Gascoyne, Randy D.

Abstract Background We have previously reported and validated that the E-IPI, provided better discrimination of overall survival (OS) than the IPI for DLBCL patients > 60 years of age treated with R-CHOP (Advani et al., BJH 2010 and 12-ICML 2013 Abstract 222). Recent reports suggest that males > 60 years treated with R-CHOP have worse outcomes likely related to differences in rituximab clearance (Muller et al., Blood 2012). In this study, we explored if the addition of male sex to the E-IPI further improved risk stratification. Methods DLBCL patients > 60 years treated with R-CHOP on the E4494, RICOVER-60 and GELA 98-5 trials were included. A multivariate analysis was performed to assess whether male sex is an independent prognostic factor for OS in addition to the five E-IPI risk factors, E-IPI score, and E-IPI risk group. Male sex (S) was added as an additional risk factor to the E-IPI (S-EIPI, 0-6) and patients regrouped according to the number of risk factors: low (L)=0-1, low intermediate (LI)=2, high intermediate (HI)=3 and high (H)=4-6 based on the observed OS using Kaplan-Meier curves. C-statistic was used to compare the discrimination ability. The 5 year OS was estimated using the Kaplan-Meier method. Results 1079 patients (E4494, n=267; RICOVER-60, n=610; GELA 98-5, n=202) with a median follow-up of 8.9 years were included. In multivariate analyses, male sex was a significant independent predictor for OS adjusting for all five E-IPI factors, (HR 1.5, p < 0.0001), E-IPI score (HR 1.42, p < 0.001), and E-IPI risk group (HR 1.42, p < 0.001) (Table 1). C-statistic was 0.66 for S-EIPI and 0.64 for EIPI. Incorporation of sex into the E-IPI shifted 35% patients to higher risk groups, including 110 patients into the highest risk group (Table 2). The estimated 5 year OS for the S-EIPI L, LI, HI, and H risk groups was 87%, 70%, 58%, and 40%, respectively (Table 3). Compared to E-IPI, the 95% C.I. did not overlap among S-EIPI risk groups. Conclusion For DLBCL patients >60 years treated with R-CHOP, our results suggest the addition of male sex to the E-IPI may improve categorization of patients into well-defined clinically relevant risk groups. Patients with low risk S-EIPI have an excellent outcome (5 year OS 87%). Patients with high risk S-EIPI have a 5 year OS of only 40% and therapies beyond standard R-CHOP need to be explored. Disclosures: Horning: Genentech: Employment; Roche: Equity Ownership.

Abstract Introduction The role of body mass index (BMI) impacting clinical outcome among lymphoma patients is controversial. Two recent studies suggest that increased BMI is associated with significantly improved survival. In this study the association between BMI at study entry and failure-free survival (FFS) and overall survival (OS) was evaluated in three phase III Eastern Cooperative Oncology Group-led trials, among patients with DLBCL (E4494), follicular lymphoma (FL) (E1496) and Hodgkin's lymphoma (HL) (E2496). Patients and Methods 537 patients with DLBCL, 730 patients with HD and 282 patients with FL were included in the analysis. BMI was calculated as weight (kilograms) divided by the square of height (meters), using data at study entry. BMI was analyzed both as continuous and categorical variables (underweight <18.5 kg/m2, normal weight: 18.5 to < 25 kg/ m2, overweight: 25 to < 30 kg/ m2, and obese :≥ 30 kg/ m2).The underweight group was excluded due to low (< 2%) prevalence. Baseline patient and clinical characteristics, treatment received and clinical outcomes were compared across BMI categories. PFS was defined as the time from study entry to relapse, progression, or death. OS was measured from study entry to death of any cause. The log-rank test and Cox regression models was used to check the association. The association between BMI and FFS/OS was also independently assessed among patients treated with rituximab. A sensitivity analysis was performed excluding patients with significant weight loss at baseline. Results Among patients with DLBCL, HL and FL, the median age was 70, 33 and 56; 29%, 29% and 37% were obese and 38%, 27% and 37% were overweight, respectively. Age was significantly different among BMI groups in all three studies. Higher BMI groups tended to have better prognosis at study entry among DLBCL and HL patients. BMI was not associated with clinical outcome, with p-values of 0.89, 0.30 and 0.40 for FFS, and p-values of 0.64, 0.67 and 0.09 for OS, for patients with DLBCL, HL and FL, respectively (Figure 1). In multivariate analysis adjusting for other clinical factors, BMI remains an insignificant predictor for all three histologies (Table 1). When limiting to patients treated with rituximab, the association remains non-significant for both FL patients (p=0.92 for PFS, p=0.36 for OS) and DLBCL patients (Figure 2). A subset analysis of males with DLBCL treated on R-CHOP, which matched the study cohort used in a recent report (Carson et al, 2012), revealed no differences in FFS (p=0.48) or OS (p=0.58) (Figure 2). Sensitivity analysis excluding patients with weight loss at study entry resulted in similar findings. Conclusion BMI was not significantly associated with clinical outcomes among patients with DLBCL, HL or FL, in three prospective phase III clinical trials. The findings contradict some previous reports of similar investigations. Further work is required to understand the observed discrepancies. Disclosures: Horning: Genentech: Employment.

Abstract Abstract 87 Background: The International Prognostic Index (IPI) remains the most powerful predictor of clinical outcome in DLBCL in the R-CHOP era, serving as a useful surrogate for the biology we are just beginning to understand. With a follow-up of more than 9 years, its uniformly staged and treated patients and its prospectively collected unstained slides for correlative studies, the clinical data set from E4494, the US Intergroup trial comparing CHOP and RCHOP in patients >60 years with DLBCL, stands as a valuable resource for investigating prognosis in DLBCL. Based on immunohistochemistry, we previously showed that rituximab modulates the prognostic significance of some biomarkers in DLBCL. With these same specimens, the quantitative nuclease protection assay (qNPA), a methodology for measuring mRNA levels in FFPET, was used to develop separate prognostic signatures for the CHOP and RCHOP arms that can be simply applied using stored unstained slides. Methods: Five micron unstained FFPET sections from 183 eligible and evaluable cases enrolled on E4494 and submitted for prospective immunohistochemical correlative studies more than ten years ago were used for this analysis. Tissue was scraped from slides and a multiplexed qNPA was performed in triplicate using a customized Array Plate assay (HTG, Inc) for 43 genes of interest. TBP served as a housekeeping gene. Association between standardized log gene expression and patient failure-free survival (FFS) and overall survival (OS) was obtained using the Cox proportional hazards model. A weighted analysis was used to eliminate the confounding effect of maintenance rituximab. Genes that showed at least marginal significance in the univariate analysis were used to perform LASSO (penalized method to select best subset) to select a final list of genes in the multivariate analysis. Using the predictive model for either CHOP or R-CHOP induction, individual risk scores were calculated based on the multivariable model, and cases were dichotomized into low and high risk groups based on the median risk score. The model was then validated using the Lenz dataset (NEJM, 2008). Results: In six cases, tissue from slides prepared >10 years ago was compared to freshly cut sections from corresponding blocks, and showed excellent concordance (corr=0.86). On-study characteristics for the 176 cases with analyzable data were representative of the greater E4494 patient population. Six gene predictors were developed for each arm of the trial: RCHOP: FN1, LMO2, AKT1, HIF1a, AKT3, BCL2; and CHOP: PDCD4, HLADRB1, COL3A1, LMO2, ROBO4, TP53. Both signatures proved powerful predictors of FFS and OS among CHOP (FFS: p=0.0031; OS: p=0.0013) and RCHOP (FFS: p=0.001; OS=p=0.0015) treated patients. When adjusted for the clinically-based IPI, the gene-risk score retained its significance (CHOP: FFS p=0.0007; OS p=0.0011; RCHOP: FFS p=0.003; OS, p=0.001) while the IPI became only marginally significant (CHOP: FFS: p=0.06, OS p=0.06; R-CHOP: FFS p=0.09, OS p=0.02), suggesting that the gene predictor accounted for much of the predictive power of the IPI. The predictive model was then validated using the Lenz dataset for OS. The predictor models for CHOP and R-CHOP-treated patients effectively dichotomized patients into prognostic subgroups (CHOP: p<0.0001; RCHOP: p=0.0014; see figure below) and this difference was maintained when the subset over age 60 was analyzed (CHOP: p=0.0008; RCHOP: p=0.017). When adjusted for the IPI, the molecular predictor developed for CHOP treated patients remained robust (OS: P=.0001; HR 2.39), while the molecular predictor for RCHOP predicted OS marginally (p=.06; HR 1.82), with shorter followup than the CHOP cohort. Conclusions: Unstained slides from FFPET stored for many years may be used to investigate gene expression in lymphoma biopsy specimens for which there is mature followup. Gene risk scores based on the expression of a limited number of genes are powerful predictors of clinical outcome. Disclosures: Pollock: HTG, Inc.: Employment, Equity Ownership. Botros:HTG, Inc.: Employment, Equity Ownership. Horning:Genentech: Employment, Equity Ownership.

Abstract Abstract 1603 Background: We have previously reported similar outcomes for patients with bulky stage I or II mediastinal HL treated with combined modality therapy either with ABVD + radiotherapy or the Stanford V regimen in the North American Intergroup trial E2496 (Advani et al, ASH 2010 abstract 416). In the current analysis, we compare the patterns of failure between the two groups. Methods: Patients with stage I/II bulky mediastinal HL (maximum mediastinal mass width > 1/3 of intrathoracic diameter) were randomized to receive chemotherapy (CT) on either Arm A (ABVD x 6–8 cycles administered q 28 days) or Arm B (12 weeks of Stanford V administered weekly). Two-3 weeks after completion of chemotherapy all patients received modified involved field radiotherapy (RT) (36 Gy) delivered to the mediastinum, hila, and supraclavicular regions. Patients on Stanford V arm also received involved field RT to any other sites ≥ 5 cm at diagnosis. Patients were assessed 3, 6 and 12 months after completing RT with computed tomography scanning and then every 6 months for 5 years. The primary end points were failure free survival (FFS) and overall survival (OS). Disease progression was defined as 'in-field', 'distant' or both relative to the radiation fields prescribed in the E2496 protocol. Distant sites of failure were further characterized as intra-thoracic, intra-abdominal or other (bone, bone marrow and axillae, if not previously irradiated). Results: Two hundred and sixty-seven patients were randomized: 136 on the ABVD arm and 131 on the Stanford V arm. Patient characteristics were well matched with no differences between two arms in overall response rates (ORR), FFS and OS. (Advani et al ASH 2010 abstract 416). At a median follow up of 5.5 years 40 patients have relapsed with no difference in ABVD (n=18, 13%) versus Stanford V (n=22, 17%) (p=0.49). Central review of RT fields available in 37/40 patients found major violations with under treatment of tumor noted in 7/37 (19%). Patterns of failure are shown in Table 1. There were no differences in patterns of relapse for the two study arms. In-field relapses occurred in <10% in both study arms. Conclusion: For patients with stage I/II bulky mediastinal HL, combined modality therapy with either ABVD +RT or the Stanford V regimen results in excellent disease control. In-field relapse was uncommon. These results set a benchmark for assessing ongoing trials omitting RT in patients with stage I/II bulky mediastinal HL. Future research efforts should focus on risk stratification to identify the small subset of patients who are likely to fail standard upfront therapy. US cooperative group efforts in this subset of patients are ongoing that use interim PET-CT imaging based risk-adapted strategies. Disclosures: Horning: Genentech: Employment, Equity Ownership.

Abstract Abstract 2687 Background: Patients with early stage (Stages I, II) diffuse large B cell (DLBCL) have been traditionally treated with either CHOP x6 alone or with CHOP followed by involved field external beam radiotherapy (IFRT). With the demonstration of the superiority of rituximab CHOP (RCHOP) in advanced stage DLBCL, RCHOP has been adopted as the chemoimmunotherapy standard of care in early stage disease with or without IFRT. Radioimmunotherapy (RIT) has the advantage of delivering high-energy, short path length radiation in a targeted approach using an anti-CD20 antibody as the carrier. Thus, radiation is potentially targeted to microscopic sites outside of known disease. Goals: To evaluate the complete response (CR) rate and functional CR rate (CR or CRu/PR and PET negative) to a treatment regimen of RCHOP followed by 90Y-ibritumomab tiuxetan (Zevalin, Spectrum Pharmaceuticals) radioimmunotherapy (RIT); only patients not achieving PET negative status after RIT were to be given IFRT. The study goal was to achieve a functional CR rate of ≥75%. Patients and Methods: Eligible patients were those with new, untreated Stages I or II DLBCL as determined by standard CT scanning, adequate blood counts, creatinine and bilirubin <2.0 mg/dl, cardiac ejection fraction >45%, and a performance status 0–2. Stage I patients were required to have ≥1 adverse risk factor (≥60 years, bulky disease, elevated LDH or PS2). Patients received standard RCHOP21 × 2 cycles and then were restaged. Patients in CR received 2 additional cycles; those in PR or CRu received 4 additional cycles. At end of RCHOP a PET scan was repeated and centrally reviewed; those with a PR or functional CR proceeded to Zevalin RIT 0.4 mCi/kg (maximum 32 mCi) within 12 weeks of the last RCHOP. Patients were restaged 12 weeks post-RIT; PET negative patients were observed without maintenance; PET positive patients received 30Gy involved field radiation and then were restaged. Descriptive statistics were used to summarize the patient characteristics, treatment and response. The Kaplan-Meier method was used to estimate failure rates. Results: Between Dec 2004 and Nov 2008, 62 patients were enrolled; after pathology review 53 were considered eligible. 42% (22/53) patients were stage I/IE; 58% (31/53) were stage II/IIE. 57% (30/53) received 6 cycles of RCHOP; 40% (21/53) received 4 cycles; and 2 patients received 1 and 2 cycles, respectively. After immunochemotherapy, 79% (42/53) were in functional CR and 19% (10/53) PR; 1 was unevaluable. Of the 53 eligible patients who completed RCHOP therapy 91% (48/53) proceeded to RIT. After RIT, 87% (46/53; 95% CI: 75–95) were in CR/CRu and 89% (47/53; 95% CI:77–96%) were in functional CR. One patient proceeded to IFRT. The median follow-up is now 4.3 years. Seven (13%) of patients have had tumor progression but only 2 have died (1 of disease). At 4 years, 88% of patients remain progression free and 98% remain alive (Fig 1,2). The median has not been reached for either PFS or OS. There has been one case of myelodysplastic syndrome. Conclusions: Combination immunochemotherapy and RIT is an active regimen for patients with early stage DLBCL. Nearly all patients will achieve functional CR without the requirement of IFRT. The regimen of RCHOP and RIT for early stage DLBCL is worthy of further study. Disclosures: Witzig: Spectrum: Membership on an entity's Board of Directors or advisory committees, Research Funding, uncompensated Other. Off Label Use: Use of Zevalin in treating patients with Stage I-II DLBCL. Kahl:Roche: Consultancy; Genentech: Consultancy, Research Funding. Horning:Genentech: Employment; Roche: Equity Ownership.

Abstract Introduction : Follicular lymphoma (FL) remains an incurable malignancy as patients eventually experience progressive disease. A subset of patients is at risk of early lymphoma-related mortality due to histological transformation (TFL) to aggressive lymphoma (2-3% of patients per year) or early progression after immuno-chemotherapy, each of which leads to shortened survival. Mutations associated with transformation and/or early progression have been reported in the literature (e.g. CDKN2A, TP53, B2M) and the m7-FLIPI clinico-genetic risk model defines a high-risk patient group with poor failure-free survival after first-line treatment. However, the current knowledge of genetic alterations underlying transformation and/or early progression is inadequate to explain the majority of transformed cases and accurately predict early progressive disease. Materials and Methods: We performed targeted capture-based sequencing of 94 genes in a large cohort of fresh-frozen and formalin-fixed and paraffin-embedded patient specimens (402 samples in total). This cohort comprised 277 samples from 159 patients that experienced transformation (including 128 samples at T1 (the time of FL) and 149 samples at T2 (the time of transformation) with 118 paired biopsies) and 125 samples from 125 patients (pre-treatment samples only) presenting with either early progression within 2.5 years after starting immunochemotherapy (n=41) or late or never progression for at least 5 years after starting immunochemotherapy or observation (n=84). Mutations were called using MutationSeq and putative single nucleotide polymorphisms were filtered out using either matching germline samples (n=84) or dbSNP (v147). Bayesian proportion tests were used to compare the prevalence of gene mutations between groups. Results : We first compared T1 (n=128) and T2 (n=149) samples from 159 patients experiencing transformation. Eleven genes were more commonly altered in transformed lymphoma. These included genes that had previously been associated with transformation, such as TP53, B2M, MYC and EBF1, as well as genes that have not yet been implicated as contributing to this process, for example EZH2, CCND3, PIM1 and ITPKB. Moreover, mutations in GNA13, S1PR2 and P2RY8, that have been implicated in dissemination of germinal centre B cells, were enriched in T2 samples. In addition, cell-of-origin classification was available for 108 of the TFL cases with DLBCL histology, 18 and 90 of which were of the ABC and GCB subtype, respectively. Although the number of ABC-TFL cases was small, we observed higher percentages of BCL10 (16% versus 1%, Fisher P=0.004), CD79B (22% versus 4%, Fisher P=0.005) and MYD88 mutations (28% versus 9%, P=0.006) in ABC-TFL than in GCB-TFL, suggesting that B-cell receptor signaling and NF-κB signaling are important contributors to the ABC phenotype in TFL. Next, we assessed the association of gene mutations with patient outcomes contrasting early progressers (n=41) and late or non-progressers (n=84). Eleven genes were mutated more commonly in early progressers than in late progressers, including KMT2C, TP53, BTG1, MKI67, XBP1 and SOCS1. Overall, 32 out of 41 early progressers (78%) had mutations in at least one of the 11 early progression-associated genes, but none of the individual early progression-associated genes were mutated at a frequency > 22%. Thus, early progression appears to be related to relatively infrequent genetic alterations. None of the early progression-associated gene mutations form part of the m7-FLIPI outcome predictor. Furthermore, in our cohort that was enriched for clinical extremes, the m7-FLIPI was similarly associated with early progression when compared to the FLIPI but it was not superior, having higher specificity (89% versus 76%), but lower sensitivity (36% versus 63%). Conclusions: We found novel associations of gene mutations with transformation and showed that TFL is molecularly heterogeneous, with the ABC subtype being characterized by differential gene mutation when compared to the GCB subtype. With regards to progressive disease after immuno-chemotherapy, our approach identified early progression as a distinct clinico-genetic disease category that is imperfectly captured by traditional prognostic tools. Disclosures Connors: Seattle Genetics: Research Funding; Bristol Myers Squib: Research Funding; F Hoffmann-La Roche: Research Funding; NanoString Technologies: Research Funding; Millennium Takeda: Research Funding. Scott:NanoString Technologies: Patents & Royalties: named inventor on a patent for molecular subtyping of DLBCL that has been licensed to NanoString Technologies.

Abstract Abstract 415 Background: The ability to cure patients (pts) with advanced Hodgkin's Lymphoma (HL) with combination chemotherapy (CC) (MOPP and variants, ABVD and variants) represented a major milestone in oncology research, and CC became a paradigm for other malignancies. Further, the rationale for combined modality therapy (CMT) (radiation (RT) and CC) in HL evolved based on the high frequency of relapse in initially involved sites. As response rates and survival improved, newer treatments such as the combined modality Stanford V regimen were developed to shorten the duration of chemotherapy, add RT to sites of disease and reduce toxicity while maintaining or improving the cure rate. Indeed, the Stanford V regimen was tested and validated in a Phase II co-operative group trial (E1492) (J Clin Oncol 2000; 18:972). In order to investigate this approach against “standard” therapy, we conducted a randomized Phase III Intergroup trial of ABVD vs. the Stanford V regimen for patients with locally extensive or advanced HL. Objectives: The trial was designed to detect a 33% reduction in the failure free survival (FFS) hazard rate with Stanford V compared with ABVD, which corresponds to a difference in five-year FFS of 64% vs. 74%. Method: Patients with locally extensive (defined as clinical Ann Arbor Stage I-IIA/B and bulky mediastinal disease (BMD) (mass > 1/3 maximum intrathoracic diameter on standing postero-anterior chest x-ray or >/−10 cm on computerized tomography) or advanced (Ann Arbor Stage III or IV) HL were randomized to receive either ABVD × 6–8 cycles (C) (51% had 6 C, 35% had 8 C, 14% had <6 C) + 36 Gy (only in pts with BMD) or Stanford V × 12 weeks (95% had 12 weeks) + 36 Gy (for sites >5cm or for macroscopic splenic disease). The log-rank test was used to compare FFS for all eligible patients stratified on extent of disease (locally extensive vs. advanced), and number of International Prognostic Factor Project (IPFP) risk factors (0–2 vs. 3–7). An extended Cox model was also used to address non-proportional hazard between the two arms. Results: 854 pts enrolled from April, 1999 to June, 2006 and 812 were eligible for analysis. 404 pts were randomized to ABVD and 408 to Stanford V. Median age was 33 yrs in both arms (range 16–83). 53% were men and 47% women; 4% had Stage I, 31% had Stage II, 39% had Stage III and 25% had Stage IV disease by Ann Arbor criteria. 35% of pts on ABVD and 35% on Stanford V had BMD. Three % of pts had nodular lymphocyte predominant HL, 77% of pts had nodular sclerosis HL, 14% had mixed cell HL. Age, stage, pathology and risk factors (0–2 vs. 3–7) were similar in both arms. In total, 65% were IPFP score 0–2 and 33% were 3–6. Response rate. There was no difference in response rates (RR) between the two arms (ABVD=72% CR+ CCR, 7.7% PR, 7.9% SD; Stanford V= 69 % CR +CCR, 7% PR and 10 % SD. 8% were not evaluable for response on ABVD and 9% on Stanford V. Toxicity was similar in both groups. The most frequent Grade 3 + 4 toxicity was neutropenia, and was similar between the 2 groups (76% Grade 3 + 4 in ABVD and 70% Grade 3+ 4 in Stanford V). Grade 5 toxicity was <1% in both groups. There was, however, more Grade 3 lymphopenia in Stanford V (78% vs. 42%, p< 0.0001) and more Grade 3 +4 sensory neuropathy in Stanford V (10%) than in ABVD (3%) (p< 0.0001). A total of 26 second primary cancers developed, 12 after ABVD and 14 after Stanford V (p=NS). FFS and OS. For 812 eligible patients, with a median follow up of 5.25 years, 5-year FFS was 73% for ABVD and 71% for Stanford V (p=0.29 by log rank) (Figure left); 5-year OS was 88% for ABVD and 87% for Stanford V (p=0.87 by log-rank, HR=0.97, 95% CI: 0.65 to 1.44) (Figure right) indicating no significant difference in either FFS or OS between the 2 arms. Conclusion: In the largest Phase III intergroup trial of HL in North America, there was no significant difference in RR, FFS, OS, and 5-year toxicity when ABVD (+ RT for BMD) is compared with Stanford V (+RT for nodal sites >5 cm and macroscopic splenic disease). There was more Grade 3 lymphopenia (p< 0.0001) and more Grade 3 + 4 sensory neuropathy (p< 0.0001) on Stanford V. Thus ABVD (plus RT for BMD) remains the standard of care because Stanford V did not meet the objective of 33% improvement in FFS. For some patients, Stanford V, when given as described with RT, remains an acceptable alternative. Disclosures: Friedberg: Genentech: Honoraria. Blum:Seattle Genetics: Research Funding; Novartis: Research Funding; Celgene: Research Funding. Horning:Genentech: Employment.

Abstract Abstract 416 Background: Standard therapy for locally extensive Hodgkin Lymphoma (HL) defined as stage I/II with bulky mediastinal disease [mediastinal mass ratio (MMR) > than 1/3 of the chest diameter on standing postero-anterior chest x-ray or 10 cm on computerized tomography] is combined modality therapy (CMT). E2496 was a North American intergroup, randomized phase III study comparing ABVD versus the Stanford V regimen for patients with locally extensive and advanced stage HL. In this subgroup analysis we compare two CMT approaches, ABVD + radiotherapy (RT) and the Stanford V regimen, in patients with stage I/II bulky mediastinal HL. Methods: Patients with stage I/II HL bulky mediastinal disease were randomized to receive chemotherapy (CT) on either Arm A (ABVD × 6–8 cycles administered q 28 days) or Arm B (12 weeks of Stanford V, administered weekly). Two-3 weeks after completion of chemotherapy, modified involved field RT was delivered at 36 Gy to the mediastinum to patients on ABVD as well as Stanford V. Patients on Stanford V also received involved field RT to any other sites >5 cm at diagnosis. The primary endpoint was failure free survival (FFS) defined as the time to either progression/relapse or death. The log-rank test was used to compare FFS and OS (overall survival) for all eligible patients. Results: Of the 812 eligible patients with advanced HL enrolled on the study 267 had locally advanced bulky mediastinal disease: 136 on ABVD and 131 on Stanford V. Patient characteristics between the two randomized groups were well matched with a median age of 30 years and 86% had stage II disease. On ABVD 61% of patients received 6 cycles, 29% 8 cycles of CT and 77% required some dose modification. In Stanford V 97% completed the assigned 12 weeks of CT and 76% required some dose modification. 82% received RT per protocol in ABVD versus 88% in Stanford V. The overall response (CR+PR) was 82% in ABVD and 86% in Stanford V. At a median follow-up of 5.47 years, there are 19 failures and 6 deaths in the ABVD group and 25 failures with 9 deaths in the Stanford V group. We failed to detect statistically significant differences between ABVD +RT and Stanford V for FFS (5y 85% versus 77% p=0.13, HR=1.56 95% CI (0.87, 2.88) and OS (5y 95% versus 92% p=0.31, HR=1.69 95% CI (0.60, 4.75). No difference in hematologic toxicity was observed between the two arms. Evaluation of pulmonary function and patterns of failure are pending. Conclusions: For stage I/II patients with bulky mediastinal disease, CMT with either ABVD +RT or the Stanford V regimen results in high cure rates and is highly effective. ABVD for 6–8 cycles plus 36 Gy RT remains the US standard of care. Longer follow up is required to assess RT related late effects. Future research efforts should focus on risk stratification to identify; a) the 15–20% of patients destined to relapse after standard therapy and evaluate treatment intensification strategies and b) the 80–85% of patients who are cured with standard therapy and determine whether a subset can achieve the same excellent outcomes with a reduction or elimination of radiation. Planned US cooperative group trials will address these questions, using ABVD as the chemotherapy backbone in conjunction with interim PET imaging for risk stratification. Disclosures: Blum: Seattle Genetics: Research Funding; Novartis: Research Funding; Celgene: Research Funding. Horning:Genentech: Employment.

Abstract Introduction: Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin’s lymphoma (NHL) comprising 3 molecular subtypes: germinal center B-cell (GCB), activated B-cell (ABC) and class III. ABC patients (pts) have a poor prognosis. The immunomodulatory drug lenalidomide (Len) produces durable responses in pts with aggressive NHL (Witzig 2011), with preferential activity reported in non-GCB DLBCL (Hernandez-Ilizaliturri 2011). Methods: This randomized, multicenter, open-label, phase 2/3 study was conducted to determine the efficacy and safety of single-agent Len vs single-agent investigator’s choice (IC) in relapsed/refractory DLBCL pts who received ≥2 prior therapies, or were ineligible for stem cell transplantation or further combination chemotherapy. DLBCL subtype (GCB vs non-GCB) was determined by a central pathology lab using immunohistochemistry (IHC) per the Hans method (Hans 2004). Pts were stratified by subtype, then randomized 1:1 to receive Len (25 mg/day, 21 days of 28-day cycle) or IC (gemcitabine, rituximab, etoposide, or oxaliplatin) until progressive disease (PD), unacceptable toxicity, or voluntary withdrawal. In the event of radiologically confirmed PD, pts in the IC arm were allowed to cross over to Len. The primary endpoint for Stage 1 was overall response rate (ORR), as determined by an Independent Response Assessment Committee. Progression-free survival (PFS), overall survival (OS) and subtype analysis using gene expression profiling (GEP) were exploratory endpoints. Concordance of GEP and IHC was evaluated from 3 separate laboratories. Results: IHC subtyping agreement rate among the 3 laboratories ranged from 87.5%-97.9%, and sensitivity of IHC to detect ABC or GCB subtypes vs GEP ranged from 92.3%-100.0%. By IHC, 102 DLBCL pts (GCB, n=48; non-GCB, n=54) were treated with ≥1 dose of Len or IC (modified intent-to-treat population) in Stage 1. In this heavily pretreated population, >90.0% of pts received ≥2 prior systemic chemotherapies; 25 pts in Len and 32 pts in IC received ≥3 prior systemic chemotherapy regimens. Median age was 65 y in the IC arm vs 69 y in the Len arm. Twenty-nine pts crossed over from IC to Len after confirmed PD. All pts, regardless of subtype or therapy group, experienced ≥1 treatment-emergent adverse event, with neutropenia, anemia, and thrombocytopenia being the most common. Efficacy data are presented in the Table. Pts with GCB or non-GCB DLBCL (per IHC) treated with Len had similar ORR, but the data suggested greater improvements in PFS and OS with Len vs IC in the non-GCB pts. In an exploratory analysis of pts subtyped by GEP, ABC pts treated with Len vs IC-treated showed greater improvements in ORR, PFS, and OS compared with GCB pts. Prespecified criterion to advance to Stage 2 was a 2-sided 15% significance level in ORR in favor of Len based on IHC-defined subtype. The data did not fulfill this requirement, and Stage 2 was not opened. Conclusion: Len monotherapy showed clinical activity in heavily pretreated pts with DLBCL. The data suggest improved ORR, PFS, and OS with Len vs IC in the non-GCB population as defined by IHC, and the difference appears to be more pronounced in the ABC population as defined by GEP. Subtyping by GEP is warranted in further studies of Len in DLBCL. Abstract 628. Table 1.Table. Efficacy DataBy IHCBy GEPOverallGCBNon-GCBGCBABCLen(n=51)IC(n=51)Len(n=23)IC(n=25)Len(n=28)IC(n=26)Len(n=14)IC(n=16)Len(n=11)IC(n=16)ORR, % (95% CI)27.5 (15.9-41.7)11.8 (4.4-23.9) 26.1 (10.2-48.4)12.0 (2.5-31.2)28.6 (13.2-48.7)11.5 (2.4-30.2)21.4 (4.7-50.8)12.5 (1.6-38.3)45.5 (16.7-76.6)18.8 (4.0-45.6)P Value .079 .279 .179 .642 .206PFS, med wk (95% CI)13.6 (8.6-17.7)7.9 (6.3-9.0) 10.1 (8.3-22.3)29.0 (6.3-20.6)15.1 (8.3-24.1)7.1 (5.3-8.4)13.2 (8.3-24.9)7.1 (6.0-20.6)82.0 (7.3-NA)6.2 (4.3-10.1)P Value .041 .550 .021 .506 .105HR (95% CI) 0.64 (0.41-0.99) 0.82 (0.43-1.57) 0.50 (0.27-0.92) 0.77 (0.35-1.68) 0.44 (0.15-1.23)OS, med wk (95% CI)31.0 (16.6-41.3)24.6 (12.7-33.9) 30.0 (14.9-44.4)24.9 (13.7-58.3)32.3 (15.9-48.1)20.4 (10.3-33.9)30.0 (18.0-34.6)20.1 (13.7-36.9)108.4 (9.6-108.4)18.6 (6.6-48.0)P Value .673 .526 .253 .767 .144HR (95% CI) 0.91 (0.59-1.41) 1.23 (0.65-2.34) 0.70 (0.38-1.30) 1.12 (0.52-2.42) 0.47 (0.17-1.33) Abbreviations: CI, confidence interval; HR, hazard ratio; med, median; NA, not applicable/not available. Disclosures Czuczman: Celgene: Consultancy. Off Label Use: This abstract describes a clinical trial of lenalidomide, which is an orally-available immunomodulatory agent under investigation for treating patients with diffuse large B-cell lymphoma.. Davies:GlaxoSmithKlein: Research Funding; Hoffman La Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding. Wagner-Johnston:Celgene: Research Funding. Gascoyne:Celgene: Consultancy, Research Funding. Salles:Pfizer: Honoraria; Gilead: Honoraria; Jansen: Honoraria; Hoffman La Roche: Honoraria; Celgene: Honoraria; Mundipharma: Honoraria. Witzig:Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Zinzani:Mundipharma: Honoraria; Pfizer: Honoraria; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; Millennium Takeda: Honoraria; Celgene: Honoraria; Teva: Membership on an entity's Board of Directors or advisory committees. Wright:Celgene: Research Funding. Staudt:Celgene Corporation: Research Funding. Repici:Celgene: Employment. Song:Celgene: Employment. Manzke:Celgene: Employment.

Abstract Abstract 1638 Introduction: Hodgkin lymphoma (HL) represents the most common subtype of malignant lymphoma in young people in the Western world. Most of the patients can be cured with modern treatment strategies. However, about 20% of patients still die due to relapse or progressive disease. Recently, elevated numbers of tumor-associated macrophages in diagnostic pretreatment and relapse biopsies have been associated with poor long-term outcomes. Furthermore, high expression of CSF1R on the malignant Hodgkin Reed Sternberg cells has been linked to shorter progression-free survival, providing the rationale to test PLX3397, a highly selective inhibitor of CSF1R (also known as Fms) and Kit receptor tyrosine kinases, in HL patients. Patients and Methods: Patients with relapsed or refractory HL were enrolled in this single-agent multicenter trial. All patients had progressed after or were ineligible for autologous stem cell transplantation, had radiographically measurable disease, and had discontinued all previous HL therapy. Patients were treated with oral PLX3397 at a dose of 900 mg/day continuously until occurrence of unacceptable toxicity or disease progression. The primary endpoint was the objective response rate according to the 2007 consensus criteria. Results: A total of 20 patients were enrolled (9 male, 11 female, median age 36 years). Six patients had tumor reduction ranging between 3% and 54% including one partial remission (overall response rate of 5%) (Figure). The median duration of progression-free survival was 56 days. The most common drug-related adverse effects were asthenia, fatigue, hair depigmentation, anemia, leukopenia, and increased LDH, all of which were grade 1 or 2 except for one grade 3 neutropenia. CD14dim/16+ labeled peripheral blood monocytes were markedly reduced in all patients at 4 weeks vs. Baseline (median=83% reduction, range of 44%-96% reduction), confirming inhibition of CSF1R signaling. Increases were observed for adiponectin in 82% of patients (median=2.6-fold, range 1.2 to 12-fold) and for CSF-1 in 94% of patients (median=4.0-fold, range 1.4 to 16.5-fold), also consistent with CSF1R inhibition. Archival formalin-fixed paraffin-embedded lymphoma tissues of sufficient quality were available for 12 patients. Biopsy material was obtained from either initial diagnosis or after relapse. CD68+ and CD163+ macrophages were highly elevated (>25% cellularity) in 42% and 58% of patients, respectively. The number of tumor-associated macrophages was not significantly associated with a reduction in lesion size after PLX3397 treatment in this small study cohort. Discussion: In this phase 2 clinical trial, PLX3397 at a dose of 900 mg/day showed limited activity in this heavily pretreated patient cohort. However, target inhibition of both Fms and Kit was clearly demonstrated. Although the efficacy of single agent PLX3397 in this study population was modest, the manageable safety profile and evidence of target inhibition may warrant further testing in combination therapy trials. Disclosures: Younes: Seattle Genetics, Inc.: Consultancy, Research Funding; Millennium: Honoraria; Novartis: Honoraria, Research Funding; Celgene: Honoraria; Affimed: Research Funding; Gilead: Research Funding; Johnson & Johnson: Research Funding. Gascoyne:Plexxikon Inc.: Consultancy, Research Funding. West:Plexxikon Inc.: Employment. Nolop:Plexxikon Inc.: Employment. Steidl:Plexxikon Inc.: Research Funding.