Citations

Abstract Background Health-related quality of life (HRQOL) is reduced in patients (pts) with ulcerative colitis (UC). We report on the HRQOL benefits of maintenance treatment with upadacitinib (UPA), a selective and reversible Janus kinase inhibitor, in pts with moderately to severely active UC in the Phase, 3 multicentre, randomised, double-blind U-ACHIEVE maintenance study (NCT02819635). Methods This study included a primary analysis of, 451 pts who achieved clinical response following treatment with UPA, 45 mg once daily (QD) in two replicate, 8-week induction studies, U-ACHIEVE induction, and U-ACCOMPLISH (NCT03653026). In U-ACHIEVE maintenance, pts from both induction studies were re-randomised, 1:1:1 to receive QD UPA, 15 mg, UPA, 30 mg, or PBO. HRQOL outcomes evaluated included the percent of pts reporting a clinically meaningful within-person change (MWPC) from induction baseline to Week, 0 (maintenance baseline) and Week, 52 (end of maintenance) in a broad range of HRQOL measures, including Inflammatory Bowel Disease Questionnaire (IBDQ), Work Productivity and Impairment Questionnaire (WPAI), Short Form, 36 (SF-36), European Quality of Life-5 Dimensions, 5 Levels (EQ-5D-5L), and Ulcerative Colitis Symptoms Questionnaire (UC-SQ). Results A total of, 149, 148, and, 154 pts received PBO, UPA, 15 mg, and UPA, 30 mg QD, respectively, during maintenance. At Week, 0 of the maintenance study, there were no significant differences between UPA and PBO treatment groups in the percentage of pts reporting MWPC relative to induction baseline for most pt-reported outcomes (PROs) as all pts enrolled in maintenance were UPA clinical responders during IP. For IBDQ, a significantly greater proportion of pts achieved MWPC criteria (p<0.001) with UPA, 15 mg (68.9%) and UPA, 30 mg (78.6%) vs, 39.6% for PBO at Week, 52 (Figure, 1). Also, a significantly greater proportion of pts treated with either, 15 mg or, 30 mg UPA dosage vs PBO over, 52 weeks achieved MWPC for the WPAI domains (p≤0.01) of overall work improvement, presenteeism, and activity impairment (Figure, 2), in both physical and mental component summaries of SF-36 (p<0.001, Figure, 3), in EQ-5D-5L (p<0.001, Figure, 4), and in UC-SQ (p<0.001). A numerically greater proportion of pts receiving UPA, 30 mg vs, 15 mg achieved MWPC in most PROs at Week 52. Conclusion A significantly higher percentage of pts with moderately to severely active UC who responded to UPA induction therapy maintained clinically meaningful improvements with UPA, 15 mg of, 30 mg compared to PBO consistently across a broad range of HRQOL outcomes after, 52 weeks of maintenance treatment. These HRQOL aspects include IBD symptoms (IBDQ, UC-SQ), work productivity (WPAI), physical and mental functioning (SF-36), and general well-being (IBDQ, EQ-5D).

Abstract Background Upadacitinib (UPA), a selective and reversible Janus kinase inhibitor, has been shown to be safe and effective when administered at a dose of 45 mg once daily (QD) as 8-week induction therapy in moderate-to-severe Ulcerative Colitis (UC). This analysis evaluated outcomes following extended induction (45 mg QD for 16 weeks) followed by maintenance (15 or 30 mg QD) treatment with UPA in patients with UC who did not achieve a clinical response after 8 weeks’ induction. Methods Patients with moderate-to-severe UC who failed to achieve a clinical response (Adapted Mayo score decrease of ≥2 points and ≥30% from baseline, plus ≥1-point decrease in rectal bleeding score [RBS] or absolute RBS ≤1) to 8 weeks’ induction treatment with UPA 45 mg QD in the U-ACHIEVE Induction (NCT02819635) or U-ACCOMPLISH (NCT03653026) studies, continued to receive UPA 45 mg QD in an 8-week open-label extension. Responders at the end of the open-label extension entered the U-ACHIEVE Maintenance study and were randomised 1:1 to UPA 15 mg or 30 mg QD for 52 weeks. The efficacy endpoints were evaluated at Week 16 for the induction studies and at Week 52 for the maintenance study. Results In total, 125 patients who failed to achieve a clinical response after 8 weeks’ induction treatment received open-label UPA 45 mg for a further 8 weeks. Of these patients, 48.3% achieved a clinical response at Week 16 and were re-randomised to UPA 15 or 30 mg in U-ACHIEVE Maintenance. Among 16-week responders who entered the maintenance study, clinical remission, maintenance of clinical response, and endoscopic improvement, respectively, at Week 52 were achieved in 33.3% versus 19.0%, 66.7% versus 35.7%, and 37.5% versus 23.8% of those who received UPA 30 versus UPA 15 mg QD as maintenance treatment (Table 1). Adverse events of special interest were reported infrequently in the two maintenance treatment groups (Table 2). Conclusion In this analysis, prolonged induction treatment for a total of 16 weeks was beneficial in almost half of UC patients who failed to achieve a clinical response after 8 weeks’ induction with UPA 45 mg. The benefit of maintenance therapy in these delayed responders was further demonstrated, with UPA 30 mg providing greater benefit than UPA 15 mg QD.

Abstract Background Upadacitinib (UPA), an oral, reversible JAK inhibitor engineered for increased selectivity for JAK1 over JAK2, JAK3, or tyrosine kinase 2 (TYK2), demonstrated significantly greater efficacy compared with placebo (PBO) for induction of remission in patients with moderately to severely active ulcerative colitis (UC) in two phase 3 trials, U-ACHIEVE Induction (NCT02819635) and U-ACCOMPLISH (NCT03653026). This analysis evaluated the efficacy of UPA on early symptomatic improvement for the first 14 days, using pooled data from U-ACHIEVE Induction and U-ACCOMPLISH. Methods U-ACHIEVE and U-ACCOMPLISH were multicentre, double-blind, PBO-controlled trials that enrolled patients who have had moderately to severely UC with an Adapted Mayo Score of 5 to 9 points and centrally reviewed endoscopy subscore of 2 to 3. A total of 998 patients were randomized to receive UPA 45mg once daily (QD) (n=658) or PBO (n=328) for 8 weeks (wks) in a 2:1 ratio. First dose of study drug was administered on Day 0. Improvement in symptoms including stool frequency subscore (SFS), rectal bleeding subscore (RBS), abdominal pain, and bowel urgency were analysed from daily symptom diary data. Multivariate regression analysis was used to determine if early changes in UC symptoms could be used to evaluate a potential correlation with patients’ likelihood of achieving clinical response or clinical remission per Adapted Mayo score at the end of induction. Results Baseline characteristics were similar between both treatment groups. Patients treated with UPA 45 mg QD experienced significant improvement in daily symptoms, with significantly more subjects achieving SFS≤1 (p<0.001), RBS of 0 (p<0.05), and SFS of 0 (p<0.05) as early as day 1 and maintained through day 14 (Figure 1). A significantly higher percentage of patients who received UPA 45 mg QD compared to PBO, achieved abdominal pain=0 and the absence of bowel urgency within 3 days of beginning treatment through day 14 (p<0.05). Multivariate analysis revealed that patients who achieved day 7 SFS≤1 (OR 2.42, 95% CI, 1.53–3.82) were more likely to attain clinical response (Table). Patients who attained day 7 SFS≤1 (OR 2.53, 95% CI 1.59–4.00) or day 7 bowel urgency absent (OR 2.40, 95% CI 1.52–3.79) were more likely to achieve clinical remission at week 8. Conclusion UPA 45 mg QD significantly improved UC symptoms as early as day 1, providing patients with rapid symptom relief. Patients who achieved early symptom improvement were more likely to attain clinical remission or clinical response at week 8. [Clinicaltrials.gov, U-ACHIEVE Induction (NCT02819635) and U-ACCOMPLISH (NCT03653026)]

BATF regulates ILC2-mediated tissue repair and inflammation resolution during acute respiratory virus infection.

Abstract Purpose: Smoking rates are higher in rural regions compared to urban regions. Given the mobility within the United States, rural norms around tobacco use may persist even after individuals move to urban areas. Little research is available regarding the difference in smoking history by demographics and rural residence history. The purpose of the study was to examine the influence of age, race, gender, and rural residence history on smoking history. Methods: In a cross-sectional study, we surveyed 1,786 adults using two sampling approaches: representative panels and a community-engaged sample. Participants were asked to complete the Florida Health and Ancestry Study (FHAS) survey through a link or by the phone with a research assistant. The smoking history question asked whether participants had smoked 100 cigarettes in their lifetime (yes/no). The rural residence question asked participants to indicate (yes/no) whether they have lived in a rural or farming community, or on a farm. We examined associations of smoking history with demographic variables using the Chi-square test and logistic regression including as predictors age group (young=18-30, middle age=31-50, old=51+ years), gender, race, and rural living by gender. Results: Participants were mostly White (16% Black, 84% White), female (47% male) and with a mean age around 50 years (mean 47.9±17.5 years, ranged 18 to 91). 36% of the sample reported a history of rural residence, and 51% reported that they had not smoked 100 cigarettes in their lifetime. A larger proportion of males (61%) smoked at least 100 cigarettes compared to females (37%) (p<.001). A significantly larger proportion of White participants (50%) smoked at least 100 cigarettes in their lifetime than Black participants (39%) (p=.001). A larger proportion of participants who had lived in a rural place (53%) had smoked at least 100 cigarettes compared to those who had not lived in a rural place (46%) (p=.005). Difference in mean age for those with or without a history of smoking 100 cigarettes was not statistically significant in this sample (p=.12). Logistic regression analysis revealed that relative to the old age group, the young age group was less likely (p<.001) and the middle age group was more likely (p=.002) to have smoked 100 cigarettes. Males (p<.001) were more likely to have smoked 100 cigarettes than females. Rural residence was associated with smoking among females (p<.001) but not among males (p=.70). Adjusting for other predictors, the association with race was not statistically significant in this sample (p=.06). Conclusion: Findings that the age group 18-30 years is more likely to have avoided becoming smokers is encouraging but must be analyzed more thoroughly relative to possible use of e-cigarettes and other tobacco products. To reduce individuals becoming smokers, we recommend increased cancer control efforts targeted to males in general and to females with a rural residence history. Additional research is planned to examine additional smoking variables and compare them to national data. Citation Format: Tyra Reed, Destiny Gordon, Brenda W. Dyal, Keesha Powell-Roach, Miriam O. Ezenwa, Versie Johnson-Mallard, Janice L. Krieger, Folakemi T. Odedina, Yingwei Yao, Diana J. Wilkie. Demographic factors and rural residence history associated with smoking history [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-012.

Abstract Photoacoustic tomography (PAT), a hybrid imaging modality that acoustically detects the optical absorption contrast, is a promising technology for imaging hemodynamic functions in deep tissues. Particularly, PAT is capable of measuring the blood oxygenation level using hemoglobin as the endogenous contrast. However, the most clinically compatible PAT configuration usually employs a linear ultrasound transducer array and often suffers from the poor image fidelity, mostly due to the limited detection view of the transducer array. PAT can be improved by employing highly-absorbing contrast agents such as droplets and nanoparticles, which, however, have low clinical translation potential due to safety concerns and regulatory hurdles. Moreover, unlike hemoglobin, these exogenous contrast agents cannot report the functional hemodynamic information. In this work, we have developed a new methodology that can improve PAT’s image fidelity without hampering its functional capability or clinical translation potential. By using clinically-approved microbubbles as virtual point sources that strongly scatter the local pressure waves generated by surrounding hemoglobin, we can overcome the limited-detection-view problem and achieve high-fidelity functional PAT in deep tissues, a technology referred to as virtual-point-source PAT (VPS-PAT). We have thoroughly investigated the working principle of VPS-PAT by numerical simulations and phantom validations, showing the acoustic origin of signal enhancement and the superiority over traditional PAT. We have also demonstrated proof-of-concept applications of functional VPT-PAT for in vivo small-animal studies with physiological challenges. We expect that VPS-PAT can find broad applications in biomedical research and accelerated translation to clinical impact.

Background: A univariate neurodegeneration biomarker (UNB) based on MRI with strong statistical discrimination power would be highly desirable for studying hippocampal surface morphological changes associated with APOE ɛ4 genetic risk for AD in the cognitively unimpaired (CU) population. However, existing UNB work either fails to model large group variances or does not capture AD induced changes. Objective: We proposed a subspace decomposition method capable of exploiting a UNB to represent the hippocampal morphological changes related to the APOE ɛ4 dose effects among the longitudinal APOE ɛ4 homozygotes (HM, N = 30), heterozygotes (HT, N = 49) and non-carriers (NC, N = 61). Methods: Rank minimization mechanism combined with sparse constraint considering the local continuity of the hippocampal atrophy regions is used to extract group common structures. Based on the group common structures of amyloid-β (Aβ) positive AD patients and Aβ negative CU subjects, we identified the regions-of-interest (ROI), which reflect significant morphometry changes caused by the AD development. Then univariate morphometry index (UMI) is constructed from these ROIs. Results: The proposed UMI demonstrates a more substantial statistical discrimination power to distinguish the longitudinal groups with different APOE ɛ4 genotypes than the hippocampal volume measurements. And different APOE ɛ4 allele load affects the shrinkage rate of the hippocampus, i.e., HM genotype will cause the largest atrophy rate, followed by HT, and the smallest is NC. Conclusion: The UMIs may capture the APOE ɛ4 risk allele-induced brain morphometry abnormalities and reveal the dose effects of APOE ɛ4 on the hippocampal morphology in cognitively normal individuals.

Abstract Multiple Myeloma (MM) is the second most common hematologic malignancy, marked by uncontrolled clonal expansion of plasma cells. MM genome is complex and heterogeneous, with a high frequency of structural variants (SVs) and copy-number abnormalities (CNAs). Single-cell sequencing technologies offer advantages over traditional bulk methods in cancer genomics research for evaluating cellular heterogeneity and investigating evolution of cellular subpopulations within the tumor. Thus, there is an impetus to translate the growing understanding of the genomic landscape of MM into dissecting the tumor heterogeneity using scRNA-seq. So far, there are no reported studies systematically comparing tumor and immune populations differences between MM NON-progressors (NPs) and RAPID-progressor (RPs) and investigating how clonal plasma cells contribute to progression in a large cohort. In addition, the bone marrow microenvironment plays an important role in the evolution of premalignant MM and MM progression. A previous study of single-cell transcriptomics analysis of Monoclonal gammopathy of undetermined significance (MGUS) and MM tumor microenvironment (TME) revealed that natural killer (NK) cell abundance is frequently increased in the early stages and associated with altered chemokine receptor expression. This study shed the light on the role of immune cells on disease progression from asymptomatic MGUS to symptomatic MM. However to date, how immune cells influence disease progression within symptomatic MM is still unclear. Here, we subjected 344 CD138-negative Bone Marrow Mononuclear cells (BMMC) samples to scRNA-seq. To control for the first line therapy, 272 patients were treated with RVD and Autologous stem cell transplant (ASCT) and were stratified into 3 groups based on progression: 200 NON-progressors (NPs) (PFS> 5 years), 7 Intermediate Progressors (IPs, PFS 2-4 years) and 38 RAPID-progressors (RPs) (PFS<=18 months). In addition, there are 72 subjects treated with RVD but without ASCT, including 34 NPs, 2 IPs and 36 RPs. From MMRF CoMMpass study (NCT01454297), we also have whole exome sequencing (WES) and bulk RNA-seq from CD138-positive fraction of BMMC samples. Our preliminary analysis of scRNA-seq of 6 samples treated by the same first-line therapies (RVD but without ASCT) revealed that plasma cells (PCs) from two patients (MMRF2550 and MMRF2562) with chromosome 13q deletion clustered together, whereas PCs from a patient (MMRF2187) with t(8;14) Myc translocation formed a distinct cluster. Interestingly, PCs from a patient (MMRF2271) with both chromosome 13q deletion and t(8;14) formed another independent cluster. These observations highlight the important role of genetic drivers in transcriptome profiles of plasma cells. In addition, we further investigated how progression features correlate with the immune microenvironment and identified differentially expressed genes between NK cells from RPs versus those from NPs, which could potentially serve as MM progression markers. Interestingly, several cytotoxicity genes are significantly upregulated in FPs, such as GZMB and KLRB1 (log Fold Change=1.44, and 8.41 respectively). Overall, our preliminary results provide a small glimpse of the interconnected nature of driver genetic alterations and progression features in MM tumor and TME. This study will provide a sufficiently broad, deep, and diverse vast dataset for accurately characterizing MM at single-cell resolution to help interrogate how genetic alterations and disease progression interplay MM tumor and TME. We hope this study could identify novel candidate targets for therapeutic approaches, and ultimately stratify patients by risk of progression for early intervention in the clinic. Disclosures Kumar: Roche-Genentech: Consultancy, Research Funding; Merck: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Novartis: Research Funding; 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; Beigene: Consultancy; Carsgen: Research Funding; Bluebird Bio: Consultancy; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Tenebio: Research Funding; BMS: Consultancy, Research Funding; Antengene: Consultancy, Honoraria; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Oh: Abbvie: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Membership on an entity's Board of Directors or advisory committees; Celgene Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Constellation: Membership on an entity's Board of Directors or advisory committees; CTI Biopharma: Membership on an entity's Board of Directors or advisory committees; Disc Medicine: Membership on an entity's Board of Directors or advisory committees; Geron: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Kartos Therapeutics: Membership on an entity's Board of Directors or advisory committees; PharamaEssentia: Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Membership on an entity's Board of Directors or advisory committees. Vij: BMS: Research Funding; Takeda: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; BMS: Honoraria; GSK: Honoraria; Oncopeptides: Honoraria; Karyopharm: Honoraria; CareDx: Honoraria; Legend: Honoraria; Biegene: Honoraria; Adaptive: Honoraria; Harpoon: Honoraria. Avigan: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Kite Pharma: Consultancy, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Partner Tx: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Aviv MedTech Ltd: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Legend Biotech: Membership on an entity's Board of Directors or advisory committees; Chugai: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Parexcel: Consultancy; Takeda: Consultancy; Sanofi: Consultancy.

Abstract Multiple myeloma (MM) cells are characterized by cell cycle dysregulation, epigenetic heterogeneity, and perturbation of the transcriptional landscape. We have previously shown that chemical and genetic perturbation of transcriptional regulator CDK7 significantly and selectively impacted MM cell growth and viability, supporting it as a pharmacologically relevant target for MM. Indeed, selective CDK7 inhibitor YKL-5-124 was active against a large panel of MM cell lines and primary MM cells, with a significantly lower IC50 compared to PHA-activated normal donor peripheral blood mononuclear cells (PBMCs). The efficacy of YKL-5-124 was confirmed in vivo in several murine models of MM, including disseminated models. Gene expression analysis after CDK7 inhibition in several MM cell lines revealed that transcripts for only a subset of genes were substantially affected by treatment with low dose of YKL-5-124, showing a strong leading-edge enrichment for downregulation of E2F expression program, cell cycle, DNA damage, and MYC targets. We have indeed confirmed a potent reduction in phosphorylation of RB protein, with consequent decrease of E2F activity in MM cells, supporting CDK7 as a central hub in the oncogenic CDK-pRb-E2F pathway in MM cells, with its expression and activity positively correlated with E2F transcriptional output in patient MM cells. Importantly, dual inhibition with low doses of YKL-5-124 and BRD4 inhibitor JQ1, displayed superior activity against a panel of MM cell lines and primary MM cells compared to single perturbation alone by both converging on a subset of key SE-associated dependencies as well as impacting distinct oncogenic expression programs. To identify synthetically lethal targets and mechanisms of resistance to CDK7 inhibition, we performed a genome-wide CRISPR-Cas9 knockout screen in the MM1S cells treated with YKL-5-124 or DMSO. We found that BCL6, NFKBIA and B, TRAF2, TSC1 and CSNK2A1, a subunit of CK2, were top synthetically lethal hits; whereas deletion of RB1, SF3B3 and the DNA-binding transcriptional activator TADA2A that regulates RNA-pol II transcription, led to resistance to YKL-5-124. Molecular mechanisms of intrinsic and acquired resistance to CDK7 inhibition are now under investigation and will be presented. In conclusion, our study demonstrates CDK7 as an attractive molecular vulnerability in MM that can be exploited therapeutically alone or in combination. Disclosures Shirasaki: FIMECS: Consultancy. Chesi: Novartis: Consultancy, Patents & Royalties: human CRBN transgenic mouse; Pfizer: Consultancy; Pi Therapeutics: Patents & Royalties: Genetically engineered mouse model of myeloma; Abcuro: Patents & Royalties: Genetically engineered mouse model of myeloma; Palleon Pharmaceuticals: Patents & Royalties: Genetically engineered mouse model of myeloma. Anderson: Millenium-Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Scientific Founder of Oncopep and C4 Therapeutics: Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Mana Therapeutics: Membership on an entity's Board of Directors or advisory committees. Mitsiades: Arch Oncology: Research Funding; Karyopharm: Research Funding; Adicet Bio: Membership on an entity's Board of Directors or advisory committees; Ionis Pharmaceuticals: Consultancy, Honoraria; Abbvie: Research Funding; FIMECS: Consultancy, Honoraria; Nurix: Research Funding; Sanofi: Research Funding; Novartis: Research Funding; H3 Biomedicine: Research Funding; EMD Serono: Research Funding; Janssen/Johnson & Johnson: Research Funding; Fate Therapeutics: Consultancy, Honoraria; BMS: Research Funding; TEVA: Research Funding. Munshi: Novartis: Consultancy; Legend: Consultancy; Pfizer: Consultancy; Adaptive Biotechnology: Consultancy; Takeda: Consultancy; Amgen: Consultancy; Janssen: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Abbvie: Consultancy; Karyopharm: Consultancy; Celgene: Consultancy; Bristol-Myers Squibb: Consultancy.

Abstract Integrated genomic analysis including whole genome and RNA sequencing in primary multiple myeloma (MM) cells have reported a universal loss of BCL7A gene in MM patients compared to normal plasma cells (PC). Our Genetic modulation in in-vitro and in-vivo MM models have also validated the loss of BCL7A as an oncogenic event responsible for acquisition of a more proliferative phenotype in MM cells. We performed a comparative mass spectrometric analysis confirming BCL7A as a member of the canonical m-SWI/SNF chromatin remodeling complex. We therefore performed the Assay for Transposase Accessible Chromatin with high-throughput sequencing (ATAC-seq) to assess genome-wide changes in DNA accessibility upon BCL7A gain or loss. We found that loss of BCL7A in wild-type KMS12BM and NCI-H929 cells resulted in enrichment of important transcription factor motifs in the transcriptionally active sites of chromatin. We identified 36 de novo accessible and 1079 de novo inaccessible regions across the genome after BCL7A shRNA KD (knock-down). These genomic regions with altered accessibility were associated with genes involved in protein binding (FDR < 0.001), GTPase activation (FDR = 0.016), and GTPase regulation (FDR = 0.030). Candidate transcription factors for the genomic regions with altered accessibility were identified by querying a database of human ChiP-seq experiments (ReMap 2020). IRF4 was identified to be enriched in regions of accessible chromatin upon BCL7A loss. IRF4 is an oncoprotein transcription factor and is a direct target of myc, generating a feedback loop in MM cells. IRF4 dependency is central to myeloma cell proliferation. Most importantly, we found that in addition to functions within the m-SWI/SNF complex, BCL7A forms a protein complex with IRF4. Altogether these data suggest a role for BCL7A in driving IRF4 oncogenic activities in MM. To understand how BCL7A-dependent changes may influence IRF4 activity, we performed CHiP assay using IRF4 antibody in BCL7A KO (knock-out) and AB (add-back) KMS12BM and NCI-H929 cells. We observed increased binding of IRF4 to the promoter of its target genes like PRDM1, CDK6, STAG2, PIM2, SQLE, Myc, CANX, IRF4, SCD, ELL2, CASP3 in BCL7A KO cells, while the binding of these target genes was significantly decreased in AB cells. While, CHiP assay using IRF4 antibody in control and ectopically expressed BCL7A in AMO1 and KMS11 cells showed significantly low binding of IRF4 to the promoter of most of its target genes in BCL7A overexpressed cells compared to control. Integrated transcriptomic analysis following BCL7A KD and overexpression revealed the existence of a set of genes transcriptionally regulated by IRF4 to be significantly upregulated following BCL7A depletion and downregulated following ectopic expression of BCL7A. To investigate whether these genes are involved in the phenotypic and functional effects observed in MM after BCL7A depletion, we performed LOF studies (si-RNA screen) in scrambled and BCL7A KD MM cells. Among others, we observed that MM cells are highly sensitive to the inhibition of EEF1B2, RPS3A, SOX2, DCC and NDUFA1 only in the context of BCL7A loss, implicating a role as critical effector molecules downstream of the IRF4-BCL7A transcriptional network. In conclusion, we observe that BCL7A binds to IRF4, functionally restricting its activity. The universally observed down regulation of BCL7A in MM provides the necessary molecular change to allow IRF4 to exert its required transcriptional activity to induce MM cell growth. Our results now provide the basis to understand the mechanism of development of IRF4 dependency in MM. Disclosures Anderson: Pfizer: Membership on an entity's Board of Directors or advisory committees; Millenium-Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Scientific Founder of Oncopep and C4 Therapeutics: Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company; Mana Therapeutics: Membership on an entity's Board of Directors or advisory committees. Munshi: Janssen: Consultancy; Karyopharm: Consultancy; Adaptive Biotechnology: Consultancy; Novartis: Consultancy; Legend: Consultancy; Bristol-Myers Squibb: Consultancy; Amgen: Consultancy; Abbvie: Consultancy; Takeda: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Celgene: Consultancy; Pfizer: Consultancy.