Jegede, Opeyemi A.

Initial therapy for MCL is effective, but most patients eventually relapse. Validated intermediate biomarkers for MCL are important to provide early assessment of treatment efficacy, prognostic information and potentially guide consolidation. The US-Canadian Intergroup trial E1411 randomly assigned patients (pts) to receive induction with BR ± bortezomib (V), followed by consolidation with R ± L. As a planned correlative, MRD was assessed after cycle 3 (I3), end of induction (EOI) and after 4 cycles of consolidation (C4) by two methods: a research version of clonoSEQ® a next generation sequencing (NGS) MRD assay, (Adaptive Biotechnologies, Seattle, WA) that leverages multiplex PCR followed by NGS to identify and track rearrangements of IgH, V-J, D-J and IgK/L loci as well as translocations in Bcl1/2-IgH, and flow cytometry (FC) (I3 and EOI only) at a central laboratory (Mayo Clinic). While outcomes by treatment arm remain blinded, we report here the results of the MRD assessments by each method and the associated progression free survival (PFS). In E1411, 373 pts, accrued between May 2012 - Sept. 2016, were randomly assigned (stratified by MIPI and age (</≥60)) to receive BR induction x 6 followed by R for 2 years, BVR followed by R, BR followed by LR or BVR followed by LR. Eligible pts were ≥ age 18 and had untreated MCL, ECOG PS 0-2, and adequate hematologic and organ function. Of the 373 pts, 296 (79%) consented to correlatives. Of these, 255 (86%) had baseline NGS samples, and 214 were analyzable. Excluded were 6 patients that were protocol ineligible, 20 without clinical follow-up; only 7 (2.7%) patients were ineligible due to inability to identify a dominant clone necessary to follow MRD by the NGS method. At baseline pre-treatment, NGS detected a dominant clone in bone marrow (BM) or peripheral blood (PB) in 92%, with only 17 (8%) requiring study of biopsy tissue. Of the 296, 240 had baseline FC data, 9 were protocol exclusions, leaving 231 analyzable. FC detected a non-MCL monoclonal B cell lymphocytosis clone in a small number of cases. While NGS may have higher sensitivity, as FC sensitivity is 10-4, for this analysis we used that cutoff for both NGS and FC. Cohen's Kappa statistic compares concordance between MRD pairs, and p-value is from exact McNemar's test. BR-based initial MCL therapy achieved early MRD negativity (< 10-4) in a high proportion of patients. Analyzing PB at mid-induction (I3): by NGS 89% MRD-, 9% MRD+ and 2% indeterminate, whereas by FC 87% MRD-, 12% MRD+ and 1% indeterminate. Concordance was high with 127 MRD- by both methods, 13 MRD+ by both, and 6 NGS-/FC+ (Kappa Statistic = 0.79, p-value = 0.031). By NGS, of 12 pts MRD+ at I3, 7 became MRD- at EOI, and 4 remained MRD+ (1 indeterminate). Analyzing at EOI: MRD- rates were 91% by NGS analysis of PB (147/161) and 90% in BM (96/107), vs 95% (174/183) by FC in PB. As some were indeterminate, only 7% were MRD+ by NGS in BM, 3% by NGS in PB and 5% by FC. In 88 informative samples with EOI NGS in both BM and PB, concordance was high, with 81 negative in both, 1 positive in both and 6 BM+/PB- (Kappa Statistic = 0.23, p-value = 0.031). Of 101 pts with data at all 3 timepoints, I3, EOI, and C4: 7 were MRD+ at I3, 5 of these were MRD- at EOI, but 2 of these 5 were again MRD+ at C4. Of 2 MRD+ EOI, 1 became MRD- at C4. By FC, of 17 patients MRD+ at I3, 11 (65%) became MRD- at EOI. MRD status correlated with progression-free survival (PFS). Due to the low MRD+ rate at EOI and C4, we focus here on MRD status at I3 (10-4 cutoff for both NGS and FC), using a landmark analysis of 4 months on study. Median PFS (Figure) for pts MRD- at I3 mid-induction was 58.9 months by either NGS or FC, while for those MRD+ by NGS it was 26.9 months, vs 29.9 months MRD+ by FC. Conclusions: Both NGS and FC were feasible to assess MRD status in this multi-center trial. Results of NGS and FC are concordant at the 10-4 cutoff. NGS can be more sensitive when adequate material is available, and analysis of this subgroup is ongoing. The high MRD- rate (≥ 90%) at EOI in this BR-based trial and MRD correlation with PFS supports its use as a platform for MCL trials, although consolidation may confound PFS. Early interim MRD testing at cycle 3 identifies a high-risk population who may benefit from alternative treatment strategies. Analysis by treatment arm with longer follow-up, as well as comparison with centrally reviewed PET/CTs included in this study, will help define the most informative method(s), cutoff values, and timing for assessing degree of response in MCL. Figure. Disclosures Smith: Astra-Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; EUSA: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Parekh:Foundation Medicine Inc.: Consultancy; Celgene Corporation: Research Funding; Karyopharm Inc.: Research Funding. Martin:Sandoz: Consultancy; Karyopharm: Consultancy; Teneobio: Consultancy; Celgene: Consultancy; Janssen: Consultancy; I-MAB: Consultancy. Till:Mustang Bio: Patents & Royalties, Research Funding. Leonard:Gilead: Consultancy; Akcea Therapeutics: Consultancy; Bayer Corporation: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; BeiGene: Consultancy; Celgene: Consultancy; Akcea Therapeutics: Consultancy; Nordic Nanovector: Consultancy; ADC Therapeutics: Consultancy; Sandoz: Consultancy; MorphoSys: Consultancy; Sutro Biopharma: Consultancy; Karyopharm Therapeutics: Consultancy; Karyopharm Therapeutics: Consultancy; Merck: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Epizyme, Inc: Consultancy; Gilead: Consultancy; AstraZeneca: Consultancy; Epizyme, Inc: Consultancy; Bayer Corporation: Consultancy; Miltenyi: Consultancy; Celgene: Consultancy; ADC Therapeutics: Consultancy; MorphoSys: Consultancy; Sandoz: Consultancy; Miltenyi: Consultancy; AstraZeneca: Consultancy; Nordic Nanovector: Consultancy; Merck: Consultancy; BeiGene: Consultancy; Sutro Biopharma: Consultancy. Friedberg:Bayer: Honoraria, Other: Data & Safety Monitoring Committee; Acerta: Other: Data & Safety Monitoring Committee. Kahl:TG Therapeutics: Consultancy; ADC Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy; BeiGene: Consultancy.

Background: Mantle Cell Lymphoma (MCL) is an aggressive form of Non Hodgkin Lymphoma (NHL) and typically presents in patients over the age of 60 years. Bendamustine and rituximab (BR) combination is one of the standard treatments for MCL and is given to patients for whom high dose chemotherapy with autologous stem cell rescue is planned in the first remission. Progression free survival (PFS) with BR is approximately 36 months (Rummel M Lancet 2013; Flinn IW Blood 2014) and the regimen is overall well tolerated. Venetoclax (VEN) is an orally available inhibitor of BCL2, an anti-apoptotic protein highly expressed in several NHL. Single agent activity has mostly been studied in a Phase I study (in various NHL histologies) where 28 MCL patients were enrolled. Overall response rate was 75% (21 of 28) but complete response (CR) rate was only 21% (6 of 28). Tumor lysis syndrome (TLS) has been associated with VEN and initial dosing requires a ramp up period (Davids MS JCO 2018). VEN has also been combined with other agents in MCL with promising activity (Tam CS NEJM 2018) VEN has been studied as a chemotherapy sensitizer and has shown pre-clinical synergy with chemotherapy. In Follicular lymphoma, BR+VEN was studied at 800mg PO continuous daily dosing and showed an excessive Grade 3-4 adverse event (AE) rate of 78% compared to historical studies of 46% (Zinzani ASH 2016). We hypothesize that, in MCL, VEN can be safely combined with BR at a lower dose and intermittent dosing with improvements to the response rate based on historical controls and maintain a better safety profile. Study Design: This Phase II single arm, multicenter study evaluates VEN at a max dose of 400mg with BR (Bendamustine 90mg/m2 IV day 1 and 2; rituximab 375mg/m2 IV or SQ equivalent day 1) for six 28-day cycles in untreated patients with MCL over the age of 60 years (NCT03834688). Cycle 1 will include a VEN dose titration over the 4 week course (20mg D1-7, 50mg D8-14, 100mg D15-21, and 200mg D22-28). For Cycles 2-6, VEN will be given at 400mg daily x 10 days starting with day 1. Participants are followed for 6 cycles, though will be followed for progression and survival afterward. Participants may receive maintenance rituximab at investigator's discretion. Eligible participants, age 60 years or older, must have biopsy proven untreated MCL with t(11;14) or cyclin D1 expression, though a short course of steroids is allowed for symptomatic MCL. They must have adequate organ function and not require any prohibited concomitant medications. Primary outcome is CR rate as assessed by the Lugano criteria. We estimate a historical CR rate of BR after induction of about 70%. A 15% increase in this rate, to 85% CR, is considered promising for the combination. To achieve this goal, the study will enroll 56 participants (53 eligible) to achieve a 90% power to detect the difference with a 10% Type I error rate. We will also evaluate PFS and overall survival. TLS is an AE of interest and will be evaluated after 19 participants have been enrolled and treated during cycle 1. Minimal residual disease (MRD) will be assessed throughout the study. MRD from peripheral blood will be compared to bone marrow aspirates in all participants undergoing bone marrow aspirate at the end of treatment. Tumor samples at screening and progression will be collected for future study. This study is conducted through PrECOG and is funded by Genentech, a member of the Roche Group. Venetoclax is co-developed by Genentech and AbbVie. The study is slated to open in Fall of 2019 at 10 US sites. Figure Disclosures Portell: AbbVie: Research Funding; Pharmacyclics: Consultancy; Janssen: Consultancy; Genentech: Consultancy, Research Funding; Amgen: Consultancy; Bayer: Consultancy; BeiGene: Consultancy, Research Funding; Kite: Consultancy, Research Funding; Acerta/AstraZeneca: Research Funding; TG Therapeutics: Research Funding; Xencor: Research Funding; Roche/Genentech: Research Funding; Infinity: Research Funding. Bennani:Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Kite Pharma: Other: Advisory board; Seattle Genetics: Other: Advisory board; Adicet Bio: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Purdue Pharma: Other: Advisory board; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Adicet Bio: Other: Advisory board; Seattle Genetics: Other: Advisory board; Kite Pharma: Other: Advisory board; Kite Pharma: Other: Advisory board. Naik:Celgene: Other: Advisory board. Parsons:Celgene: Speakers Bureau; Amgen: Speakers Bureau. Kahl:BeiGene: Consultancy; ADC Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy; TG Therapeutics: Consultancy. OffLabel Disclosure: Venetoclax is not approved for use in MCL.

Abstract Background: There remains a critical need to identify untreated HR FL patients (pts) who are at increased risk of early progression and death with conventional treatment. Data examining baseline PET has been reported to be prognostic in FL, however, there remains a paucity of data analyzing this in the context of bendamustine/rituximab (BR) induction followed by maintenance rituximab (MR). We examined the prognostic impact of baseline PET metabolic imaging from the randomized BIONIC study for pts with untreated HR FL. Methods: The BIONIC study conducted by the ECOG-ACRIN Cancer Research Group enrolled untreated grade I/II or IIIa FL pts with HR disease defined as GELF high tumor burden and/or FLIPI score of 3-5. Pts were randomized to: a) standard BR induction x 6 followed by maintenance rituximab (MR) q 2 months x 2 years vs b) bortezomib + BR x 6 followed by MR q 2 months x 2 years vs c) BR x 6 followed by q 2 months MR x 2 years + lenalidomide given concurrently with the first year of MR. Survival analyses showed no significant differences in 4-year progression-free survival (PFS) or overall survival (OS) for any study arm (Evens AM et al, ASH 2017). All pts were thus pooled for the purpose of analyzing baseline PET imaging and other characteristics and for correlation with clinical outcomes. Kruskal-Wallis & Wilcoxon Rank Sum test were used to assess differences in distribution of: metabolic measurements (SUVmax and SUVmean of the dominant mass (i.e., the mass/lesion with the highest SUV uptake); metabolic tumor volume (MTV); and total lesion glycolysis (TLG) by categorical variables); induction treatment response; and end-of-induction (EOI) PET response vis-à-vis Deauville scoring (1-3 = negative). Cox proportional hazards regression was used to correlate these metabolic measurements with PFS & OS and multivariable analyses were conducted. An optimal cutoff threshold (grouping into 'High' or 'Low' categories) was used for the metabolic measurements that were significantly associated with PFS & OS. Results: Metabolic data were received and measurements were analyzed centrally on 182 (71%) of 257 eligible pts. The EOI overall response rate (ORR) for all pts on study was 92% with a complete remission (CR) rate of 73%. Additionally, 12% of pts experienced early progression of disease (POD) within 2 years. SUVmax was borderline for association with PFS (P=0.06) and MTV and TLG were not associated with PFS or OS. We demonstrated a statistically significant linear relationship between continuous SUVmean score with PFS and OS, and thereafter, used the minimum p-vlaue approach to determine the optimal cutoff threshold of 7.03 to group pts into 'High' and 'Low' risk groups; with this threshold, baseline SUVmean of the dominant mass was categorized as high risk in 27% pts. The 4-year PFS rates for SUVmean low vs high groups were 80% (95% CI 72, 90%) vs 55% (40, 74%), respectively, P<0.001; and the corresponding 4-year OS rates were 93% (89, 98)% vs 80% (95% CI 69, 93%), respectively, P=0.01 (see Fig. 1). Sensitivity analyses showed no differences in baseline SUVmean by study arm, GELF or FLIPI. The only clinical characteristic that varied among patients with low vs high baseline SUVmean was Black race (0.8 vs 8.0%, respectively, Chi-square P=0.08); there were no other differences based on age, sex, stage, FLIPI, GELF status, ECOG PS, LDH, or # of extranodal sites. In addition, baseline SUVmean correlated with EOI PET (negative EOI PET with baseline SUVmean Low vs High: 81% vs 62%, respectively, P=0.03). In multivariable analyses, both baseline SUVmean and EOI PET remained significant (SUVmean: PFS HR 2.62 (95% CI 1.40-4.92), P=0.001, OS HR 2.37 (95% CI 1.01-5.56), P=0.02; EOI PET PFS HR 4.70 (95% CI 2.74-9.54), P<0.001, OS HR 2.78 (95% CI 1.18-6.56), P=0.01). Finally, baseline SUVmean was also strongly predictive of FL pts who experienced early 2-year POD (Chi-square P<0.001). Conclusions: High baseline SUVmean of the dominant mass was a strong independent prognostic factor for survival for untreated HR FL pts treated with BR-based induction with rituximab maintenance and significance was independent of FLIP or GELF criteria. Collectively, this represents a novel and simple method to identify FL pts at increased risk of early POD and poor survival with standard therapy. Continued investigation of combined PET imaging analyses and other correlative studies to enrich prognostication are warranted. Disclosures Hong: Merck: Consultancy. Advani:Bristol Myers Squibb: Other: Consultancy/Advisory role and Institutional Research Support; Kyowa: Other: Consulting/Advisory Role; Infinity: Other: Institutional Research Support; Pharmacyclics: Other: Institutional Research Support; Seattle Genetics: Other: Consultancy/Advisory role, Institutional Research Support; Regeneron Pharmaceuticals, Inc.: Other: Institutional Research Support; Millenium: Other: Institutional Research Support; Bayer Healthcare Pharmaceuticals: Other: Consultancy/Advisory Role; Autolus: Other: Consultancy/Advisory Role; Takeda: Other: Consultancy/Advisory Role; Celgene: Other: Institutional Research Support; Roche/Genentech: Other: Consultancy/Advisory Role, Institutional Research Support; AstraZeneca: Other: Consultancy/Advisory Role; Cell Medica: Other: Consultancy/Advisory Role; Gilead/Kite: Other: Consultancy/Advisory Role; Agensys: Other: Institutional Research Support; Kura: Other: Institutional Research Support; Forty Seven, Inc: Other: Institutional Research Support; Merck: Other: Institutional Research Support; Janssen Pharmaceutical: Other: Institutional Research Support. Gascoyne:NanoString: Patents & Royalties: Named Inventor on a patent licensed to NanoString Technologies. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kahl:Acerta: Consultancy; Celgene: Consultancy; Abbvie: Consultancy; Juno: Consultancy; CTI: Consultancy; Gilead: Consultancy; Seattle Genetics: Consultancy; Genentech: Consultancy; AstraZeneca: Consultancy; ADC Therapeutics: Consultancy. Evens:Affimed: Consultancy; Novartis: Consultancy; Acerta: Consultancy; Bayer: Consultancy; Tesaro: Research Funding; Pharmacyclics International DMC: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy.