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CD19-targeted chimeric antigen receptor T (CART19) cell therapy has shown outstanding clinical success. However, patients can develop CART-induced toxicities, including cytokine release syndrome (CRS) and neurotoxicity. Studies have found that activation of myeloid cells by granulocyte monocyte-colony stimulating factor (GM-CSF) can contribute to toxicity development. GM-CSF depletion leads to reduced myeloid activation, prevention of CART-induced toxicities, and improved CART efficacy. CART cells upregulate cytokine receptors upon activation, and our results indicate that CART19 cells significantly upregulate GMCSFR upon antigen-specific stimulation (<10% vs >30%, p<0.01). This led us to hypothesize that GMCSFR signaling contributes to CART cell activity. To understand the role of GM-CSFR upregulation on CART cell functions, we compared the impacts of neutralizing GM-CSF or blocking GM-CSF receptor alpha (GM-CSFRα) on CART19. First, 4-1BB-costimulated CART19 cells generated from healthy donors were stimulated with CD3/CD28 beads at a 1:3 ratio for 6 days. CART cells were maintained at 1 x 106/mL throughout the culture and supplemented with IgG isotype control, GM-CSF neutralizing antibody, or GM-CSFRα blockade at 10 μg/mL, 20 μg/mL, or 100 μg/mL. On day 6, cells were debeaded and rested for 2 days. Then, CART cells were cocultured with NALM6, a CD19+ acute lymphoblastic leukemia cell line, at a ratio of 1:1 for 3 days. The cocultures were supplemented with the same doses of antibodies listed above. Antigen-specific proliferation of CART cells was measured by flow cytometry. Our data suggested that CART19 proliferated is not impacted by GM-CSF neutralization but is inhibited by GM-CSFRα blockade (IgG isotype vs 10 μg/mL GM-CSFRα blockade, p<0.0001; IgG isotype vs 20 μg/mL GM-CSFRα blockade, p<0.0001; IgG isotype vs 100 μg/mL GM-CSFRα blockade, p=0.009). CART cells were assessed in a cytotoxicity assay with NALM6 luciferase+ cells as well, which did not show significant impacts from GM-CSF neutralization or GM-CSFRα blockade. To evaluate the impacts of GM-CSF neutralization and GM-CSFRα blockade in a mouse model, we engrafted NSG mice with 1 million NALM6 luciferase+ cells intravenously. Mice were then treated with 1.4 million CART19 plus 10 mg/kg IgG isotype control, GM-CSF neutralizing antibody, or GM-CSFRα blockade intraperitoneally. GM-CSFRα blockade drastically suppressed antitumor activities of CART (CART19+GM-CSFRα blockade vs CART19+IgG isotype control, p<0.0001; CART19+GM-CSFRα blockade vs CART19+GM-CSF neutralizing antibody, p<0.0001; CART19+ GM-CSFRα blockade vs untransduced T cell, n.s.). Serum cytokines were analyzed 2 days after CART treatment, showing that mice with GM-CSFRα blockade had significantly lower levels of human IFNγ (p=0.0189) and IL-2 (p=0.0121) compared to IgG isotype control group, while GM-CSF neutralization did not show significant impacts. Mice treated with CART plus IgG isotype control or GM-CSF neutralizing antibody showed prolonged survival compared to mice treated with GM-CSFRα blockade or untransduced T cells (p=0.0285). To unravel the mechanisms behind functional differences between GM-CSFRα blockade and GM-CSF neutralization, CART cells (n = 3 biological replicates) were cocultured with NALM6 at a 1:1 ratio supplemented with 10 μg/mL GM-CSF neutralizing antibody, GM-CSFRα blockade, or IgG isotype control overnight, followed by T cell isolation, bulk RNA isolation, and RNA sequencing (RNAseq) analysis. Our RNAseq data indicated significant upregulation (Log2FC>0.5, padj. <0.05) of T cell exhaustion- and dysfunction-associated genes (RGS16, PDCD1, CTLA4, NR4A3, CD101, LAG3) as well as negative regulators of T cell functions (G0S2, PIK3IP1, LGALS3) in the GM-CSFRα blockade group compared to GM-CSF neutralizing antibody or IgG isotype control groups. T cell activation-associated pathways were enriched in the GM-CSFRα blockade group. Overall, our data show that GM-CSFRα blockade impacts CART functions differently from GM-CSF neutralization. Specifically, GM-CSFRα blockade inhibits CART proliferation in vitro and antitumor activity in vivo. Interestingly, GM-CSFRα blockade leads to enrichment of T cell exhaustion- and dysfunction-associated genes in CART19, which is worth further investigation. These findings may be applicable to other cytokine receptors upregulated on activated CART cells.

Abstract The vision of the ASPEN Rhoads Research Foundation is to promote innovation and research discovery to improve nutrition care and health. The Foundation was launched in 1993, incorporated in 2002, and established as a nonprofit 501(c)(3) organization in 2007. On the occasion of American Society for Parenteral and Enteral Nutrition (ASPEN)'s 50th anniversary, this article examines the creation of the Foundation, the state of clinical nutrition research funding, the Foundation's philanthropic mission, and the return on investment of Foundation grant support. To date, 114 investigators have received 2.78 million dollars in funding. The article examines the success of ASPEN research programs and Foundation grant support in career development, leadership, and mentorship. It is important to document a historical account of the ASPEN Rhoads Research Foundation and encourage innovation and discovery and ongoing financial support.

Introduction Clinical trials are the avenue whereby the effects of interventions on health-related outcomes are evaluated. It is imperative that these trials are diverse and inclusive to reduce disparities in overall health outcomes as individuals can experience the same disease differently. When populations are not underrepresented in clinical trials, the results are not generalizable. Despite efforts to facilitate diverse representation across clinical trials, including guidance from the United States Food and Drug Administration, gaps persist in regard to understanding approaches to achieve this goal. With this in mind, we designed an international survey-based research study with the primary objectives to understand current tools and tactics investigators are employing in their clinical research and to identify gaps to ensure diversity, equity and inclusion (DEI). Methods This study was approved through the Institutional Review Board at the University of Alabama at Birmingham. The survey was developed using QuestionPro software (Austin, TX, USA). The target population for this study was the members of the American Society of Hematology (ASH) along with individuals who attended or were presenting authors at the 2023 ASH Annual Meeting, and individuals on the “This Week in Blood email list.” Surveys were distributed via email to potential participants between April and July 2024. Reminder emails were sent on 2 occasions. The survey was also advertised via various social media platforms (e.g., Twitter, Instagram, Facebook and LinkedIn). No incentives were provided for completion of the survey. In the introductory email, participants were assured of the anonymous nature of the survey and were instructed to proceed only if they consented to participate voluntarily in this research study. Results The survey was viewed by 5171 individuals. There were 774 total responses, for a response rate of 15%. Complete responses were provided by 502 respondents. Fifty-seven percent of survey respondents were based in the United States and 56% were ASH members. Seventy-one percent of respondents were clinicians, of which the majority (74%) were primarily adult providers and 86% reported hematology as their clinical specialty, a large proportion of whom were malignant hematologists. Regarding clinical research involvement over the last 5 years, 29% identified as sub investigators, 23% were site principal investigators (PI) in multicenter studies, and 19% reported roles as overall PI for studies. Respondents reported employing tactics to enhance DEI in all phases of prospective clinical research studies. Nineteen percent stated that they engage patients in the research planning phase, in protocol design, review and revision. During the implementation phase, 21% reported outreach to community providers to increase trial awareness and encourage patient referrals. Patient groups were engaged to disseminate study findings in language that patients can understand by 22% of respondents. Among the tools that were used, the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use Guidance on Clinical Practice was the most frequently reported tool in the planning phase (24%). Respondents reported no consistent use of any tool or tactic during the implementation and dissemination phases of clinical research and a large proportion reported using no tools to enhance DEI in their studies. Seventy-four percent of respondents reported that they had received no formal training or guidance on how to incorporate DEI principles and enhance DEI in clinical research. There were mixed opinions on the importance of incorporating DEI principles into clinical research, ranging from acknowledging the significance to dismissal of the concept. The majority of survey respondents (79%) indicated willingness to participate in a learning community developed by ASH. Conclusions The findings from this survey not only shed light on what resources and strategies investigators are employing most and at what stages of their clinical research, but also highlight a critical need for more training on and awareness of resources for incorporating DEI principles into clinical research. Results of this study will empower ASH to develop comprehensive resources that resonate with the dynamic needs of trialists in the pursuit of a more equitable and effective approach to clinical research.

Introduction In ELM-2 (NCT03888105), a Phase 2, open-label, multicohort study, odronextamab monotherapy demonstrated encouraging clinical efficacy, generally manageable safety, and maintenance of patient-reported outcomes in R/R FL (Chong et al. AACR 2024; Tessoulin et al. ASH 2023). In the absence of head-to-head clinical trials comparing CD20×CD3 bispecific antibodies in R/R FL, two unanchored MAICs were conducted to evaluate the efficacy of odronextamab versus mosunetuzumab and epcoritamab in patients with R/R FL in the third-line or later (3L+) setting. Methods Patient-level data from the ELM-2 R/R FL cohort receiving odronextamab (N=128; data cutoff: October 2023) were compared with published data from similar cohorts in the GO29781 trial of mosunetuzumab (N=90; Budde et al. Lancet Oncol 2022) and EPCORE NHL-1 trial of epcoritamab (N=128; Linton et al. Lancet Haematol 2024). To adjust for baseline differences in the trial populations, a priori-identified prognostic variables (progression of disease within 2 years, primary refractory, refractory to last line of therapy [LOT], number of prior LOTs, serum lactate dehydrogenase level, Eastern Cooperative Oncology Group performance status, Follicular Lymphoma International Prognostic Index, age at start of LOT, and Ann Arbor disease stage) were included in the base-case MAICs. Two additional variables (double refractory and prior autologous stem cell transplant), reported in ELM-2 and the comparator studies, were included in a sensitivity analysis. The MAICs reported here were focused on response outcomes as assessed by independent central review, which were reported across trials. Relative treatment effects before and after matching were presented as odds ratios (ORs), along with 95% confidence intervals (CIs). Results The effective sample size for odronextamab was 102.0 after matching with mosunetuzumab and 90.6 after matching with epcoritamab in the base-case MAICs. All key prognostic variables were balanced between ELM-2 and both comparator trials in each analysis. Before and after matching, odronextamab demonstrated comparable objective response rates (ORRs) and significantly higher complete response (CR) rates versus mosunetuzumab (before matching: ORR 80.5% vs 80.0%, OR 1.03 [95% CI 0.52-2.03], p=0.93; CR rate 73.4% vs 60.0%, OR 1.84 [95% CI 1.04-3.28], p=0.04; after matching: ORR 83.5% vs 80.0%, OR 1.27 [95% CI 0.61-2.65], p=0.53; CR rate 75.7% vs 60.0%, OR 2.08 [95% CI 1.12-3.86], p=0.02). Odronextamab demonstrated numerically higher CR rates versus epcoritamab before and after matching (before matching: CR rate 73.4% vs 62.5%, OR 1.66 [95% CI 0.98-2.82], p=0.06; after matching: CR rate 69.4% vs 62.5%, OR 1.36 [95% CI 0.77-2.41], p=0.29). The ORRs of odronextamab and epcoritamab were comparable before matching (ORR 80.5% vs 82.0%, OR 0.90 [95% CI 0.48-1.69], p=0.75) and after matching (ORR 78.1% vs 82.0%, OR 0.78 [95% CI 0.40-1.53], p=0.47). Consistent results were observed in the sensitivity analyses. Conclusions In the absence of head-to-head clinical trials comparing bispecific antibodies in the setting of 3L+ FL, MAICs demonstrate that odronextamab was associated with higher CR rates compared with mosunetuzumab and epcoritamab. Since achieving a CR in the R/R FL setting is an important treatment goal, our results highlight the potential of odronextamab as an effective treatment option in R/R FL.

Background: Disseminated marginal zone lymphoma (MZL) is an indolent disease often observable at diagnosis with treatment indications similar to other indolent lymphomas. First-line therapy is typically rituximab alone or in combination with chemotherapy (e.g. bendamustine). Due to the long-life expectancy, avoiding alkylating agents to reduce bone marrow damage could be beneficial. In addition, a “chemotherapy free” option could have fewer and less severe complications. Bruton tyrosine kinase inhibitors (BTKi) are active and approved or NCCN-recommended beyond first line therapy in MZL. Moreover, BTKi are approved for first line therapy in Waldenstrom's Macroglobulinemia, a disease with both diagnostic and pathophysiologic overlap with MZL. We conducted a multicenter randomized trial of rituximab induction plus ibrutinib/placebo (RI vs RP) for patients with MZL in need of first line systemic therapy. Complete response (CR) rate at 30 months was the primary endpoint and progression free survival (PFS) was secondary. The target sample size was 63 in each arm. The study was closed after 22 eligible patients enrolled due to low accrual. Methods: Patients (pts) with either nodal, splenic or extranodal MZL were eligible. Prior surgery, radiation, antibiotic or antiviral therapy for MZL were allowed if followed by disease progression requiring treatment. Documented evidence of need for treatment included, but was not limited to, threatened end-organ function, bulky disease (>5 cm), symptoms, requirement for transfusion or growth factor support, or significant need for intervention. Transformation to DLBCL was excluded prior to entry including bone marrow assessment. Randomization occurred prior to rituximab weekly x 4 to either daily placebo (RP) or ibrutinib (RI) 560 mg starting on day 1 and continued until disease progression (PD), intolerance or CR at 30 months. Those with partial response (PR) or stable disease (SD) at 30 months could continue placebo or ibrutinib. CR assessment required both a negative FDG-PET and bone marrow biopsy. RESULTS: 22 pts enrolled (Feb 2020-March 2023) with baseline characteristics including: median age 67 years (35-78) and White race 17. Stage II (3), III/IV (17). Subtype: splenic 16, nodal 4, extranodal 2. Prior therapy: splenectomy 1, radiation 0, other surgery 0, antiviral/antibiotic 0. Median maximal tumor dimension was 3.7 cm (range 1.6-23.6); with >5 cm in 9 pts. Median time from diagnosis to treatment was 32 days (5-4712 with only 3 > 1 year). 11 pts were randomized to each arm. Responses: RP: 3 CR, 4 PR, 3 SD, 1 inevaluable; RI: 7 CR, 4 PR. No patient achieved CR30, but 3 had CR at 29 months: 2 RP, 1 RI. With a median follow up of 35 months (13-50), the median PFS by Log Rank was 14 mo (RP) vs 29 (RI), though this difference was not statistically significant in the setting of small numbers. Treatment was well tolerated. Only 1 pt experienced grade 3 events at least possibly related: hypoxia and dyspnea. This was attributed to COVID-19 and occurred on the RP arm. 1 CR patient with baseline clonal hematopoiesis developed myelodysplasia. Treatment improved baseline activities in 4/5 pts (1 RP, 3 RI). Baseline pain improved in 8 pt: 4 RP, 4 RI. All pts were alive at the data cuff off. Conclusions: This study is a chemotherapy free frontline trial in MZL and the first to utilize ibrutinib in frontline MZL. All pts received rituximab induction and were randomized at entry to RP vs RI. The COVID-19 pandemic affected site activation and accrual, ultimately contributing to low accrual and early study termination. Nonetheless, the results suggest a marked difference in median PFS favoring the RI arm, although small numbers preclude a statistically significant result. Notably, our results are qualitatively similar to those of Dimopoulos (NEJM, 2018) in Waldenstrom's Macroglobulinemia, a disease with similar characteristics to MZL. In that study, the median PFS by Log Rank was 20 months (RP) vs not reached (RI); and 30-month PFS 28% (RP) vs 82% (RI). (Hazard ratio for progression or death, 0.20; P<0.001). Further, our trial supports pursing a chemotherapy free first line approach in MZL.

Introduction: Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of malignant lymphocytes in the lymph nodes, spleen, blood, and bone marrow. Although current clinical treatment approaches targeting Bruton Tyrosine Kinase (BTK) and Bcl-2, either as monotherapy or in combination are highly effective with high overall response, complete responses, and achievement of undetectable measurable residual disease (MRD), most patients eventually experience disease relapse. In this study, we utilized our unique mesenchymal stromal cells (MSCs) system, which mimics the in vivo stromal environment in CLL, to explore the combination interaction effect of the first-in-class BTK inhibitor, ibrutinib, with novel tumor microenvironment (TME)-directed drugs in CLL. Methods: Since 1999, patients with CLL seen at Mayo Clinic in Rochester, MN have been offered participation in a longitudinal study of CLL B-cell Biology (CLL Tissue Bank). This Tissue Bank is seamlessly integrated into the Mayo Clinic CLL Database where the clinical characteristics of all patients are prospectively maintained. Using this resource, we identified previously untreated CLL patients (n=10) for our experiments. Individuals with high risk CLL (defined as those with both unmutated IGHV gene mutations and either del17p- or del11q- by FISH) (n=5) and with low risk CLL (defined as those with both mutated IGHV genes and no del17p- or del11q- by FISH) (n=5) were studied. Annexin-V/PI apoptotic cell death assays were employed to evaluate the effects of TME-directed drugs including everolimus (mTOR inhibitor), MI-2 (MALT1 inhibitor), ruxolitinib (JAK1/2 inhibitor), S63845 (MCL-1 inhibitor), and venetoclax (Bcl-2 inhibitor) either as single agent, or in combination with ibrutinib on CLL B cells in direct contact with MSCs. Dose response curves and IC50 levels were generated for single agent killing effect in CLL. The combination interaction effects were determined by Combination Index (CI) values generated by CalcuSyn software indicating synergistic (CI < 0.9), additive (CI between 0.9 - 1.1), or antagonistic (CI > 1.1) interactions. Among drug combinations with synergistic CI values, the following indicated different levels: below 0.1 very strong, 0.1 - 0.3 strong, 0.3 - 0.7 good, and 0.7 - 0.9 moderate synergism. Results: All tested drugs exhibited different IC50 levels in CLL cells co-cultured with MSCs: MI-2 IC50 of 3.5uM, ruxolitinib IC50 of 18.5uM, S63845 IC50 of 0.115uM, venetoclax IC50 of 0.006uM, and both everolimus and ibrutinib did not reach IC50 levels at maximum tested doses. Of interest we observed more killing in high versus low-risk cohort when treated with everolimus (19uM vs. undetectable), MI-2 (2.5 vs. 4uM) and S63845 (0.09 vs. 0.14uM) as single agents (IC50, high vs. low, respectively), while ruxolitinib and venetoclax showed no differences. Combination interaction effect results showed highly synergistic interactions for all patients (good to strong synergism) when ibrutinib was combined with S63845 or venetoclax, moderate to strong synergism for ibrutinib and everolimus, moderate synergism to additive levels for ibrutinib and MI-2, and moderate synergism to antagonism for ibrutinib and ruxolitinib. We also observed more synergism in the low-risk cohort when treated with ibrutinib and MI-2/ruxolitinib combinations, but no difference with ibrutinib and everolimus/S63845/venetoclax combinations between low and high-risk cohort. Conclusions: In summary, we evaluated the pre-clinical combination effects of ibrutinib when used together with other novel agents on CLL B cells in the presence of TME, where patients were assigned to low or high-risk cohorts. Our study showed that ibrutinib exhibits highly synergistic effects with venetoclax, S63845 and everolimus in both cohorts. The observed difference in effectiveness between high and low-risk cohorts when treated with ibrutinib plus MI-2 or ruxolitinib suggests these combinations would be beneficial for a subset of patients with high risk CLL. These preclinical data offer preliminary insights that support the evaluation of therapeutic combinations in patient with high-risk CLL: a population with significant unmet medical needs. Funding Statement: This study was funded and supported by Pharmacyclics LLC, an AbbVie company.

Background: Zanubrutinib and acalabrutinib are next-generation Bruton's tyrosine kinase (BTK) inhibitors used in chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). They have demonstrated lower cardiotoxicity compared to first-generation BTK inhibitor ibrutinib. However, there is limited data comparing cardiovascular outcomes between zanubrutinib and acalabrutinib. This study aims to investigate the cardiovascular risks associated with these two agents in a real-world setting. Method: A retrospective, propensity score-matched study was conducted using the TriNetX database, which includes de-identified electronic health records from over 101 million individuals across 70 healthcare organizations. Patients with CLL and SLL treated with either zanubrutinib or acalabrutinib were included, excluding those who received ibrutinib. The primary outcome of interest was major cardiovascular adverse events, composed of heart failure, myocardial infarction, and cardiac arrest. Other outcomes of interest were new-onset hypertension, new-onset atrial fibrillation/flutter, ventricular arrhythmia, myocardial infarction, new-onset heart failure, conduction block, and stroke within 18 months of therapy initiation. Propensity score matching accounted for demographics, comorbidities, disease status, other CLL/SLL-directed therapies, and concomitant cardiovascular agents. Relative risk and 95% confidence intervals were calculated to assess the outcomes. Results: A total of 907 patients treated with zanubrutinib were matched to 907 patients treated with acalabrutinib. At 18 months, the zanubrutinib group experienced 106 major cardiovascular adverse events, compared to 144 in the acalabrutinib group (RR (relative risk), 0.73 [95% CI: 0.58-0.93]; p=0.009). New-onset hypertension occurred in 35 zanubrutinib and 31 acalabrutinib patients (RR, 1.14 [95% CI: 0.72-1.82]; p=0.579). New-onset atrial fibrillation/flutter occurred in 15 zanubrutinib and 30 acalabrutinib patients (RR, 0.49 [95% CI: 0.27-0.91]; p=0.020). Ventricular arrhythmia occurred in 13 zanubrutinib and 9 acalabrutinib patients (RR, 1.44 [95% CI: 0.62-3.36]; p=0.402). Myocardial infarction occurred in 18 zanubrutinib and 25 acalabrutinib patients (RR, 0.72 [95% CI: 0.40-1.31]; p=0.286). New-onset heart failure occurred in 34 zanubrutinib and 40 acalabrutinib patients (RR, 0.82 [95% CI: 0.52-1.28]; p=0.385). Conduction block occurred in 43 zanubrutinib and 48 acalabrutinib patients (RR, 0.90 [95% CI: 0.60-1.34]; p=0.593). Stroke occurred in 20 zanubrutinib and 19 acalabrutinib patients (RR, 1.05 [95% CI: 0.57-1.96]; p=0.873). Conclusion: Zanubrutinib was associated with a 27% lower risk of major cardiovascular adverse events and a 51% lower risk of new-onset atrial fibrillation/flutter compared to acalabrutinib, suggesting its preference for patients with high cardiovascular risks. The risks of new-onset hypertension, ventricular arrhythmia, myocardial infarction, new-onset heart failure, conduction block, and stroke were similar between the two groups. Further studies with long-term follow-up data will be valuable for evaluating the safety of next-generation BTK inhibitors.

Background: Patients with immunocompromising conditions, including those affected by hematologic malignancies, have a disproportionately high burden of morbidity and mortality related to COVID-19 compared to individuals without such conditions.Clinical practice guidelines (CPGs) recommend the use of remdesivir, a broad-spectrum antiviral, for treatment of mild to severeCOVID-19 in immunocompetent patients not requiring invasive mechanical ventilation. While the CPGs issued by the World Health Organization (WHO, 2023), National Institutes of Health (NIH, 2023) and the Infectious Diseases Society of America (IDSA, 2022) also recommended the use of remdesivir in patients with immunocompromising conditions at high risk for severe disease, there was limited evidence available at the time the recommendations were communicated, more than two years after the start of the pandemic. The European Conference on Infections in Leukemia (ECIL, 2022) guidelines include remdesivir among the treatment options for mild to moderate COVID-19 patients with hematologic malignancies. The lack of evidence for treatment efficacy and safety in patients with immunocompromising conditions, a population underrepresented or excluded from clinical trials, was mentioned in CPGs as a knowledge gap and as need for further research. In this research, we summarize the evidence for remdesivir efficacy and safety for treatment of COVID-19 in hospitalized patients with hematologic malignancies accumulated since the start of the pandemic. Methods: We systematically searched MEDLINE, Embase and Cochrane Library databases from January 2019 through December 2023 for interventional and observational studies examining remdesivir efficacy and safety. Case reports and case studies were excluded. A dual-reviewer approach was used for screening and data extraction. Results: Of the 7,654 references retrieved through the implementation of the extensive search strategy 59 (0.8%) reporting on patients with hematologic malignancies, unspecified cancers, or immunodeficiencies were identified and reviewed in full text. Only eight unique studies (8 of 59) were conducted in patients with hematologic malignancies, of which two reported remdesivir use in a minority of participants (n<5) and were excluded from further analyses. The remaining six studies, of which four were peer-reviewed original articles, one was a letter to editor and the last was a conference abstract, used a retrospective cohort design and reported efficacy outcomes for a combined total of 1,579 individuals across the studies. Three of the six studies were conducted during the pre-Omicron variant era (November 2021) while the remaining three started data collection in December 2021. There were four studies reporting number of deaths or the mortality rate, while a fifth study based on medical chart reviews of 313 patients in Israel found a significantly reduced risk of mortality among remdesivir recipients compared to patients not receiving remdesivir (OR: 0.297; 95% CI: 0.105, 0.834). In addition, a study including 466 patients from the Spanish Hematopoietic Stem Cell Transplantation and Cell Therapy Registry reported mortality among remdesivir treated group related to baseline disease progression, use of corticosteroids for COVID-19 therapy and the presence of coinfections while B-cell malignancy as underlying disease, severe COVID-19, late antiviral initiation (≥5 days after first positive PCR) and longer treatment duration (≥5 days) were factors significantly associated with prolonged viral shedding. The same Spanish study reported safety outcomes indicating that adverse events of grade 3 or above were rare, occurring in 0.5% of remdesivir treated patients. Conclusion: Despite the call for research to fill the knowledge gap signaled by the CPGs, our comprehensive systematic literature review identified only a few publications conducted since the start of the pandemic in patients with hematological malignancies. In the current endemic era, these patients are among the most at risk for severe outcomes and COVID-19 related hospitalizations. While the limited evidence suggests that remdesivir use can reduce mortality in patients with hematologic malignancies, additional research will be instrumental to inform development and updating of evidence-based recommendations to support and guide clinical management of oncology patients.

Multiple myeloma (MM) is an incurable plasma cell (PC) malignancy. Despite therapeutic advances that have vastly improved survival, all patients are expected to relapse. Current standard of care includes autologous stem cell transplant (ASCT) with high-dose melphalan (HDM) administered as a conditioning agent. Cytotoxic chemotherapies such as melphalan have been shown to drive therapy-induced senescence (TIS) in several tissues. We hypothesize that HDM activates TIS pathways in surviving MM cells and that this may correlate with patient outcomes post-ASCT. We developed an in vitro HDM model using 5TGM1 mouse MM cells treated with vehicle (Veh) or HDM (10µM, IC90) for 6h, followed by co-culture with primary mouse bone marrow stromal cells. Image analysis was performed to quantify proliferation by cumulative population doublings (CPDs) over 10 days, after which 5TGM1 cells were evaluated for cell size, telomere-associated DNA damage foci (TAFs), sensitivity to senolysis, and senescence gene expression (scRNA-seq and RT-qPCR). The effect of HDM on CPDs and cell size was also evaluated in human MM cell lines RPMI-8226 and H929. scRNA-seq was used to analyze CD138+ PCs from MM patients at various timepoints post-ASCT. Longitudinal MM patient iliac crest biopsies (diagnosis, post-ASCT; N=20) were stained for CD138+ PCs; PC burden was quantified by AI-assisted histology. Lastly, we established an in vivo model of induction therapy (bortezomib) followed by HDM/SCT in Vk*MYC mouse MM engrafted C57BL/6 mice. Tumor burden was tracked by serum protein electrophoresis for M-spike using submandibular bleeds. Bone marrow was then flushed from long bones and analyzed by flow cytometry and immunofluorescence. HDM-5TGM1 showed decreased CPDs (HDM 0.32±0.31, Veh 6.72±0.69, p<0.0001, N=3), increased size (median pixel size: HDM 413.2±99.98, Veh 207±8.88, p<0.05, N=3), and increased TAF+ cells (Percent TAF+ cells: HDM 34.77%±10.74%, Veh 11.41%±1.58%, p<0.05, N=3) consistent with known TIS features. Preliminary assessment (N=1) of human MM cell lines showed similar growth arrest (RPMI-8226 CPDs: HDM 0.058±0.101, Veh 4.185±0.358; H929 CPDs: HDM 0±0, Veh 4.61±0.243) and size increase (RPMI-8226 mean pixel size: HDM 804.1±6.048, Veh 526.9±2.115; H929 mean pixel size: HDM 371.2±26.95, Veh 130.3±41.43), suggesting a translatable mechanism. HDM-5TGM1 cells were more sensitive to senolysis by dasatinib+quercetin (viability: HDM 54.9%±0.09%, Veh 76.0%±0.05%, N=2). scRNA-seq analysis showed that HDM-5TGM1 were enriched for gene sets related to senescence pathways, including the published set SenMayo (FDR<0.25). HDM-5TGM1 cells also exhibited myeloid gene expression consistent with previous publications on MM dormancy. RT-qPCR confirmed significant increases in HDM-5TGM1 (p<0.001, N=3) in senescence markers (Cdkn1a, Cdkn1c, Glb1), senescent cell anti-apoptosis pathway genes (SCAPs, Bcl2l1), senescence associated secretory phenotype (SASP) genes (Ccl5, Icam1, Mmp13), and myeloid markers (Axl, Fcer1g, Mpeg1). scRNA-seq of patient CD138+ PCs confirmed a myeloid-like cluster that gained prominence in relapsed patients with resistant disease. CD138+ PCs were detected in patient bone biopsies post-ASCT. Interestingly, patients who relapsed (≤3 years, N=9) had a greater percent reduction in PC burden from diagnosis to post-ASCT when compared to patients that did not relapse (N=11) in that time (p=0.02). Further, CD138+ PC burden post-ASCT positively correlated with time in remission in relapsed patients (R=0.697, p=0.03). Bortezomib reduced serum M-spike in Vk*MYC-engrafted mice (p=0.0003); M-spike was further reduced by HDM/SCT compared to Veh-treated mice (p=0.0007). Flow cytometry confirmed a decrease in Vk*MYC cells after HDM/SCT (p=0.0043), and the percentage of Vk*MYC cells with greater size and complexity was increased compared to Veh-treated mice (p=0.0043), consistent with our in vitro data. Vk*MYC cells from HDM-treated mice also trended for more TAF+ cells (>3 TAFs) compared to Veh-treated mice (p=0.0714). Our findings suggest that HDM can induce a TIS and myeloid signature in surviving MM cells. Greater MM burden post-ASCT appears to be associated with longer durable response, again suggesting that these cells may be in growth arrest consistent with TIS. Finally, senolytics may be a novel approach to eliminate surviving MM cells and prevent relapse.

Background Blast or accelerated phase myeloproliferative neoplasm (MPN-BP/AP) carries a dismal prognosis, with 3-year survival estimates of <5% (BCJ 2023;108). Patients with MPN-BP/AP were excluded from venetoclax (Ven) plus hypomethylating agent (HMA) clinical trials for acute myeloid leukemia (NEJM 2020;383:617). In the current retrospective study, we examined response patterns and long-term survival of newly-diagnosed MPN-BP/AP patients who received treatment with Ven+HMA, outside of clinical trials. Methods Newly-diagnosed patients with MPN-BP/AP treated with Ven+HMA at the Mayo Clinic, between March 2019 and May 2024, were retrospectively reviewed. Diagnostic criteria were according to the International Consensus Classification (Blood 2022;140:1200). Cytogenetic and molecular studies were performed by conventional karyotype and next-generation sequencing, respectively. All patients received at least one cycle of Ven+HMA (azacitidine 75 mg/m2 days 1-7 or decitabine 20 mg/m2 days 1-5). Response was assessed according to the 2022 European Leukemia Net criteria (Blood 2022;140:1345). Standard statistical analyses were performed using JMP Pro (Version 17.1.0). Results Patient characteristics 70 patients (median age 73 years, 59% males, 48% splenomegaly >14 cm, 4% isolated myeloid sarcoma) with newly-diagnosed MPN-BP (n=58) or AP (n=12) received Ven+HMA with (n=13) or without (n=57) concomitant JAK2 inhibitor. Driver mutation distribution was 69% JAK2, 21% CALR, 6% MPL, and 4% triple negative. Mutations involved ASXL1 (31%), TP53 (28%), TET2 (28%), RUNX1 (25%), SRSF2 (18%), IDH2 (12%), U2AF1 (11%), DNMT3A (9%), IDH1 (7%), and K/NRAS (7%). Karyotype was abnormal in 50 (76%) of 66 informative cases, of which 28 (56%) were complex (CK). Median TP53 mutation variant allele frequency (VAF) was 30% (8-96%) and all evaluable cases displayed CK (n=18). Response and Survival Complete remission (CR; 21%) or CR with incomplete count recovery (CRi; 19%) was documented in 28 (40%) patients with residual MPN in 18 (64%) patients. Median response duration was 5.5 months (1-60 months). After a median follow up of 7 months (1-62 months), 48 (69%) deaths, 13 relapses (46%), and 15 (21%) allogeneic stem cell transplants (ASCT; 12 in CR/CRi) were recorded. Median overall survival (OS) was 9 months and was superior with ASCT (median 22 vs. 8 months; p=0.01). In univariate analysis, transplant-censored survival was superior with CR/CRi (12 vs. 5 months; p<0.01) and IDH1 mutation (33 vs. 8 months; p=0.04) and inferior with CK (7 vs. 10 months; p=0.05), TP53 mutation (5 vs. 10 months; p<0.01), post polycythemia vera myelofibrosis (post-PV MF) (3 vs. 9 months; p=0.01), and splenomegaly >14 cm (5 vs. 16 months; p<0.01). Multivariable analysis confirmed the negative survival impact of not achieving CR/CRi (HR 3.8; p<0.01) and presence of TP53 mutation (HR 4.0; p<0.01); median survival (1/3-year survival rate) was 3 months (10%/0%) in TP53 mutated patients not achieving CR/CRi (n=11) vs. 27 months (65%/28%) in TP53 unmutated cases achieving CR/CRi (n=19) (p < 0.01). Median survival in patients with TP53 mutations or CK who achieved CR/CRi (n=7; 7 months) was inferior to that in treatment responders without TP53 mutations or CK (n=18; 23 months; p=0.01). CR/CRi rates in the presence vs. absence of TP53 mutations were 42% vs. 39% (p=0.80) and of CK (25% vs. 50% (p=0.04). Importantly, responses in the presence of TP53 mutations or CK were too short-lived to allow successful bridging to ASCT (median 2 vs. 9 months; p<0.01). Additional predictors of inferior treatment response included splenomegaly >14 cm (24% vs. 53%; p=0.01), and post-PV MF (0% vs. 46%; p<0.01) while SRSF2 (67% vs. 34%; p=0.04) and IDH2 mutations (75% vs. 35%; p=0.03) were associated with favorable response. In multivariable analysis, CK (p=0.04) and splenomegaly >14 cm (p=0.01) remained independent predictors of inferior response. The use of concomitant JAK2 inhibitor therapy did not impact treatment response (CR/CRi 46% vs. 39%; p=0.62) or survival (median 9 vs. 8 months; p=0.71). Conclusions TP53 mutations and CK undermine the value of Ven+HMA, with or without concomitant JAK2 inhibitor, in enabling successful bridging of newly-diagnosed MPN-BP/AP to ASCT. An alternative treatment approach is advised, in the particular scenario, while the observed 3-year survival rate of 28%, in treatment responders without TP53 mutations, is encouraging.