Citations

7574 Background: Patients (pts) with relapsed aggressive NHL are usually treated with intensive platinum-based chemotherapy regimens prior to stem cell transplant (SCT). This study was designed to learn the toxicity and efficacy of adding 4 doses of rituximab to the standard DHAP salvage chemotherapy regimen. Methods: Eligible pts had biopsy-proven relapsed CD20+ NHL and were eligible for platinum-based chemotherapy. Pts were treated with rituximab 375 mg/m2 d1,8,15, and 22 as well as cis-platinum 100 mg/m2 d3, cytosine arabinoside 2 g/m2 IV q 12 hours x two doses d4, dexamethasone 40 mg PO/IV d3–6, and G-CSF d5–14. Pts were restaged after 1 and 2 cycles; responding pts could proceed to SCT or further cycles of DHAP at MD discretion. There was no provision for rituximab maintenance. The goal was to achieve an overall response rate (ORR) of ≥ 75%. Results: Fifty-eight pts were enrolled between 10/29/00 and 6/20/03. The median age was 63 years (range, 43–83). One pt was ineligible because the tumor was CD20-. All 57 eligible pts completed one cycle; 48 pts completed 2 cycles. The ORR was 70% (40/57) with 16 (28%) CR/CRu and 24 (42%) PR. For all 57 pts, the median TTP was 13.1 months (mos) (95% CI: 7.3–18.2) and the median OS 30.5 mos (95% CI: 17.8–52.5). Seventeen pts (30%) proceeded to SCT. The median duration of response (DR), time to progression (TTP) and overall survival (OS) for the SCT pts were 41.6, 42.3, and 43.6 mos, respectively. The median DR, TTP, and OS for the 25 pts who responded to RDHAP but did not proceed to SCT were 12.4, 13.1, and 38.8 mos, respectively. The incidence of grade 3 and 4 thrombocytopenia was 53% and 39%, respectively. The incidence of grade 3 and 4 neutropenia was 11% and 68%, respectively. Six pts (11%) had nephrotoxicity–five grade 3 and two grade 4 (one pt had both) and one pt required dialysis. Conclusions: The addition of rituximab to standard DHAP is safe with similar toxicity profile to DHAP alone. Despite a high ORR, the CR rate and the % pts proceeding to SCT in this cooperative group setting remain low. New agents are needed that can be added to these regimens to increase the effectiveness and reduce toxicity to allow more pts to proceed to SCT. No significant financial relationships to disclose.

8055 Background: mTOR inhibition with intravenous temsirolimus (Wyeth Pharmaceuticals) has been associated with responses in mantle cell lymphoma (J Clin Oncol 23;5347, 2005) as well as other lymphomas (Blood 108 (11) 2483; 2006). This phase II study tested the oral mTOR inhibitor everolimus (RAD001, Novartis Pharmaceuticals) in three simultaneous two-stage phase II lymphoma studies - aggressive (group 1), indolent (group 2), or uncommon (group 3). The goals were to learn the toxicity profile and to assess the anti-tumor response. Planned interim analysis for groups 1 and 3 have been completed and are the subject of this report. Methods: Patients (pts) received 10 mg PO daily for each 28 day cycle (up to 12) and restaged after 2, 6, and 12 cycles. The primary endpoint is the confirmed response rate, including CR, CRu or PR. 12 pts were enrolled in stage 1 of each study. At least 1 success in 12 is required to proceed to stage 2, to a total of 37 pts. Overall, the treatment will be considered promising if 4 or more successes are observed in all 37 pts in each group. Results: The median age of the 12 pts in group 1 was 68.5 yrs (range: 53–80), with a median of 3 (range, 1–15) prior therapies. Four pts had a prior stem cell transplant (SCT). Pts completed a median of 7 (range, 1–12) cycles of therapy. 6 confirmed responses have been achieved (1 CR, 5 PR), meeting the overall criteria for promising results in this study. Common grade 3 adverse events (AEs) include thrombocytopenia (3 pts) and anemia (2 pts). For group 3, the median age was 49 yrs (range, 27–78), with a median of 7 (range, 1–13) prior therapies and 6 pts had a prior SCT. Pts have completed a median of 6.5 cycles (range, 1–11). 5 confirmed responses have been achieved (5 PR), meeting the criteria for this regimen to be considered promising. Of these 5 patients, 3 had HD, 1 T-cell NHL, and 1 had macroglobulinemia. Common grade 3 AEs include anemia (3 pts) and thrombocytopenia (2 pts). No grade 4 AEs were reported. Conclusions: Oral everolimus has activity in a spectrum of lymphomas with acceptable toxicity. The responses observed in both group 1 and group 3 met the criteria to continue accrual. These results provide the rationale for additional studies with this novel class of agents and to integrate mTOR inhibitors into salvage treatment regimens. No significant financial relationships to disclose.

Introduction: Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of mature aggressive T-cell non-Hodgkin lymphomas. They carry a worse prognosis for most subtypes compared with their B-cell counterparts. Despite the recent approval of newer therapies, the response rate and duration of clinical benefit is short and the outlook for patients with relapsed/refractory (RR) PTCL remains poor. There is therefore a need for novel effective therapies in PTCL. Targeting the profoundly immunosuppressive tumor microenvironment (TME) in PTCL is one such approach. Preclinical data show that malignant cells in PTCL overexpress programmed death ligand 1 (PD-L1), which signals via programmed death-1 (PD-1) receptor, and provides an inhibitory signal further suppressing antitumor immunity. PD-1/PD-L1/2 interactions in PTCL are particularly complicated as both the receptor and ligands can be expressed on the malignant T-cell. While the use of anti-PD-1 blocking antibodies has shown remarkable efficacy particularly in relapsed Hodgkin lymphoma, only a small number of patients with PTCL have been treated with checkpoint blockade. We conducted an investigator-initiated phase 2 prospective study of single-agent nivolumab for RR PTCL. We report here the results of the prespecified interim analysis. Study design and patient selection: Nivolumab was given at a flat dose of 240 mg intravenously (IV) every 2 weeks for 8 cycles then 480 mg IV every 4 weeks starting cycle 9. The primary objective was to assess the overall response rate (ORR) defined as proportion of subjects achieving either a partial response (PR) or complete response (CR) within 12 cycles of treatment. Secondary objectives were to assess safety and tolerability of nivolumab in PTCL and to assess progression-free survival (PFS), duration of response (DOR) and overall survival (OS). Pre-planned sample size was 39, assuming that an ORR of 10% or less would be considered negative and an ORR of 30% or greater would warrant further study. We used a one-stage design with an interim analysis (upon enrolling 12 subjects) based on a Simon optimal design to assess efficacy. This design had a 90% power with a 1-sided 10% level test. The Duffy and Santner method was utilized to determine confidence intervals for the ORR. Kaplan-Meier methods were used to assess PFS, OS, and DOR. This study was sponsored by Bristol-Myers Squibb (NCT03075553). Results: Twelve patients who received at least one cycle of nivolumab were included in this interim analysis. Patient characteristics are illustrated in table 1. Half (6/12) of the patients had angioimmunoblastic T-cell lymphoma (AITL), 3/12 had PTCL, not otherwise specified (NOS), one had ALK negative anaplastic large cell lymphoma (ALK- ALCL). Most (11/12) were advanced stage (stage 4), had extranodal disease and half of the patients had received a prior autologous transplant. The ORR was 33% (4/12) (95% CI: 12.3 - 63.7%): 1 CR seen in ALK-ALCL; 2 PR, 1 in PTCL, NOS and 1 in enteropathy associated T-cell lymphoma; 1 CR in AITL. The median DOR was 3.6 months (95% CI: 1.9-6.9). The median PFS for all 12 patients was short at 1.9 months (95% CI: 1.5-8.7); median OS was 7.9 months (95% CI: 3.4-10.8) (Panel A). Hyperprogressive disease (defined as dramatic progression within 1 cycle of treatment) occurred in 4 patients. Observed grade 3 and higher adverse events (AEs) were as follows: non-hematologic AEs in 5/12 (41.7%), while hematologic AEs were seen in 3/12 (25%) patients. Conclusions: Nivolumab had modest clinical activity in patients with R/R PTCL and the study met the criteria at interim analysis to continue accrual. However, due to the high number of patients with hyperprogressive disease, the moderate activity of the drug, and short DOR, a decision was made to halt the study. These findings likely reflect the distinct biology of PTCL and should be considered when designing future studies using checkpoint inhibitors in these diseases. Further studies are indicated using nivolumab in combination (rather than a single-agent) and use of biomarkers to better predict the responders. Disclosures Bennani: Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board. Nowakowski:Selvita: Membership on an entity's Board of Directors or advisory committees; NanoString: Research Funding; Celgene: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Curis: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Genentech, Inc.: Research Funding; MorphoSys: Consultancy, Research Funding. Ansell:Merck: Other: research funding for clinical trials; Seattle Genetics: Other: research funding for clinical trials; Takeda: Other: research funding for clinical trials; Bristol Myers Squibb: Other: research funding for clinical trials; Regeneron: Other: research funding for clinical trials; Affimed: Other: research funding for clinical trials; Pfizer: Other: research funding for clinical trials; AI Therapeutics: Other: research funding for clinical trials.

AbstractHistological transformation in Waldenström macroglobulinemia (WM) is an uncommon complication, with limited data, particularly regarding the impact of MYD88 L265P mutation on transformation. We examined risk factors and outcomes associated with transformation in WM, highlighting the role of MYD88 L265P mutation. Patients with WM seen at Mayo Clinic, Rochester, USA and University Hospital of Reims, France, between 01/01/1996 and December 31, 2017 were included; 50 (4.3%) of 1147 patients transformed to a high‐grade lymphoma, with median time‐to‐transformation of 4.5 (range 0‐21) years in the transformed cohort. The MYD88 L265P mutation status was known in 435/1147 (38%) patients (406 with non‐transformed WM and 29 patients in transformed cohort). On multivariate analysis, MYD88 WT status alone was an independent predictor of transformation (odds ratio, 7[95%CI: 2.1‐23]; P = .003). Additionally, the MYD88 WT status was independently associated with shorter time‐to‐transformation (HR 7.9 [95%CI: 2.3‐27; P = .001]), with a 5‐year transformation rate of 16% for MYD88 WT vs 2.8% with MYD88 L265P mutated patients. Patients with transformation demonstrated a significant increase in risk of death compared to patients who did not transform (HR 5.075; 95%CI: 3.8‐6.8; P < .001). In conclusion, the MYD88 WT status is an independent predictor of transformation and associated with a shorter time‐to‐transformation. Additionally, transformation conferred an inferior overall survival in patients with WM.

Abstract Background: Vitamin D insufficiency (VDI) has been associated with inferior outcomes in patients with follicular lymphoma (FL) treated with chemotherapy and an anti-CD20 monoclonal antibody (immunochemotherapy; IC), but whether this association holds for other FL treatment strategies is not known. Furthermore, the subset of FL patients who experience clinical failure (progression, treatment failure) within 12 months of diagnosis have an inferior outcome compared to those achieving event-free status at 12 months (EFS12). We tested the hypothesis that VDI is predictive of early clinical failure (failure to achieve EFS12), overall survival (OS), and lymphoma-specific survival (LSS) among FL patients overall and in subgroups who were initially observed, treated with IC, rituximab monotherapy, or other therapies. Methods: We evaluated this hypothesis in a prospective cohort study of 642 newly diagnosed patients with grade 1-3a FL enrolled from 2002-2012 in the Molecular Epidemiology Resource of the Iowa/Mayo Lymphoma SPORE. Serum 25-hydroxyvitamin D [25(OH)D] was measured by liquid chromatography-tandem mass spectroscopy, and VDI was defined as serum total 25(OH)D <20 ng/mL (per Institute of Medicine criteria) determined within 120 days of diagnosis. We used logistic regression to estimate Odds Ratios (ORs) and 95% confidence intervals (CIs) and Cox regression to estimate hazard ratios (HRs) and 95% CIs. We adjusted for FLIPI, body mass index, and month of blood draw; for the full cohort, we additionally adjusted for treatment. Results: The mean age at diagnosis was 60 years (range 23-93); 19% of patients had VDI. The median follow-up period was 59 months (range 1-144), with 297 events and 78 deaths (42 due to lymphoma). Treatment included IC (N=252), observation (N=218), rituximab monotherapy (N=76), or other (N=96). OS and EFS curves are shown in figures 1 and 2. In the full cohort, VDI was associated with inferior EFS12 (OR=2.05; 95% CI 1.18-3.54), OS (HR=2.35; 95% CI 1.37-4.02), and LSS (HR=2.97; 95% CI 1.52-5.80). In the IC subset, VDI was associated with inferior EFS12 (OR=3.00; 95% CI 1.26-7.13), OS (HR=2.86; 95% CI 1.39-5.85), and LSS (HR=2.96; 95% CI 1.29-6.79). VDI was associated with inferior OS in patients who were observed (HR=2.25; 95% CI 1.20-6.76) or received other therapies (HR=3.06; 95% CI 1.01-9.24). VDI was positively but not statistically significantly associated with inferior EFS12 in the patients who were observed (OR=1.71; 95% CI 0.70-4.17) or received other therapies (OR=2.31; 95% CI 0.41-13.07), with low power for these associations; LSS could not be estimated due to lack of deaths. There were too few events (N=10) and deaths (N=5) in the R-monotherapy group for analysis. Conclusions: We confirm previous findings that vitamin D insufficiency is associated with adverse long-term prognosis among patients with FL treated with IC, and extend these findings to patients who are initially observed or treated with other therapies. For the first time, we observed an association of vitamin D insufficiency with early clinical failure, suggesting a potentially modifiable factor to address in this subset of patients with poor outcomes. Whether treating VDI improves outcomes in FL warrants assessment. Disclosures Ansell: BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding. Nowakowski:Celgene: Research Funding; Morphosys: Research Funding; Bayer: Consultancy, Research Funding.

Background: Neurolymphomatosis (NL) is a highly rare disorder defined as infiltration of peripheral nervous system by a lymphoproliferative neoplasm, both presented as the first manifestation of the malignancy (primary NL) or as a site of disease progression or relapse (secondary NL). Due to rarity of this disorder data on clinical features, best approach and outcome are limited. Furthermore diagnosis of this disease is often uncertain and based on radiological images only. Methods: We retrospectively reviewed clinical records of all histologically confirmed-NL, diagnosed and treated at the Division of Hematology of Mayo Clinic in Rochester, MN between January 2002 and December 2018. Clinical features and outcome were analyzed. Responses to therapy were assessed by post-treatment radiological changes and clinical symptoms improvement. Survival analysis such as progression free survival (PFS) and overall survival (OS) were estimated using Kaplan Meier curves with log-rank test. Comparison between subgroups was investigated using Fisher's exact test and Wilcoxon test for categorical and continuous variables, respectively. Results: Over a 16-year period 40 patients with biopsy-proven NL were included in study. Primary and secondary NL were 19 (48%) and 21 (52%) respectively, with a median age of 60.5 years (range 37-83) and male sex 24/40 (60%). The predominant histology was represented by B-cell lymphomas (39/40, 97%) with a vast majority large B-cell lymphoma (LBCL) 27/40 (67%) and only 1 case of T-cell lymphoma. The affected structures included brachial plexus (12/40, 35%), lumbosacral plexus (5/40, 12%), cauda equine and nerve roots (14/40, 35%), sciatic nerve (12/40, 30%), femoral nerve (4/40, 10%), cranial nerves (8/40, 20%), multiple nerves involved in 23/40 (57%). Four out of 40 cases had brain involvement and cerebrospinal fluid (CSF) was positive in 7/29 (24%). NL clinical manifestations included muscular weakness (33/4, 82%), sensory deficit (32/40, 80%), pain (28/40, 70%) and autonomic dysfunction (3/40, 7%). Magnetic resonance imaging (MRI) detected neural abnormalities in 35/36 cases (97%), CT imaging identified disease in 3/8 (37%) and FDG-PET scan was positive in 22/31 (71%); electromyography showed some grade of neuropathy in 28/29 (97%). Treatment included systemic chemotherapy in 38/40 (95%) cases, containing high dose methotrexate (HD-MTX) in 26/40 (65%) and rituximab in 20/40 (50%); 11/39 (28%) patients underwent consolidative autologous stem cell transplant (ASCT); 4/40 received consolidative radiotherapy (RT), 1/40 was treated with RT alone; intrathecal chemotherapy was infused in 1/40 cases; one patient with solely great auricular nerve NL involvement was cured with surgery only. Treatment efficacy evaluated by imaging and clinical improvement consisted with an overall response rate (ORR) of 73% (27/37) with a 24% (9/37) of complete remission (CR); No statistical difference in rate of response was observed by different systemic treatments. Of note, patients undergoing HDC-ASCT consolidation obtained 100% of ORR (n=10) versus 61.5% (n=16) achieved by others (P=0.03). With a median follow up of 45.1 months (range 0.5-186.7) a 36 months-OS of 77% (95% CI, 60-88) was observed for the whole cohort. A trend of longer survival rate for primary NL was observed, with a 36-month OS of 95% (95% CI, 72-99) vs. 55% (95% CI, 30-77) for secondary NL (p 0.134). A strong benefit in terms of outcome was observed for patients receiving rituximab-containing regimens with a 36 months-PFS of 72% (95% CI, 55-92) vs 28% (95% CI, 12-53) (P=0.001), and a 36 months-OS of 87% (CI 95%, 60-98) vs. 65% (95% CI , 41-84) (P=0.04) (figure 1); no survival difference was observed for patients treated with systemic therapy containing HD-MTX vs. others. ASCT consolidation was associated with a trend of improved survival with a 36 months-PFS of 69% (95% CI, 35-90) vs. 47% (95% CI, 29-66) for others (P=0.09). Conclusions: With the limit of a retrospective analysis, LBCL represent the predominant histologic subtype of NL; MRI and FGD-PET appeared to be the most accurate radiological tools to detect neural disease. Systemic treatments including rituximab should be preferred, HD-MTX seems to be not so effective while ASCT consolidation may be considered in selected patients. Due to the spare number of cases treated with RT its role cannot be clarified by our study. Disclosures Nowakowski: NanoString: Research Funding; MorphoSys: Consultancy, Research Funding; Genentech, Inc.: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Curis: Research Funding; Bayer: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Selvita: Membership on an entity's Board of Directors or advisory committees.

Background: Central nervous system (CNS) involvement by peripheral T cell lymphoma (PTCL) is a rare condition. Among primary CNS lymphomas, only 2% are secondary to PTCL, while the risk of CNS relapse in all cases of PTCL is estimated at 2% to 6%. Little is known about the presentation and outcomes of PTCL patients with CNS involvement given the rarity of this entity. In this study, we describe patient characteristics, histology, and clinical course of patients with CNS involvement by PTCL. Methods: The Mayo Clinic Lymphoma Database was used to identify PTCL patients with primary or secondary CNS involvement seen at our institution between 2000 and 2018. A total of 12 patients were identified and their medical records were reviewed for patient and disease characteristics, CNS-directed treatment modality, and outcomes. The Kaplan-Meier method was used for time-to-event analysis. Results: The median age at CNS diagnosis was 63 years (range 41 to 76) and 11 (93%) patients were male. The histological diagnoses were PTCL, NOS in 9 (75%) patients, enteropathy-associated T-cell lymphoma in 2 (17%) patients, and angioimmunoblastic T-cell lymphoma in 1 (8%) patient. Five patients presented with primary T-cell CNS lymphoma (all with a PTCL, NOS histology), while the remaining 7 (58%) patients also had systemic involvement. All patients presented with neurologic symptoms at the time of CNS involvement diagnosis including: focal motor deficits in 6 patients (unilateral upper extremity weakness, gait impairments, and hemiparesis), cognitive decline in 5 patients (memory impairments, reduced attention, and confusion), headache in 4 patients, and seizure in 3 patients. The CNS disease location included the brain parenchyma in 9 (75%) patients, leptomeninges in 1 (8%) patient, and lumbar plexus in 1 (8%) patient. One patient (8%) had positive CSF finding only without radiologic evidence of involvement. CSF analysis was performed in 11 patients. Elevated protein levels were noted in 3 (27%) patients, malignant cells in 2 (18%), and no clear abnormalities in the remaining 6 (55%) patients. Concomitant bone marrow involvement was seen in only 1 patient. Elevated LDH was seen in 2 patients. The a median LDH was 195 U/L (range 139 to 4,360) The most common CNS-directed therapies were: high-dose methotrexate (MTX)-based regimens in 8 (67%) patients, including high-dose MTX in combination with temozolomide (n=2), or cytarabine and thiotepa (n=2). Intrathecal MTX, temozolomide and dexamethasone, lenalidomide, high-dose steroids, and surgical resection were the treatment modality used for one patient each. At a median follow up of 18 months, eight (75%) out of 12 patients were not alive at the time of last follow up. The median overall survival (OS) from diagnosis was 16 months (95% CI: 2.8-173). The median progression free survival (PFS) from initiation of CNS-directed therapy was 9 months (95% CI: 1.6-33) (figure). Four patients had a PFS longer than 12 months. These 4 patients were treated with: temozolomide/dexamethasone, high-dose MTX, lenalidomide, and high-dose MTX followed by cytarabine/thiothepa. Conclusion: CNS involvement by T-cell lymphoma is a rare complication that carries a poor prognosis. Early onset of neurologic symptoms should trigger prompt investigation of CNS involvement. Despite the short OS and PFS, some patients may achieve a relatively longer disease free interval. Disclosures Bennani: Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Kite Pharma: Other: Advisory board. Cerhan:Celgene: Research Funding; NanoString: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees. Nowakowski:Celgene: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Curis: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Genentech, Inc.: Research Funding; MorphoSys: Consultancy, Research Funding; NanoString: Research Funding; Selvita: Membership on an entity's Board of Directors or advisory committees. Ansell:Mayo Clinic Rochester: Employment; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding. Paludo:Celgene: Research Funding; Verily Life Sciences: Research Funding; Verily Life Sciences: Research Funding; Celgene: Research Funding.

Introduction: Front-line immunochemotherapy (IC) with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is expected to cure 60-70% of newly diagnosed DLBCL. Up to one third of newly diagnosed DLBCL patients will have relapsed or refractory (r/r) disease.1 Current standard of care for these patients is salvage chemotherapy and, if chemosensitive, to be followed by high dose chemotherapy with hematopoietic cell rescue (autoHCT).2,3 Event-free survival at 24 months (EFS24) after frontline IC is associated with excellent long-term outcomes with overall survival (OS) similar to that of age- and sex-matched controls.4 In comparison, those achieving EFS24 following autoHCT for relapsed or refractory disease may have increased risk for late-mortality compared to the general population with advanced age and intensive salvage therapy contributing to the risk of late complications.5 We sought to better characterize EFS24 after autoHCT to determine the utility of this end-point for informed clinical decisions, patient management, and future clinical trials. Methods: Patients were prospectively enrolled onto the Molecular Epidemiology Resource (MER) of the University of Iowa/ Mayo Clinic Specialized Program of Research Excellence (SPORE). Patients were followed for relapse, retreatment, and death; all events were validated by medical record review. For this analysis patients were included if they were consented within 9 months of initial diagnosis of DLBCL between 2002-2012, had received anthracycline-based IC (R-CHOP, or similar), and eventually had undergone autoHCT for r/r DLBCL. Patients with primary central nervous system (CNS) lymphoma or post-transplant lymphoproliferative disorders (PTLD) were excluded. Overall survival (OS) was defined as time from autoHCT until death due to any cause. Event-free survival (EFS) was defined as time from autoHCT until progression, relapse, retreatment, or death due to any cause. OS from achieving EFS24 after autoHCT was compared to age- and sex-matched general US population. Results: 108 patients underwent autoHCT for relapsed DLBCL between 2002 and 2017. Median age at autoHCT of the patients was 60 years (range 20-78) and 72 (67%) were male. The most common transplant conditioning regimen was BEAM (82%). At a median follow-up after autoHCT of 85 months (range 1-171), 72 patients (67%) had an event and 64 patients (59%) had died. Kaplan-Meier estimates for EFS and OS at 24 months from the time of autoHCT were 49% (95% CI: 40-59) and 61% (95% CI: 52-71), respectively. 52 patients had a progression within 24 months of autoHCT; OS from progression was poor (median OS=2.8 months, 95% CI: 1.8-6.0; 5 year OS = 9%, 95% CI: 2-22). 48 patients achieved EFS24 after autoHCT; median OS from achieving EFS24 was 136 months (95% CI: 92-NE) and 5 year OS was 79% (95% CI: 68-93). This was inferior to the background population (Figure 1, SMR=3.64, 95% CI: 2.11-6.27, p<0.0001). Eight patients had a progression after achieving EFS24 from autoHCT. OS from progression in these 8 patients (median OS=27.3 months, 95% CI: 14.4-NE; 5 year OS = 16%, 95% CI: 3-93) was improved compared to progression within 24 months of autoHCT (p=0.072, figure B). Cause of death (COD) in EFS24 achievers was progression of lymphoma (n=6), infection (n=1), secondary malignancy related to therapy (n=3), heart disease (n=1), and unknown (n=1). Conclusions: Patients achieving EFS24 after salvage chemotherapy and autoHCT have a favorable long-term prognosis; however, overall survival remained inferior to the general population. Most common COD after achieving EFS24 was progression of lymphoma. In spite of this, EFS24 remains a valuable end-point for informed clinical decisions, patient management, and future clinical trials. Figure 1 Disclosures Maurer: Morphosys: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Nanostring: Research Funding. Ansell:Mayo Clinic Rochester: Employment; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding. Cerhan:Celgene: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; NanoString: Research Funding. Farooq:Celgene: Honoraria; Kite Pharma: 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.