Inwards, David J.

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.

7532 Background: Mantle Cell Lymphoma (MCL) is characterized by t(11;14) resulting in over expression of cyclin D1, a member of the phosphatidylinosital 3-kinase (PI3K) pathway. Temsirolimus is a novel inhibitor of the mammalian target of rapamycin (mTOR) kinase. Previous studies with weekly temsirolimus at a dose of 250mg demonstrated a 38% overall response rate in 35 patients (JCO 23 (23); 5347–56, 2005). Thrombocytopenia was frequently observed and was dose limiting. The current study tested whether low-doses (25mg) of temsirolimus could produce a similar overall response rate (ORR) with less toxicity. Methods: Eligible patients had biopsy proven cyclin D1 positive MCL and had relapsed or were refractory to therapy. Patients received temsirolimus 25mg IV weekly as a single agent. Patients were restaged after 1 cycle (4 doses), after 3 cycles, and every 3 cycles thereafter. Patients with a tumor response after 6 cycles were eligible to continue drug for a total of 12 or 2 cycles after complete remission (CR) and then were observed without maintenance. The goal was to achieve an ORR of at least 20%. Results: Twenty-nine patients were enrolled between March and August 2005. Twenty-two patients have completed therapy. One patient with a major protocol violation on cycle-1 and one ineligible patient were excluded, leaving 27 evaluable patients. The ORR was 41% (11/27), with 1 CR and 10 PRs. Early evaluation of TTP showed a median of 5.5 months (95% CI: 3.3–7.7) and the duration of response for the 11 responders was 6.2 months (95% CI: 3.6 to not yet reached). These results compare favorably with the 6.5 months and 6.9 months, respectively, found in previous trials that used 250 mg. The median dose delivered per month was 80 mg (range, 10–100 mg). Sixteen (59%) of patients required a dose reduction. The median time on treatment was 4.4 months (95% CI, 3.3–7.7). The incidence of grade 3 and 4 thrombocytopenia was 12% and 0%, respectively. One patient experienced grade 5 infection without neutropenia, which was considered unrelated to CCI-779. Conclusions: Single agent CCI-779 at a dose of 25mg has anti-tumor activity in relapsed MCL similar to the 250 mg dose. This study indicates that combinations of temsirolimus with other agents should be feasible. [Table: see text]

17505 Background: A previous trial of 2-CDA as a single agent for therapy of mantle cell lymphoma demonstrated this agent to be efficacious with an overall response rate of 81% (31% complete responses) (Blood 1999 Nov 15; 94:660a). A phase II study of the addition of rituximab to 2-CDA was conducted by the North Central Cancer Treatment Group based on improved outcomes achieved by the addition of rituximab to other regimens active in MCL. Methods: This one-stage phase II study was designed to determine the complete response (CR) or complete response/unconfirmed (CRu) rate. Central pathology confirmation of cyclin D1 positive mantle cell lymphoma was required. No previous therapy for lymphoma was allowed, with the exception of splenectomy. The shedule was rituximab 375 mg/m2 IV day 1; 2-CDA 5 mg/m2/d IV days 1–5 of a 4-week cycle. After 2 of the first 6 patients developed grade 4 neutropenia, subsequent patients received either pegfilgrastim or filgrastim support. Patients received 2–6 cycles of therapy, depending on response. Patients were required to achieve at least a PR after 2 cycles of therapy to continue on protocol therapy. Results: Patient characteristics of all 29 eligible pts: median age: 70 (range: 41–86); 21 male, 8 female; PS 0 (55.2%), PS 1 (41.4%), PS 2 (3.5%); stage II (6.9%), stage III (3.5%), stage IV (89.7%); prior splenectomy (20.7%). The only grade 4 adverse event occurring more than once was neutropenia (20.7%). One patient died of cerebral ischemia in the setting of pneumonia without neutropenia. Response has been determined in 26 pts with 50.0% (95% CI: 30.0–70.0%) achieving a CR, none of whom have relapsed to date. Three patients progressed early at 17, 45, and 46 days, two of whom have died, and a fourth relapsed day 222. 10 pts (34.0%) went on to receive further therapy off study, 5 in less than a PR after 2 cycles, 2 in PR after study therapy, and 1 who went off study for a rash. At last contact, 26 (89.7%) were alive (median follow-up 10.7 months; range: 1–28). Conclusions: Rituximab and cladribine were well tolerated for the treatment of MCL in a group including elderly patients. The response rate may have been underestimated due to the study design, which required at least a PR after 2 cycles to continue therapy. Despite this, 50% achieved a complete remission. [Table: see text]

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.

Background With lymphoma survival rates increasing and a growing population of long-term survivors, the development of cardiovascular disease (CVD) in this patient population is of increasing importance. Anthracyclines are critical in the management of many lymphoma subtypes. However, there is a risk of developing anthracycline-induced CVD. Here, we estimate the cumulative incidence of CVD in adult lymphoma survivors and investigate risk factors associated with post diagnosis CVD. Methods Participants were from the Mayo component of the Molecular Epidemiology Resource (MER) of the University of Iowa/Mayo Clinic Lymphoma Specialized Program of Research Excellence (SPORE). From 2002-2015, the MER offered enrollment to all patients with newly diagnosed lymphoma who are US residents and age >18 years. Participants completed a risk factor questionnaire, and clinical and treatment data were abstracted from medical records. Patients were contacted every 6 months for the first 3 years after diagnosis and annually thereafter to assess disease status, re-treatment and new onset morbidity including CVD. CVD events, including congestive heart failure (CHF), coronary artery disease (CAD), valvular heart disease (VHD), and arrhythmia were identified and validated against medical records. CHF was validated with the Cardiovascular Health Study Criteria and/or the Framingham Criteria. CAD, arrhythmia, and VHD were validated using clinical definitions. We calculated the cumulative incidence of CVD, with death modeled as a competing risk. The association of risk factors and treatments with risk of CVD was estimated using hazard ratios (HR) and 95% confidence intervals (CI) from Cox regression with a competing risk of death. Risk factors included age, sex, diabetes, smoking, body mass index (BMI), and treatment with anthracyclines or radiation therapy. Results The study consisted of 3,063 lymphoma patients after excluding those with chronic lymphocytic leukemia and CVD prior to lymphoma diagnosis. The median age at diagnosis was 59 years (range 18-95), and 56% were males. At a median follow-up was 6.9 years (range 0.8-17.1), 640 patients (21%) had died without CVD and 485 patients self-reported CVD post lymphoma diagnosis, of which 280 (57.7%) were validated. Cardiovascular events included 86 CHF, 78 CAD, 40 VHD, and 164 arrhythmias. The cumulative incidence of CVD (Figure 1) at 5 and 10 years was 6.0% (95% 5.2%-7.0%) and 10.7% (95% CI 9.5%-12.1%), respectively. In multivariable analysis, increasing age (HR=3.93 per 5 years, p<0.001), male sex (HR=1.33, p=0.03), former smoker (HR=1.04, p=0.77), current smoker (HR=1.96, p<0.001), BMI>30 kg/m2 (HR=1.50, p=0.01), and anthracycline treatment (HR=1.49. p<0.001) were all significantly associated with risk of overall CVD, while there was no association with diabetes (HR=0.92, p=0.70) or radiation therapy (HR=1.05, p=0.78) in the multivariable model. Anthracycline use was significantly associated with increased risk of CHF (HR=2.64, p<0.001) and arrhythmia (HR=1.51, p<0.01), but not VHD (HR=0.83, p=0.56) or CAD (HR=1.23, p=0.31) after adjustment for the cardiac risk factors. The number of anthracycline cycles ranged from 0 to 12. 63.2% of individuals that received anthracyclines received 6 cycles. The 5-year cumulative incidence of CVD for 0, 1-5, 6, and >6 anthracycline cycles was 5%, 6.9%, 7.4%, and 7.7%, respectively. Adjusting for cardiac risk factors, the number of anthracycline cycles was significantly associated with increased risk of CVD (1-5 cycles HR=1.34, p=0.11; 6 cycles HR=1.51, p<0.01; >6 cycles HR=2.04, p=0.03). Furthermore, the number of anthracycline cycles was associated with CHF (1-5 cycles HR=2.82, p<0.001; 6 cycles HR=2.46, p<0.001; >6 cycles HR=5.33, p<0.001) and arrhythmia (1-5 cycles HR=1.31, p=0.27; 6 cycles HR=1.60, p<0.01; >6 cycles HR=1.65, p=0.27). Conclusions In the modern treatment era, the risk of new onset CVD in patients with lymphoma without a history of CVD is approximately 1% per year after diagnosis. Arrhythmia and CHF were the most commonly occurring CVD events in this cohort. Both traditional CVD risk factors and treatment with anthracyclines was associated with an increased risk of developing CVD, and anthracyclines were a risk factor for arrhythmia and CHF in particular. Prevention of CVD in lymphoma patients will need to address both treatment and traditional lifestyle factors. Figure 1 Disclosures Maurer: Morphosys: Membership on an entity's Board of Directors or advisory committees; Nanostring: Research Funding; Celgene: Research Funding. Nowakowski:Selvita: Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Curis: Research Funding; Bayer: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; NanoString: Research Funding; MorphoSys: Consultancy, Research Funding. Cerhan:NanoString: Research Funding; Celgene: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees.

Background Although rituximab‐based high‐dose therapy is frequently used in diffuse large B cell lymphoma (DLBCL) patients undergoing autologous hematopoietic cell transplantation (auto‐HCT), data supporting the benefits are not available. Herein, we report the impact of rituximab‐based conditioning on auto‐HCT outcomes in patients who have DLBCL. Methods Using the Center for International Blood and Marrow Transplant Research (CIBMTR) registry, 862 adult DLBCL patients undergoing auto‐HCT between 2003 and 2017 using BEAM (BCNU, etoposide, cytarabine, melphalan) conditioning regimen were included. All patients received frontline rituximab‐containing chemoimmunotherapy and had chemosensitive disease pre‐HCT. Early chemoimmunotherapy failure was defined as not achieving complete remission (CR) after frontline chemoimmunotherapy or relapse within 1 year of initial diagnosis. The primary outcome was overall survival (OS). Results The study cohort was divided into 2 groups: BEAM (n = 667) and R‐BEAM (n = 195). On multivariate analysis, no significant difference was seen in OS ( P = .83) or progression‐free survival (PFS) ( P = .61) across the 2 cohorts. No significant association between the use of rituximab and risk of relapse ( P = .15) or nonrelapse mortality ( P = .12) was observed. Variables independently associated with lower OS included older age at auto‐HCT ( P < .001), absence of CR at auto‐HCT ( P < .001) and early chemoimmunotherapy failure ( P < .001). Older age ( P < .0002) and non‐CR pre‐HCT ( P < .0001) were also associated with inferior PFS. There was no significant difference in early infectious complications between the 2 cohorts. Conclusion In this large registry analysis of DLBCL patients undergoing auto‐HCT, the addition of rituximab to the BEAM conditioning regimen had no impact on transplantation outcomes. Older age, absence of CR pre auto‐HCT, and early chemoimmunotherapy failure were associated with inferior survival.

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: 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.