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Introduction: Preclinical studies have suggested synergism between lenalidomide (LEN) and ibrutinib (IBR) in multiple myeloma (MM). Both downregulate IRF4, a master transcriptional factor that regulates myeloma cell survival. Single agent oral IBR combined with dexamethasone proved well tolerated and active in advanced, steroid refractory relapsed MM as part of a large Phase1/2 study in 60 patients, with durable stabilization and minimal response seen in most evaluable patients (Richardson PG et al, BJH 2018). LEN is considered a standard of care in newly diagnosed MM, as maintenance and in relapsed disease, and a backbone of oral therapy in the MM treatment paradigm (Laubach JP et al, Leukemia 2016). Methods: We therefore conducted a 3+3 phase I trial to determine the maximum tolerated dose (MTD) of IBR in combination with LEN + dexamethasone (DEX) in patients with relapsed/refractory (RR) MM who had at least 2 prior lines of therapy. Three dose levels (DL) were planned. Cycle length was 28 days. IBR was administered orally daily at 560mg on DL1-2 and 840mg on DL3, LEN orally days 1-21 at 15mg on DL1 and 25mg on DL2-3, and DEX orally days 1, 8, 15, and 22 at 40 mg if age < 75 or 20 mg if ≥75 for DL1-3. Patients with GFR ≥ 30 and < 60 were treated according to manufacturer's instructions with lenalidomide dosed at 10mg/d. Dose limiting toxicities (DLT) included grade 4 thrombocytopenia; grade 4 neutropenia lasting more than 5 days or febrile neutropenia; grade 4 nausea, vomiting or diarrhea; grade 3 thrombocytopenia with bleeding or platelet transfusion; grade 3-4 hyperglycemia or thrombotic/embolic event, treatment delays ≥ 21 days for toxicity; and treatment related death. Due to changes in standard of care during the study, eligibility was modified to allow the enrollment of patients with RRMM who had at least 1 prior line of therapy. Response was assessed using IMWG/Uniform Criteria. Results: Fourteen patients (DL1-6 pts; DL2-3 pts; DL3-5 pts) registered to the study from March 2019 to May 2023, prior to its closure due to slow accrual. One patient on DL3 cancelled participation prior to start of treatment due to disease progression (PD). The remaining 13 patients are included in summary of toxicities and response but 2 patients on DL3 are excluded from determination of MTD due to discontinuing cycle 1 treatment due to COVID and receiving 280 mg/day of IBR instead of assigned 840 mg/day dose during cycle 1, respectfully. Twelve patients were evaluable for response. The median number of prior lines of therapy was 3 (range: 2-9), reflecting a heavily pretreated relapsed and refractory population. One of the 6 patient on DL1 developed a DLT, grade 3 non-viral hepatitis. None of the 3 patients on DL2 or the 2 patients on DL3 had a DLT. One patient on DL1 remains on treatment with stable disease for 42+ cycles. The median number of cycles administered was 3 (range: 1-42+). Severe toxicities reported included grade 3 lymphocytopenia (3), anemia (2), alanine aminotransferase increase (1), aspartate aminotransferase increase (1), blood bilirubin increase (1), hypocalcemia (1), hypokalemia (1) hypophosphatemia (1), febrile neutropenia (1), chronic kidney disease (1), non-viral hepatitis (1), soft tissue infection (1), and fatigue (1); grade 4 lymphocytopenia (1), and grade 5 sepsis (1). End of treatment reasons included: PD (7), toxicity (2), death [soft tissue infection that turned into sepsis considered to be likely related to DEX] (1), and concomitant conditions (2). Stable disease (SD) or better was achieved in 10 of 12 evaluable patients (83%), including one patient who achieved disease control for over 3.5 years. One patient (8%) on DL3 had a complete response (CR) but stopped treatment after 2 cycles due to reversible toxicity and comorbid conditions, based upon physician advice and patient choice. Conclusions: The combination of lenalidomide with Ibrutinib as an all-oral approach in RR MM proved feasible and generally tolerable, with the majority of discontinuation seen in this Phase I study due to disease progression. No COVID related - mortality was seen. SD or better was achieved in 83% of patients, including one CR. Potential future directions include combination approaches with next generation IMids such as pomalidomide, as well as other orally bioavailable novel agents with potent immune activating properties, such as CelMoDs. Support: AFT; Pharmacyclics; Clinicaltrials.gov Identifier: NCT03702725

Introduction: Despite the improved clinical outcomes with novel therapies in patients with chronic lymphocytic leukemia (CLL), Richter transformation (RT) of CLL remains a major clinical challenge. Our group showed a selective response (~40%) with the PD-1 blocking antibody pembrolizumab in patients with RT, particularly after prior exposure to ibrutinib (Ding et al, Blood, 2017). It has been established that PD-1 inhibits cytotoxic T-cell functions via the interaction with its ligands, PD-L1 and PD-L2. However, the role of PD-1 in tumor B-cells is understudied. Here we show the expression and functional implications of the PD-1 signaling axis in B-cell pathobiology. Methods: CLL-involved lymph node (LN) (n=26) and RT (with diffuse large B-cell lymphoma [DLBCL] histology) -involved LN (n=20) samples were tested for PD-1 expression by immunohistochemistry (IHC) (mouse clone NAT105, Abcam). Then, PD-1 expression was examined in 10 lymphoma cell lines and 1 CLL-like cell line (MEC-1) by both flow cytometry (FC) and Western blot (WB) analysis. PD-1 overexpression using pLEX-lentiviral packaging system (Thermo Scientific) was evaluated for its impact on in vitro cell cycle regulation and in vivo tumor growth. CRISPR/CAS9 mediated PD-1 knockdown evaluated on cell growth in MEC-1 and Mino cells. Role of PD-1 was further examined on the regulation of cell signaling pathways using human phospho kinase array kit (R&D) and WB analysis. Additionally, gene expression signatures were evaluated by RNA-seq using pLEX-lentiviral-PD-1 transfected DLBCL cell lines OCI-LY7 and OCI-LY19. Results: PD-1 expression was significantly increased in RT-LN compared to CLL-LN (mean ± SEM in RT vs. CLL, 30.6% ± 4.7% vs. 11.5% ± 2.8%, p<0.001) as determined by IHC. PD-1 expression was highest in patients with RT where the last prior CLL therapy was ibrutinib. To test the role of PD-1 in tumor B-cells, its expression was assessed in lymphoma and CLL cell lines. The expression of PD-1 was found to be variable by both FC and WB analysis, but at very low-levels in DLBCL cell lines OCI-LY7 and OCI-LY19. Constitutive lentiviral (pLEX-PD-1)-mediated overexpression of PD-1 in OCI-LY7 and OCI-LY19 cells led to increased cell growth (1.4 and 1.9 fold, respectively, compared to original lines after 4 days of culturing of equal number of cells), which was further confirmed by cell cycle analysis which showed an increase in S phase by 20.4% (p<0.05) and 24.5% (p<0.05) in OCI-LY7 and OCI-LY19 cells, respectively. When the luciferase+ PD-1 overexpressing OCI-LY7 cells (1X10 6) were injected intravenously into NSG mice, increased tumor growth (p<0.01) was observed by bioluminescence imaging after 22 days of follow-up. PD-1 knockdown in MEC-1 and Mino cells (high basal PD-1 expression) led to significant inhibition of cell growth (85% and 79.5%, respectively, p<0.05). Using phospho-kinase array, an overall decrease of phosphorylation was detected on multiple sites of p53 (S392, S15, S46) and Chk-2 (T68) in PD-1 overexpressing OCI-LY7 and OCI-LY19 cell lines. This finding was further confirmed by WB analyses. In addition, decreased total p53 and increased phosphorylation on both SHP-1 and SHP-2 were found in PD-1 overexpressing OCI-LY7 and OCI-LY19 cell lines. SHP-1 (TPI-1) and SHP-1+SHP-2 (TPI-1+TNO155) inhibitor treatment promoted OCI-LY19 cell death and led to recovery of phosphorylation on ATM, Chk-2 and p53 in these cells. RNA sequencing data in PD-1 overexpressing OCI-LY7 and OCI-LY19 cells revealed increased expression of genes that promote cell cycle progression and DNA replication. Conclusion: Our data showed robust PD-1 expression in patients with Richter transformation from CLL to DLBCL. PD-1 overexpression in DLBCL lymphoma cell lines enhanced cell proliferation in vitro and in vivo. Further investigation identified that PD-1 modified the phosphorylation/function of SHP phosphatases and thereby regulated p53 pathways ( Figure 1). These findings indicate that RT with DLBCL cells have the ability to “hijack” the PD-1 pathway which results in downregulation of p53 mediated DNA repair. This novel finding provides for new strategies to further evaluate the interaction of PD-1 signals with DNA repair pathways and suggest potential novel targets for RT.

INTRODUCTION Chronic lymphocytic leukemia (CLL) and SLL represent a single entity in current classifications per the WHO-HAEM5 and ICC. Both are characterized by malignant B cells with an identical immunophenotype, but they are distinguished by the predominant site of disease burden, such as peripheral blood for CLL and nodal compartments for SLL. Most clinical trials and retrospective studies involving CLL/SLL do not separate out SLL patients. In this study, we report reasons for treatment initiation and outcomes in a cohort of SLL patients seen at our institution. METHODS Using the Mayo Clinic CLL Database, we retrospectively identified patients with SLL who received first line therapy between 12/1995 and 2/2023. Patients were classified as having SLL if they met at least one of the following criteria for diagnosis: 1) presence of lymphadenopathy or splenomegaly (either by exam or scans) and an absolute clonal B cell count of < 5 x 109/L; or 2) presence of lymphadenopathy or splenomegaly (either by exam or scans) and an absolute lymphocyte count of < 11 x 109/L (if absolute clonal B cell count was not available). Although the presence of anemia (hemoglobin < 11 g/dL) and thrombocytopenia (platelets < 100 x 109/L) are considered as exclusion criteria for a diagnosis of SLL, patients were included if these cytopenia were due to autoimmune hemolytic anemia (AIHA) or immune thrombocytopenia (ITP) with < 50% bone marrow involvement by SLL (bone marrow biopsy confirmed). Patients treated for SLL with extranodal involvement were also included. Indications for SLL treatment were abstracted by chart review and included one of the following: 1) symptomatic or progressive lymphadenopathy and/or splenomegaly, 2) autoimmune cytopenias, 3) extranodal/direct organ infiltration; and 4) other (e.g., cryoglobulinemia, paraneoplastic, non-infiltrative renal disease such as minimal change disease). Overall survival (OS) was defined as the time from treatment start until date of death or last known to be alive. Treatment-free survival (TFS) was defined as the time from treatment start until the earliest of date of next treatment, or death. Kaplan-Meier method was used to display OS and TFS. Cox proportional hazards regression models were used to estimate associations of factors with time-to-event outcomes. RESULTS We identified 182 patients with SLL who received first line treatment. The median age at treatment start was 66 years, and 132 (73%) were male. Unmutated IGHV was identified in 60/82 (73%) patients and peripheral blood fluorescent in situ hybridization (FISH) assessed pre-treatment start showed del13q in 10%, trisomy 12 in 43%, del11q in 7%, del17p in 8%, and no abnormalities in 33%. TP53 disruption (del17p and/or TP53 mutation) was present in 7/89 (8%) patients prior to first therapy. The median follow-up after diagnosis was 6.9 years. The indications for treatment were grouped as follows: symptomatic or progressive lymphadenopathy/splenomegaly (n=130), extranodal/direct organ infiltration (n=30), AIHA/ITP (n=10), and other (n=12). For the entire cohort, the median TFS was 2.9 years and the median OS was 12.3 years. The median TFS by the treatment indication groups were 3.3, 5.1, 1.6, and 5.3 years, respectively (Figure 1). The median OS by treatment indication groups were 11.1, 10.5, 8.8, and 19.9 years, respectively. Among the 160 patients with symptomatic or progressive lymphadenopathy/splenomegaly or extranodal disease, the treatments administered include: mAb alone (n=35), chemotherapy alone (n=33), chemoimmunotherapy (n=57), targeted agent (n=33; Bruton tyrosine kinase inhibitor [BTKi] based n=28; venetoclax-based n=3, BTKi + venetoclax n=2), and other (n=2). The median TFS by treatment groups were 2.4, 2.0, 3.8, and 6.0 years (Figure 2), respectively (excluding the small “other” subgroup of 2 patients). The median OS for these groups were 9.5, 9.7, 15.0, and not evaluable, respectively. Only older age at treatment start predicted for shorter TFS (HR 1.02; 95%CI 1.002-1.038; p=0.03) and shorter OS (HR 1.05; 95%CI 1.03-1.07; p<0.01). CONCLUSIONS In this study of patients with SLL who received therapy, the most frequent indications for treatment included symptomatic lymphadenopathy and/or splenomegaly, followed by extranodal disease. Trisomy 12 was the most frequently detected abnormality on peripheral blood FISH testing. Treatment with novel agents achieved durable TFS and OS.

Abstract BACKGROUND In GBM, effective chimeric antigen receptor T-cell (CART) therapy remains a challenge; immunosuppressive components within the tumor microenvironment (TME) inhibit CART cells. EphA3 is a receptor tyrosine kinase with low expression in adult tissues but is highly expressed in tumor neovasculature and tumor stromal cells in GBM and other solid tumors. METHODS We performed RNA sequencing and Immunohistochemical staining for of EphA3 in a clinically annotated GBM PDX biobank and M01 M1 and M2 polarized macrophages. We then investigated the suppressive capability of M2 macrophage on EphA3-CART in an SNB-19 GBM cell co-culture. We tested the antiantitumor potential of EphA3-CART against luciferase+ SNB-19 GBM cells in vivo with flank and orthotopically engrafted NOD-SCID-ɣ-/- (NSG) mice. Engraftment was confirmed by bioluminescent imaging (BLI) and vernier caliber (flank) for 7-14 days post-injection. Mice were randomized to be treated with EphA3-CART or untransduced T-cells (UTD). Subsequently tumor size and mouse survival was monitored to determine the antitumor effect. RESULTS EphA3 was highly expressed on GBM PDX models as well as M2 macrophages. Compared to M0 and M1 macrophages, M2 macrophages significantly suppressed EphA3-CART However, despite the suppressive activity of the M2 macrophage, EphA3-CART exhibited significant antitumor activity . In both flank and orthotopically implanted mouse models, there was an observed reduction in tumor volume with EphA3-CART treated model compared to the UTD counterpart. EphA3-CART treatment resulted in significantly improved survival of the treated models compared to UTD models (hazard ratio = 0.053 **p = 0.005). CONCLUSION We demonstrate that EphA3 is expressed on GBM cells as well as on M2 macrophages. EphA3 CART is able to overcome and ameliorate the effect of a major component of the tumor microenvironment (TME), M2 macrophages. EphA3 CART appears effective in flank and orthotopic mouse models of GBM.

Abstract Background Guidelines recognize the role of exercise stress testing in evaluating functional capacity in patients with asymptomatic severe aortic stenosis (AS). Exercise stress echocardiography (ESE) allows the detection of pulmonary congestion with B-lines by lung ultrasound (LUS). Aim To identify the prevalence, determinants, and functional correlates of B-lines during ESE in asymptomatic severe AS. Methods We enrolled 35 asymptomatic patients (age= 69±16 years, 69% male) with severe AS, aortic valve area (AVA) <0.6 cm2/m2, mean aortic gradient (MAG) ≥ 40 mmHg, left ventricular ejection fraction ≥55%. All patients were referred for ESE (treadmill in 1, bicycle in 34 patients) in 7 experienced centers from 4 countries between 2021-2022. ESE assessment at rest and peak stress included global longitudinal strain (GLS), left atrial volume index (LAVI) and cardiac output (CO). B-lines were assessed by simplified LUS from 4 lung zones across the third intercostal space (2 on each side). Heart rate reserve (HRR) was measured as the peak/rest heart rate. CO reserve was calculated as the difference between peak stress CO and rest CO. Results B-lines (≥2) were present in 2 patients at rest and in 15 patients during ESE (6% vs 43%, p<0.001). When compared to patients without B-lines during ESE (Group 1, n=20), patients with B-lines during ESE (Group 2, n=15) were older (Group 1= 64±18 vs Group 2=75±8 years, p=0.030) had larger LAVI, higher logNT-pro-BNP and a trend to higher systolic pulmonary artery pressures (SPAP), see Table. The 2 groups showed similar values of resting AVA (Group 1= 0.52±0.11 vs Group 2=0.47±0.15 cm2/m2, p=0.311), stress AVA (Group 1= 0.45±0.09 vs Group 2=0.49±0.13 cm2/m2, p=0.663), resting MAG (Group 1= 45±15 vs Group 2=46±10 mm Hg, p=0.491), and stress MAG (Group 1= 59±19 vs Group 2=58±11 mm Hg, p=0.665). Patients with B-lines during ESE showed lower HRR and CO reserve, with a trend towards lower peak GLS, see Table. Conclusions Exercise-induced pulmonary congestion as evidenced by development of sonographic B- lines on LUS were present commonly (43%) among patients with "asymptomatic" severe AS undergoing ESE. Patients with exercise-induced B-lines have larger resting LAVI, higher NT-pro-BNP levels, lower CO reserve, and blunted HRR. Exercise-induced B-lines might provide an early sign of cardiac decompensation in "asymptomatic" patients with severe AS, which is an important factor to consider in the decision to intervene.TableFigure

Novel targeted therapies (small molecule inhibitors, antibody–drug conjugates, and CD19-directed therapies) have changed the treatment landscape of relapsed/refractory B-cell lymphomas. Bruton’s tyrosine kinase (BTK) inhibitors continue to evolve in the management of mantle cell lymphoma (MCL), in both the relapsed/refractory and the frontline setting. Anti-CD19 CAR T-cell therapies are now effective and approved treatment options for relapsed/refractory follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and MCL. Bispecific T-cell engagers represent a novel immunotherapeutic approach for relapsed FL and DLBCL after multiple lines of therapies, including prior CAR T-cell therapy. These NCCN Guideline Insights highlight the significant updates to the NCCN Guidelines for B-Cell Lymphomas for the treatment of FL, DLBCL, and MCL.

Abstract In the development of various strategies of anti-CD19 immunotherapy for the treatment of B-cell malignancies, it remains unclear whether CD19 monoclonal antibody therapy impairs subsequent CD19-targeted chimeric antigen receptor T-cell (CART19) therapy. We evaluated the potential interference between the CD19-targeting monoclonal antibody tafasitamab and CART19 treatment in preclinical models. Concomitant treatment with tafasitamab and CART19 showed major CD19 binding competition, which led to CART19 functional impairment. However, when CD19+ cell lines were pretreated with tafasitamab overnight and the unbound antibody was subsequently removed from the culture, CART19 function was not affected. In preclinical in vivo models, tafasitamab pretreatment demonstrated reduced incidence and severity of cytokine release syndrome and exhibited superior antitumor effects and overall survival compared with CART19 alone. This was associated with transient CD19 occupancy with tafasitamab, which in turn resulted in the inhibition of CART19 overactivation, leading to diminished CAR T apoptosis and pyroptosis of tumor cells.