Fenske, Timothy S.

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.

(Text above this line is not copy/pasted in the abstract body) INTRODUCTION Allogeneic HCT using RIC regimens is the standard treatment for patients with relapsed/refractory cHL, however there is significant heterogeneity amongst the different regimens and a lack of data supporting a preferred RIC regimen. Using the CIBMTR database we evaluate the outcomes of the 3 most commonly used RIC regimens for cHL. METHODS In the CIBMTR registry, 492 adult patients underwent a first alloHCT using either a matched related or unrelated donor for cHL between 2008-2016, utilizing a RIC regimen with either fludarabine/ i.v. busulfan (6.4mg/kg) (Flu/Bu, n=102), fludarabine/melphalan 140mg/m^2 (Flu/Mel140, n=318) or fludarabine/cyclophosphamide (Flu/Cy, n=72). Graft-versus-host disease (GVHD) prophylaxis was calcineurin inhibitor (CNI) plus methotrexate, mycophenolate mofitil (MMF) or other agents, however post transplantation cyclophosphamide (post-CY) was excluded. The primary endpoint was overall survival (OS). Secondary endpoints included acute (a) and chronic (c) GVHD, non-relapse mortality (NRM), relapse/progression and progression-free survival (PFS). Probabilities of OS and PFS were calculated using the Kaplan-Meier estimator. Multivariable regression analysis was performed for GVHD, relapse/progression, NRM, PFS, and OS. Covariates with a p<0.01 were considered significant. RESULTS Baseline characteristics are shown in Table 1. The median patient age of the complete study cohort was only 33 years, with more than 80% receiving a prior autologous HCT. On multivariate analysis (Table 2), the 3 conditioning regimen cohorts were not statistically different in either risk of cGVHD nor risk of grade 3-4 aGVHD. No significant differences were seen in the NRM risk between the three regimens (p=0.54). Similarly, the risk of relapse (p=0.02) and PFS was comparable between regimens (p=0.14). Flu/Cy conditioning was associated with decreased risk of mortality in first 11months after alloHCT (OR 0.28, 95% CI 0.10-0.73, p=0.009, but beyond 11 months post alloHCT it was associated with a significantly higher risk of mortality, (OR 2.46, 95% CI 0.1.32-4.61, p=0.005; Figure 1) [11months post alloHCT cutoff chosen on the basis of the maximum likelihood value in the Cox model]. Four year adjusted PFS and OS were similar across the three regimens at 29% for Flu/Bu, 37% for Flu/Mel140 and 25% for Flu/Cy (p=0.07) for PFS and 62% for Flu/Bu, 59% for Flu/Mel140 and 55% for Flu/Cy (p=0.64) for OS, respectively. Relapse was the most common cause of death across all the regimens, followed by organ failure and GVHD. CONCLUSIONS The most commonly used RIC regimen in alloHCT for cHL is Flu/Mel140, which was compared to Flu/Bu and Flu/Cy, the next most frequently used regimens. The choice of conditioning regimen, in these young cHL patients (median age 33 years) did not confer any benefit in terms of the risk of relapse, decrease in NRM or improvement in PFS. There was no OS benefit between, Flu/Bu and Flu/Mel 140, but Flu/Cy was associated with a significantly higher risk of mortality in patients beyond 11 months from allo-HCT. Novel approaches are still needed to decrease post-HCT relapse risk and improve overall results. Figure 1 Disclosures Ghosh: Seattle Genetics: Consultancy, Speakers Bureau; Genentech: Research Funding; Gilead/Kite: Consultancy, Speakers Bureau; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; T G Therapeutics: Consultancy, Research Funding; Celgene: Consultancy, Research Funding, Speakers Bureau; Forty Seven Inc: Research Funding; Spectrum: Consultancy, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; Astra Zeneca: Speakers Bureau. Kharfan-Dabaja:Daiichi Sankyo: Consultancy; Pharmacyclics: Consultancy. Sureda:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support; Gilead: Honoraria; Novartis: Honoraria; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Roche: Honoraria; Sanofi: Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hamadani:Merck: Research Funding; Janssen: Consultancy; Otsuka: Research Funding; Takeda: Research Funding; Medimmune: Consultancy, Research Funding; ADC Therapeutics: Consultancy, Research Funding; Celgene: Consultancy; Sanofi Genzyme: Research Funding, Speakers Bureau; Pharmacyclics: Consultancy.

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.

Abstract Introduction: The optimal initial management of mantle cell lymphoma (MCL) is unknown, but aggressive induction chemoimmunotherapy followed by autologous stem cell transplant confers long remission durations and is standard for younger patients. Cytarabine-based induction achieves higher rates of MRD-negativity compared to anthracycline-based induction regimens and correlates with improved outcomes. Whether a similar benefit exists after bendamustine-rituximab (RB) induction is unknown. S1106 compared induction R-HyperCVAD/MTX/ARAC (RH) or RB followed by autologous stem cell transplantation (ASCT). We previously reported similar 2-year (yr) progression-free survival (PFS) and overall survival (OS) with either regimen, and provocatively found that MRD negativity was similar with both regimens. RH was more toxic than RB and had higher stem cell mobilization failure rates. Methods: Inclusion criteria were untreated stage III, IV or bulky stage II MCL, Cyclin D1 +, age > 18-65, and adequate organ function. Randomization was stratified by MIPI. Patients (pts) received either 4 cycles of RH or 6 cycles of RB followed by ASCT. MRD was assessed at baseline and post induction. Extraction of genomic tumour DNA from paraffin embedded tissue or bone marrow aspirate and PCR amplification of IGH-VDJ, IGH-DJ, and IGK regions was performed followed by high-throughput sequencing to determine the tumor clonotype(s) (Adaptive Biotechnologies). DNA from peripheral blood mononuclear cells (PBMC) and plasma was amplified and sequenced to determine lymphoma molecules per million diploid genomes. Herein we report the results of the updated analysis at a median follow-up (mFU) of 5 yrs. Results: Fifty-two of 53 pts were evaluable. Baseline characteristics were similar between the two groups except for more female pts in the RH group. This study was closed based on prespecified criteria of stem cell mobilization failures in the RH arm. With mFU of 5 yrs (range, 29 days-6yrs), updated ORR (94.1% RH vs. 85.7% RB) and CR (41% RH vs. 43% RB) rates were similar. The 5-yr estimated PFS was 62% and 66% and the 5-yr estimated OS was 74% and 80% for RH and BR, respectively (Fig.1). Increased grade 3/4 toxicity and inadequate stem cell mobilization was seen in the RH arm thus challenging its use as an induction platform for future upfront MCL trials. 9/17 pts in RH and 23/35 pts in RB arm underwent ASCT. A landmark analysis was performed evaluating 5-yr PFS and 5-yr OS with and without ASCT in each arm. (Table 1) 27 patients consented to optional MRD assessment, with 12 paired serial samples (baseline and post induction). Overall, the estimated 5 yr PFS was 90% for all patients who achieved MRD negative status at the end of RB. Long-term toxicity included acute myeloid leukemia (N=1) in the RH arm at 5.4 yrs after diagnosis and lung cancer (n=1) in the RB arm at 2.9 yrs after diagnosis. Conclusion: The optimal induction regimen prior to ASCT in the initial management of MCL is a source of significant debate. Our initial findings supported RB as an effective platform with the ability to achieve MRD negativity. Long-term results of this study continue to demonstrate excellent response rates, 5-yr PFS and 5-yr OS with either RH or RB without any new toxicity signal. The 5-yr outcomes with RB compare favorably to more aggressive cytarabine-based induction regimens. Thus, R-Bendamustine could be an excellent backbone for induction therapy in transplant eligible patients and needs to be tested in larger phase III trials. Support: NIH/NCI grants CA180888, CA180819, CA180821, CA180820, and in part by Sequenta, Inc. (Adaptive Biotechnologies) Disclosures Kamdar: Seattle Genetics: Speakers Bureau; Genentech: Consultancy. Chen:Millennium Pharmaceuticals: Consultancy, Research Funding; Affimed: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Merck & Co., Inc.: Consultancy, Research Funding, Speakers Bureau; Genentech Inc.: Consultancy. Rimsza:NanoString: Other: Inventor on the patent for the Lymph2Cx assay. Barr:AbbVie, Gilead: Consultancy. Phillips:Genentech: Consultancy; Seattle Genetics: Consultancy; Bayer: Consultancy; Gilead: Consultancy; Pharmacyclics: Consultancy, Research Funding; Abbvie: Research Funding. Leonard:ADC Therapeutics: Consultancy; Karyopharm: Consultancy; Bayer: Consultancy; Pfizer: Consultancy; Genentech/Roche: Consultancy; Gilead: Consultancy; Juno: Consultancy; Sutro: Consultancy; AstraZeneca: Consultancy; BMS: Consultancy; Novartis: Consultancy; Celgene: Consultancy; MEI Pharma: Consultancy; United Therapeutics: Consultancy; Biotest: Consultancy. Kahl:Seattle Genetics: Consultancy; AstraZeneca: Consultancy; Gilead: Consultancy; Abbvie: Consultancy; Celgene: Consultancy; Acerta: Consultancy; CTI: Consultancy; Juno: Consultancy; ADC Therapeutics: Consultancy; Genentech: Consultancy. Friedberg:Bayer: Honoraria. Smith:Portola: Honoraria; BMS: Consultancy.

Abstract Background: Checkpoint blockade therapies (CBT) have substantially improved outcomes for patients in a variety of cancers. However, they are associated with a unique spectrum of immune-related adverse events (AEs). Additionally, unlike standard chemotherapy, many patients (pts) remain on CBT for prolonged periods of time, thus immune-related symptomatic AEs may be chronic or low grade therefore important to capture long term tolerability when used as a single agent or in combination with chemotherapy. In this study, we applied the Toxicity over Time (ToxT) analytic approach (Thanarajasingam et al, Lancet Oncol 2016), which incorporates the dimension of time and includes chronic lower grade events, to the first 6 cohorts (A-F) of a Phase 1/2 ECOG-ACRIN sponsored study of the combinations of Brentuximab Vedotin (BV) and the CBT therapies ipilimumab (Ipi) and nivolumab (Nivo) in pts with relapsed or refractory Hodgkin lymphoma (R/R HL). Methods: Pts with confirmed R/R HL were treated with BV 1.8mg/kg + Ipi 1or 3 mg/kg (n=23); or Nivo 3mg/kg + BV: 1.2 or 1.8 mg/kg (n=19). BV was administered every 21 days for 16 cycles; Ipi every 21 days x 4 and then every 3 months for one year and Nivo every 21 days for up to 2 years. Seven symptomatic (subjective) AEs were selected: fatigue, peripheral sensory neuropathy (PSN), nausea/vomiting (NV), rash/skin (RS), diarrhea, ocular-all types, and hair loss. Treatment-related AEs of any grade were investigated by conventional maximum grade toxicity analysis (ToxC) and ToxT methods up to 12 cycles. Using ToxT, mean AE grades over cycles were analyzed for time trend with repeated measures models, time to grade 2 or higher AE (gr2+) was analyzed with time-to-event analysis; AE profile over the entire course of the study was summarized by area under the curve (AUC) analyses. Comparisons were performed between treatment groups: BV/Ipi(A-C arms) and BV/Nivo (D-F arms). Results: 9/23 (BV/Ipi) and 6/19 (BV/Nivo) pts completed 10 cycles. For BV/Ipi vs. BV/nivo, ToxC provides overall incidence rates (any grade): fatigue 52% vs 26% (p=0.09); PSN 61% vs 53%; NV 70% vs 53% ; RS 65% vs. 37% (p=0.07); diarrhea 57% vs. 21% (p=0.02); ocular 17% vs. 21% ; and hair loss 17% vs. 0% (p=0.06), respectively. Gr3 AE occurred in 1 pt (2.4%) each for PSN, NV, diarrhea, and 6 pts (14.3%) for RS, and were similar between BV/ipi and BV/nivo. AUC from ToxT which captures chronic lower grade AEs suggested for BV/Ipi: diarrhea (p=0.02) and NV (p=0.03) are significantly more substantial over time with a trend seen for fatigue (p=0.07), RS (p=0.07) and hair loss (p=0.07) . Additionally, ToxT captures the trajectory of AEs, demonstrated a rising incidence and worsening grade of PSN (BV-related) on BV/Ipi (c1: 9% gr1, c2: 21% gr1 5% gr2, c5: 11% gr1 and c10: 22% gr2 [p=0.005], Fig 1a). In contrast there was a slow but significant decreasing incidence of NV on both combinations; for BV/Nivo (c1:52% gr1, c5: 26% gr1 and c10: 22% gr1) and BV/Ipi (c1: 47% gr1 ,c5: 0% and c10 1% gr1) with p=0.006 (Fig 1b). RS and diarrhea appear early on treatment and are not cumulative (Fig1c and 1d). There is no significant difference in the time to gr 2+ toxicities in any of the 7 AE. Combining all 7 AEs and using the maximum grade as a pilot measure of overall AE burden , ToxC indicates no difference in any grade (100% vs 100%) but a significantly higher gr 3+ incidence (35% vs. 11%) for BV/Ipi. Additionally, ToxT further elucidates that BV/Ipi is associated with significantly higher overall AE over time (Fig 2a, p=0.02) and compared to BV/Nivo a significantly higher risk of developing gr 2+ toxicity ( 57% vs 16% gr2 + event by day 50) (HR=0.41, p=0.02, Fig 2b). Conclusions: The CBT therapies Ipi and Nivo, in combination with BV, are overall both well tolerated over time, although BV/Ipi has a higher overall AE burden. Neither regimen has significant cumulative immune toxicity. Results of this analysis should be interpreted in the context of limited number of pts in both cohorts. A larger scale examination of this analysis is planned to incorporate both phase 1 and the ongoing phase 2 components of E4412. Compared with conventional tox analysis, ToxT delineated important additional and clinically relevant depictions of AEs over time and adds a more comprehensive assessment of the tolerability of chronically administered immune therapies for lymphoma. Disclosures Hong: Merck: Consultancy. Ansell:Regeneron: Research Funding; Merck & Co: Research Funding; Takeda: Research Funding; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Pfizer: Research Funding; Celldex: Research Funding; Trillium: Research Funding; LAM Therapeutics: Research Funding. Cohen:Bristol-Myers Squibb: Research Funding; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Janssen: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BioInvent: Consultancy; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; BioInvent: Consultancy; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding. Advani:Kura: Research Funding; Janssen: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Autolus: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Cell Medica: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Kyowa: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Astra Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Millenium: Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Celgene: Research Funding; Agensys: Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Infinity: Research Funding; Forty Seven Inc.: Research Funding; Celgene: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Regeneron: Research Funding; Gilead/Kite: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board. Barta:Janssen: Membership on an entity's Board of Directors or advisory committees; Merck, Takeda, Celgene, Seattle Genetics, Bayer: Research Funding. Svoboda:Pharmacyclics: Consultancy, Research Funding; Merck: Research Funding; KITE: Consultancy; TG Therapeutics: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Regeneron: Research Funding; Seattle Genetics: Consultancy, Research Funding; Kyowa: Consultancy. Karmali:AstraZeneca: Speakers Bureau; Gilead: Speakers Bureau. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dueck:Bayer: Employment; Phytogine: Employment; Pfizer: Honoraria. Kahl:Genentech: Consultancy; Acerta: Consultancy; AstraZeneca: Consultancy; Abbvie: Consultancy; Juno: Consultancy; Celgene: Consultancy; Seattle Genetics: Consultancy; ADC Therapeutics: Consultancy; CTI: Consultancy; Gilead: Consultancy. Diefenbach:Merck: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Acerta: Research Funding; Millenium/Takeda: Research Funding; Genentech: Consultancy; Denovo: Research Funding; Incyte: Research Funding; Seattle Genetics: Consultancy, Research Funding; Trillium: Research Funding.

Abstract Introduction: AITL is a distinct clinicopathologic entity among the mature T-cell and NK-cell lymphomas, accounting for approximately 1-2% of all non-Hodgkin lymphomas. Although autologous HCT (auto-HCT) provides high response rates, there is a high relapse risk associated with this procedure. Allo-HCT may result in a lower risk of relapse in part due to a graft-versus-lymphoma effect mediated by alloreactive donor cells. The role of allo-HCT in AITL with advanced disease (prior auto-HCT failure, or chemorefractory state) is not well described. Using the CIBMTR registry, we report here the outcomes of AITL patients undergoing an allo-HCT. Methods: We evaluated 249 adult (≥18years) patients with AITL who received a first allo-HCT during 2000-2016. Patients receiving mismatched unrelated donor, cord blood or haploidentical donor transplantation were excluded due to small numbers. The primary end-point was overall survival (OS). Secondary endpoints included cumulative incidence of acute graft-versus-host disease (GVHD), chronic GVHD, non-relapse mortality (NRM), relapse/progression (R/P) and progression-free survival (PFS). Results: Baseline patient characteristics are summarized in Table. The median patient age was 56 years (range=21-77 years). The graft source was mainly peripheral blood. Median follow-up of survivors was 49 months (range=4-170 months). The cumulative incidence of grade 2-4 and grade 3-4 acute GVHD at day 180 were 36% (95% CI=30-42)% and 12 (95% CI=8-17)%, respectively. The cumulative incidence of chronic GVHD at 2 years was 58% (95% CI=51-64)%. The 1-year NRM was 19% (95% CI=14-24)%, while the 4-year R/P, PFS, and OS were 21% (95% CI=16-27)%, 49% (95% CI=42-56)% and 56% (95% CI=49-63)%, respectively [Figure]. On multivariate analysis, chemoresistant status at allo-HCT was associated with a significantly higher risk for progression (RR=1.73 95% CI=1.08-2.77), while KPS <90% was associated with a significantly higher risk of mortality (RR=3.46 95% CI=1.75 - 6.87). Subgroup analysis looking at the effect of prior auto-HCT (no prior auto-HCT vs prior auto-HCT), the 4-year PFS (50% vs 47%, p=0.60) and OS (57% vs 54%, p=0.70) were not significantly different. Similarly, on comparing the disease status at allo-HCT (CR1 vs CR>1 vs PR vs refractory), there was no significant difference in the 4-year PFS (58% vs 45% vs 47% vs 38%, p=0.41) or OS (70% vs 54% vs 50% vs 52%, p=0.27). The 1-year NRM was 24%, while the 4-year R/P, PFS, and OS in patients with refractory AITL were 32%, 38%, and 52%, respectively. The most common cause of death was organ failure. Conclusion: In this largest series of mostly advanced AITL patients, allo-HCT was shown to provide durable disease control (4-year PFS=47%) with a clear plateau in relapse at 1-year post-transplantation. Allo-HCT provided durable disease control even in patients with a failed prior auto-HCT and those subjects with refractory disease at the time of allografting. Disclosures Kharfan-Dabaja: Alexion Pharmaceuticals: Speakers Bureau; Incyte Corp: Speakers Bureau; Seattle Genetics: Speakers Bureau. Smith:BMS: Consultancy; Portola: Honoraria. Sureda:Sanofi: Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Merck: Consultancy, Honoraria; Roche: Honoraria; BMS: Consultancy, Honoraria. Hamadani:Merck: Research Funding; Celgene Corporation: Consultancy; ADC Therapeutics: Research Funding; Sanofi Genzyme: Research Funding, Speakers Bureau; Ostuka: Research Funding; Janssen: Consultancy; MedImmune: Consultancy, Research Funding; Takeda: Research Funding; Cellerant: Consultancy.

Abstract Background: Relapsed/refractory (R/R) Hodgkin lymphoma (HL) remains a significant clinical challenge. We hypothesized that using immune checkpoint blockade to activate the immune cells in the tumor microenvironment, and concurrently targeting tumor cells with the CD30 targeting antibody-drug conjugate brentuximab vedotin (BV) could overcome tumor resistance. E4412 is a Phase 1/2 ECOG-ACRIN sponsored study of the combinations of BV, nivolumab (Nivo), and ipilimumab (Ipi) in patients with R/R HL. Here we present the preliminary safety and response data on the full cohort of patients treated in Phase 1 with BV + Ipi + Nivo (Arms G-I). Methods: Patients with confirmed R/R HL were treated with Nivo 3mg/kg, Ipi 1mg/kg and BV 1.2mg/kg (Arm G) or 1.8mg/kg (Arm H) with a 3+3 design, and an expansion cohort (Arm I) of 9 patients with BV at 1.8mg/kg. BV and Nivo are given every 21 days for 16 cycles; Nivo may be continued for an additional 12 months. Ipi is given every 12 weeks except for the first 2 patients in Arm G who received Ipi every 6 weeks for the first 3 cycles. Dose limiting toxicity (DLT) was defined within the first cycle of therapy. Results: As of 6/30/18 22 patients with a median of 2 prior therapies (range 1-5) have been treated; 7 in Arm G, 6 in Arm H, and 9 in Arm I. Median age was 35, range (19-60); 11 patients were male. Nine patients had prior SCT (1 alloSCT, 8 autoSCT); 1 patient had prior BV. Safety: All 22 enrolled patients are evaluable for safety. There were 3 DLTs, one in each arm. In Arm G one patient experienced grade 4 diabetic ketoacidosis and hyperglycemia, and went off treatment after cycle 1. In Arm H, one patient had transient grade 3 AST elevation; this was of no clinical significance and did not require a delay in therapy. In Arm I a post AlloSCT patient had grade 4 Steven-Johnson syndrome with grade 3 pruritis, rash, and GVHD, and came off therapy. Common toxicities considered at least possibly related to drug, are shown in Table 1, and grade 3 or greater toxicity in Table 2. There were no grade 5 AEs or additional grade 4 AEs. Significant grade 3 AEs were: rash, colitis, gastritis, pancreatitis, and arthritis each in one patient, resulting in dose delays but not discontinuation of therapy. One patient experienced grade 2 angioedema in cycle 1 and came off therapy. No significant infusion reactions were noted. Response: Nineteen of 22 patients are evaluable for response. Three patients discontinued treatment after cycle 1 and are not evaluable for response. For the full population the overall response rate (ORR) was 82% (18/22), with a complete response (CR) rate of 68% (15/22). For patients treated with at least 3 cycles of therapy who were evaluable for response, the ORR is 95% (18/19) with a CR rate of 79% (15/19). Six patients went from treatment to SCT. With a median follow-up of 0.52 years median progression free survival (PFS) has not been reached (Figure 1), and with a median follow-up of 0.82 years overall survival (OS) has not been reached (Figure 2). Conclusion: In this study of the triplet combination of BV, Ipi and Nivo for R/R HL, therapy was generally well tolerated, although more grade 3 AEs were seen than in the doublets. In a heavily pretreated patient population, with 9 patients post SCT, the ORR of 95% and CR rate of 79% in evaluable patients is extremely promising. Data will be updated to include longer term PFS and OS by the time of the meeting. Optimization of this strategy is ongoing in E4412, now a randomized phase 2 study comparing the doublet of BV-Nivo to the triplet of BV-Ipi-Nivo. Disclosures Diefenbach: Trillium: Research Funding; Incyte: Research Funding; Genentech: Consultancy; Seattle Genetics: Consultancy, Research Funding; Denovo: Research Funding; Acerta: Research Funding; Millenium/Takeda: Research Funding; Merck: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding. Hong:Merck: Consultancy. Cohen:Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Infinity Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Takeda: Research Funding; BioInvent: Consultancy; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Advani:Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Merck: Research Funding; Autolus: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Kura: Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Cell Medica: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Janssen: Research Funding; Millenium: Research Funding; Infinity: Research Funding; Regeneron: Research Funding; Agensys: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Astra Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Gilead/Kite: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Kyowa: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Forty Seven: Research Funding. Barta:Janssen: Membership on an entity's Board of Directors or advisory committees; Merck, Takeda, Celgene, Seattle Genetics, Bayer: Research Funding. Svoboda:Regeneron: Research Funding; Seattle Genetics: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Merck: Research Funding; Kyowa: Consultancy; TG Therapeutics: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; KITE: Consultancy. Karmali:AstraZeneca: Speakers Bureau; Gilead: Speakers Bureau. Kahl:Genentech: Consultancy; Abbvie: Consultancy; Acerta: Consultancy; Celgene: Consultancy; AstraZeneca: Consultancy; ADC Therapeutics: Consultancy; Seattle Genetics: Consultancy; Juno: Consultancy; CTI: Consultancy; Gilead: Consultancy. Ansell:LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Pfizer: Research Funding; Celldex: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Merck & Co: Research Funding; Takeda: Research Funding.

Abstract Background: Despite advances in chemotherapy, R/R HL remains a significant clinical problem with over 1,000 primarily young lives lost annually. HL is a unique tumor in which a small number of malignant Hodgkin Reed-Sternberg (HRS) cells propagate an immunosuppressive microenvironment that augments HRS growth and survival. We hypothesized that immune checkpoint inhibitor therapy could activate the tumor immune microenvironment, while the CD30 expressing HRS cells could be targeted by brentuximab vedotin (BV), thereby overcoming tumor cell resistance and deepening clinical responses. E4412 is a phase 1 ECOG-ACRIN sponsored study of the combination of BV and the checkpoint inhibitors ipilimumab (IPI) and nivolumab (NIVO) in patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL). Here we report the data on the patients treated with BV + IPI, the first cohort of the study. Methods: Patients with biopsy proven R/R HL were treated with BV 1.8mg/kg and two escalating doses of IPI: 1 mg/kg or 3mg/kg. After safety was determined an expanded cohort was treated with BV 1.8mg/kg IV and IPI 3mg/kg IV. The schedule consisted of BV administered every 21 days for 16 cycles and IPI every 21 days x 4 doses and thereafter every 3 months for up to a year. Dose limiting toxicity (DLT) was defined for purposes of dose escalation within the first cycle of therapy. Patients are followed for toxicity up to 30 days beyond their last treatment. Results: As of 7/2015 19 of 23 planned patients have been treated with BV + IPI. We report the data on the full dose escalation population (13 patients: Dose level 1 (6), Dose level 2 (7)). The median age was 33 years (range: 20-49). Seven patients were male. Patients were heavily pretreated with a median of 4 prior therapies (2-13). Fourpatients had prior treatment with BV; 8 patients had prior SCT (7 autologous, 1 allogeneic). Safety: Overall the regimen of BV + IPI was extremely well tolerated with no DLTs noted during dose escalation. Toxicities considered at least possibly related to drug during any cycle of treatment are shown according to grade in Table 1. The most common treatment related adverse events were: diarrhea, rash, and peripheral sensory neuropathy. Other AEs of interest included: alopecia, transaminitis, and uveitis. Grade 3 and 4 treatment related adverse events (AEs) included: Dose level 1: one grade 3 infusion reaction, which led to a protocol amendment to include premedication, no further grade 3 infusion reactions were noted; Dose level 2: one each: grade 3 rash, vomiting, and peripheral sensory neuropathy, and one grade 4 thrombocytopenia in patient with pre-existing thrombocytopenia. Response: For the 12 evaluable patients, the overall response (ORR) for the combination of BV + IPI was 67% with a complete response (CR) rate of 42% (5 of 12 patients). An additional 2 patients had stable disease (SD) giving a clinical benefit rate of 83%. Three of 5 of the CRs occurred at dose level 1 (1mg dose of IPI). The median progression free survival (PFS) is 0.74 years with a median follow-up of 0.66 years. Conclusion: In this first reported study of the combination of checkpoint inhibitor and ADC, toxicity was low, primarily grades 1 and 2. In a heavily pretreated patient population, 33% of whom had had prior BV and 67% of whom were s/p ASCT, the ORR of 67% and CR rate of 42% suggests a potential deepening of response compared to monotherapy. More than half of these CRs occurred at 1mg of IPI suggesting that in combination with ADC, low doses of immune stimulation may be highly active. Optimization of this combination strategy is planned with ongoing accrual to cohorts receiving BV + NIVO, and BV + IPI + NIVO. Data will be updated to include the full BV + IPI cohort by the time of the annual meeting. Table 1. Common and Immune Toxicities Toxicity Type Dose Level 1 (n=6) Dose Level 2 (n=7) Grade Grade 1,2 3 4 5 1,2 3 4 5 (n) (n) (n) (n) (n) (n) (n) (n) Fatigue 5 - - - 3 - - - Fever 1 - - - 3 - - - Pain 2 - - - 3 - - - Alopecia 2 - - - 1 - - - Pruritus 1 - - - 2 - - - Rash maculo-papular 4 - - - 2 1 - - Diarrhea 4 - - - 4 - - - Dyspepsia 2 - - - 1 - - - Nausea 6 - - - 4 - - - Vomiting 3 - - - 2 1 - - Papulopustular rash 1 - - - 1 - - - Alanine aminotransferase increased 3 - - - 3 - - - Aspartate aminotransferase increased 3 - - - 2 - - - Platelet count decreased - - - - - - 1 - Anorexia 3 - - - - - - - Headache 2 - - - 2 - - - Peripheral sensory neuropathy 5 - - - 4 1 - - Dry eye 2 - - - - - - - Uveitis 1 - - - - - - - Cough 2 - - - 1 - - - Disclosures Diefenbach: Molecular Templates: Research Funding; Immunogen: Consultancy; Celgene: Consultancy; Idera: Consultancy; Jannsen Oncology: Consultancy; Gilead: Equity Ownership, Research Funding, Speakers Bureau; Incyte: Research Funding; Genentech: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding. Off Label Use: Presentation will discuss the experimental use of the checkpoint inhibitor Ipilimumab in relapsed/refractory Hodgkin lymphoma.. Cohen:Celgene: Consultancy; Millennium: Consultancy; Pharmacyclics: Consultancy; Seattle Genetics: Consultancy; BMS: Research Funding; Janssen: Research Funding. Robertson:Eli Lilly: Equity Ownership. Fenske:Pharmacyclics: Honoraria; Seattle Genetics: Honoraria; Millennium/Takeda: Research Funding; Celgene: Honoraria. Kahl:Roche/Genentech: Consultancy; Seattle Genetics: Consultancy; Millennium: Consultancy; Cell Therapeutics: Consultancy; Celgene: Consultancy; Infinity: Consultancy; Pharmacyclics: Consultancy; Juno: Consultancy. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding.