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Oncoprotein-driven human cancers exhibit replication stress (RS), leading to an increase in DNA double-strand breaks (DSB). These DSBs are repaired by one of the three main pathways - homologous recombination repair (HR), non-homologous end-joining (NHEJ), and microhomology-mediated end joining (MMEJ). Cyclin D1 (CCND1) is one of the most overexpressed oncoproteins and is universally overexpressed in mantle cell lymphoma (MCL). While CCND1 overexpression drives cells into the S-phase, its specific effects on RS and DSB repair pathways are poorly understood. Here, we investigated the impact of CCND1 overexpression on RS and DSB repair mechanisms in MCL. First, the expression level of CCND1 positively correlated with heightened RS, as indicated by elevated p-RPA-S33 and p-RPA S8 levels, and increased DNA damage, assessed by g-H2AX, especially in the mitotic phase, across diverse cell models, including MCL. Since CCND1-overexpressed cells proliferate rapidly, we hypothesized that some DNA repair pathways might be upregulated to meet the demand for repairing the excess RS-driven DSBs. Reporter assays demonstrated that the MMEJ pathway was specifically upregulated upon CCND1 overexpression, whereas no significant changes were observed in the HR and NHEJ pathways. Furthermore, CRISPR interference (CRISPRi)-mediated knockdown of CCND1 in MCL cells led to a significant reduction in MMEJ activity. This finding suggests the specificity of CCND1 in mediating the upregulation of the MMEJ pathway. Consistent with this, increased MMEJ activity, assessed via foci formation and immunoblotting of DNA polymerase theta expression (POLQ, encoded by POLQ gene), the primary polymerase for the MMEJ pathway, correlated with CCND1 overexpression, suggesting the crucial role of MMEJ in DSB repair processes under CCND1-overexpressed conditions. Sincethe MMEJ pathwayplays a pivotal role in repairing DSB during mitosis, we assessed the dependency of MCL cells on MMEJ-mediated DSB repair for cell survival. As expected, genetic deletion or pharmacological inhibition (ART558 and novobiocin) of POLQ in MCL cells led to increased RS and increased unrepaired DNA damage during mitosis, ultimately leading to chromosomal instability, mitotic catastrophe, and apoptosis. Additionally, the deficiency of POLQ in MCL cells resulted in increased levels of single-strand DNA, another critical biomarker for RS. Second, we found that ATM deficiency, the second most common genetic alteration after CCND1 overexpression in MCL, further increased the cellular dependence on MMEJ. Interestingly, the accumulation of unrepaired DNA damage during mitosis was notably increased in ATM-deficient CCND1-overexpressed cells. When POLQ was inhibited, a significant antitumor effect was evident in MCL cells, including ibrutinib-resistant MCL, both in vitro and in vivo, and this effect was enhanced by ATM deficiency. Further, simultaneous inhibition of both ATM (AZD0156) and POLQ was synthetic lethal in MCL cell lines and primary tumor cells from patients with MCL. Mechanistically, we observed the direct binding of CCND1 to the POLQ promoter and a corresponding upregulation of POLQ mRNA in CCND1-overexpressing cells. Consistently, a significant overexpression of POLQ mRNA was observed in primary MCL cells, compared to other non-Hodgkin lymphoma cells without CCND1 overexpression. Moreover, the positive correlation between POLQ and CCND1 expression was further validated using syngeneic B-lymphoma cells with and without CCND1 overexpression. Importantly, CRISPRi-mediated CCND1 knockdown reduced POLQ mRNA expression and the dependency of MCL cells on the MMEJ pathway for survival. In addition, ATM deficiency showed a further increase of endogenous POLQ expression and foci formation in cells with CCND1 overexpression, suggesting ATM negatively regulates the MMEJ pathway, especially in the CCND1 overexpressed background. In summary, CCND1 overexpression leads to a substantial increase in RS, intensifying the reliance on MMEJ-mediated mitotic DSB repair. Within MCL, POLQ is crucial in mitigating the adversities of CCND1-driven RS. Our data suggest that targeting the MMEJ pathway via POLQ inhibition, particularly in the presence of CCND1 overexpression and ATM deficiency, emerges as a promising therapeutic approach in oncoprotein-driven hematologic malignancies such as MCL.

Introduction: Oncologists increasingly recognize the need to evaluate the impact of cancer therapies on patients' time, known as “treatment-related time toxicity”, which is measured as the number of days of contact with the healthcare system (Gupta A et al. J Clin Oncol 2022). Current standard-of-care options for patients with TCE RRMM require frequent clinic visits for treatment administration. Reducing treatment-related time toxicity of treatment without compromising efficacy or safety may have an impact on patients' quality of life and influence treatment choice. BCMA-directed bispecific antibodies (BCMA bsAbs) provide a novel treatment option for TCE RRMM, with response-adapted dosing frequency allowing for extended dosing intervals for patients. The frequency of extended dosing intervals varies between BCMA bsAbs according to their prescribing information or pivotal trial protocol. The aim of this analysis was to evaluate the impact of BCMA bsAbs' extended dosing intervals on treatment-related contact (TRC) days corresponding to treatment administration as a component of time toxicity. Methods: An Excel-based longitudinal model was developed to quantify the number of TRC days experienced by patients with TCE RRMM within the healthcare system when receiving treatment with BCMA bsAbs (linvoseltamab, teclistamab, or elranatamab) over 1-2 years. TRC days included all planned treatment administration days. Model inputs were sourced from product labels or pivotal trial protocols for bsAbs, as well as the published literature. To allow for a comparison of total dosing regimens, it was assumed that patients continued receiving treatment throughout the study period with no discontinuation. Dosing intervals for each product during the first 6 months were once weekly (QW), except for linvoseltamab (QW for Weeks 1-14, then once every 2 weeks [Q2W] from Weeks 16-24, per Phase 2 trial protocol). The extended dosing interval for linvoseltamab was Q4W for patients reaching very good partial response or better at or after 24 weeks, and Q2W for both teclistamab patients who maintained a complete response (CR) or better for ≥6 months and for elranatamab patients who reached partial response or better at or after 6 months. Two switching scenarios were considered for teclistamab: an earliest possible switch (at Week 26), and a time-varying switch based on digitized time to CR data from MajesTEC-1 (Usmani SZ et al. ASCO 2023). Results were calculated to evaluate the difference in TRC days between the scenarios with and without extended dosing intervals for each treatment. Results: In the first year of treatment, the total number of TRC days with and without extended dosing intervals was lowest with linvoseltamab. TRC days with linvoseltamab were reduced from 33 to 26 days with extended dosing intervals. Next lowest was elranatamab (53 to 39 days), followed by teclistamab (54 to 41 days for earliest possible switch and 54 to 50 days with time-varying switching). Over 2 years, linvoseltamab had the lowest number of TRC days (59 to 39 days), followed by elranatamab (105 to 65 days) and teclistamab (106 to 67 days for earliest possible switch and 106 to 80 days with time-varying switching). Conclusions: Extended dosing intervals with BCMA bsAbs can substantially reduce time toxicity for patients with RRMM. Linvoseltamab had the lowest number of TRC days among BCMA bsAbs.

Background: Continuous single-agent ibrutinib (Ibr) treatment has been associated with extended progression-free survival in patients with Waldenström macroglobulinemia (WM). Previous clinical studies have shown that Ibr dose reductions (DRs) improved or resolved adverse events (AEs) in most patients, while hematologic responses were sustained. However, real-world data on long-term outcomes for patients with WM undergoing Ibr DR in first-line (1L) settings remain limited. Methods: Medicare Fee-for-Service (FFS) medical and pharmacy records were used to identify patients diagnosed with WM who initiated 1L single-agent Ibr (420 mg/day) or 1L Ibr + rituximab from January 1, 2015, to September 30, 2022. Observed patients were enrolled in Medicare FFS ≥12 months before and after 1L treatment initiation and had ≥1 qualifying post-treatment initiation AE of special interest (AESI; both prevalent and incident AEs), as identified via ICD-9-CM or ICD-10-CM diagnosis codes. Ibr DR was defined as a reduction of the starting dose (420 mg/day) following the first AESI during 1L treatment. Patients without an Ibr DR were defined as those who had received Ibr at 420 mg/day during 1L treatment. Patients without an AESI post-Ibr initiation and prior to DR were excluded from the analysis. Demographics, clinical characteristics, time to AESI, duration of therapy (DOT), and time to treatment discontinuation (TTD) were assessed in cohorts with and without DRs. DOT was measured at the date of Ibr treatment initiation through treatment discontinuation (end of 1L treatment). Patients were considered to have discontinued treatment if they received a subsequent systemic therapy after the 1L regimen, had a gap of ≥120 days with no systemic therapy following the last administration, or died while on the 1L regimen. Patients without a discontinuation were censored at the earliest date of end of follow-up or disenrollment. TTD was analyzed using the Kaplan-Meier method. A Cox proportional hazards model adjusted for patient demographics and clinical characteristics was used to identify factors associated with treatment discontinuation. Results: A total of 407 patients with WM were included in the analysis (DR, n=55 [14%]; no DR, n=352 [86%]). Patients in the DR and no DR cohorts, respectively, had similar a median age (78 years vs 77 years), Charlson Comorbidity Index score (3 vs 4), and prevalence of the most common baseline comorbidities: hypertension (67% vs 68%) and cardiovascular conditions (31% vs 28%). The median time between treatment initiation and the occurrence of the first AESI was 89 days versus 76 days, and total Ibr DOT mean ± SD [median] was 786.1 ± 692.6 [661] days versus 454.8 ± 510.4 [279] days (P=0.001) for DR cohort versus no DR cohort. Following DR, patients remained on Ibr for mean ± SD [median] 336.0 ± 422.8 [179] days until the end of 1L therapy. After adjusting for variations in baseline characteristics, patients with a DR had significantly longer TTD post-treatment initiation than those without a DR (median TTD, DR vs no DR: 22.5 months vs 9.3 months; adjusted HR [95% CI], 0.52 [0.37-0.72]). Conclusion: This real-world evidence study suggests that implementing DRs to manage AEs can be a valuable strategy in supporting patients with WM to remain on 1L Ibr longer, thus maintaining beneficial clinical outcomes. These findings are consistent with previous studies, demonstrating that Ibr DRs help to improve tolerability while maintaining treatment efficacy.

Introduction Multiple Myeloma (MM) precursors Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM) have variable risk of progression to active MM, and identifying which patients may progress remains a clinical challenge. Deep proteome profiling of peripheral blood (PB) plasma may advance non-invasive precursor disease staging, monitoring and characterization. Here, we performed plasma proteomic profiling on patients across the MM disease continuum as well as progressive and stable disease to provide insights into MM disease biology and identify protein-based high-risk disease features that may improve prognostication. Methods We performed high-throughput profiling of >5400 proteins using the Olink® Explore HT library and Proximity Extension Assay (PEA) technology. We profiled 529 PB plasma samples from 485 individuals, including MGUS (n=100), SMM (n=203), MM (n=100), and healthy donors (HDs) (n=82). Sequential samples from SMM-MM progressors (n=32) and stable SMM-SMM non-progressors (n=32) were also profiled, where precursor samples ranged 1.04-6.91 years (median 2.33 years) prior to MM progression. T-tests, ANOVAs, and linear mixed effect (LME) models were used to identify significant proteins across disease stages, progression status, and time. Results were adjusted for multiple testing using Benjamini-Hochberg procedure. A subset of 86 individuals (13 HDs, 14 MGUS, 41 SMM, 18 MM) also had single-cell RNA sequencing (scRNA-seq) performed on tumor and immune cells from paired PB/BM collected at the same timepoint to enable cellular mapping of signals detected in plasma. Results We successfully captured significantly dysregulated proteins including proteins highly expressed on the surface of plasma cells, such as BCMA, SLAMF7 and CD38, highlighting the utility of PEA technology to monitor soluble levels of clinically relevant targets. Given SMM patients are clinically heterogeneous and can resemble MGUS or MM, we aimed to improve discrimination of disease states using biological features obtained from the plasma proteome. We developed a classifier using an Elastic Net model for each stage, where plasma proteins such as SLAMF7, BCMA, TACI, FCRL5 and others had the highest importance scores for the model. We demonstrated 97% SMM/MM samples could be identified from healthy samples (AUC=0.82), indicating our classifier could reliably screen disease-related cases. Moreover, 84% of SMM cases were correctly classified as clinically defined SMM, while misclassified samples were labelled as MM cases. Interestingly, the misclassified patients had consistently rising M-spike levels during clinical follow-up but without a shift in clinical stage or risk status, suggesting the plasma proteome may provide earlier indication of evolving disease. Since proteomic information may also hold value for improved risk stratification, we evaluated protein levels in precursor stage timepoint samples from SMM-MM progressors and stable SMM non-progressors. We identified a prognostic five-protein signature that was significantly elevated in SMM-MM progressors, of which BCMA and TACI were top proteins, as well as proteins vital for calcium homeostasis and integrin-mediated cell adhesion. BCMA and TACI levels also had a strong positive correlation with BM plasma cell infiltration, which suggests these proteins may be useful surrogates of BM tumor burden during routine blood-based assessment of precursor patients. Lastly, integrative analysis of scRNA-seq of tumor and immune cells was used to elucidate cell origin level information of the prognostic signature proteins. Four proteins were highly expressed in malignant versus non-malignant plasma cells, suggesting our prognostic signature partially provides a readout of plasma cell biology. Meanwhile, one protein was constitutively expressed on most leukocytes, suggesting that the interplay of other cell types in the immune microenvironment involved in progression may also be reflected in the plasma. Conclusion We performed the first comprehensive analysis of the plasma proteome of MM and its precursor conditions. Overall, we developed a classifier that utilizes plasma proteins alone to accurately classify disease stages and identified a prognostic protein signature associated with progressive disease.

Introduction E1910 randomized pts with ALL aged 30-70 years who were measurable residual disease negative (MRD-) by multi-color flow cytometry (FC) after intensification to conventional chemotherapy (chemo) with or without blinatumomab (blina). The addition of blina resulted in improved overall survival (OS) (Litzow, NEJM 2024) and led to a new standard of care. Older ALL pts have inferior outcomes when compared to younger pts in part due to increased treatment toxicity. In E1910, exposure to dexamethasone and pegasparagase was reduced for older pts (age >55 years). We present results of subgroup analyses describing outcomes of older pts enrolled in E1910. Methods Details of the E1910 protocol remission induction (step 1), high dose methotrexate with pegaspargase intensification (step 2), blina randomization (step 3), and maintenance (step 4) or allogeneic hematopoietic stem cell transplant (HCT) were previously presented (Litzow, NEJM 2024). MRD status was determined after step 2 centrally with 6-color FC with MRD- defined as <0.01% in the bone marrow (BM). Following approval of blina in the US for MRD positive (MRD+) disease in 2018, MRD+ pts were assigned to the blina arm and no longer randomized. The primary objective was to compare the OS and relapse free survival (RFS) among older pts aged >55 years (pre-specified stratification factor) who received chemo + blina to that of pts who received chemo alone (step 3 treatment). Estimates of OS and RFS were calculated using the Kaplan-Meier method. Comparison of OS and RFS between treatment arms was conducted using the two-sided stratified log-rank test and Cox model with CD20 status, rituximab use, and whether pts intended to receive HCT or not as stratification factors. Stratified Multivariate Cox models of OS and RFS were used to further evaluate the effect of step 3 treatment, adjusted by gender, white blood cell count (WBC), platelets, hemoglobin, peripheral blood blasts, BM blasts, performance status and combined molecular risk category. Results Among the 488 enrolled pts, 211 were ≥55 years old with median age of 61 (range 55-70). Among older pts, 49.3% were female and 83.4% were white, 17 (8.1%) pts had WBC >30.000/uL at the time of diagnosis. 156 (73.9%) pts had CD10+ early B-ALL and 46 (21.8%) had CD10- B-ALL immunophenotype. The most common genetic subgroups were low hypodiploid (n=58, 27.5%), BCR::ABL1-like (n=34, 16.1%) and KMT2A rearranged (n=26, 12.3%). 8.1% of pts had low, 9.0% intermediate, 63.5% high combined molecular risk disease and in 19.4% of pts risk could not be assigned. Baseline characteristics were not significantly different in chemo + blina and chemo only pts. The median follow-up for this analysis from step 1 registration was 54.6 months. Complete response with (CR) or without (CRi) count recovery after induction was observed in 174 (82.5%) pts (167 CR, 7 CRi). 93 (44%) pts were MRD-. 32 (15.1%) pts received HCT on study and 24 (11.4%) pts received it off study. Among MRD- pts (n=93), 46 were randomized to and 45 received blina: 6 (13.3%) pts had 1, 14 (31.1%) had 2, 2 (4.4%) had 3 and 23 (51.1%) had 4 cycles. 3-year OS were 71% and 67% for the blina and the chemo only arm (univariate model: HR 0.75, 95% CI: 0.37-1.50; multivariate model: HR 0.56, 95% CI: 0.25-1.27). 3-year RFS were 69% and 59% for the blina and the chemo only arm (univariate model: HR 0.75, 95% CI: 0.39-1.45; multivariate model: HR 0.67, 95% CI: 0.32-1.42). Among MRD+ pts (n=25), 14 were randomized to and 11 received blina: 7 (63.6%) pts had 2, and 4 (36.4%) had 4 cycles. 3-year OS were 66% and 44% for the blina vs the chemo only arm (univariate model: HR 0.66, 95% CI: 0.12-3.64). 3-year RFS were 64% and 31% for the blina vs the chemo only arm (univariate model: HR 0.64, 95% CI: 0.15-2.74). Frequency of treatment-related toxicities among older pts during different study phases and treatment assignments will be presented. Conclusion Despite evidence of improved outcomes in the whole study cohort, the addition of blina to consolidation chemo for older pts with ALL was not associated with statistically significant improvement of OS or RFS in this exploratory analysis not powered to detect the difference in subgroups. This is possibly due to sample size but may be due to biologic differences in the older adult population. Further studies are needed to definitively determine tolerance and benefit of blina addition to consolidation for older pts with ALL.

Background: AL amyloidosis is a potentially fatal plasma cell dyscrasia. In a randomized phase 3 study (Kastritis E et al, NEJM 2021;385:46-58), the addition of daratumumab to cyclophosphamide, bortezomib and dexamethasone (Dara-CyBorD) significantly improved hematological and organ responses, and prolonged event-free survival (EFS). There was no overall survival (OS) difference at a median follow-up of 11.4 months. Methods: A retrospective study of AL amyloidosis patients seen at our institution between January 2018 and December 2022 who received upfront Dara-CyBorD or CyBorD. We excluded patients who received other forms of upfront therapy (including modifications of the above regimens, such as bortezomib-dexamethasone or daratumumab-dexamethasone). We compared the hematologic and organ responses, EFS and OS between the two treatment groups. Hematologic response was assessed at 2 and 6 months from therapy initiation, while cardiac and renal responses at 6- and 12-month landmarks. In all response evaluations, we included responses up to autologous stem cell transplantation (ASCT) if used or second-line therapy for any reason. For EFS analysis, an event was defined as death of any cause, hematological progression, end-stage cardiac or renal failure, or need for subsequent anti-plasma cell therapy in the absence of hematological progression. OS was calculated from the time of treatment initiation to death or last follow-up. Results: Among 641 newly diagnosed patients seen at our center between 2018 and 2022, 361 patients (56%) were included on intention-to-treat analysis [Dara-CyBorD =147 (41% of the cohort); CyBorD=214 (59%)]. There was no difference in the baseline characteristics between the treatment groups, including age, sex, difference between involved and uninvolved light chains, bone marrow plasma cells percentage, NT-proBNP and 24-hour proteinuria. The 2-month hematologic complete response (hemCR; 15.3% vs 4.4%, P<0.001) and very good partial response or better (≥hemVGPR; 62.2% vs 32.5%, respectively; P<0.001) were higher with Dara-CyBorD compared to CyBorD. At 6 months, the hemCR and ≥hemVGPR were again in favor of the Dara-CyBorD group compared to CyBorD (32.0% vs 13.7%, and 72.8% vs 46.7%, respectively; P≤0.002). The 6- and 12-month cardiac response rate in the Dara-CyBorD and CyBorD groups were 40.2% vs 22.6% (P=0.01) and 44.1% vs 23.2%, respectively (P=0.006). Cardiac ≥VGPR at the 6- and 12-month landmarks were statistically higher with Dara-CyBorD compared to CyBorD and increased in both arms between 6 and 12 months [20.5 % vs 9.3% (P=0.03) and 34.3 % vs 20.0% (P=0.04), respectively]. The 6-month and 12-month renal response to first-line therapy were numerically higher with Dara-CyBorD compared to CyBorD but were not statistically significant (48% vs 31.3%, P=0.10; 54.1% vs 30.1%, P=0.05). The 6 month and 12 months, renal ≥VGPR were numerically higher with Dara-CyBorD compared to CyBorD, again without statistical significance (26% vs 19.6%, P=0.63; 35.7% vs 17.2%, P=0.11, respectively). Treatment with Dara-CyBorD was significantly associated with lower 6-month mortality rate compared to CyBorD (8.8% vs 16.3%, P=0.04). With a median follow-up of 43.3 months (30 vs 59.4 months for Dara-CyBorD vs CyBorD, respectively; P<0.001), the two-year EFS was superior in the Dara-CyBorD group compared to CyBorD (69.1% vs 30.3%, hazard ratio (HR) 0.36, 95% confidence interval (CI), 0.26 to 0.48, P<0.001). The 2-year OS was also statistically higher in the Dara-CyBorD group compared to CyBorD (82.0% vs 69.6%, HR 0.53, 95% CI, 0.36 to 0.79, P=0.003). 148 patients (40.9%) proceeded to second-line therapy with a median of 5.1 months from first line therapy. To adjust for difference in follow-up time between the two treatment groups, we analyzed the second line therapy utilization at the 12-month mark which was statistically higher with CyBorD compared to Dara-CyBorD (42.9% vs 14.9%, P<0.001). Also, at 12 months, a higher proportion of patients treated with CyBorD received ASCT compared to Dara-CyBorD (24.3% vs 13.6%, P= 0.01). Conclusions: In this cohort of newly diagnosed AL amyloidosis patients in a large referral center, we confirmed higher hematological and organ response rates with Dara-CyBorD compared to CyBorD. We have also demonstrated that these higher response rates translate into a survival advantage of Dara-CyBorD over CyBorD.

Background Venetoclax + hypomethylating agent (Ven-HMA) therapy results in favorable response rates (CR/CRi 66%) and overall survival (OS; median 14.7 months) in unfit patients with newly-diagnosed acute myeloid leukemia (ND-AML; N Engl J Med 2020;383). However, there is substantial heterogeneity in individual patient outcomes based on response to treatment. The objective of the current study was to develop a genetic risk model to predict survival outcome in treatment responders and non-responders, analyzed separately, and also account for allogeneic stem cell transplant (ASCT). Methods Treatment-naïve AML patients receiving Ven-HMA, outside of a clinical trial, at the Mayo Clinic, USA (MN, AZ, FL) were retrospectively recruited. Molecular studies (48-gene panel) were performed by next-generation sequencing. Response was assessed according to the 2022 European LeukemiaNet (ELN) criteria (Blood 2022;140). Standard statistical analyses were performed using JMP Pro (Version 17.0.0). Results 400 ND-AML patients (median age 73 years, 64% male, 60% de novo) received Ven-HMA. ELN cytogenetic risk included favorable 2%, intermediate 60%, or adverse 38%. Mutations involved TP53 in 26%, TET2 19%, RUNX1 19%, SRSF2 18%, ASXL1 18%, DNMT3A 15%, K/NRAS 13%, NPM1 12%, IDH2 12%, FLT3-ITD 10%, IDH1 7% and DDX41 in 4% of informative cases. 153 (38%) patients achieved CR, 94 (24%) CR with incomplete count recovery (CRi), resulting in CR/CRi in 247 (62%) patients. CR/CRi rates were higher with NPM1 (86% vs 59%), IDH2 (77% vs 60%), and DDX41 mutations (93% vs 61%) and lower with TP53 (45% vs 67%), FLT3-ITD (41% vs 64%), RUNX1 (49% vs 65%) mutations and adverse karyotype (48% vs 71%), with all retaining significance in multivariable analysis. CR/CRi rate was highest (87%) in 75 patients with one or more favorable mutations (NPM1, IDH2, DDX41) and no unfavorable mutation (TP53, FLT3-ITD, RUNX1). CR/CRi rate was lowest in 171 patients with at least one unfavorable mutation and no favorable mutation (44%; p<0.01). After a median follow up of 10.5 months (0.5-66), 105 relapses (43% of patients in CR/CRi), 248 (62%) deaths and 65 (16%) ASCT were documented. Univariate analysis for transplant-censored OS disclosed superior survival in patients achieving CR/CRi (median 21 vs 3.6 months; HR 5.4, 95% CI 4.1-7.1). Among patients achieving CR/CRi, IDH2 mutation was associated with superior (median not reached vs 20.5 months) and male gender (median 17.6 vs 29.2 months), TP53 mutations (median 11.9 vs 24.3 months) and adverse karyotype (median 12.6 vs 29.4 months) with inferior survival; multivariable analysis resulted in HRs (95% CI) of 2.1 (1.3-3.4) for male gender, 2.1 (1.2-3.8) for adverse karyotype, and 2.5 (1.1-5.7) for absence of IDH2 mutations. Male gender did not show an association with karyotype, or TP53 mutations (p>0.1). Accordingly, an HR-weighted genetic risk model was generated with assignment of one point each to male gender, adverse karyotype, and absence of IDH2 mutation: high risk = 3 risk factors (n=38; median 9.6 months; 3-year survival 0%); intermediate risk = 2 risk factors (n=129; median 22 months; 3-year survival 38%); and low-risk = ≤1 risk factor (n=78; median not reached; 3-year survival 69%; p<0.01). In patients bridged to ASCT (n=60), post-transplant survival was inferior in the presence of ≥ 2 risk factors (n=42; median 46 months) vs. ≤1 risk factor (n=18; median not reached; p=0.1). In patients not achieving CR/CRi, risk factors for OS included male gender (median 3.4 vs 6.1 months), adverse karyotype (median 3.3 vs 4.5 months) and TP53 mutation (median 3.1 vs 4.5 months) while those with IDH2 mutations lived longer (median 8.4 vs 3.4 months). In multivariable analysis, HRs (95% CI) were 1.9 (1.3-2.9) for male gender, 2.0 (1.4-2.9) for adverse karyotype, and 2.1 (1.1-4.3) for absence of IDH2 mutations. OS was shortest for non-responders harboring 3 risk factors (n=45; median 3 months; 1-year survival 0%) and longer for those harboring two (n=80; median 6 months, 1-year OS 15%) or ≤ 1 risk factor (n=25; median 14 months; 1-year OS 56%; p<0.01). Conclusion The current study describes a molecular profile for predicting response to Ven-HMA in ND-AML and also introduces a novel approach to survival prediction that considers treatment response as the starting point. In both responders and non-responders, male gender and adverse karyotype were identified as unfavorable and IDH2 mutation favorable risk factor for OS.

Background: Indolent non-Hodgkin lymphomas (iNHL) are incurable and disproportionately affect adults age >65 in whom frailty and functional impairment can impact disease management. The Vulnerable Elders Survey (VES-13) is a 13-item screening tool that incorporates age, self-rated health, physical function limitations, and functional disabilities to identify vulnerable older community-dwelling adults. Adults with a VES-13 score of >3 have a fourfold increased risk of death or functional decline over 2 years as compared to adults with a score <3 (Saliba et al, JAGS 2001). Our team previously showed that VES-13 >3 was associated with a higher risk of 1-year mortality in NHL (OR 3.26, 95% CI 2.15-4.96, Fama et al, ASH 2019), including in adults age <65. In this study, we determined whether VES-13 scores >3 were associated with quality of life (QOL) changes in adults with iNHL across the age spectrum. Methods: We used the Lymphoma Epidemiology of Outcomes (LEO) Cohort Study to identify adults enrolled from 2015-2020 with grade 1-3A follicular and marginal zone lymphoma (FL, MZL) who completed the VES-13 at enrollment and QOL surveys at enrollment and follow-up. The LEO Cohort Study enrolls participants within 6 months of diagnosis and collects information on disease status, QOL, health behaviors, and patient-reported functional assessment. For this analysis we included QOL measured using the Functional Assessment of Cancer Therapy-General (FACT-G) at years 1 and 2 post-enrollment. The FACT-G total score was the sum of 4 subscales (range): physical (PWB, 0-28), social/family (SFWB, 0-28), emotional (EWB, 0-24), and functional (FWB, 0-28) well-being. A higher FACT-G total score (range 0-108) indicated better overall QOL. VES-13 scores ranged from 0 (lowest risk for death or decline) to 10+ (highest risk). Generalized linear mixed models evaluated changes in QOL from baseline based on VES-13 score >3 (vulnerable) vs <3 (non-vulnerable), within groups by age at enrollment >65 and <65. Results: Our study included 1,186 participants: 42% age >65, 54% female, 84% non-Hispanic White, 10% Hispanic, 3.3% Black, and 1.4% Asian/Pacific Islander. Most (68%) were diagnosed with FL. FLIPI was high risk for 20%, and MALT-IPI was high risk for 23%. In the VES-13 <3 group, the mean (SD) baseline FACT-G total score was 86.5 (12.0), PWB 21.0 (3.5), SFWB 24.3 (4.3), EWB 18.8 (3.7), and FWB 22.3 (4.9). In the VES-13 >3 group, the mean (SD) baseline FACT-G total score was 70.4 (16.5), PWB 15.4 (5.6), SFWB 22.3 (5.5), EWB 17.5 (4.5), and FWB 15.3 (6.4); all significantly lower than the VES-13 >3 group (all p<0.01). In adults <65, 63 (9%) had a VES-13 >3, which was associated with a significant improvement from baseline in PWB at years 1 and 2 when compared to VES-13 <3 (changes in baseline PWB were 2.1, 2.9 for VES-13 >3 vs 0.2, 0.1 for VES-13 <3, all p<0.05). Similarly, we observed improvement in FWB from baseline at years 1 and 2 in the VES-13 >3 vs <3 group (2.4, 2.9 vs 0.4, -0.1, respectively all p<0.05). The VES-13 >3 group had a decline in their EWB at 1 year vs the VES <3 group (-0.5 vs 1.2, respectively, p=0.003). At year 2, total FACT-G improved from baseline in the VES-13 >3 group (5.6 for VES-13 >3 vs -0.5 for VES-13 <3, p=0.002). SFWB changes from baseline did not differ between groups. In adults >65, 83 (17%) had a VES-13 >3, which was associated with a significant improvement from baseline PWB (1.3, 1.5 for VES-13 >3 vs. 0.1, -0.1 for VES-13 <3), FWB (3.3, 2.2 for VES-13 >3 vs. 0.5, 0.1 for VES-13 <3), and total FACT-G score (5.2, 3.4 for VES-13 >3 vs. 1.0, -0.4 for VES-13 <3) when compared to VES-13 <3 at years 1 and 2 (all p<0.05). SFWB and EWB changes from baseline did not differ between groups. While there was improvement from baseline PWB and FWB in the VES-13 >3 group, QOL scores across all subscales remained below the VES-13 <3 group in the study period for both age groups. Statistical significance was maintained in models adjusted for baseline characteristics, including initial treatment strategy (observation, systemic, vs local) for both age groups. Conclusion: Although the vulnerable group reported worse QOL throughout the study period compared to the non-vulnerable group, survivors in the vulnerable group saw greater improvement in their physical and functional well-being at 1- and 2-years post-diagnosis. Additional analyses are underway to identify drivers of improvement in physical and functional well-being in vulnerable adults diagnosed with iNHL.

Introduction: Chronic myelomonocytic leukemia (CMML) is a myeloid stem cell neoplasm with few effective therapies and poor prognosis. This disease is characterized by an expansion of malignant monocytes which express high and homogeneous levels of the homing chemokine receptor CCR2. We have developed a CCR2 targeting Cytotoxicity Targeting Chimera (CCR2-CyTAC, STX-0712), which potently binds CCR2 on cells, and when combined with the CyTAC platform antibody, eliminates target cells via enhanced effector mediated killing. We present here the characterization of CCR2 expression in CMML patient samples, ex vivo depletion of CMML cells via treatment with STX-0712, and the dose dependent depletion of MO1 monocytes (classical monocytes) in non-human primates, supporting CMML as a promising indication for STX-0712. Methods: IRB approval was obtained from Mayo Clinic for patient sample use. For CCR2 characterization and depletion experiments, we used bone marrow biopsy specimens and peripheral blood mononuclear cells (PBMCs) obtained from CMML patients and controls from healthy donors. CCR2 expression and monocyte depletion were evaluated via flow cytometry, as previously described. In vivo pharmacokinetic (PK) and pharmacodynamic (PD) studies were conducted in cynomolgus monkeys. Results: First, we evaluated CCR2 expression in peripheral blood and bone marrow in CMML samples by flow cytometry. In 6/6 (100%) peripheral blood samples CCR2 was highly expressed on >98% of the monocytes. Also, in 3/3 (100%) bone marrow samples, CCR2 was expressed on a subset of CD34+ progenitors, while low/no expression was observed in healthy controls. This progenitor subpopulation had characteristics of the inflammatory granulocyte-macrophage progenitor (GMP)-like cells. Next, STX-0712 was added to freshly isolated PBMCs from CMML donors and CCR2+ monocyte depletion, mediated by endogenous Fc gamma receptor 3a positive (FcγRIIIa) effector cells, was assessed. In 5/5 (100%) CMML patient samples, the drug selectively induced depletion of CD14+, CCR2+ cells with an average potency of 3nM and 66-91% target cell killing vs no drug control. Finally, we evaluated the effects of STX-0712 in cynomolgus monkeys to evaluate PK and PD effects on CCR2 MO1 monocytes in vivo. STX-0712 demonstrated PK supportive of dosing in man. In 9/9 (100%) animals, STX-0712 effectively depleted >95% of CCR2+ monocytes which returned after drug levels dropped below ~10ng/mL. All doses were well tolerated and the findings of comprehensive immunophenotyping were to be as expected, predictable and mechanism directed. Conclusion: These results demonstrate high and homogenous CCR2 expression on malignant monocytes, ex vivo human target engagement and pharmacodynamics, and in vivo depletion of CCR2 MO1 monocytes in a potent and dose dependent manner. Based on this data we plan a First in Human, phase 1 clinical trial for patients with relapsed/refractory CMML.

Introduction: Uniform assessment of response to treatment is crucial to managing myeloma and developing new therapies. Measurement of the monoclonal protein (s) secreted by the myeloma cells forms the cornerstone of disease assessment in MM and has primarily been performed by electrophoretic methods in the serum and urine, as well as assessment of free light chains in the serum. According to international myeloma working group (IMWG) guidelines, serial serum-free light chain (sFLC) is included in MM response assessment to define stringent complete response and for evaluating partial response (PR) or progressive disease (PD) in non/oligo-secretory MM. This study aims to determine the added value of serial sFLC measurements in monitoring response and progression in MM with measurable disease by comparing the kinetics of FLC with M spike measured by electrophoresis in serum or urine. Methods: This retrospective observational study included newly diagnosed MM patients evaluated at Mayo Clinic in Rochester between 2011-2021. All patients had measurable sFLC (involved FLC level ≥ 10mg/dL, with abnormal sFLC ratio) along with measurable M-protein by serum or urine protein electrophoresis at diagnosis. Serial measurements of sFLC and M-protein by electrophoresis (sPEP/uPEP) were prospectively collected from the electronic medical records at different time points. FLC-response and FLC-PD were evaluated based on IMWG criteria. Results: The study cohort included 839 patients, 52% with measurable M protein by electrophoresis in serum, 27% in both serum and urine, and 21% in urine-only. A significant association was observed between sFLC and electrophoretic response during the induction and at the time of best response (p <.001). Serum FLC showed a comparable response rate of 98% (≥ PR) at the time of best electrophoretic response (p <.001). Ninety-nine percent of early FLC responders eventually achieved an overall response by sPEP/uPEP (p <.001). In the urine-only group, 99% achieved at least a PR by uPEP, and all showed at least a PR based on sFLC. We observed comparable median percentage changes in serial dFLC and urine M-protein, with parallel trends (p <0.001). The correlation coefficients between the change of sFLC and urine M-protein showed a moderate/strong correlation with coefficients (r) of 0.791, 0.597, 0598, 0.545, after cycles 1, 2, 3, 4, respectively, (p < .001). The response for all cohorts was detected earlier by dFLC (median time 1.1 months, 95% CI: 1.06-1.17), in comparison with serum M-protein (1.5 months, 95% CI: 1.40-1.62) and urine M-protein (2.8 months, 95% CI: 2.42-3.10) with p < .001. In the urine-only group, earlier detection of response by dFLC (1.1 months, 95% CI: 1.00-1.2) was observed, compared to urine M-protein (2.4 months, 95% CI: 2.00-2.7) (p <.001). After a median follow-up of 52 (IQR 27.6, 72.3) months, 56% had PD: 62% by s-FLC, 56% by serum M-protein, and 24% by urine M-protein. Among patients with PD by uPEP, all except one patient met sFLC-PD. Within patients with PD, sFLC was the only detectable tumor marker in 12% of cases at the time of the second line of treatment. After four cycles of induction, there was no difference in PFS between VGPR response determined by sFLC, sPEP, and uPEP (p =0.538). The median second-PFS for patients with onlysFLC-PD was similar to those with urine M-protein PD with or without sFLC-PD (HR 1.28, 95% CI =0.77-2.13. p 0.334). However, the median overall survival (OS) from the first relapse was significantly better for patients with onlysFLC-PD than those with urine M-protein PD (HR 1.87, 95% CI =1.07-3.27. p 0.026). Conclusions: In this study, achieving sFLC-VGPR has a similar impact on PFS as electrophoretic-VGPR after induction, indicating that serial sFLC can potentially replace the requirement for urine M-protein response (< 100mg in 24-hours urine) as part of the electrophoretic-VGPR criteria, as required by IMWG. A similar response rate between sFLC and urine paraprotein confirms the current cutoffs (90% for urine and 50% for dFLC for VGPR) used for response categories for s-FLC. We also observed that in 12% of patients with PD, sFLC was the only marker of progression, highlighting the value of serial s-FLC in monitoring relapse. In conclusion, our study supports the integration of serial sFLC measurements for monitoring response and progression in MM, even with electrophoretic measurable disease.