Citations

Abstract Introduction: Idecabtagene vicleucel (ide-cel, bb2121) is the first chimeric antigen receptor (CAR) T cell therapy approved for the treatment of relapsed or refractory multiple myeloma after four or more prior lines of therapy, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody. bb21217 is a B-cell maturation antigen (BCMA) directed CAR T cell therapy which uses the same CAR molecule as ide-cel, with the addition of a PI3K inhibitor (bb007) during ex vivo culture to enrich the drug product (DP) for memory-like T cells and decrease the proportion of highly differentiated or senescent T cells. We hypothesize that DPs enriched for memory like CAR T cells will persist and function longer than non-enriched DPs and this increased persistence will positively influence duration of response (DOR). We previously demonstrated patients with sustained response are more likely to have drug product enriched for naïve gene signatures and depleted of effector gene signatures compared to patients without a sustained response. Methods: CRB-402 (NCT03274219) is a multi-center phase 1 trial of bb21217 in RRMM patients who received ≥3 prior lines of antimyeloma therapy, including a proteasome inhibitor and an immunomodulatory agent, or are double-refractory to both classes. In expansion, patients were required to have prior exposure to an anti-CD38 antibody and were required to be refractory to their last line of therapy. Patients underwent lymphodepletion with fludarabine (30 mg/m 2) and cyclophosphamide (300 mg/m 2) daily for 3 days, then received a single infusion of bb21217 at 150, 300 or 450 x 10 6 CAR+ T cells. The primary outcome measure is incidence of adverse events (AEs), including dose-limiting toxicities (DLTs). Additional outcome measures include overall response rate and DOR by IMWG Uniform Response Criteria. Exploratory analyses include correlation of outcome with the molecular characteristics of materials collected temporally through the treatment course, including PBMCs at apheresis, CAR+ T cells from drug product and CAR+ T cells collected from patients around the time of peak expansion. Results: Asof Feb 16, 2021, 72 patients received bb21217, 12 at 150, 14 at 300 and 46 at 450 x 10 6 CAR+ T cells; median follow up for all patients is 9.0 (<1-36) months (M). Patients had a median of 6 (3-17) prior lines of therapy with 49/72 (68%) triple refractory. Cytokine release syndrome (CRS) developed in 54/72 (75%) patients and was predominately G1/2 (51 pts), with 1 G3 event and 2 deaths (previously reported). Median time to first onset of CRS was 2 days (1-20); tocilizumab (38 pts) + corticosteroids (12 pts) was used to manage CRS. Eleven (15%) patients developed neurotoxicity [8 G1/G2, 2 G3, 1 G4] with median time to first onset of 7 (2-24) days. Response was assessed per investigator for 72 patients treated with bb21217 (Table). CAR+ T cells remained detectable in 30/37 (81%) patients and 9/15 (60%) patients at 6 and 12 M respectively, post bb21217 infusion. Of the 15 patients evaluable for MRD with ≥CR, 14 (93%) were MRD negative at 10 -5 by NGS. Analysis of peripheral blood samples collected 15 days post bb21217 infusion demonstrated patients with higher than the median number of CD8+ CAR+ T cells expressing CD27 and CD28 had significantly longer DOR (p=0.0024), compared to patients with lower than the median values. This suggests less differentiated, more proliferative CAR+ T cells at peak expansion are associated with prolonged disease response (median DOR in high vs low: 27.2M (95% CI; 16.8, NE) vs 9.4M (95% CI; 5.1, NE). Conclusions: Adverse events are consistent with known toxicities of CAR T cell therapies. Efficacy results are encouraging with a median DOR estimate of 17M, CR rate continues to mature. Patients with higher levels of proliferative, less differentiated memory like CAR+ T cells at peak expansion are more likely to experience prolonged DOR, continuing to support the hypothesis that the memory like T cell phenotype associated with bb21217 results in prolonged DOR. Figure 1 Figure 1. Disclosures Raje: Caribou: Other; Janssen: Other; bluebird bio: Other; Amgen: Other; Celgene: Other; BMS: Other. Shah: Poseida: Research Funding; Precision Biosciences: Research Funding; Sanofi: Consultancy; Sutro Biopharma: Research Funding; Karyopharm: Consultancy; Janssen: Research Funding; Oncopeptides: Consultancy; Kite: Consultancy; Nektar: Research Funding; Indapta Therapeutics: Consultancy; GSK: Consultancy; CSL Behring: Consultancy; CareDx: Consultancy; BMS/Celgene: Research Funding; Bluebird Bio: Research Funding; Amgen: Consultancy; Teneobio: Research Funding. Kaufman: BMS: Consultancy, Research Funding; Tecnofarma SAS, AbbVie: Honoraria; Incyte, celgene: Consultancy; Janssen: Honoraria; Incyte, TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Heidelberg Pharma: Research Funding; Amgen: Research Funding; Fortis Therapeutics: Research Funding; Novartis: Research Funding; Roche/Genetech, Tecnopharma: Consultancy, Honoraria; Sutro, Takeda: Research Funding; Genentech, AbbVie, Janssen: Consultancy, Research Funding. Siegel: Celularity: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Honoraria, Speakers Bureau; Takeda: Honoraria; Bristol Myers Squibb: Honoraria, Speakers Bureau; Amgen Inc.: Honoraria; Karyopharm: Honoraria; Janssen: Honoraria, Speakers Bureau. Munshi: Janssen: Consultancy; Bristol-Myers Squibb: Consultancy; Legend: Consultancy; Adaptive Biotechnology: Consultancy; Amgen: Consultancy; Takeda: Consultancy; Abbvie: Consultancy; Novartis: Consultancy; Celgene: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Karyopharm: Consultancy; Pfizer: Consultancy. Rosenblatt: Parexel: Consultancy; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Imaging Endpoints: Consultancy; Attivare: Consultancy; Wolters Kluwer Health Inc: Consultancy, Patents & Royalties. Lin: Sorrento: Consultancy; Takeda: Research Funding; Juno: Consultancy; Celgene: Consultancy, Research Funding; Merck: Research Funding; Vineti: Consultancy; Legend: Consultancy; Bluebird Bio: Consultancy, Research Funding; Novartis: Consultancy; Gamida Cell: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding; Janssen: Consultancy, Research Funding. Jakubowiak: BMS: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Gracell: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees. Timm: bluebird bio: Current Employment. Yeri: bluebird bio: Current Employment. Martin: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Campbell: Bristol Myers Squibb: Current Employment, Current holder of individual stocks in a privately-held company. Finney: bluebird bio: Current Employment, Current equity holder in publicly-traded company. Truppel-Hartmann: bluebird bio: Current Employment. Petrocca: blue bird bio: Ended employment in the past 24 months. Berdeja: Abbvie, Acetylon, Amgen: Research Funding; Celularity, CRISPR Therapeutics: Research Funding; Bluebird bio, BMS, Celgene, CRISPR Therapeutics, Janssen, Kite Pharma, Legend Biotech, SecuraBio, Takeda: Consultancy; EMD Sorono, Genentech: Research Funding; GSK, Ichnos Sciences, Incyte: Research Funding; Lilly, Novartis: Research Funding; Poseida, Sanofi, Teva: Research Funding.

Abstract MAJIC is a phase II trial of Ruxolitinib (RUX) vs Best Available Therapy (BAT) in polycythemia vera (PV) patients with resistance/intolerance to Hydroxycarbamide (HC). This analysis involved a primary comparison between the RUX and BAT arms for quality of life (QOL) durability over 60 months, with secondary comparisons of best QOL response within first year in complete hematologic responders (CR) vs a group of partial or no response (NR/PR). This is a unique analysis due to cross-over nature of prior studies. Patients were stratified by treatment arm with either RUX or BAT. QOL was assessed over 0-60 months using the Myeloproliferative Neoplasms Symptom Assessment Form (MPN-SAF). MPN-SAF Total Symptom Score (TSS) was computed as the average of all completed items multiplied by 10 (scale 0-100, higher score represents higher symptom burden). Estimates of change from baseline and between arm differences in change by timepoint were made using a linear mixed model with compound symmetry covariance structure, which included covariates for categorical time point, treatment arm, and the interaction between time point and treatment arm. The difference between arms in proportion of patients with best post-baseline TSS response of 50% or greater was testing using a Chi-square test. In this study, 147 of the 190 trial patients had started treatment and completed at least their baseline assessment and were included in the analysis with 39 patients completing through 60 months. Groups were comprised of 76 patients in the RUX group (31 females, 45 males, mean age 64.2 [SD 11.4]) and 71 patients in the BAT group (29 females, 42 males, mean age 64.6 [SD 11.5]). Symptom scores at baseline were similar between arms, with MPN-SAF weight loss the only statistically significant difference (BAT 0.7 [SD 1.71] vs RUX 1.7 [SD 2.83], p=0.02). Significant, durable improvements in TSS were noted in RUX patients with symptom improvements lasting a mean of 52 months. BAT patients experienced a worsening of their symptom burden with improvements back to baseline notable at 56 months (Figure 1). MPN-SAF TSS there were significant differences between treatment arms in change from baseline to months 2-32, 44, and 48 (all p<0.05). In all months the trend was in the direction of larger improvement in the RUX arm, with the point estimate for difference ranging from 2.1 (at month 56) to 11.3 (at month 4) with most prominent changes occurring between months 2 and 32. Of the 80 patients with MPN-SAF TSS scores at baseline and at least one post-baseline timepoint, 13/41 (31.7%) BAT and 24/39 (61.5%) RUX patients had TSS reduction of 50% or greater in at least one time point, which was statistically significant (p=0.008). In regard to specific symptoms, there was a statistically significant between arm difference seen in over 5 timepoints for fatigue, early satiety, night-sweats, itching, bone pain, and weight loss. Comparing MPN-SAF TSS in Complete Response (CR n=51) vs Non-Responder/Partial Responders (NR/PR) (n=96) there was no difference at baseline in any of the measures at any time point. A possible limitation of this study is the potential for bias in which the patients who were lost to follow up could be different then the patients who remained in the study through all 60 months which would affect generalization, particularly at time points at the later years. The novel findings of this investigation demonstrate that Ruxolitinib ameliorates the PV symptom burden in patients resistant or intolerant to HC in a robust durable manner over at least four years, while patients receiving BAT have worsening of their symptom burden over this same time period. Figure 1 Figure 1. Disclosures Mead: Novartis: Consultancy, Honoraria, Speakers Bureau; Celgene/BMS: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria. Yap: Celgene: Honoraria; Faron Pharmaceuticals: Honoraria. Scherber: Incyte Corporation: Current Employment, Current holder of stock options in a privately-held company. Knapper: Novartis: Consultancy, Research Funding, Speakers Bureau; Astellas: Ended employment in the past 24 months, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Jazz: Consultancy, Speakers Bureau. Drummond: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; CTI: Membership on an entity's Board of Directors or advisory committees. McMullin: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: clinical trial support, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan: Research Funding, Speakers Bureau. Mesa: CTI: Research Funding; AOP: Consultancy; Celgene: Research Funding; Novartis: Consultancy; Gilead: Research Funding; Pharma: Consultancy; Promedior: Research Funding; Constellation Pharmaceuticals: Consultancy, Research Funding; CTI: Research Funding; Samus: Research Funding; Sierra Oncology: Consultancy, Research Funding; Genentech: Research Funding; Incyte Corporation: Consultancy, Research Funding; Abbvie: Research Funding; La Jolla Pharma: Consultancy. Harrison: CTI BioPharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead Sciences: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Geron: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Constellation Pharmaceuticals: Research Funding; Galacteo: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte Corporation: Speakers Bureau; Sierra Oncology: Honoraria; Promedior: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keros: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Abstract Background: Hypomethylating agents (HMA) are well established standard of care for patients (pts) with higher-risk MDS (HR-MDS). However, approximately half of the pts do not respond to HMA therapy and most of the responders eventually lose response (HMA failure). There is no standard of care for pts after HMA failure and median overall survival (OS) post HMA failure is around 6 months (Jabbour et al. 2015). While the mutational landscapes and their role in prognosis are increasingly becoming apparent in pts with HR-MDS at diagnosis, mutational profiles at the time of HMA failure and their impact on clinical outcomes are not well understood. Here, using samples collected from a global Phase 3 trial randomizing HR-MDS pts post HMA failure to I.V. rigosertib (RGS) or physician's choice (PC) (INSPIRE: NCT02562443), we analyzed the landscape of driver mutations in HR-MDS after HMA failure and investigated the association with the clinical outcomes. Since RGS is a non-ATP-competitive small molecule RAS mimetic (Athuluri-Divakar 2016), the study also offered an opportunity to test the hypothesis whether HR-MDS pts with oncogenic RAS pathway mutations benefit from RGS. Methods: HR-MDS pts after HMA failure were randomized 2:1 to RGS or PC. All pts failed to respond to or progressed on prior HMA therapy. Bone marrow samples or peripheral blood samples were collected at the time of trial screening. Genomic DNA was sequenced by the targeted capture deep sequencing of 295 genes (median 500x). Results: 372 pts were enrolled in INSPIRE trial (248 to RGS and 124 to PC). The median age of the trial participants was 73 (range: 40-85). All pts were previously treated and with an HMA with the median duration of prior HMA therapy of 6.7 months. 64% and 28% of the pts were classified as IPSS-R very high risk or high risk, respectively, at the time of randomization. Among the 372 participants, DNA sequencing of pre-treatment samples was performed in 188 pts (51% of the participants, N = 122 in RGS arm, N = 66 in PC arm). The most frequently identified driver mutations involved ASXL1 (36%) followed by RUNX1 (24%), TET2 (23%), STAG2 (22%) and TP53 (21%). Mutations in splicing pathway genes were found in 36% of the pts. Oncogenic RAS pathway mutations were detected in 15% of the pts (NRAS = 3 %, KRAS = 2%, CBL = 4%, NF1 = 5%, PTPN11 = 3%, and 1% had multi-hit mutations). Compared to the previously untreated MDS pts (N = 446, Papaemmanuil et al. Blood 2013), mutations in ASXL1 (36% vs. 18%, P < 0.0001), BCOR (9% vs. 3%, P = 0.002), CEBPA (4% vs. 0.2%, P = 0.001), NF1 (5% vs. 0.9%, P = 0.003), RUNX1 (25% vs. 11%, P < 0.0001), STAG2 (22% vs. 5%, P < 0.0001), TP53 (21% vs. 6%, P < 0.0001), and IDH1/2 (13% vs. 7%, P =0.016) were significantly more enriched in pts with HMA failure, whereas mutations in SF3B1 (7% vs. 37%, P < 0.0001), TET2 (23% vs. 35%, P = 0.006), and splicing pathway genes (36% vs. 68%, P < 0.0001) were significantly less frequent in HMA failure pts. These results are consistent with the high-risk profiles of HMA failure pts. Frequency of oncogenic RAS pathway mutations were similar between HMA failure and previously untreated MDS pts (15% vs. 13%, P = 0.612). Correlation analysis between the types of HMA failure and gene mutations showed that TP53 mutations were significantly enriched in pts who relapsed after initial response to HMA (P = 0.001), whereas oncogenic RAS pathway mutations were significantly enriched in pts who progressed during the HMA therapy (P = 0.03). Overall, RGS did not significantly improve the overall survival (OS) of HMA failure pts compared to PC. Survival difference between RGS arm and PC arm was not observed in any subgroups stratified by the gene mutations. The only subgroup that showed improved OS with RGS compared to PC was pts with RAEB-t (median OS 7.5 vs. 3.9 months, P = 0.049). Of note, among pts with oncogenic RAS pathway mutations, no survival difference was observed between RGS and PC arms. Conclusion: High-risk gene mutations, such as TP53, ASXL1, RUNX1, and STAG2 (Ogawa. Blood 2019). were significantly enriched in MDS pts with HMA failure, suggesting their role in HMA resistance and disease progression. Identifying the mutations present de novo and with HMA failure offers the opportunity to determine prognosis based on these mutations as well as potential strategies to target these mutations with new medical entities. Disclosures Takahashi: GSK: Consultancy; Celgene/BMS: Consultancy; Novartis: Consultancy; Symbio Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees. Luger: Syros: Honoraria; Agios: Honoraria; Daiichi Sankyo: Honoraria; Jazz Pharmaceuticals: Honoraria; Brystol Myers Squibb: Honoraria; Acceleron: Honoraria; Astellas: Honoraria; Pfizer: Honoraria; Onconova: Research Funding; Celgene: Research Funding; Biosight: Research Funding; Hoffman LaRoche: Research Funding; Kura: Research Funding. Al-Kali: Novartis: Research Funding; Astex: Other: Research support to institution. Diez-Campelo: BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. OffLabel Disclosure: Rigosertib for MDS patients after HMA failure

Abstract The myeloproliferative neoplasms (MPN) polycythaemia vera (PV) and essential thrombocythaemia (ET) are associated with significant symptom burden with impaired quality of life (QoL). In the MAJIC study patients refractory/intolerant to hydroxycarbamide (HC), were randomised to treatment with ruxolitinib (Rux) or best available therapy (BAT). In this unique and comprehensive analysis we explore quality of life (QoL) outcomes in the MAJIC study using the MPN10 Self-Assessment Form (SAF) in particular using this unique dataset to explore for the first time differences between JAK2 ET vs PV, and JAK2 ET vs CALR ET at baseline and 12 months of therapy with Rux or BAT. Methods 306 patients were randomised, (190, PV and 116 ET arm) and followed for 5 years, no cross over was permitted. MPN10 SAF was assessed at baseline, 2, 4, 8 and 12 months in both arms. Equal variance two sample t-tests were used to test differences between diagnosis groups (JAK2 ET vs PV & JAK2 ET vs CALR ET) in baseline scores and 12-month change from baseline scores, here negative change from baseline indicates improvement. QoL data was also collected using MD Anderson Symptoms Inventory (MDASI) and 5 level EQ5D at the same time points as the MPN10 SAF. Results JAK2 ET vs PV 110 participants with JAK2 mutation were included in the analysis for JAK2 ET vs PV. 81 (74%) had PV and 29 (26%) had JAK2 ET; 44 patients (54.3%) with PV and 18 (62.1%) patients with ET were randomised to Rux, and 37 (45.6%) patients with PV and 11 (37.9%) with ET to BAT. Baseline mean total symptom score (TSS) was similar (JAK2 ET: 18.9. SD 18.4 and PV: 23.7, SD 17.81 (p=0.27). Mean for pruritus was 1.9 (SD 2.47) in JAK2 ET and 3.5 (SD 2.99) in PV (p=0.03). Other baseline scores were comparable: mean scores for fatigue was 3.3 (SD 3.07) for JAK2 ET vs 4.7 (SD 2.68) for PV, for early satiety was 2.6 (SD 2.78) for JAK2 ET vs 2.1 (SD 2.40) for PV, for abdominal discomfort 3.0 (SD 3.34) for JAK2 ET vs 2.0 (SD 2.78) for PV, for inactivity was 2.4 (SD 2.86) for JAK2 ET vs 3.2 (SD 2.72) for PV; for concentration problems was 2.2 (SD 2.51) for JAK2 ET vs 2.9 (SD 3.11) for PV, for night sweats was 1.6 (SD 2.20) for JAK2 ET vs 2.1 (SD 2.66) for PV, for bone pain was 1.8 (SD 2.97) for JAK2 ET vs 2.0 (SD 2.86) for PV, for fever was 0.5 (SD 1.46) for JAK2 ET vs 0.5 (SD 1.70) for PV and for weight loss was 0.3 (SD 0.73) for JAK2 ET vs 1.0 (SD 2.15) for PV (p>0.05 for all). Concerning change at 12 months, mean (SD) change in TSS was -0.5 (SD 10.86) for JAK2 ET (n=21) vs -0.8 (SD 13.32) for PV (n=66) (P=0.93). Mean for individual symptom scores at 12 months were also not significantly different between the two phenotypic disease group (P>0.05 for all parameters). (Fig 1, top panels). CALR vs JAK2 ET Exploring symptoms for CALR vs JAK2 ET: 45 patients were included; 9/16 (56.3%) CALR and 18/29 (62.1%) JAK2 patients were assigned to Rux (p=0.70). 10/16 (62.5%) CALR ET and 19/29 (65.5%) JAK2 ET. Baseline mean total symptom score (TSS) was similar (JAK2 ET: 18.9, SD 18.4 and CALR ET: 18.8, SD 16.99 (p=0. 0.98). All other baseline scores were comparable in this intolerant/ refractory population (p>0.05 for all. Concerning change at 12 months, mean (SD) change in TSS was -0.5 (SD 10.86) for JAK2 ET vs -2.8 (SD 9.96) for CALR ET (P=0.56). Mean for individual symptom scores at 12 months were also not significantly different between the two phenotypic disease group (P>0.05 for all parameters); the mean change in night sweats approached but did not reach significance similar (JAK2 ET: 0.2 (SD 1.89) and CALR ET: 1.8 (SD 3.07) (p=0. 0.06). (Fig 1, lower panels). Preliminary analysis of the MDASI and EQ5D-5L data at baseline and at 12 months shows similar results and will be presented. Conclusion This first analysis of its kind compared the symptom burden and other parameters of QoL of patients with PV and ET, resistant/intolerant to HC shows that with the exception of pruritus at baseline there were no substantial differences between JAK2 ET or PV. Equally changes in symptom burden across 12 months did not substantially differ between JAK2 ET or PV. A second analysis of JAK2 vs CALR ET also failed to show substantial differences. This data should be expanded in a larger cohort but supports a symptom continuum of JAK2 ET and PV and also JAK2 vs CALR ET. Figure 1 Figure 1. Disclosures Mead: Abbvie: Consultancy, Honoraria; Celgene/BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Speakers Bureau. Yap: Faron Pharmaceuticals: Honoraria; Celgene: Honoraria. Knapper: Novartis: Consultancy, Research Funding, Speakers Bureau; Astellas: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau. Drummond: CTI: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Mesa: Pharma: Consultancy; CTI: Research Funding; Abbvie: Research Funding; Genentech: Research Funding; Gilead: Research Funding; AOP: Consultancy; Incyte Corporation: Consultancy, Research Funding; Sierra Oncology: Consultancy, Research Funding; Novartis: Consultancy; La Jolla Pharma: Consultancy; Samus: Research Funding; Promedior: Research Funding; Constellation Pharmaceuticals: Consultancy, Research Funding; Celgene: Research Funding; CTI: Research Funding. Scherber: Incyte Corporation: Current Employment, Current holder of stock options in a privately-held company. McMullin: Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan: Research Funding, Speakers Bureau; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: clinical trial support, Research Funding. Harrison: CTI BioPharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Promedior: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead Sciences: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keros: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sierra Oncology: Honoraria; Constellation Pharmaceuticals: Research Funding; Incyte Corporation: Speakers Bureau; Geron: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Galacteo: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Abstract Introduction: Patients with relapsed or refractory diffuse large B-cell lymphoma (RR DLBCL) who cannot tolerate or who are not eligible for autologous or chimeric antigen receptor T cell (CAR-T) therapy have limited therapeutic options and suboptimal long-term outcomes. In patients who were not eligible for HSCT, the rituximab plus gemcitabine, dexamethasone and cisplatin (R-GDP) regimen (and variations using methylprednisolone or carboplatin/oxaliplatin) have shown an overall response rates (ORR) of ~50%, a complete response (CR) rate of ~25% (Gopal, Leuk Lymphoma, 2010), and a median progression-free survival (PFS) and an overall survival (OS) of 3 and 9 months, respectively (Crump, Hematol Oncol Clin N Am. 2016; Gopal Leuk Lymphoma, 2010; Ng, Br J Cancer, 2005; Sirohi, Hematology, 2007; Barton, Eur J Haematol. 2015; Moccia Leuk Lymphoma, 2017). Selinexor is an oral small molecule selective inhibitor of exportin-1 (XPO1) mediated nuclear export (SINE) compound leading to activation of tumor suppressor proteins and reduction in oncoprotein levels. It also reduces the expression of deoxyribonucleic acid (DNA) damage repair proteins and therefore potentiates DNA damage-based therapies leading to an increased death of cancer cells. Selinexor has synergistic effects with gemcitabine and cisplatin, and enhanced anti-lymphoma effects with dexamethasone. In the SADAL study (n=134), single-agent oral selinexor 60 mg twice weekly induced an ORR of 29% and a CR rate of 13% in patients with RR DLBCL. The response rates were consistent across various subgroups including patients <70 vs ≥70 years old, those with de novo and transformed DLBCL, and GCB and non-GCB subtypes of DLBCL. The median duration of response (DOR) was 9.3 months, and 23 months for patients who achieved CR. OS was 9.0 months. In June 2020, selinexor monotherapy was approved in the US for the treatment of adult patients with RR DLBCL, not otherwise specified, including DLBCL arising from follicular lymphoma, after at least 2 lines of systemic therapy. Selinexor in combination with R-GDP was evaluated in a Phase 1 clinical trial (SELINDA), in which patients with DLBCL received either 40 or 60 mg selinexor once or twice weekly in combination with standard dose R-GDP. The recommended phase 2 dose for further exploration was 40 or 60 mg once weekly with an ORR of 60-80%. Therefore, combining selinexor with R-GDP is expected to improve response rates, and continuation of treatment with single-agent selinexor is expected to prolong the duration of responses, improve PFS (and potentially OS) in patients with RR DLBCL. Materials and methods: XPORT-DLBCL-030 is a Phase 2/3, multicenter study. The Phase 2 portion of the study is an open-label randomized study to identify the optimal dose of selinexor (40 or 60 mg) in combination with R-GDP in patients (n=120) with RR DLBCL. Patients ≥18 years with 1-3 prior lines of therapy and ECOG performance status ≤2 who are not intended for HSCT or CAR-T therapy are randomized 1:1:1 to one of 3 treatment arms: Arm 1: selinexor 40 mg+R-GDP (S40+R-GDP); Arm 2: selinexor 60 mg+R-GDP (S60 + R-GDP); Arm 3: R-GDP. Combination treatment will be given for up to 6 cycles (21 days/cycle). After completing the SR-GDP combination therapy (EoC), patients in Arms 1 and 2 who reach at least partial response (PR), will receive weekly single-agent selinexor 60 mg (28 days/cycle) as "continuous therapy" until disease progression (PD) or unacceptable toxicity. After PD, patients will be followed up for survival. Patients in the R-GDP arm will be followed up for PD and survival. Patients who are ineligible for HSCT due to an active disease, or those who have primary refractory DLBCL, defined as no response or relapse within 6 months after ending first-line treatment, will be allowed to enroll in the study (up to 15% and 25%, respectively of all patients enrolled). The primary endpoint of the study is ORR according to the Lugano 2014 criteria. Secondary endpoints include PFS, OS, ORR-EoC, DOR and incidence and severity of adverse events. Figure 1 Figure 1. Disclosures Pinto: Takeda: Consultancy; MSD: Honoraria; Incyte: Honoraria; Roche: Honoraria, Speakers Bureau; Bristol Myers Squibb-CELGENE: Honoraria. Yimer: Texas Oncology: Current Employment; Pharmacyclics: Speakers Bureau; Amgen: Speakers Bureau; Sanofi: Speakers Bureau; GSK: Speakers Bureau; Beigene: Speakers Bureau; Janssen: Speakers Bureau; Astrazeneca: Speakers Bureau; Karyopharm: Current equity holder in publicly-traded company, Speakers Bureau. Manda: Morphosys: Honoraria; Genmab: Current equity holder in publicly-traded company. Canales: Sanofi: Consultancy; Incyte: Consultancy; Novartis: Consultancy, Honoraria; Sandoz: Honoraria, Speakers Bureau; iQone: Honoraria; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Gilead/Kite: Consultancy, Honoraria; Eusa Pharma: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria. Jurczak: European Medicines Agency, Sandoz-Novartis, Janssen China R&D, BeiGene, Epizyme, Acerta, AstraZeneca: Consultancy; AbbVie, AstraZeneca, Bayer, BeiGene, Celtrion, Celgene, Debbiopharm, Epizyme, Incyte, Janssen, Loxo Oncology, Merck, Mei Pharma, Morphosys, Novo Nordisk, Roche, Sandoz, Takeda, TG Therapeutics, Pharmacyclics, Affirmed, Gilead Sciences, Nordic Nanovecto: Research Funding; Jagiellonian University: Ended employment in the past 24 months; Maria Sklodowska-Curie National Research Institute of Oncology: Current Employment; AstraZeneca, BeiGene, Janssen, Loxo Oncology, Sandoz, Roche: Membership on an entity's Board of Directors or advisory committees. Sureda: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; Bluebird: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Consultancy; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau. Ma: Karyopharm Therapeutics Inc.: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Li: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Ingalls: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Arriola: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Arazy: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Shah: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Shacham: Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Abstract Introduction Central nervous system relapse (secondary central nervous system lymphoma -SCNS) is an uncommon but devastating complication of aggressive B-cell lymphoma. Patients (Pts) with CNS-IPI 4-6 are at greatest risk (10.2% at 2 years). Intravenous high-dose methotrexate (HD-MTX) is widely used to mitigate SCNS risk but data supporting this practice are limited. Methods We performed a multicentre, retrospective study at 21 sites in Australia, Asia, North America and Europe. Chart or registry review was performed for consecutively diagnosed pts with diffuse large B-cell lymphoma (DLBCL) and CNS-IPI 4-6, high grade B-cell lymphoma (HGBL) with rearrangements of MYC+BCL2 and/or BCL6 and primary breast/testicular DLBCL irrespective of CNS-IPI. Pts were diagnosed between 2000-2020, 18-80 years at diagnosis, and treated with curative intent anti-CD20 based chemo-immunotherapy. Pts with CNS involvement at diagnosis were excluded. HD-MTX was defined as at least one cycle of intravenous MTX at any dose. Time to SCNS was calculated from date of diagnosis (all-pts), and from the end of frontline systemic lymphoma therapy, defined as 6x21 days from diagnosis (complete response (CR-pts)), until SCNS, systemic relapse, death, or censoring, whichever came first. Cumulative risk of SCNS was computed using the Aalen-Johansen estimator treating death and systemic relapses as competing events. Adjusted cumulative risks were obtained by using an inverse probability of treatment weighting approach. The average treatment effect was computed as the difference in adjusted 5-year risk of SCNS. Results - 2300 and 1455 pts were included in the all-pts and CR-pts analyses, respectively. Baseline demographics and details of therapy are summarised in Table 1. Except for a predominance of males, pts ≤60 years and pts with ECOG 0-1 in the HD-MTX vs no HD-MTX groups, the demographics and treatments were well balanced. At a median follow up of 5.9 years (range 0.0-19.1) and 5.5 years from diagnosis (range 0.0-18.7), 201/2300 and 84/1455 pts experienced CNS events in the all-pts and CR-pts analyses respectively. For all-pts(n=2300), CNS-IPI was 4-6 in 2052(89.2%), with R-CHOP-like therapy given to 93.8%. 410 pts (17.8%) received HD-MTX (265 HD-MTX alone, 145 in combination with intrathecal methotrexate (IT-MTX);435 received IT-MTX alone;1455 received neither. There were 32/410 and 169/1890 SCNS events, with median time from diagnosis to SCNS of 8.8 and 6.7 months in the HD-MTX and no HD-MTX groups respectively. 5-year OS was 70% (95% CI, 65-76%) and 55% (95% CI 53-57%) in HD-MTX and no HD-MTX groups respectively. There was no difference in the adjusted 5-year risk of SCNS between the HD-MTX and no HD-MTX groups (8.4% vs 9.1%, adjusted hazard ratio [HR] 0.71, p=0.100) (Figure 1). For CR-pts(n=1455), CNS-IPI was 4-6 in 1267(87.0%), with R-CHOP-like therapy given to 93.3%. 284 pts (19.5%) received HD-MTX (170 HD-MTX alone, 114 with IT-MTX);298 received IT-MTX alone;873 received neither. There were 16/284 and 68/1171 SCNS events, with median time from diagnosis to SCNS of 11.0 and 10.3 months in the HD-MTX and no HD-MTX groups respectively. 5-year OS was 74%(95% CI 67-81%) and 75%(95% CI 72-78%) in the HD-MTX groups and no HD-MTX groups respectively (adjusted HR 1.08, p=0.622). There was no difference in the 5-year risk of CNS relapse between the HD-MTX and no HD-MTX groups 5.0% vs 6.0% (adjusted HR 1.03, p=0.903) (Figure 2). Exploratory analysis of the impact of HD-MTX among the highest risk groups CNS IPI 5 (n=368), CNS-IPI 6 (n=59) and CNS-IPI 6 plus all pts with testicular, renal or adrenal involvement (n=349) did not reveal differences in SCNS rates in HD-MTX treated pts. Additional subgroup analyses will be presented at the meeting. Conclusions To our knowledge, this is the largest study of the efficacy of HD-MTX in reducing SCNS events focusing exclusively on high-risk pts. The overall incidence of CNS relapse observed was consistent with previous reports in similar patient cohorts at 9%. The use of HD-MTX did not lower SCNS rates overall or when analysis was confined to CR pts at completion of curative intent therapy to compensate for potential immortal bias associated with HD-MTX therapy. Despite the limitations of the non-randomized and retrospective design, it appears unlikely that HD-MTX is associated with a clinically meaningful reduction in SCNS rates in pts with high risk for SCNS. Figure 1 Figure 1. Disclosures Lewis: AstraZeneca: Consultancy, Honoraria; Novartis: Patents & Royalties: Conference attendance; Janssen: Honoraria, Patents & Royalties: Conference attendance; Roche: Consultancy, Honoraria. Villa: Janssen: Honoraria; Gilead: Honoraria; AstraZeneca: Honoraria; AbbVie: Honoraria; Seattle Genetics: Honoraria; Celgene: Honoraria; Lundbeck: Honoraria; Roche: Honoraria; NanoString Technologies: Honoraria. Bobillo: F. Hoffmann-La Roche Ltd: Consultancy, Speakers Bureau; Gilead: Speakers Bureau. Ekstroem Smedby: Takeda: Consultancy; Janssen Cilag: Research Funding. Savage: Merck: Consultancy, Honoraria, Other: Institutional clinical trial funding; BMS: Consultancy, Honoraria, Other: Institutional clinical trial funding; AbbVie: Consultancy, Honoraria; Roche: Research Funding; Takeda: Other: Institutional clinical trial funding; Servier: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Beigene: Other: Institutional clinical trial funding; Genentech: Research Funding. Eyre: Beigene: Honoraria, Research Funding; Incyte: Consultancy; Secura Bio: Consultancy, Honoraria; Janssen: Honoraria; Gilead/KITE: Honoraria, Other: Travel support for conferences, Research Funding, Speakers Bureau; Loxo Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Other: Travel to conferences; AstraZeneca: Honoraria, Research Funding; Roche: Consultancy, Honoraria. Cwynarski: Incyte: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Atara: Consultancy; Celgene: Consultancy; Takeda: Consultancy, Other: travel to scientific conferences, Speakers Bureau; Kite, a Gilead Company: Consultancy, Other: travel to scientific conferences, Speakers Bureau; Janssen: Consultancy, Other: travel to scientific conferences; Roche: Consultancy, Other: travel to scientific conferences, Speakers Bureau; BMS/Celgene: Other: travel to scientific conferences. Stewart: Teva: Honoraria; Sandoz: Honoraria; Amgen: Honoraria; AstraZeneca: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Gilead: Honoraria; Abbvie: Honoraria; Janssen: Honoraria; Roche: Honoraria. Bishton: Gilead: Honoraria, Other: Travel grants; AbbVie: Honoraria, Other: Travel grants; Celgene/BMS: Honoraria, Other: travel grants; Celltrion: Honoraria, Other: Travel grants; Takeda.: Honoraria, Other: Travel grants . Fox: F. Hoffmann-La Roche Ltd: Consultancy, Membership on an entity's Board of Directors or advisory committees. Joffe: Epizyme: Consultancy; AstraZeneca: Consultancy. Eloranta: Janssen Pharmaceutical NV: Other: NV. Sehn: Genmab: Consultancy; Novartis: Consultancy; Debiopharm: Consultancy. Manos: Bristol-Myers Squibb: Other: Travel and meetings. Hawkes: Specialised Therapeutics: Consultancy; Gilead: Membership on an entity's Board of Directors or advisory committees; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Antigene: Membership on an entity's Board of Directors or advisory committees; Regeneron: Speakers Bureau; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck KgA: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Janssen: Speakers Bureau. Minson: Novartis: Research Funding; Hoffman La Roche: Research Funding. Dickinson: Celgene: Research Funding; Amgen: Honoraria; Takeda: Research Funding; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, accommodation, expenses, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Øvlisen: Abbvie: Other: Travel expenses. Gregory: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, Speakers Bureau; Janssen: Consultancy; Novartis: Consultancy. Ku: Roche: Consultancy; Antegene: Consultancy; Genor Biopharma: Consultancy. Talaulikar: Roche: Honoraria, Research Funding; Jansenn: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; EUSA Pharma: Honoraria, Research Funding. Maurer: Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Genentech: Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees, Research Funding; Nanostring: Research Funding. El-Galaly: Abbvie: Other: Speakers fee; ROCHE Ltd: Ended employment in the past 24 months. Cheah: Roche: Consultancy, Honoraria, Other: advisory and travel expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: advisory; MSD: Consultancy, Honoraria, Other: advisory, Research Funding; Gilead: Consultancy, Honoraria, Other: advisory; Ascentage pharma: Consultancy, Honoraria, Other: advisory; Beigene: Consultancy, Honoraria, Other: advisory; AbbVie: Research Funding; Celgene: Research Funding; AstraZeneca: Consultancy, Honoraria, Other: advisory; Loxo/Lilly: Consultancy, Honoraria, Other: advisory; TG Therapeutics: Consultancy, Honoraria, Other: advisory.

Abstract Background: GLUT4 inhibition is an attractive therapeutic option in multiple myeloma (MM) given the dependence of MM cells on glucose transport. Furthermore, combining a GLUT4 inhibitor with an oxidative phosphorylation inhibitor in MM cells to counter the possibility of therapeutic resistance to GLUT4 inhibition has demonstrated synergistic promise (Dalva-Aydemir et al, Clin Can Res 2015). Using a GLUT4 inhibitor such as the HIV protease inhibitor nelfinavir is an attractive choice since it not only inhibits the transport function of GLUT4, but it also lowers the cytotoxicity resistance of MM cells against proteasome inhibitors such as bortezomib (Driessen et al, Blood 2018). Thus, in summary the FDA-approved oral HIV-PI nelfinavir, long used for the treatment of HIV disease, can bind to glucose transporters (GLUT4) on MM cells and reversibly inhibit glucose uptake, thus disrupting the Warburg effect. Nelfinavir can also enhance the activity of PIs such as bortezomib overcome its resistance in MM cells. Metformin, an oral FDA-approved drug for the treatment of Type II Diabetes has the ability to disrupt the electron transport chain of defective mitochondria within MM cells, thus blocking the ability of such mitochondria to generate energy and anabolic substrates as compensatory mechanisms required for proliferation in the setting of GLUT4 inhibition. Thus, this study will look at the safety and tolerability of repurposing the existing FDA-approved drugs for Type II diabetes and HIV in combination with bortezomib for the treatment of relapsed and/or refractory myeloma. Methods: This study is a phase 1 clinical trial of metformin and nelfinavir in combination with bortezomib for patients with relapsed and/or refractory myeloma. Part A of this trial is a 3+3 dose escalation design with 3 dose levels planned. Part B is a dose expansion cohort at the Maximal Tolerated Dose (MTD) determined in Part A. Up to a maximum of 36 patients will be enrolled and treated for a maximum of six 21-day cycles. Bortezomib is administered in its usual weekly subcutaneous dosing schedule of days 1, 8 and 15 of a 21-day cycle at a dose level of 1.3 mg/m2. Metformin will be administered for 14 days of a 21-day cycle and started at a dose level of 500 mg twice daily and will be investigated to a maximum dose of 1000 mg twice daily. Nelfinavir will also be administered for 14 days of a 21-day cycle and started at a dose level of 1250 mg twice daily and will be investigated to a maximum dose of 2500 mg twice daily. Key inclusion criteria include having relapsed/refractory myeloma with at least 2 prior lines of therapy and prior exposure to PIs, immunomodulators and Anti-CD38 monoclonal antibodies, adequate hematologic reserve, kidney function and liver function. This trial especially allows patients with non-secretory disease yet measurable by bone marrow assessments or cross-sectional imaging of plasmacytomas to be enrolled which constitutes an unmet need in the real-world MM population. Finally, this allows patients to be treated with a dexamethasone-free regimen. The primary objective of this trial is to determine the MTD of metformin and nelfinavir in combination with bortezomib. The secondary objective is to evaluate the safety and tolerability as well as the overall response rate (ORR) associated with this combination. Potential predictive biomarkers as well as resistance mechanisms using genomic RNA, immunohistochemistry and metabolomics-based assessment platforms will be evaluated in this study. Recruitment is ongoing with no safety concerns. This trial is registered on clinicaltrials.gov: NCT03829020. This investigator-initiated trial was funded by the generous gift of the Helen Diller Family Foundation. Disclosures Kumar: Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Antengene: Consultancy, Honoraria; Novartis: Research Funding; Carsgen: Research Funding; Roche-Genentech: Consultancy, Research Funding; Beigene: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Merck: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; BMS: Consultancy, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Ailawadhi: Karyopharm: Consultancy; AbbVie: Consultancy; Genentech: Consultancy; Takeda: Consultancy; GSK: Consultancy, Research Funding; Xencor: Research Funding; Cellectar: Research Funding; Medimmune: Research Funding; Ascentage: Research Funding; Pharmacyclics: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; BeiGene, Ltd.: Consultancy; Sanofi: Consultancy; Oncopeptides: Consultancy.

Abstract Interferon-alpha (IFN), the first approved immunotherapy for cancer, remains an effective therapy for patients with myeloproliferative neoplasms (MPN). The mechanisms of action of IFN on MPN cells are poorly understood, particularly in patients with CALR mutated (MUT) MPNs, who often exhibit clinical but not molecular responses. Previously, by developing Genotyping of Transcriptomes (GoT) that captures mutation status and single-cell RNA-seq (scRNA-seq) in high-throughput, we observed that CALR mutations led to cell identity-dependent effects on CD34 + cells, including a strong megakaryocytic progenitor (MkP) differentiation bias and fitness. We hypothesized that the IFN effects may be cell identity and mutation status dependent; thus we applied GoT to serial bone marrow aspirates (BM) from 5 patients with CALRmutated ET treated with pegylated-IFN-alfa2a who participated in MPD-RC-111/112 clinical trials. To capture the transcriptional impact of IFN, we removed experimental batch effects with Cell Hashing, in which CD34 + cells from serial BM were uniquely labeled and combined for the same GoT experiment (Fig. 1A). Cell clustering based on transcriptomic data alone revealed that the cells on active treatment clustered based on cell identity and IFN effects (Fig. 1B). When off therapy for 3 weeks, the strong transcriptional effects of IFN were largely lost (Fig. 1B). Next, we batch corrected and integrated across time points for each BM sample (Fig. 1C). We observed that IFN caused large shifts in the composition of wildtype (WT) and MUT cell subsets (Fig. 1D). IFN resulted in a dramatic expansion of WT lymphoid progenitors with a corresponding diminution of other progenitors (Fig. 1E). MUT cells at baseline were enriched for MkPs, compared to WT cells; after treatment, we observed an expansion of the immature myeloid (IMP) and neutrophil progenitors, with a less striking expansion of lymphoid progenitors (Fig. 1E). As IFN has been reported to induce cell cycling of murine hematopoietic progenitor cells, we examined whether a differential increase in proliferation by IFN underlies the differentiation shifts in WT and MUT cells. Cell cycle gene expression of ProB cells increased after treatment similarly in MUT and WT cells, while cell cycle expression of IMPs was increased to a greater extent in MUT cells (Fig. 1F), consistent with the differential shifts in populations. Next, we performed differential expression analysis between baseline and treated WT and MUT cells, respectively. We observed enrichment of the IFN pathways post-therapy, whereas TNF-a signaling was downregulated (Fig. 1G). Uniquely in the MUT cells, TGF-b signaling was downregulated, which may underlie improvements in marrow fibrosis following IFN therapy (Fig. 1G). Finally, as the differentiation biases of IFN persisted after discontinuation, we hypothesized that IFN results in chromatin remodeling of the earliest hematopoietic stem progenitor cells (HSPCs), with respect to transcription factor (TF) accessibility. We leveraged single nuclei chromatin accessibility (snATAC-seq) as a powerful measure of TF regulatory activities. We developed GoT-ATAC, an adaptation of the Multiome platform (10x Genomics), to capture snRNA-seq, snATAC-seq and somatic genotyping within the same cells in high-throughput (Fig. 1H). We applied GoT-ATAC to CD34 + cells from the same clinical trial cohorts (Fig. 1I, n = 3 patients: 3 baseline, 2 treated) and identified the expected enrichment of IRFs and STAT2 in treated HSPCs (Fig. 1J). Accessibility of BCL11A, critical for early lymphoid development, was increased in treated MUT and WT HSPCs. We also identified enhanced motif accessibility of PU.1 which can associate with IRF and is essential for myeloid and lymphoid differentiation. Uniquely within the treated MUT cells, we observed enhanced CEBPA motif enrichment, which regulates myeloid differentiation, together with PU.1. In conclusion, GoT revealed that IFN reshapes the differentiation landscape by promoting early lymphoid development and, uniquely in MUT cells, myeloid differentiation, providing a novel mechanism of actions underlying the effects of IFN in MPN patients. Downregulations of TNF-a and TGF-b signaling were other key molecular consequences of IFN. Lastly, GoT-ATAC demonstrated that IFN governs master regulators of hematopoietic differentiation as a function of the underlying mutational status. Figure 1 Figure 1. Disclosures Mimitou: Immunai: Current Employment. Smibert: Immunai: Current Employment. Hoffman: AbbVie Inc.: Other: Data Safety Monitoring Board, Research Funding; Novartis: Other: Data Safety Monitoring Board, Research Funding; Protagonist Therapeutics, Inc.: Consultancy; Kartos Therapeutics, Inc.: Research Funding.

Salicylic acid (SA) has observationally been shown to decrease colorectal cancer (CRC) risk. Aspirin (acetylsalicylic acid, that rapidly deacetylates to SA) is an effective primary and secondary chemopreventive agent. Through a Mendelian randomization (MR) approach, we aimed to address whether levels of SA affected CRC risk, stratifying by aspirin use. A two-sample MR analysis was performed using GWAS summary statistics of SA (INTERVAL and EPIC-Norfolk, N = 14,149) and CRC (CCFR, CORECT, GECCO and UK Biobank, 55,168 cases and 65,160 controls). The DACHS study (4410 cases and 3441 controls) was used for replication and stratification of aspirin-use. SNPs proxying SA were selected via three methods: (1) functional SNPs that influence the activity of aspirin-metabolising enzymes; (2) pathway SNPs present in enzymes’ coding regions; and (3) genome-wide significant SNPs. We found no association between functional SNPs and SA levels. The pathway and genome-wide SNPs showed no association between SA and CRC risk (OR: 1.03, 95% CI: 0.84–1.27 and OR: 1.08, 95% CI: 0.86–1.34, respectively). Results remained unchanged upon aspirin use stratification. We found little evidence to suggest that an SD increase in genetically predicted SA protects against CRC risk in the general population and upon stratification by aspirin use.

Mitogen-Activated Protein 3 Kinase 7 (MAP3K7, MIM 602614) encodes the ubiquitously expressed transforming growth factor β (TGF-β)–activated kinase 1 (TAK1), which plays a crucial role in many cellular processes. Variants in the MAP3K7 gene have been linked to 2 distinct disorders: frontometaphyseal dysplasia type 2 (FMD2, MIM #617137) and cardiospondylocarpofacial syndrome (CSCF, MIM #157800). The fact that different variants can induce 2 distinct phenotypes suggests a phenotype/genotype correlation, but no side-by-side comparison has been done thus far to confirm this. Here we significantly expand the cohort and the description of clinical phenotypes for individuals with CSCF and FMD2 who carry variants in MAP3K7. We show that in contrast to FMD2-causing variants, CSCF-causing variants in MAP3K7 have a loss-of-function effect. Additionally, patients with pathogenic variants in MAP3K7 are at risk for cardiac disease, have symptoms associated with connective tissue disease and we show overlap in clinical phenotypes of CSCF with Noonan syndrome. Together, we provide evidence for a molecular fingerprint of FMD2- versus CSCF-causing MAP3K7 variants and conclude that variants in MAP3K7 should be considered in the differential diagnosis of patients with syndromic congenital cardiac defects and/or cardiomyopathy, syndromic connective tissue disorders and in the differential diagnosis of Noonan syndrome.