc.: Consultancy; Seattle Genetics: Consultancy, Research Funding; Celmed: Consultancy, Membership on an entity's Board of Directors or advisory committees; Forty-Seven: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Kura: Research Funding; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millennium: Research Funding; Gilead Sciences, Inc./Kite Pharma, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Infinity Pharma: Research Funding; Janssen: Research Funding; Merck: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cell Medica, Ltd: Consultancy; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agensys: Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Stanford University: Employment, Equity Ownership; Regeneron: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ansell:Seattle Genetics: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Affimed: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Mayo Clinic Rochester: Employment. O'Brien:Pfizer: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; Acerta: Research Funding; Alexion: Consultancy; Amgen: Consultancy; Aptose Biosciences, Inc: Consultancy; Astellas: Consultancy; Celgene: Consultancy; Eisai: Consultancy; Gilead: Consultancy, Research Funding; GlaxoSmithKline: Consultancy; Kite: Research Funding; Janssen: Consultancy, Honoraria; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; Regeneron: Research Funding; Verastem: Consultancy; Sunesis: Consultancy, Research Funding; Vaniam Group LLC: Consultancy; TG Therapeutics: Consultancy, Research Funding. Chavez:Janssen Pharmaceuticals, Inc.: Speakers Bureau; Kite Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees; Genentech: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees. Duell:Regeneron Pharmaceuticals, Inc.: Research Funding. Martin:I-MAB: Consultancy; Karyopharm: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Sandoz: Consultancy; Teneobio: Consultancy. Charnas:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Ambati:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Adriaens:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Ufkin:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Zhu:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Li:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Gasparini:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Ibrahim:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Jankovic:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Fiaschi:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Aina:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Zhang:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Deering:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Hamon:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Thurston:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Murphy:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Weinreich:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Yancopoulos:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Lowy:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Sternberg:Regeneron Pharmaceuticals, Inc.: Employment, Equity Ownership. Topp:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Regeneron Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: The data described in the abstract will report on use REGN1979 in a Phase 1 clinical trial of patients with B-NHL.