Citations

Introduction Limited stage disease accounts for 30-40% of Diffuse Large B-cell Lymphoma (DLBCL), with better overall survival than advanced stage disease, but with increased late relapses regardless of treatment strategy (Stephens 2016). Preferred treatment for these patients (pts) per NCCN guidelines is abbreviated R-CHOP followed by radiotherapy. Based on promising results of radioimmunotherapy consolidation in SWOG S0313 (Persky 2015), and of PET-directed experience by the BC Cancer Agency (Sehn 2011), we designed a National Clinical Trials Network (NCTN) PET-directed study to tailor therapy after 3 cycles of R-CHOP, to improve outcomes and decrease toxicities. Methods Pts had non-bulky (< 10 cm) stage I/II untreated DLBCL. Mediastinal, HIV-associated, testicular, central nervous system, and indolent lymphoma were excluded. Pts received standard R-CHOP therapy and had an interim PET scan on day 15-18 of cycle 3, which was centrally reviewed in real time. Pts with negative PET scan (Deauville 1-3, iPET-neg) proceeded with 1 additional cycle of R-CHOP. Pts with positive PET scan (Deauville 4-5, iPET-pos) initiated 36 Gy of involved field radiation therapy (IFRT), plus additional boost to FDG-avid area up to 9 Gy, within 5 weeks of 3rd cycle of R-CHOP. This was followed by ibritumomab tiuxetan (IFRT-Zevalin) 3-6 weeks after completing IFRT. Final PET scan was performed 12 weeks after treatment completion. Results The study completed accrual in June 2016. Safety, response, interim PET, and immunohistochemistry-based cell of origin (COO) and MYC/BCL2 analyses were presented previously (Persky 2017, Stephens 2017). Of 159 pts enrolled, 1 was upstaged by PET, and 26 pts were ineligible - due to incorrect histology (mostly concurrent indolent or follicular lymphoma grade 3B) (21), lack of diagnostic tissue submission for central pathology review (3), and bulky disease (2). In 132 eligible pts, median age was 62 years, 62% had stage I, 17% had B symptoms, 14% had elevated LDH, 43% had extranodal involvement, and 66% had exclusive involvement of the head and neck region. Stage modified IPI (smIPI, Miller 1998) was 0 in 27%, 1 in 42%, 2 in 28%, and 3 in 4% of the pts. COO by Lymph2Cx was assessable in 87 pts - 68% were GCB, 23% were ABC, and 9% were unclassifiable. Double protein expressers (MYC and BCL2, DPE) were 16%, while 4 (3%) pts had "double hit" lymphoma (DHL) - 2 with MYC/BCL2 and 2 with MYC/BCL6 rearrangements - none of which were DPE. Of 132 eligible pts, 128 had an interim PET scan centrally reviewed, of which 110 were iPET-neg. Only 18 were iPET-pos, 4 of them due to infection (Deauville X) which were treated as iPET-neg. Of 14 truly iPET-pos pts (11%), 2 refused radiation, and 12 pts received IFRT-Zevalin. Eight pts (67%) converted from PR to CR after IFRT-Zevalin and 4 (33%) had PR, for an overall CR of 92% and PR of 4% (with 4% unevaluable). With median follow up of 4.5 yrs (range 1.1 - 7.5 yrs), only 5 pts progressed and 2 died from lymphoma. Of 5 progressors, 3 received R-CHOP x 4, 1 was iPET-pos but declined radiation, and 1 went off treatment after 1 cycle of R-CHOP. Eleven pts died from non-lymphoma causes, including 1 pt from secondary AML (iPET-neg arm), and 1 of lung adenocarcinoma diagnosed upon iPET. S1001 5-yr PFS estimate is 87% and OS estimate is 90% (figure 1), with iPET-pos and iPET-neg pts having similar outcomes - PFS 86% vs. 88%, OS 93% vs. 91%, respectively. Five-yr PFS by smIPI was 97% for smIPI of 0, 86% for 1-2, and 30% for 3. GCB had 5-yr PFS of 95%, vs. 70% for ABC and 47% for unclassifiable. DPE pts had 5-yr PFS of 70, vs. 89% for non-DPE pts. All 4 DHL pts maintain remission. Conclusions S1001 is the largest US study of limited stage DLBCL in the rituximab era, with best NCTN results in this disease subset. Only 5 patients progressed and 2 died from lymphoma. Our study confirms the distinct biology of limited stage DLBCL, with predominance of GCB origin (68%), and head and neck location (66%). Due to small number of lymphoma events, no strong conclusions about prognostic ability of smIPI, COO, DPE, or DHL, could be made. S1001 demonstrated that 89% of pts maintained excellent outcomes after R-CHOP x 4 with PET-directed therapy. Only 11% of pts were iPET-pos and required radiation, but they also had excellent outcomes. Together with the FLYER trial in younger pts (Poeschel 2018), this NCTN trial establishes R-CHOP x 4 alone as the new standard approach to limited stage disease for majority of the pts. Disclosures Persky: Sandoz: Consultancy; Morphosys: Other: Member, Independent Data Monitoring Committee; Debiopharm: Other: Member, Independent Data Monitoring Committee; Bayer: Consultancy. Stephens:Acerta: Research Funding; Karyopharm: Research Funding; Gilead: Research Funding. Park:BMS: Consultancy, Research Funding; Rafael Pharma: Membership on an entity's Board of Directors or advisory committees; G1 Therapeutics: Consultancy; Teva: Consultancy, Research Funding; Gilead: Speakers Bureau; Seattle Genetics: Research Funding, Speakers Bureau. Bartlett:Seattle Genetics: Research Funding; ADC Therapeutics: Consultancy, Research Funding; Pfizer: Research Funding; Millenium: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Genenetech: Research Funding; Immune Design: Research Funding; Gilead: Research Funding; Forty Seven: Research Funding; Janssen: Research Funding; Affimed: Research Funding; Merck: Research Funding; Pharmacyclics: Research Funding. Swinnen:Pharmacyclics: Consultancy; AbbVie: Consultancy. Barr:Celgene: Consultancy; Merck: Consultancy; Seattle Genetics: Consultancy; Genentech: Consultancy; Verastem: Consultancy; Gilead: Consultancy; Astra Zeneca: Consultancy, Research Funding; Janssen: Consultancy; AbbVie: Consultancy; Pharmacyclics LLC, an AbbVie company: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding. Leonard:Nordic Nanovector: Consultancy; Akcea Therapeutics: Consultancy; BeiGene: Consultancy; Gilead: Consultancy; Miltenyi: Consultancy; ADC Therapeutics: Consultancy; Nordic Nanovector: Consultancy; Akcea Therapeutics: Consultancy; Sandoz: Consultancy; ADC Therapeutics: Consultancy; Miltenyi: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Karyopharm Therapeutics: Consultancy; Epizyme, Inc: Consultancy; Sutro Biopharma: Consultancy; AstraZeneca: Consultancy; AstraZeneca: Consultancy; Bayer Corporation: Consultancy; Bayer Corporation: Consultancy; Celgene: Consultancy; Epizyme, Inc: Consultancy; Celgene: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Merck: Consultancy; MorphoSys: Consultancy; Karyopharm Therapeutics: Consultancy; Gilead: Consultancy; Sutro Biopharma: Consultancy; BeiGene: Consultancy; Merck: Consultancy; MorphoSys: Consultancy; Sandoz: Consultancy. Kahl:TG Therapeutics: Consultancy; ADC Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy; BeiGene: Consultancy. Fisher:Celgene: Consultancy; AstraZeneca: Consultancy; Barclays: Honoraria; prIME: Honoraria. Rimsza:NanoSting: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution]. Smith:Portola Pharmaceuticals: Research Funding. Friedberg:Bayer: Honoraria, Other: Data & Safety Monitoring Committee; Acerta: Other: Data & Safety Monitoring Committee. OffLabel Disclosure: Ibritumomab tiuxetan in diffuse large B-cell lymphoma

Abstract Pediatric large B-cell lymphomas (LBCLs) share morphological and phenotypic features with adult types but have better prognosis. The higher frequency of some subtypes such as LBCL with IRF4 rearrangement (LBCL-IRF4) in children suggests that some age-related biological differences may exist. To characterize the genetic and molecular heterogeneity of these tumors, we studied 31 diffuse LBCLs (DLBCLs), not otherwise specified (NOS); 20 LBCL-IRF4 cases; and 12 cases of high-grade B-cell lymphoma (HGBCL), NOS in patients ≤25 years using an integrated approach, including targeted gene sequencing, copy-number arrays, and gene expression profiling. Each subgroup displayed different molecular profiles. LBCL-IRF4 had frequent mutations in IRF4 and NF-κB pathway genes (CARD11, CD79B, and MYD88), losses of 17p13 and gains of chromosome 7, 11q12.3-q25, whereas DLBCL, NOS was predominantly of germinal center B-cell (GCB) subtype and carried gene mutations similar to the adult counterpart (eg, SOCS1 and KMT2D), gains of 2p16/REL, and losses of 19p13/CD70. A subset of HGBCL, NOS displayed recurrent alterations of Burkitt lymphoma–related genes such as MYC, ID3, and DDX3X and homozygous deletions of 9p21/CDKN2A, whereas other cases were genetically closer to GCB DLBCL. Factors related to unfavorable outcome were age >18 years; activated B-cell (ABC) DLBCL profile, HGBCL, NOS, high genetic complexity, 1q21-q44 gains, 2p16/REL gains/amplifications, 19p13/CD70 homozygous deletions, and TP53 and MYC mutations. In conclusion, these findings further unravel the molecular heterogeneity of pediatric and young adult LBCL, improve the classification of this group of tumors, and provide new parameters for risk stratification.

Abstract Background: Southwest Oncology Group (SWOG) S0016 was a phase III randomized study that compared safety and efficacy of cyclophosphamide, doxorubicin, vincristine, prednisone and rituximab (CHOP-R) with CHOP followed by consolidation with (131) iodine-tositumomab radioimmunotherapy (CHOP-RIT) for previously untreated follicular lymphoma (FL) patients. As reported previously, the study demonstrated excellent outcomes in both arms with 2-year progression-free survival (PFS) of 76% and 80% and 2-year overall-survival (OS) of 97% and 93% in the CHOP-R and CHOP-RIT arms, respectively. (Press. et al. JCO, 2012) We now report the long term outcome of patients who were treated on the S0016 study. Methods: Between 2001 and 2008, 531 previously untreated advanced follicular lymphoma patients were randomized to receive either 6 cycles of CHOP every 3 weeks with 6 doses of rituximab (CHOP-R) or 6 cycles of CHOP every 3 weeks followed by RIT. Patients with advanced-stage disease (bulky stage II, III or IV) with any pathologic grade (1, 2 or 3) were eligible. Results: Patients on CHOP-R (n=264) and CHOP-RIT (n=267) arms had balanced baseline characteristics including age (median 54.5 vs. 53.4 years), presence of B symptoms (29% vs. 26%), pathologic grade 3 (8% vs. 9%), "high" FLIPI risk group (22% vs. 26%), stage IV disease (59% vs. 63%), elevated β2M (53% vs. 55%), bone marrow involvement (56% vs. 55%) and bulky disease (24% vs. 26%). Objective remissions were documented in 226 of 267 eligible patients treated with CHOP-R (85%) and in 226 of 264 patients with CHOP-RIT (86%). Complete remission (CR) rate was 40% in the CHOP-R and 45% in the CHOP-RIT arm. Neutropenia was the most common adverse event (AE) in both arms (48% vs. 51%). Rate of grade 3-5 AEs were not different except for thrombocytopenia which was more common in the CHOP-RIT group (18% vs. 2%). After a median follow-up of 9.6 years (range 0.1 - 14.4 years), the estimated 10-year PFS was 42% (95% CI: 35.6%, 48.5%) in the CHOP-R arm and 57% (95% CI: 50.5%, 63.2%) in the CHOP-RIT arm (p-value = 0.01). 51% of responders on the CHOP-R arm and 38% of responders on the CHOP-RIT arm have relapsed (p-value= 0.01). The estimated 2-year relapse-free survival was 76% for CHOP-R patients and 81% for CHOP-RIT patients (p-value=0.15). There were 48 deaths in the CHOP+R arm and 59 deaths in the CHOP-RIT arm with an estimated 10-year OS of 82% (95% CI: 76.3%, 86.4%) with CHOP-R and 77% (95% CI: 70.5%, 81.4%) with CHOP-RIT (p-value = 0.18). (Figure-1) During the follow-up, 41 patients (15.4%) in the CHOP-R arm and 37 patients (14%) in the CHOP-RIT arm developed secondary malignancies. MDS/AML were more common in the CHOP-RIT arm (11 patients; 4.2%) compared to CHOP-R arm (5 patients; 1.9%) with a relative risk of 2.2 (95% CI: 0.8-6.3) (P-value 0.12). Conclusion: With almost 10 years of follow-up, patients with FL treated on protocol S0016 show outstanding survival in both CHOP-R and CHOP-RIT arms, and represent the best published long-term outcomes to date in this disease. Indeed, almost half of patients enrolled still remain progression-free, confirming registry experiences. While CHOP-RIT provided significantly longer PFS and lower relapse rate compared to CHOP-R in our study, the OS rate was not different between 2 arms due in part to higher incidence of fatal MDS/AML in the CHOP-RIT group, emphasizing the importance of long-term follow-up, and calling into question the validity of PFS as a surrogate for OS in this setting. Given these outstanding outcomes, we believe chemoimmunotherapy should remain the standard induction approach for patients with high-risk FL until long-term follow-up of alternative approaches demonstrates superiority. Support: NIH/NCI grants CA180888, CA180819, CA180821 and in part by GlaxoSmithKline Disclosures Shadman: Emergent: Research Funding; Acerta: Research Funding; Gilead: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding. Rimsza:NCI/NIH: Patents & Royalties: L.M. Rimsza is a co-inventor on a provisional patent, owned by the NCI of the NIH, using Nanostring technology for determining cell of origin in DLBCL.. Gopal:Paid Consultancy- Gilead, Janssen, Seattle Genetics, Spectrum, Research funding- Gilead, Janssen, Pfizer, BMS, Merck, Teva, Takeda, Spectrum, Seattle Genetics: Consultancy, Honoraria, Research Funding. Maloney:Juno Therapeutics: Research Funding; Genentech/Roche: Honoraria. Cheson:Gilead: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Membership on an entity's Board of Directors or advisory committees, Research Funding. Smith:Amgen: Other: Educational lecture to sales force; TGTX: Consultancy; Celgene: Consultancy; Pharmacyclics: Consultancy; Genentech: Consultancy, Other: on a DSMB for two trials ; Portola: Consultancy; Juno: Consultancy; Gilead: Consultancy; AbbVie: Consultancy. Fisher:Seattle Genetics: Consultancy; Gilead: Consultancy; Johnson and Johnson: Consultancy. Friedberg:Bayer: Other: Data Safety Monitoring Committee. Press:Roche / Genentech: Consultancy, Research Funding.

Introduction: HIV infected individuals are 17x more likely to receive a diagnosis of Diffuse Large B cell Lymphoma (DLBCL) compared to their uninfected counterparts. Moreover, DLBCL is more aggressive in HIV infected individuals. However, the molecular pathology driving the aggressive nature of HIV related DLBCL is poorly understood. Previously, we demonstrated that HIV-associated [HIV(+)] germinal center B-cell (GCB) DLBCL tumors are more proliferative, with enhanced genomic stability and increased expression of DNA repair genes compared to their HIV-not associated [HIV(-)] counterparts (Maguire et al, Int J Cancer,2019). Given the immunocompromised nature of these patients, herein we assessed whether specific immunological signaling pathways are also altered in HIV(+) GCB DLBCL tumors, that may work in conjunction with, or independently of, increased DNA repair, to drive the enhanced aggressive nature of HIV related DLBCL. Methods: We used our previously studied cohort of patient samples, which included a total of 39 molecularly defined GCB DLBCL cases. Of these, 18 were HIV(+) cases from the AIDS Cancer Specimen Resource Network (https://acsr.ucsf.edu/) and 21 were HIV(-) institutional cases. Samples underwent hematopathologist review for diagnosis confirmation and tumor content assessment. Samples with <60% tumor content were macrodissected, with a total of 4x 5µm FFPE sections per sample used for RNA/DNA extraction. Digital gene expression profiling was used to assess differential expression of 579 immune related genes using the NanoString PanCancer Immune Profiling panel. The data was normalized using nSolver, and differential expression analysis was performed using the R statistical software package NanoStringDiff. The resulting expression data were then analyzed using Gene Set Enrichment Analysis (GSEA), and GSEA Molecular Signatures Database (MSigDB) overlap analyses. Results: A total of 110 genes were differentially expressed between the HIV(+) and HIV(-) cohorts at p<0.05. As expected due to immunosuppression in HIV(+) individuals, 100 genes (91%) were significantly reduced and 10 genes (9%) were significantly increased in the HIV(+) cohort compared to the HIV(-) cohort. GSEA and MSigDB analyses revealed that the genes with reduced expression in the HIV(+) cohort were associated with losses in both adaptive and innate immune signaling including cytokine interactions, the IL1 pathway and B-cell receptor signaling amongst others. MSigDB overlap analyses of the 10 genes upregulated in the HIV(+) cohort identified 3 Gene Ontology molecular functions, all of which were receptor signaling related; including Receptor Binding (CD8A, CD160, CCL8, C1QBP, MIF), Receptor Activity (CD8A, CD160, CCRL1, TFRC, KLRC2), and Cargo Receptor Activity (CCRL1, TFRC). Gene overlaps between the subsets include genes associated with NK and cytolytic T cells (CD8A, CD160), as well as the transferrin receptor TRFC/CD71, which with a fold increase of 3.9, was the most significantly increased gene in the HIV(+) cohort (p=0.002, FDR=0.0025). Conclusions: As expected, the results demonstrate a loss in both adaptive and innate immune signaling in the HIV(+) cohort compared to the HIV negative cohort as well as alterations in receptor signaling. In line with our previous observation that HIV(+) GCB DLBCL tumors have higher expression of proliferation genes and the Ki67 antigen than their HIV(-) counterparts, the results of this study also reveal overexpression of TRFC/CD71 mRNA in HIV(+) GCB DLBCL tumors compared to the HIV(-) cases. TFRC/CD71 is well known as a mediator of iron uptake in erythroid cells. Iron uptake through TFRC/CD71 is also necessary for, and positively regulates T and B cell proliferation; and is commonly expressed on aggressive B cell lymphomas. We suggest that TFRC/CD71 may play a role in the enhanced proliferative capabilities of HIV(+) GCB DLBCL. These effects may be mediated through the HIV protein Nef, which has known effects on TFRC/CD71 protein recycling in lymphoid populations (Madrid et al, J Biol Chem 2005), and has been shown to be transferred from HIV infected macrophages to uninfected B-cells via contact-dependent cellular conduits (Xu et al, Nat Immunol 2009). Nef transfer between cells has also been described to occur via microvesicle transfer and trogocytosis (reviewed in Ellwanger et al, Infect Genet Evol 2017). Further analysis of these pathways is ongoing. Disclosures Rimsza: NanoSting: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution].

Background: Although diffuse large B cell lymphoma (DLBCL) can be cured using immuno-chemotherapy, 40% of patients experience relapse or refractory disease. Large-scale profiling studies have mainly focused on DLBCL at diagnosis, resolving different outcome groups based on gene expression (e.g. cell-of-origin (COO) or molecular high grade), MYC/BCL2 translocations (double-hit lymphoma) or gene mutations and copy number aberrations (Schmitz et al, NEJM 2018; Chapuy et al, NatureMedicine 2018). In comparison, longitudinal studies have been hindered by the limited availability of sequential biopsy samples. To date, the relapse-specific gene mutations identified are limited and inconsistent across studies. In our study, we have focussed attention on the changes in gene expression profile (GEP) accompanying DLBCL relapse. Methods: We retrospectively collected archival paired diagnostic/relapse formalin fixed paraffin embedded tumor biopsies from 38 de novo DLBCL patients collected from multiple UK sites treated with rituximab-based immuno-chemotherapy, where partial or complete remission was reported following treatment. COO classification was performed by the Lymph2Cx assay on NanoString to distinguish activated B-cell-like (ABC) and germinal center B-cell-like (GCB) subtypes. The Ion AmpliSeq™ Transcriptome Human Gene Expression Kit was used to measure the expression levels of > 20,000 genes on the paired samples. Results: COO remained stable from diagnosis to relapse in 17 ABC-ABC pairs, 11 GCB-GCB pairs and 4 unclassified (UNC)-UNC pairs. Frank COO switching was observed in 6 cases (1 ABC-GCB, 2 ABC-UNC, 2 GCB-UNC, 1 UNC-ABC). Pairs with stable COO were taken forward for further analysis. Gene expression analysis using the limma R package identified 163 and 136 genes as differentially expressed (DE) (p <= 0.01 and absolute log2FC > 1) between the diagnostic and relapse biopsies in ABC and GCB tumors respectively, with only a one gene overlap. Gene Set Enrichment Analysis further suggested that ABC and GCB relapses are mediated via different mechanisms, with tumor growth and proliferation signatures enriched in ABC relapses, whilst adaptive immunity-related signatures accompanied GCB relapses. Next, we aimed to utilise our relapse-specific genes to identify outcome predictors at diagnosis using publicly available GEP datasets. In order to increase our discovery power and accuracy, a larger set of DE genes from the paired differential analysis (796 genes in ABC pairs and 387 from GCB pairs) were selected (p <= 0.05) and subsequently used in a training cohort (GEP from Reddy et al, Cell 2017). The Prediction Analysis for Microarrays R (PAMR) algorithm identified a 30-gene signature within DE genes from ABC pairs (Fig1.A), capable of separating the 249 ABC cases into 136 low and 113 high-risk cases with significantly inferior overall survival (Hazard Ratio (HR)=1.89, log-rank p=0.0017, measure of goodness-of-fit C-index=0.71; Fig1.B). No equivalent signature was found in the GCB cases using this approach. The prognostic significance of this 30-gene discriminator was successfully validated using a linear predictor in two independent GEP datasets: 1) a population-based cohort (Lenz et al, NEJM 2008) with 93 R-CHOP-treated ABC cases identifying 47 low and 46 high-risk cases (HR=1.92, p=0.046, C-index=0.77; Fig1.C) and 2) a clinical trial dataset (REMoDL-B, Davies et al, Lancet Oncol 2019) with 255 ABC cases identifying 110 low and 145 high-risk ABC cases (HR=1.95, p=0.0051, C-index=0.70; Fig1.D). Conclusions: Here we describe a 30-gene discriminator in ABC-DLBCL, derived from genes differentially expressed between diagnosis and relapse, that allowed the definition of clinically distinct high and low risk subgroups in ABC-DLBCLs at diagnosis. The clinical translation of such a tool may be useful to guide therapy for this unfavourable subgroup of ABC-DLBCLs. Validation of this signature is currently underway in additional datasets and further study is required to understand the contribution of these genes in DLBCL pathology. Disclosures Korfi: Roche: Consultancy. Burton:Celgene: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees. Rule:TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Kite: Consultancy; Pharmacyclics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Crosbie:Janssen: Honoraria. Scott:Celgene: Consultancy; Janssen: Consultancy, Research Funding; NanoString: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution], Research Funding; Roche/Genentech: Research Funding. Rimsza:NanoSting: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution]. Davies:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Research Funding; Bayer: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Research Funding; Karyopharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; Acerta Pharma: Honoraria, Research Funding; ADCT Therapeutics: Honoraria, Research Funding; BioInvent: Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; MorphoSys AG: Honoraria, Membership on an entity's Board of Directors or advisory committees. Gribben:Abbvie: Consultancy, Honoraria, Research Funding; Acerta/Astra Zeneca: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Okosun:Gilead Sciences: Honoraria, Research Funding. Johnson:Epizyme: Honoraria, Research Funding; Novartis: Honoraria; Kite: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria; Boehringer Ingelheim: Honoraria; Takeda: Honoraria; Genmab: Honoraria; Celgene: Honoraria; Incyte: Honoraria. Fitzgibbon:Epizyme: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Speakers Bureau.

Background: Diffuse large B-cell lymphomas (DLBCL) are a heterogeneous group of aggressive B-cell non-Hodgkin lymphomas (NHL). Primary mediastinal B-cell lymphoma (PMBCL) is often grouped and managed as DLBCL, yet PMBCL is biologically and clinically different. Although about two-third of patients are cured with initial therapy, those who are refractory or progress within the first two years do poorly and will die from their disease. There is an unmet need for effective therapeutic approaches in this patient population. Evasion of the host immune responses is an important mechanism for inducing resistance to cancer therapy. Strategies to block molecular and cellular mediators of cancer induced immunosuppression such as programmed death -1 receptor (PD-1) have been explored. Targeting PD-1 immune checkpoints has the potential to play a major role in cancer therapy by reversing tumor immune escape. Trials using PD-1 blockers in advanced hematological malignancies demonstrated remarkable activity in Hodgkin lymphoma. Unfortunately, results in the DLBCL cohort with nivolumab were marginal and short lived. A phase 1b trial in heavily pre-treated relapsed/refractory (RR) PMBCL using pembrolizumab (a PD-1 blocker) showed that it was safe and active with an ORR of 41%. In recent years, several signaling pathways implicated in DLBCL pathogenesis have been targeted, including the PI3K-AKT-mTOR pathway. Copanlisib, a pan-PI3K inhibitor, with particularly potent PI3K-α/PI3K-δ inhibition, showed activity in both indolent and aggressive NHL, with a safer toxicity profile than the FDA-approved agent idelalisib. In a preclinical DLBCL mouse model, treatment with copanlisib resulted in effective down regulation of tumor‐infiltrating T-regulatory cells (Tregs). In the same model, copanlisib, when combined with a surrogate anti‐mouse PD‐1, showed in vivo responses in 75% vs 0% in the monotherapy groups. These data support the rational for the combination of copanlisib and checkpoint blockade in DLBCL. We developed a phase 2 prospective study with two RR cohorts (DLBCL and PMBCL), treated with the combination of copanlisib and nivolumab. Study Design: copanlisib hydrochloride 60 mg is given IV on days 1, 8 and 15 of cycles 1-8 and days 1 and 15 of subsequent cycles. Nivolumab 240 mg IV is given on days 1 and 15 of cycles 1-8 and 480 mg on day 1 of subsequent cycles. Cycles repeat every 28 days for up to 2 years in the absence of disease progression or unacceptable toxicity. Copanlisib dose will be determined using a safety cohort in 6 patients. The primary outcome is to assess ORR defined as complete and partial responses (CR+PR). Secondary outcomes are to evaluate safety of the combination; to assess progression free survival (PFS), duration of response (DOR), CR rate, and overall survival (OS). Exploratory objectives are to characterize the effects of the copanlisib and nivolumab combination regimen on tumor cells, tumor microenvironment and the immune response in RR DLBCL and PMBCL. We will also do Lymph3CX assay as an integrated biomarker to distinguish between DLBCL and PMBCL. Key inclusion criteria: adult patients with RR DLBCL and PMBCL who have measurable disease with at least one lesion that is >15mm in the longest diameter on cross-sectional imaging; After failure of ASCT or after failure of frontline therapy in subjects who declined or are not ASCT candidates; and have appropriate organ function. Key exclusion criteria: High grade B-cell lymphomas; Active, known or suspected autoimmune disease or patients on any prohibited therapies; History of active CNS involvement or leptomeningeal involvement This study is expected to enroll a maximum of 96 (6 safety cohort, 44 DLBCL and 46 PMBCL) evaluable patients. We anticipate accruing 10 additional patients to account for ineligibility, cancellation, or other reasons. Therefore, the study is expected to accrue a maximum of 106 patients. The largest success proportion where the proposed treatment regimen would be considered ineffective in DLBCL is 25% and 30% in PMBCL. The smallest success proportion that would warrant subsequent studies with the proposed regimen is 45% in DLBCL and 50% in PMBCL. This design has a 90% power with a 1-sided 10% level test. This study is conducted through NCI-CTEP (NCI Protocol #10193; NCT03484819) and is funded by Bayer. The study is to open in fall of 2019 at 11 ECTCN sites, and is available to interested sites to join in. Figure. Disclosures Bennani: Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Purdue Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Purdue Pharma: Other: Advisory board; Adicet Bio: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board. Nowakowski:Celgene: Consultancy, Research Funding; Selvita: Membership on an entity's Board of Directors or advisory committees; 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. Rimsza:NanoSting: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution]. Ansell:Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Regeneron: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Affimed: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Seattle Genetics: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding.

Background: Activation induced cytidine deaminase (AICDA or AID) causes somatic hypermutation (SHM) of the immunoglobulin heavy chain variable genes (IGHV). It has been widely hypothesized that aberrant targeting of AICDA creates additional driver mutations and intra-clonal heterogeneity which enables clonal evolution and thus disease progression. This hypothesis predicts that greater AICDA-mediated intraclonal heterogeneity will be associated with shortened progression free survival (PFS). To definitively test this hypothesis that AICDA-mediated heterogeneity is linked to risk of progression, we evaluated available samples from the largest US-based phase 3 trial of untreated follicular lymphoma patients treated with CHOP-based therapies, SWOG trial S0016. Methods: We have previously shown that ultradeep sequencing of two genes, the expressed IGHV and the 5' UTR of the translocated BCL2 allele, provide unrelated measures of AICDA-mediated genetic heterogeneity (Spence, J Immunol. 2014). Furthermore, the number of AICDA-mediated mutations in the 5' UTR of BCL2, but not in IGHV, correlates with the number of AICDA-mediated mutations at other known AICDA sites throughout the genome (such as PIM1, BCL6, RHOA, etc). Genomic DNA was prepared from all available paraffin-embedded specimens. Ultra-deep, amplicon-based sequencing (~10,000x) with internal controls to establish specimen-specific signal-to-noise parameters allowed sensitive and specific detection of sequence variants at 0.2% (FDR 1%). Results: For subjects with (152) and without (419) available specimens, the median duration of follow-up (11.3 years), the number of patients who progressed (60%), and other patient characteristics (demographics, histology, stage, FLIPI) were indistinguishable. Sequencing data that fulfilled strict quality metrics for low frequency variants were obtained for >75% of the specimens (114 for BCL2; 120 for IGHV); further analysis was restricted to these subjects. The extent of intraclonal variation within both the IGHV and the 5' UTR of BCL2 was highly variable. For BCL2, a median of 7 mutations/case were detected (range 0-61); the mutations were highly skewed to the RCYW motif (p<0.001), the preferred target of AICDA. These mutations defined a median of 5 subclones/case (range 1-22). The clonal IGHV was somatically mutated (<0.98 germline identity) in 94% of samples (median 0.89). For IGHV, a median of 113 subclones/case were detected (range 0-1531). Consistent with our prior study, no correlation was seen between the number of mutations detected in the IGHV and BCL2 or the number of subclones defined by IGHV and BCL2. Neither the number of mutations in nor the number of subclones defined by BCL2 or IGHV were prognostic. Cox regression showed no relationship between PFS and mutation number or subclone count based on either IGHV or BCL2 (hazard ratios are indistinguishable from 1; parameters were treated both as a continuous variables and dichotomized as quartiles). Furthermore, receiver operator curves did not suggest a cut point for any of these measures that would predict disease progression at any time (areas under the curve are indistinguishable from 0.5). Conclusions: Several measures of AICDA-mediated mutation and resulting subclonal heterogeneity were not found to be prognostic in previously untreated, advanced stage FL treated with CHOP-based regimens. In contrast, AICDA-mediated mutations have been reported to accrue during transformation from low grade FL to large cell lymphoma. This paradox calls for a more refined model to explain the role of AICDA in the progression of FL. Support: NIH/NCI grants U10CA180888, U10CA180819, U10CA180821, R21CA198072(WRB); and in part by GlaxoSmithKline. Disclosures Rimsza: NanoSting: Patents & Royalties: Named inventor on a patent licensed to NanoSting [Institution]. Leonard:Bayer Corporation: Consultancy; AstraZeneca: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Sandoz: Consultancy; ADC Therapeutics: Consultancy; Miltenyi: Consultancy; BeiGene: Consultancy; Sutro Biopharma: Consultancy; Celgene: Consultancy; Nordic Nanovector: Consultancy; Gilead: Consultancy; Karyopharm Therapeutics: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Bayer Corporation: Consultancy; Celgene: Consultancy; Epizyme, Inc: Consultancy; Merck: Consultancy; MorphoSys: Consultancy; AstraZeneca: Consultancy; Epizyme, Inc: Consultancy; Akcea Therapeutics: Consultancy; Miltenyi: Consultancy; ADC Therapeutics: Consultancy; BeiGene: Consultancy; Karyopharm Therapeutics: Consultancy; Merck: Consultancy; Sandoz: Consultancy; Gilead: Consultancy; Akcea Therapeutics: Consultancy; MorphoSys: Consultancy; Nordic Nanovector: Consultancy; Sutro Biopharma: Consultancy. Fisher:Celgene: Consultancy; Barclays: Honoraria; AstraZeneca: Consultancy; prIME: Honoraria. Smith:Portola Pharmaceuticals: Research Funding. Friedberg:Bayer: Honoraria, Other: Data & Safety Monitoring Committee; Acerta: Other: Data & Safety Monitoring Committee.

Key Points Five-year follow-up of S1106 demonstrates similar efficacy, MRD negativity, and 5-year survival with RH or RB, but RH was more toxic than RB. RB showed excellent efficacy and survival and less toxicity compared with a cytarabine-based regimen in transplant-eligible MCL patients.