Citations

299 Background: In 2011, ASCO launched a forum for the oncology research community to facilitate and promote the implementation of quality clinical research. The ASCO Research Community Forum (RCF) was created to provide a solution-oriented venue for research sites to address common challenges with conducting clinical trials. It offers in-person and virtual forums and resources to learn and share best practices with peers on a variety of topics, including site quality assessment and improvement, research site operations, and clinical trial access and accrual. Methods: An assessment was performed to measure the ASCO RCF output and to gather information on its potential impact on the cancer community. Results: The ASCO RCF has provided an in-person venue for physicians and research administrators with a steady increase in attendance, from 52 attendees in 2012 to 159 in 2018. Multi-stakeholder meetings and manuscripts have promoted best practices and solutions to address challenges with implementing quality clinical trials. Tools and resources to facilitate best practices and quality improvement at trial sites have been accessed by a range of types of research sites from across the U.S. and internationally. Its web-based library of resources was accessed over 27,000 times in 2018, alone. An online forum was launched in 2019 to provide a new opportunity to connect and impact the research community. Conclusions: The ASCO RCF is a productive and esteemed resource for the cancer research community. In-person and virtual forums, along with practical tools, promote access and accrual to clinical trials by facilitating networking, developing solutions, and providing education and resources. The ASCO RCF impact has extended from community-based oncology practices to larger research networks and academic centers across the U.S. and internationally. Its efforts to promote and facilitate access to quality clinical trials align with the vision and mission of ASCO to conquer cancer through research, education, and promotion of the highest quality patient care.

Abstract Background: IRAK4 kinase activity is required for toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling in a variety of myeloid and lymphoid cell types. Recruitment of IRAK4 to these receptors and its subsequent activation is facilitated by the MYD88 adaptor protein. The MYD88-L265P activating mutation is prevalent in DLBCL (~30% in ABC subtype) and WM (>90%). MYD88- L265P leads to constitutive activation of NF-κB signaling that is associated with worse prognosis. In MCL, dysregulation of B-cell receptor (BCR) and TLR pathway components correlate with constitutive NF-κB signaling. CA-4948 is a small molecule inhibitor of IRAK4 kinase that modulates the TLR and IL-1R signaling cascades. CA-4948 is being developed as a novel agent for the treatment of hematologic cancers with dysregulated IRAK4 signaling and is currently in a Ph1 trial for R/R NHL (clinicaltrials.gov NCT03328078). In preclinical studies, CA-4948 demonstrates pharmacodynamic and antitumor activity in in vitro and in vivo models with MYD88 alterations, and was previously shown to have a synergistic anti-tumor activity when combined with venetoclax in vivo. To further guide CA-4948's clinical development in NHL, we report here nonclinical studies exploring a twice-daily dosing schedule in DLBCL xenograft models. We also investigated the use of an ex-vivo whole-blood TLR-stimulation assay as a surrogate PD response biomarker. Additionally, we tested the efficacy of CA-4948 alone or in combination with the BTK inhibitor ibrutinib in DLBCL and MCL tumor models. Furthermore, preliminary PK and PD data from the first-in-human Ph1 trial are presented. Methods: Mice bearing DLBCL PDX tumors were orally administered CA-4948 twice-daily (BID) with 37.5 or 75 mg/kg doses and once-daily (QD) with 75 or 150 mg/kg doses. The ex-vivo whole blood assay involved TLR-stimulation of blood isolated at various time-points after CA-4948 administration. For the drug combination studies, mice bearing subcutaneous tumors of a MYD88-L265P DLBCL cell line or six MCL cell lines were treated. Results: (1) CA-4948 exhibited dose-dependent tumor growth inhibition in two DLBCL PDX xenograft tumor models with BID dosing showing equal or enhanced efficacy as compared to the equivalent total daily QD dose. The BID schedule was well tolerated with only a slight body weight loss as compared to the equivalent total QD dose schedule. (2) Overall, in mouse, the ex-vivo blood assay showed a time and exposure dependent relationship with the level of cytokine production after TLR-stimulation. A similar CA-4948 dose-dependent inhibition of TLR-stimulated cytokine production was observed in healthy human whole blood samples in which CA-4948 was spiked into the blood sample. Based on these findings, CA-4948 exposure levels capable of inhibiting TLR-stimulation are anticipated to be readily achievable in clinical studies. This was also supported by preliminary clinical PD data showing post treatment, on-target, reduced release of NF-κB-associated cytokines in 2 of 4 patients treated so far. (3) In xenograft efficacy studies using MCL models, single agent CA-4948 and ibrutinib exhibited anti-tumor activity and showed an additive effect when combined in the majority of the models known to have BCR-driven constitutive canonical NF-kB signaling (REC-1, MINO, and JeKo-1). Interestingly, neither CA-4948, ibrutinib, nor the combination had anti-tumor activity in Z-138 and GRANTA-591 xenograft models, consistent with these cell lines having activated NF-κB through the alternative NIK signaling pathway. (4) The human QD PK data (n=4) demonstrated that CA-4948: was rapidly absorbed, Tmax 1-3 hr, and t1/2 of 3.6 -6.8 hr. The bioavailability and exposure, as assessed by Cmax and AUC, is within the expected range compared to non-clinical PK and did not show any evidence of accumulation after QD dosing for 15 consecutive days. Conclusion: These results provide a rationale for CA-4948 BID dosing and incorporating the use of an ex-vivo whole-blood TLR-stimulation assay as a surrogate PD response biomarker, the former of which will be evaluated in the current Ph1 dose escalation soon and the latter of which is currently being implemented in the Ph1 trial for patients with advanced NHL. The murine xenograft results further support exploration of CA-4948 as monotherapy and in combination with canonical and alternative NF-κB pathway-targeted agents in DLBCL and MCL. Disclosures Booher: Curis, Inc: Employment, Equity Ownership. Patel:Juno Therapeutics: Consultancy; Pharmacyclics/Janssen: Speakers Bureau; Genentech: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy; Sunesis Pharmaceuticals: Consultancy. Lunning:Celgene: Consultancy; AbbVie: Consultancy; Astra-Zeneca: Consultancy; Bayer: Consultancy; Genentech: Consultancy; Genzyme: Consultancy; Genentech: Consultancy; Gilead: Consultancy; Janssen: Consultancy; Juno: Consultancy; Kite: Consultancy; Portola: Consultancy; Seattle Genetics: Consultancy; Spectrum: Consultancy; TG Therapeutics: Consultancy; Verastem: Consultancy. Samson:Curis, Inc: Employment, Equity Ownership. Atoyan:Curis, Inc: Employment, Equity Ownership. Ma:Curis, Inc: Employment, Equity Ownership. Xu:Curis, Inc: Employment, Equity Ownership. Dellarocca:Curis, Inc: Employment, Equity Ownership. Modafferi:Curis, Inc: Employment, Equity Ownership. Borek:Curis, Inc: Employment, Equity Ownership. Zhang:Curis, Inc: Employment, Equity Ownership. Parker:Curis, Inc: Employment, Equity Ownership. Whitney:Curis, Inc: Employment, Equity Ownership. Wang:Curis, Inc: Employment, Equity Ownership. Tuck:Curis, Inc: Employment, Equity Ownership. Younes:Merck: Honoraria; Roche: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Pharmacyclics: Research Funding; Celgene: Honoraria; Abbvie: Honoraria; Seattle Genetics: Honoraria; Sanofi: Honoraria; Takeda: Honoraria; Incyte: Honoraria; Bayer: Honoraria; BMS: Honoraria, Research Funding; J&J: Research Funding; Novartis: Research Funding; Genentech: Research Funding; Astra Zeneca: Research Funding; Curis: Research Funding.

Abstract Backgroud. The treatment landscape of mantle cell lymphoma (MCL) has significantly changed in last decades. Improvement in diagnosis and understanding of disease biology has been coupled with emergence of new therapeutic options, including targeted agents. While MCL outcome data comes primarily from clinical trials (CT), the impact of therapeutic advances on pattern of care (POC) and outcome in MCL in the general population is not well characterized. This study sought to characterize changes in pattern of care and outcomes of patients with MCL in a prospective observational series in the rituximab era. Methods. The study included consenting adult patients with newly diagnosed MCL that were prospectively enrolled into the University of Iowa/Mayo Clinic Lymphoma Specialized Program of Research Excellence (SPORE) Molecular Epidemiology Resource, from 09/01/2002 to 06/30/2015. Demographic, clinical and prognostic factors were abstracted, and all patients were actively followed for re-treatment, relapse and death. Since bendamustine-rituximab (BR) regimen starting to be used in 2010, we defined patients enrolled from 09/01/2002 to 12/31/2009 as era 1 and those enrolled 01/01/2010 to 06/30/2015 as era 2. Baseline characteristics and outcomes, evaluated in terms of event free survival (EFS), overall survival (OS) and cause of death, were analyzed and compared between the two eras identified. Results. 348 patients with newly diagnosed MCL were enrolled. Five patients had no available data for front-line treatment and were excluded. The analysis was thus conducted on 343 patients: 169 patients were diagnosed in era 1 with a median follow-up of 131.2 months vs. 174 in era 2 with a median follow-up of 58.9 months. Baseline clinical characteristics and MIPI score were similar across the two eras ( Table 1). Frontline induction treatment was significantly different in the two eras. BR use was 0 vs 49 (28.2% ), R-CHOP/CHOP like regimen in 89 (52.7%) vs 45 (25.9%), high-dose cytarabine (HiDAC)-based therapy in 1 (0.6%) vs 28 (16.1%), intensified regimens (HyperCVAD) in 16 (9.5%) vs 8 (4.5%), other regimens (including R-cladribine, R-fludarabine-mitoxantrone, rituximab monotherapy) in 35 (20.7%) vs 13 (7.5%) patients in era 1 vs era 2 respectively. Non-systemic treatment (observation, surgery or radiation only) was performed in 25 (14.8%) vs 31 (17.8%), while 9 (8%) vs 12 (7.7%) patients were enrolled in clinical trials, in era 1 vs era 2 respectively. Autologous stem cell transplantation (ASCT) as consolidation of first line treatment or use of Rituximab maintenance was not different between Era 1 and Era 2. Among the entire cohort of 343 MCL patients, 3y-EFS and 3y-OS were 51.9% (95% IC 46.7-57.6) and 73.5 (95% CI 68.8-78.4), respectively (Figure 1). 3y-EFS was 45.9% (95% CI 39.0-54.1%) vs 58.4 (95% CI, 51.2-66.6%) in Era 1 vs Era 2 (HR 0.69 (0.51-0.92), p=0.006), 3y-OS was 70.9% (95% CI, 63.4-78.1%) vs 76.1% (95% CI, 69.7-83.1%) in Era 1 vs Era 2 (HR 0.87 (0.61-1.24), p=0.26), respectively (Figure 1). In a univariate analysis, high risk simplified MIPI was prognostic of lower EFS and OS in both the era groups. Conclusion. The BR regimen entered front line therapy of MCL resulting in decline of R-CHOP use in the MER. While rates of ASCT remain similar over the two eras, high dose cytarabine usage in induction therapy has increased. While POC in MCL continue to evolve, the introduction of bendamustine and high-dose citarabine based regimens resulted in an improvement in EFS but not OS in this observational cohort-based analysis. Findings in this study are important for design and planning of future clinical trials incorporating novel agents in induction therapy of MCL. Figure 1. Figure 1. Disclosures Cohen: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BioInvent: Consultancy; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Bristol-Myers Squibb: Research Funding; Infinity Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BioInvent: Consultancy; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Cerhan:Celgene: Research Funding; Jannsen: Other: Scientific Advisory Board; Nanostring: Research Funding.

Abstract Background: The majority of subjects with a diagnosis of primary central nervous system lymphoma (PCSNL) have diffuse large B-cell lymphoma (DLBCL) as their histology. However, there are a sub-set of PCSNL patients who present with other histologies. This retrospective study was conducted to evaluate histological morphology, risk factors and clinical course in subjects with non-diffuse large B-cell primary CNS lymphoma. Methods: We used the Mayo Clinic Lymphoma Database to search for patients with PCSNL during the time period from January 1995 to June 2018. One hundred and fifty nine patients met the criteria and underwent record review. One hundred and nine patients were excluded as they had PCSNL with DLBCL histology (N=47, 43%), secondary central nervous system lymphoma (N=56, 51%) and post-transplant lymphoproliferative disorders (PTLD) with DLBCL morphology (N=6, 5%). We identified fifty patients with PCSNL Non-DLBCL histology, by evaluating the biopsy reports. We abstracted clinical data and outcomes for these groups through medical chart review. Kaplan-Meier analysis was used to estimate survival. Results: The mean age of the study population was 70 ± 11.3 years and 66% were male. Of the 50 patients, the most common histology was low grade CNS lymphoma (N=14, 28%) while Hodgkin's lymphoma (N= 1, 2%), Burkitt's lymphoma (N= 1, 2%) and histiocytic lymphoma (N= 1, 2%) were the least common. The frequencies of other PCSNL Non-DLBCL histology are demonstrated in Table1. Most patients showed good ECOG performance status of 0-2 and four patients had ECOG performance status of grade 3 (N=4, 8%). Six of the patients were immunocompromised (N=6, 12%), PPD positive tuberculosis; corticosteroids and PTLD with DLBCL histology were the causes for the immunocompromised state. The location of the CNS lymphoma included brain (N=24, 50%); spinal cord (N=9, 18%); orbits (N=5, 10%); deep structures which included brainstem, cerebellum, cerebellopontine angle and cauda equina (N=5, 10%); leptomeninges (N=4, 8%) and neural involvement which included sciatic, peroneal and facial nerve (N=3, 6%). CSF examination revealed increased protein levels (N=10, 20%), malignant cells (N=11, 22%), negative cytology (N=14, 28%) and unknown or not done (N=15, 30%). Most patients presented with neurological symptoms such as seizures, peripheral neuropathy (numbness/weakness/tingling), headache, confusion & cognitive disturbances (memory changes), gait disturbances (difficulty with balance/ataxia), visual disturbances (blurry vision) and paraplegia, but none of them presented with B-cell symptoms such as fever, night sweats and weight loss. Treatment modalities included chemotherapy, radiation and surgery. Fourteen patients underwent radiation therapy (N=14, 28%); three of the patients had undergone surgery of which the patient with peripheral T-cell lymphoma had undergone a complete excision, the patient with marginal zone lymphoma had undergone debulking with subtotal craniotomy and the patient with MALT lymphoma had undergone resection with gamma knife. Table 2 demonstrates the various chemotherapy drugs used and the distribution of frequency of biopsy, radiation and surgical treatment in the different pathology of PCSNL Non-DLBCL. The median overall survival period using Kaplan-Meier analysis showed that Burkitt's Lymphoma had the least median time survival of less than a month and PTLD had the highest median survival of 146.25 months (p=0.0017). Table 3 shows the median survival time for all the different pathology's of PCSNL Non-DLBCL. Conclusion: This retrospective study reinforces the critical need for a histologic diagnosis when a patient is diagnosed with PCNSL. PCSNL is considered to be DLBCL but there are other histology's that could potentially be PCSNL and the treatment should be tailored to the individual patient's histology. Disclosures No relevant conflicts of interest to declare.

Abstract Introduction Primary testicular lymphoma (PTL) and testicular involvement of systemic lymphoma (secondary testicular lymphoma, STL) are uncommon. Most testicular lymphomas are aggressive B-cell lymphomas and portend a high risk of extranodal relapse, including CNS relapse. As such, when testicular lymphoma is identified, the management strategy is often changed to include CNS prophylaxis. It is, therefore, essential to evaluate testicular involvement in diagnosis and staging. F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is a standard imaging modality to stage aggressive lymphoma. Physiologic testicular FDG activity can be challenging to distinguish from involvement by lymphoma given a wide range of normal. An imaging threshold for testicular PET uptake would be clinically relevant and would help guide management. We compare testicular FDG avidity in testicular lymphoma with physiologic testicular FDG avidity. Methods Records of patients (pts) diagnosed with PTL or STL from 2002-2018 enrolled in the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource were reviewed, yielding 36 pts with testicular lymphoma. Physiologic testicular avidity by FDG PET/CT was determined from analysis of 70 randomly selected patients who received FDG PET/CT from 2013-2018 prior to treatment for non-lymphoma indications including pulmonary nodule, lung carcinoma, head & neck squamous cell carcinoma, gastrointestinal carcinomas, and metastatic melanoma, without known hematologic malignancy, testicular pathology, or history of testicular infection/surgery by medical chart review. Imaging parameters compared in this analysis were SUVmax and SUVmean. All FDG PET/CT exams were reviewed centrally by a nuclear medicine radiologist and a radiology resident. Results Of the 36 pts with testicular lymphoma, 19 had an orchiectomy prior to FDG PET/CT and 7 pts did not have a staging FDG PET/CT scan. Of the 10 pts with intact testes at the time of staging FDG PET/CT, 1 pt with low-grade lymphoma was excluded. 9 pts with aggressive lymphomas were included in this analysis: 7 pts with diffuse large B cell lymphoma (DLBCL), and 1 pt each with Burkitt lymphoma and peripheral T-cell lymphoma, not otherwise specified. Testicular lymphoma was diagnosed by orchiectomy in 3 pts, and by percutaneous biopsy in 3 pts. 3 pts did not have tissue sampling of testes or scrotal contents, but had an overtly FDG-avid testicle highly suggestive of lymphomatous involvement. These 3 pts had biopsy-proven lymphoma in parotid, bone marrow, and stomach, respectively, with mean testicular SUVmax 6.8 among the 3 pts. The median age in this analysis cohort was 62 years (range 35-88). Of the 7 analyzed DLBCL pts, 6 were non-germinal center B-cell, and 1 was germinal center B-cell. The 70 control pts had a median age of 55 years (range 18-90). In known testicular lymphoma cases and control pts, SUVmax and SUVmean were assessed from the most FDG-avid testicle. Median SUVmax for the testicular lymphoma cases was 13.3 (range 5.5-29.9), compared to a median of 3.8 (range 2.1-5.5) for controls (Wilcoxon p <0.0001). Median SUVmean for testicular lymphoma was 9.2 (range 3.3-18.6), compared to a median of 3.1 (range 1.8-4.8) for controls (Wilcoxon p <0.0001) (Figure). Based on this dataset, an SUVmax cutoff of 5.0 has a sensitivity of 100% (95% CI 66.3-100) and a specificity of 98.6% (98% CI 92.3-99.9) for the detection of testicular involvement by an aggressive lymphoma. Conclusions FDG PET/CT shows significantly greater FDG avidity for testicular aggressive lymphomas as compared with physiologic testicular FDG uptake in this single institution study with centralized radiology review of cases and controls. Testicular FDG avidity greater than an SUVmax 5.0 in staging aggressive lymphoma is highly suggestive for testicular involvement, warranting follow-up clinical exam and ultrasound, at a minimum. In addition, testicles with SUVmax <5.0 in a patient with known lymphoma but no symptoms or signs of testicular involvement should be considered negative for the purposes of staging and treatment planning. A pragmatic limitation of this study is that most patients with testicular involvement of lymphoma underwent orchiectomy prior to FDG PET/CT scan, which decreased our sample size. Larger, pooled studies would be helpful to validate these clinically relevant findings. Figure. Figure. Disclosures Witzig: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Cerhan:Celgene: Research Funding; Jannsen: Other: Scientific Advisory Board; Nanostring: Research Funding.

Abstract Introduction: Outcomes of multidisciplinary and molecular tumor boards have been reported. Lymphoma specific tumor board outcomes have not been reported in the molecular era. In addition, the utility of multi-site, interactive tumor boards using videoconference technology are not widely reported. We prospectively followed the outcomes of a multidisciplinary multi-site lymphoma tumor board in the molecular era and during a change in the revision of the World Health Organization Classification in first published in 2016. Methods: The Mayo Clinic Lymphoma Tumor Board is a component of the international Mayo Clinic Care Network (MCCN). The format includes the clinical case presentation, presentation of radiology and hematopathology findings by the appropriate specialist, proposed treatment options, review of the literature pertinent to the case, and discussion followed by recommendations. Requirement for presentation includes having a diagnosis of lymphoma with pathology reviewed at Mayo Clinic, Rochester, MN (MCR). Pathology and radiology material, when relevant to the case, are required to be reviewed at MCR and presented by MCR pathologists/radiologists. Patients must be presented prospectively, and have active clinical issues or questions to be addressed. Four cases are presented per 60-minute meeting. 309 consecutive highly selected cases with a diagnosis of lymphoma were presented at the Mayo Clinic Lymphoma Tumor Board from 2014 to 2018. The pathology material was independently reviewed by the presenting hematopathologists and radiology material by the presenting radiologist. Participants are office based and included multiple members of the health care team which also incudes pharmacists, clinical research associates affiliated with lymphoma research, and physicians in training. Recommendations were prospectively tracked for changes in radiology interpretation, pathologic diagnosis, and treatment approaches. Actual follow-up of all patients after the meeting was not allowed in the MCCN. Participation in the meeting can be either via in-room attendance at MCR, video conference at a participating MCCN site, or via non-participatory live-stream online. Results: 309 cases were presented were presented from 2014-2018. 258 cases were from MCR, and 51 were not physically seen at MCR. 16 cases were presented at a subsequent meeting for further recommendations in the course of their disease after the initial presentation. 54% of patients presented had changes in some aspect of their care as a result of the meeting. Changes in radiologic interpretation occurred in 5 (1.6%) patients. The pathologic diagnosis changed in 27 (8.7%). Additional testing was recommended in 44 (14%). Clinical management changes were recommended in 90 (29%) cases. These included alterations in treatment approach in 43 (14%), change from undecided to pursuit of treatment 10 (3%), change from undecided regarding treatment approach to further diagnostic testing 4 (1.3%), change from observation to treatment 9 (3%), change from treatment to observation 4 (1.3%), and treatment to further tests in 2 (0.6%) Site in room average attendance (internal/external) was 16.8/8.6. Non-participatory live-stream attendance was not possible to track. In an annual electronic evaluation of this activity, 93% of the responders reported an improvement in knowledge and competence, and 100% recommended no changes to the format of the conference. Enhancements over time have included Continuous Medical Education credit, an in room microscope, and real-time radiology images. Selected cases will now be on line on an international web site. Conclusion: In this highly selected group of lymphoma cases from multiple sites over a 4-year period, 54% of the (167/309) case presentations resulted in changes to some aspect of care as a direct result of this tumor board. A multidisciplinary lymphoma tumor board approach was of value, efficacious, and meaningfully impacted lymphoma patients while substantially enhancing interdisciplinary interactions. Disclosures Ansell: Celldex: Research Funding; Seattle Genetics: Research Funding; Takeda: Research Funding; Bristol-Myers Squibb: Research Funding; Pfizer: Research Funding; Merck & Co: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Affimed: Research Funding.

Abstract Background: Limited data exist regarding histological transformation in patients with Waldenström macroglobulinemia (WM). In this study, we present the disease characteristics, outcomes and risk factors for histological transformation in WM. Methods: Patients with WM seen at Mayo Clinic, Rochester, MN between January 1996 and December 2017 were included. Patients with aggressive non-Hodgkin lymphoma in the setting of WM were considered to have transformation. Univariate analysis for comparing baseline characteristics of transformed versus non-transformed WM was performed using Wilcoxon, Fisher's exact and Chi square tests, as appropriate. Multivariate analysis was performed using logistic regression analysis. Cox proportional hazard method was used to assess the impact on time-to-transformation. All time-to-event analyses were calculated by the Kaplan-Meier method. Results: Of 1014 patients with WM, 42 patients (4.1%) developed histological transformation. The median follow-up for the entire cohort was 9.5 years (95% CI: 8.8-10.5 years). The cumulative probability of transformation was 2.3% at 5 years, 5.3% at 10 years and 8.5% at 15 years from diagnosis of WM, respectively. There was no difference in the 5-year cumulative probability of transformation in patients with WM diagnosed between 1996-2000 (2.1%), 2001-2005 (2.9%), 2006-2010 (2.7%) and 2011-2015 (3.8%), p=0.61.The disease characteristics, laboratory parameters and histology at transformation are outlined in Table 1. In patients with DLBCL histology (n=39), Revised-International Prognostic Index was calculable in 28 patients, with 50% (n=14), 46% (n=13) and 4% (n=1) of DLBCL belonging to poor, good and very good risk groups, respectively. For DLBCL histology, 18 patients were classifiable using Hans algorithm into germinal center B-cell (GCB) type (n=3, 17%) and non-GCB type histology (n=15, 83%). The median lines of therapy received prior to transformation for the entire cohort was 2 (range 0-9), with 5 (11%) patients not having received any therapy for WM before transformation. Number of lines of alkylator-based therapy used prior to transformation [median 1 line (range 0-4)] was comparable to that used in patients in whom WM did not occur [median 1, (range 0-6); p=0.78]. The median time-to-transformation from diagnosis of WM was 4.8 years (95% CI: 2.6- 6.8 years). Overall survival (OS) from transformed disease was 3.2 years (95% CI 1.1-3.9 years). The 10-year OS of patients with WM who transformed was lower (46%) compared to patients without transformation (60%) with a trend towards statistical significance (p=0.08), Figure 1. The MYD88L265P mutation status was available in 333 patients in the entire cohort (22/42 pts in the transformed cohort and 311/972 in the non-transformed cohort. Of the 22 patients in the transformed WM cohort, 13 (59%) exhibited MYD88WT genotype and 9 (41%) exhibited MYD88L265P genotype. The risk of transformation was higher in patients with MYD88WT status [Odds ratio 6.3 (95% CI: 2.6-15.5); p<0.0001]. Additionally, serum lactate dehydrogenase (LDH) was higher at diagnosis of WM in patients who transformed, Table 2. On multivariate analysis, MYD88WT status remained an independent predictor of disease transformation [p=0.003; odds ratio 10 (95% CI: 2.1-48)]. On univariate Cox proportional hazard analysis for identifying predictors of time-to-transformation, only MYD88WT mutational status was associated with shorter time-to-transformation with a 5-year transformation rate of 15.5 % for MYD88WT versus 2.6 % with MYDL265P mutated patients [risk ratio 6.2 (95% CI: 2.5-16.4); p<0.0001]. Treatment-related details in the transformed cases were available for 37 (90%) patients; R-CHOP was the most common (41%) frontline therapy for transformation; 33% patients underwent autologous stem cell transplantation for transformed disease during their disease course. Conclusion: Histological transformation is an uncommon event in WM but confers poorer survival. MYD88WT genotype is independently associated with histological transformation a shorter time-to- transformation in patients with WM. Disclosures Ansell: Trillium: Research Funding; Pfizer: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Takeda: Research Funding; Celldex: Research Funding; Regeneron: Research Funding; Merck & Co: Research Funding; Bristol-Myers Squibb: Research Funding. Gertz:Apellis: Consultancy; Alnylam: Honoraria; spectrum: Consultancy, Honoraria; janssen: Consultancy; annexon: Consultancy; Prothena: Honoraria; Abbvie: Consultancy; Amgen: Consultancy; celgene: Consultancy; Teva: Consultancy; Medscape: Consultancy; Ionis: Honoraria; Research to Practice: Consultancy; Physicians Education Resource: Consultancy. Dingli:Millennium Takeda: Research Funding; Millennium Takeda: Research Funding; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding. Lacy:Celgene: Research Funding. Kumar:Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kapoor:Takeda: Research Funding; Celgene: Research Funding.

Abstract Introduction. Vitreoretinal lymphoma (VRL) is a rare ocular malignancy. Diagnosis and optimal treatment remain a challenge for clinicians. We present clinical characteristics and outcome of a cohort of 69 patients affected by vitreoretinal diffuse large B-cell (DLBCL) lymphoma treated at Mayo Clinic over a 28-year period. Methods. We accessed the Mayo Clinic Lymphoma Data Base to identify all patients > 18 years old with VRL diagnosed between 01/01/1990 and 01/31/2018. Only patients with DLBCL, confirmed at pathological review, were included. Clinical characteristics, therapies, response, relapse patterns and follow up status were collected and analyzed in the cohort and in the different subgroups: primary (PVRL, localized only in eye at diagnosis) vs concurrent (CVRL) vs secondary VRL (SVRL). Chi-squared test, Fisher's exact test and Wilcoxon's signed-rank test were used for analysis. Failure-free survival (FFS), overall survival (OS), central nervous system (CNS) and eye relapse-free survival were analyzed according to Kaplan Meier method. Differences between subgroups were compared with log-rank test. Since the group of SVRL can be affected by a survivorship selection bias, it was investigated separately for the outcome analysis. Results. A total of 69 patients with vitreoretinal DLBCL were included. At diagnosis, 33 (48%) were PVRL, 18 (26%) CVRL (eye plus CNS (N=17) or systemic (N=1) disease) and 18 (26%) had SVRL (9 primary CNS lymphomas, 9 systemic at diagnosis, among which 4 were primary testicular lymphomas). Unilateral intraocular involvement was observed in 16 (23%) cases. Clinical characteristics are reported in Table I. At diagnosis, patients received a systemic treatment in 35 (50%, including high-dose systemic MTX (HD-MTX, N 14, 20%), MTR (HD-MTX, Temozolomide and Rituximab) (N 7, 10%) and CHOP (Cyclophosphamide, Doxorubicin, Vincristine and Prednisone) with or without Rituximab (N 10, 15%)), combined systemic plus intraocular treatment in 15 (22%), local radiotherapy in 10 (14%) and intraocular therapy (intraocular injections of rituximab or MTX or steroids or a combination of these) in 9 (13%) cases. Systemic Rituximab, autologous stem cell transplantation (ASCT) and therapeutic vitrectomy/enucleation were performed in 36 (53%), 20 (29%) and 5 (7%) patients, respectively. The median number of treatments was 2 (range 0-10). Among PVRL and CVRL (N=51), median FFS, CNS relapse-free survival, eye relapse-free survival and OS were: 1.8 y, 4.9 y, 3.8 y and 4.1 y, respectively (Fig 1). Among PVRL they were: 2.6 y, not reached (NR), 5.2 y and 9.3 y, respectively. No CNS relapse occurred beyond 4 years in the PVRL subgroup. The median OS for patients diagnosed between 1990 and 1999, in contrast to 2000 and 2018 was 1.5 y vs 9.4 y respectively (p= 0.0002). OS was significantly higher in PVRL, as compared to CVRL (p= 0.04). Previous immunosuppression and poor performance status were predictive of worse outcome (p=0.04), while ASCT correlated with higher OS (p= 0.009). In PVRL, a combined systemic + intraocular therapy was associated with higher FFS (p=0.002) and CNS-relapse free survival (p= 0.003), but no difference in OS was observed. Among 18 SVRL, at a median follow-up of 1.1 y after vitreoretinal relapse, median FFS and OS were 0.3 y and 1.3 y, respectively. Systemic toxicities included 8 (11.6%) acute renal failures, 8 (11.6%) infections, and 3 (4.3%) hemorrhages. Intraocular toxicities included cataract in 11, vitreal detachment in 3 , ocular hypertension in 5, retinal vessel occlusion in 3 and keratitis in 2 cases. Of 69 patients, 39 (56.5%) died secondary to lymphoma (N=21, 53.8%), infectious toxicity (N=2, 5.2%), unrelated (N=3, 7.7%) or unknown (N=13, 33.3%) causes. Conclusions. VR DLBCL is a rare disease, which can occur as primary, concurrent with systemic, or in relapsed disease. OS over the decades has significantly improved. In PVRL, no late CNS relapses were observed, while late intraocular relapses can occur. A combined approach with intraocular + systemic HD-MTX based treatment at diagnosis was associated with a higher FFS and CNS-relapse free survival in PVRL and is recommended in bilateral involvement, even though no differences in OS were observed. Treatment consolidation with ASCT can be considered in cases with concurrent systemic disease. Further studies are needed to confirm these results and to better define the role of new drugs in treatment of this uncommon malignancy. Disclosures Witzig: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract Background Diffuse large B cell lymphoma post-transplant lymphoproliferative disorder (DLBCL-PTLD) represents a fatal complication after a solid organ transplant (SOT). Approximately 50% of DLBCL-PTLD can be related to Epstein Barr Virus (EBV) infection. However, the EBV status is not taken into account in the DLBCL-PTLD categorization, although increasing evidence suggests its critical role in biological, clinical and prognostic aspects of the disease. In this single center retrospective study, we compared clinical and histological features, as well as outcomes of DLBCL-PTLDs by EBV status. Methods This study focused on patients with SOT who were diagnosed with DLBCL-PTLD at Mayo Clinic (Rochester, MN). Patients were identified through the Mayo Clinic Lymphoma Data base and the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER), between 1989 and 2017. The histology was re-reviewed (RLK) and classified according to the WHO Classification or Tumours of Haematopoietic and Lymphoid Tissues 2017. Cell of origin (COO) was performed by Hans algorithm. EBV RNA in situ hybridization (EBER) was performed. Cox proportional hazards models were used to assess the association of clinical factors in overall survival (OS). Results 148 DLBCL-PTLD were identified. The median age at SOT and at the time of PTLD diagnosis were 50 years (range: 15-71) and 56 years (range: 18-82), respectively. The median time to PTLD diagnosis from SOT was 38 months (range: 1-499). The types of SOT included renal (44%), liver (36%), cardiac (9%), renal/pancreas (5%), pancreas (8%), lung (7%) and multiorgan (4%). 62% were stage III-IV, 30% had elevated LDH and 67% had an IPI >1. 88% of patients presented with extranodal disease, and 16% had involvement of the grafted organ. Eighty-three (56%) cases were EBV positive. The COO information was available on 35 cases. The non-GCB subtype was identified in 24 cases and GCB subtype in 11 cases. The initial treatment was as follows: reduction in immunosuppression (12%), immunosuppression reduction with rituximab (26%), rituximab alone (5%), chemotherapy with or without rituximab (35%). Patients with EBV positive PTLD were more likely to have grafted organ involvement (20% vs. 8%, p=0.047) and late PTLD (occurring after 12 months from SOT - 60% vs. 8%, p<0.001) than patients with EBV negative PTLD. There was no association between EBV status and age, sex, stage, LDH, and extranodal site involvement. At a median follow-up of 80 months (range 9-269), 83 patients (56%) had died. The 5-year survival rate from PTLD diagnosis was 56% (95% CI: 48-65%). The median OS was 85 months (95% CI: 37-148). There was no difference in OS in patients with EBV positive PTLD (median OS=84.7 months, HR=1.21, 95% CI: 0.77-1.92) versus patients with EBV negative DLBCL-PTLD (median OS=85.4 months, p=0.41). Conclusion Our study assessed the impact of EBV status on the presentation and clinical outcome of DLBCL-PTLD in a 148-patient single-institution cohort. 56% of cases were EBV positive. EBV positivity was associated with grafted organ involvement and late PTLD diagnosis. Patients with EBV-negative and EBV-positive disease had similar survival from PTLD diagnosis. Disclosures Maurer: Celgene: Research Funding; Morphosys: Research Funding; Nanostring: Research Funding. Cerhan:Nanostring: Research Funding; Jannsen: Other: Scientific Advisory Board; Celgene: Research Funding.

Abstract Background: Indolent non-Hodgkin lymphoma (iNHL), including follicular lymphoma (FL) and marginal zone lymphoma (MZL), is typically responsive to initial chemoimmunotherapy, but relapse is expected. Single-agent rituximab is FDA approved and frequently administered for patients with relapsed/refractory (R/R) low-grade or follicular CD20-positive B-cell NHL. Lenalidomide is an immunomodulatory agent with preclinical and clinical antilymphoma activity alone and in combination with rituximab. We compared the efficacy and safety of lenalidomide plus rituximab (R2) to rituximab (plus placebo) in patients with R/R iNHL. Methods: AUGMENT (NCT01938001) is a multicenter, double-blind, randomized phase III study of R2 vs rituximab/placebo (control) in patients with FL grade 1-3a or MZL who were previously treated with ≥ 1 prior systemic therapy with documented relapsed or refractory disease but not refractory to rituximab (refractory was defined as < partial response to rituximab or rituximab-chemotherapy OR disease progression < 6 months after last rituximab dose). Patients were stratified by prior rituximab treatment (yes vs no), time since last antilymphoma therapy (≤ 2 vs > 2 years), and histology (FL vs MZL), and then randomized 1:1 to R2 or control for up to 1 year. R2 patients received oral lenalidomide 20 mg/day (d), d1-21/28 for 12 cycles plus rituximab IV 375 mg/m2 weekly in cycle 1 and d1 of cycles 2-5. Control patients received rituximab and placebo on the same schedule. Dose modifications were pre-specified in the protocol to manage toxicities. The primary endpoint was progression-free survival (PFS) per 2007 IWG criteria without PET as assessed by Independent Review Committee (IRC; central review). Secondary endpoints included overall response rate (ORR), complete response (CR), duration of response (DOR), time-to-next antilymphoma treatment (TTNLT), overall survival (OS), and safety. Results: A total of 358 patients were randomized (n = 178 R2; n = 180 control), median age was 63 years (range, 26 - 88), 34% FLIPI score ≥ 3, and histologies of 82% FL/18% MZL. Median number of prior systemic treatments was 1 (range, 1 - 12); 84% received prior rituximab and 51% had prior antilymphoma therapy within 2 years of enrollment. At median follow-up of 28.3 months, the study met its primary endpoint of PFS with HR = 0.46 (95% CI, 0.34 - 0.62; P < 0.0001) (Figure 1). Median PFS was 39.4 months for R2 vs 14.1 months for control. IRC-assessed ORR for R2 was 78% vs 53% for control (P < 0.0001). CR was 34% for R2 vs 18% for control (P = 0.001). Median DOR was 36.6 and 21.7 months for R2 and control arms, respectively. TTNLT was improved for R2 vs control with HR = 0.54 (95% CI, 0.38 - 0.78; P = 0.0007). OS data were not mature with 16 deaths reported in the R2 arm vs 26 deaths in control (HR = 0.61 [95% CI, 0.33 - 1.13]). Selected all-grade treatment-emergent adverse events (TEAEs) of interest more common in the R2 vs control arm (≥ 10% difference) were infections (63% vs 49%), cutaneous reactions (32% vs 12%), constipation (26% vs 14%), thrombocytopenia (15% vs 4%), and tumor flare reaction (11% vs 1%). Grade 3/4 TEAEs were reported in 69% R2 and 32% control patients. More frequent grade 3/4 TEAEs in the R2 vs control arm were primarily attributable to increased neutropenia (50% vs 13%) and leukopenia (7% vs 2%). Grade 5 TEAEs were reported in 2 patients in each arm. TEAEs leading to discontinuation of lenalidomide occurred in 9% of patients vs 5% for rituximab + placebo. Neutropenia was the only TEAE leading to discontinuation of lenalidomide in > 1 patient (n = 5). Seventy-one percent of R2 patients completed all 12 cycles of planned treatment vs 61% of control. Disease progression was the leading reason for discontinuation of lenalidomide/placebo (n = 21 R2, n = 54 control). Conclusions: R2 demonstrated superior efficacy over rituximab monotherapy (plus placebo) as measured by the primary endpoint of progression-free survival as well as secondary endpoints of ORR, CR, DOR, and TTNLT in patients with R/R FL grade 1-3a and MZL. At this early analysis, fewer deaths have been observed in the R2 arm. Despite additional hematologic toxicity, greater efficacy of the R2 regimen (and fewer early progressions) allowed more patients to complete the planned therapy and delayed the need for subsequent treatment. R2 represents an important new treatment option in patients with previously treated FL/MZL, with meaningful advantages over single-agent rituximab. Disclosures Leonard: Celgene: Consultancy; Karyopharm: Consultancy; ADC Therapeutics: Consultancy; MEI Pharma: Consultancy; Juno: Consultancy; Bayer: Consultancy; AstraZeneca: Consultancy; Sutro: Consultancy; Biotest: Consultancy; United Therapeutics: Consultancy; Pfizer: Consultancy; Novartis: Consultancy; Genentech/Roche: Consultancy; Gilead: Consultancy; BMS: Consultancy. Trněný:F. Hoffman-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board, Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Abbvie: Honoraria, Research Funding; Gilead: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Morphosys: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Sandoz: Honoraria. Izutsu:Otsuka: Honoraria; Bristol- Myers Squibb: Honoraria; Nihon Medi-Physics: Honoraria; Novartis: Honoraria; Mundhi: Honoraria; HUYA Bioscience International: Research Funding; Kyowa Hakko Kirin: Honoraria; Takeda: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Amgen: Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Gilead Sciences: Honoraria; Eisai: Honoraria, Research Funding; Chugai: Honoraria, Research Funding; Daiichi Sankyo: Honoraria, Research Funding; Astellas: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Zenyaku: Research Funding; Celltrion: Research Funding; MSD: Honoraria; Ono: Honoraria, Research Funding; Symbio: Research Funding; Celgene: Consultancy, Research Funding; Solasia: Research Funding; Sanofi: Research Funding; Meiji Seika: Honoraria; Shionogi: Honoraria; Asahi Kasei: Honoraria. Fowler:Janssen: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding. Zhu:Beijing Cancer Hospital (Peking University Cancer Hospital): Employment. Scheliga:INCA - Instituto Nacional Do Cancer, Brazil: Employment. Pinto:Servier: Consultancy; BMS: Honoraria, Research Funding; MSD: Honoraria; Roche: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Gilead: Honoraria. Scheinberg:Novartis: Consultancy, Speakers Bureau; Janssen: Honoraria, Research Funding; Pfizer: Speakers Bureau. Flinn:Trillium: Research Funding; Takeda: Research Funding; Calithera: Research Funding; Incyte: Research Funding; Verastem: Research Funding; ArQule: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Research Funding; Forty Seven: Research Funding; Agios: Research Funding; BeiGene: Research Funding; Kite: Research Funding; Portola: Research Funding; Verastem: Consultancy, Research Funding; Celgene: Research Funding; Pfizer: Research Funding; Forma: Research Funding; Merck: Research Funding; Novartis: Research Funding; Constellation: Research Funding; Curis: Research Funding; Infinity: Research Funding; TG Therapeutics: Research Funding; Genentech: Research Funding; Gilead: Research Funding. Moreira:Instituto Português de Oncologia do Porto FG, EPE, Porto, Portugal: Employment. Liu:Celgene: Employment, Equity Ownership. Kalambakas:Celgene: Employment, Equity Ownership. Fustier:Celgene: Employment, Equity Ownership. Wu:Celgene: Employment, Equity Ownership. Gribben:Cancer Research UK: Research Funding; Unum: Equity Ownership; Novartis: Honoraria; Abbvie: Honoraria; Wellcome Trust: Research Funding; Acerta Pharma: Honoraria, Research Funding; Kite: Honoraria; NIH: Research Funding; Roche: Honoraria; Janssen: Honoraria, Research Funding; Medical Research Council: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; TG Therapeutics: Honoraria; Pharmacyclics: Honoraria.