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Abstract Background: Talquetamab (Talq), a GPRC5D-targeting bispecific antibody, shows promising activity in relapsed/refractory multiple myeloma (RRMM). However, outcomes in patients (pts) with soft tissue plasmacytoma (STP) remain poorly characterized. Method: We retrospectively analyzed 463 RRMM pts treated with Talq at 15 U.S. centers by Dec 2024. Pts were grouped by presence of STP at Talq start: (1) extramedullary disease (EMD; lesions not contiguous with bone), (2) paraskeletal disease (PSK; bone-contiguous), (3) EMD + PSK, and (4) No-STP. Those receiving Talq as a bridge-to-CAR T (n=103, 22%) were censored at CAR T infusion if progression had not occurred. Time-to-event endpoints were calculated from Talq step-up, using Kaplan-Meier/Cox models. Result: Median age was 66 years (y) (35–89); 54 (11.7%) had EMD, 26 (5.6%) PSK, 60 (13%) EMD+PSK, and 320 (69%) No-STP. EMD pts were younger than No-STP (62 vs 66 y, p=.009), while PSK (66.5) and EMD+PSK (64.5) were similar to No-STP. Median prior lines were higher in PSK (7) vs EMD (5), EMD+PSK (6) and No-STP (6) (p=.035). Median time from diagnosis to Talq was shortest in EMD (3.8 y), followed by EMD+PSK (4.6 y), vs PSK (6.4 y), and No-STP (5.9 y) (p=.015). Among pts with any EMD (EMD or EMD+PSK), 81 (69%) had visceral involvement and 85 (73%) had multiple lesions. Rates of prior BCMA- or GPRC5D-directed therapy, plasma cell leukemia (≥5% circulating plasma cells at the time of Talq), and penta-refractoriness were similar across groups. ECOG ≥ 2 at Talq was more common in EMD (42%), PSK (39%), EMD+ PSK (37%) than in No-STP (23%) (p = .002). Other baseline features were similar. Cytokine release syndrome (CRS) rate/severity were similar across groups. The immune effector cell–associated neurotoxicity syndrome (ICANS) was more frequent in PSK (38%) vs EMD (11%), EMD + PSK (18%), and No-STP (11%), with the most PSK cases (60%, 6/10) being grade ≥2 (p=.006). No difference in CRS/ICANS onset or duration. Infection rates were lower in No-STP (36%) vs EMD (55%), PSK (46%), and EMD+ PSK (48%) (p=.025). Best overall response rates (ORR) were 71% in EMD, 68% in PSK, 67% in EMD+PSK, and 71% in No-STP (p=.9). Complete response (CR) rates were 14% in EMD, 20% in PSK, 13% in EMD+ PSK, and 25% in No-STP (p=.1) [CRs were not required to be confirmatory, which may not meet full IMWG criteria]. Radiographic response was evaluable in 41 EMD (86%), 16 PSK (61.5%), and 48 EMD+PSK (80%) pts, with partial response (PR) or better observed in 48%, 27%, and 38%, respectively. Among pts with any STP, 34% received radiation (XRT) (4 as bridge-to-CAR T), 24 (51%) were evaluable, and 71% (n=17) achieved ≥PR. The median follow-up from Talq initiation was 10.1 months (mo) (95% CI: 8.8–11.4) and was longest in EMD (13.9 mo) compared with PSK (10.8 mo), EMD+PSK (12.4 mo), and No-STP (9.8 mo) (p = .040). Median progression-free survival (PFS) was 4.3 mo (95% CI: 3.6–5.06) in EMD, 4.8 mo (95% CI: 2.2–7.3) in PSK, 3.8 mo (95% CI: 3.1-4.5) in EMD+ PSK, and 8.3 mo (95% CI: 7.0–9.6) in No-STP (p <.001). Among pts receiving XRT for any STP (within 4 weeks prior to or during Talq), responders had longer PFS vs non-responders (15.4 vs. 2.4 mo; p=.009). Multivariable analysis (MVA) showed inferior PFS with EMD (Hazard Ratio (HR) 1.58; 95% CI, 1.04-2.3; p=.029), EMD+PSK (HR 1.91; 95% CI, 1.2–2.8; p = .001), ECOG ≥ 2 (HR 1.4; 95% CI, 1.04–1.9; p = .024), and del(17p) at any timepoint (HR 1.99; 95% CI, 1.1–3.5; p=.017), while longer time from diagnosis to Talq was modestly protective (HR 0.95 per year; p = .016), likely reflecting less aggressive biology in those reaching 5th+ line later. PSK alone showed a non-significant trend toward inferior PFS (HR 1.5; p = .1). Median overall survival (OS) was 13.0 mo (95% CI: not reached [NR]–NR) in EMD, 12.9 mo (95% CI: 6.9–18.9) in PSK, 10.9 mo (95% CI: NR–NR) in EMD+PSK, and NR (95% CI: NR–NR) in No-STP (p = .017). The primary cause of death was disease-related across all groups (p = .6). MVA for OS showed worse outcomes with EMD+PSK (HR 1.7; p=.033), ECOG ≥ 2 (HR 1.98; p <.001), and active PCL at Talq (HR 2.1; p =.010). Conclusion: Soft tissue plasmacytoma, particularly EMD and EMD+PSK, remain strong adverse prognostic factors in Talq-treated patients, with significantly shorter PFS and OS despite similar response rates. Radiation to STP sites was associated with improved outcomes in select cases. Prospective strategies are needed to optimize management for this high-risk population.

Abstract Background Patients (pts) with multiple myeloma and CNS involvement (CNS MM) have poor outcomes, and we recently showed that CAR-T has activity and is reasonable in this population (Gaballa et al., 2025). We sought to evaluate the safety and efficacy of Bispecific T-cell engagers (BsAbs) in CNS MM pts, with specific interest in evaluating ICANS. Methods We conducted a retrospective study of CNS MM pts treated with BsAbs via the MM immunotherapy consortium. Primary endpoints were toxicity rates, with a specific focus on ICANS. Secondary endpoints were systemic responses, CNS responses, and survival outcomes. CNS MM was defined as involvement of the brain parenchyma, spinal cord tissue, leptomeningeal disease, or CSF positivity. CNS response was determined based on CSF and imaging, as complete CNS response, partial CNS response, and non-response/progression. Results The study included 24 pts from 13 US institutions treated with teclistamab (33%), talquetamab (50%), elranatamab (17%), and were used as monotherapy in 83% while 17% received them in combination with either daratumumab or IMiDs. The median age was 64.5 (range 41-82), 50% female, 79% white, and 17% black. High-risk cytogenetics were identified in 39%, 4% had prior primary PCL, and 21% had secondary PCL (2 active within 30 days of BsAb initiation). All pts were triple-refractory, 33% were penta-refractory, and 39% had non-CNS EMD. Pts received a median of 5 prior lines of therapy (IQR 4-7), 71% prior transplant, and 21% prior CAR-T. Prior BCMA therapy was received in 83% of the talquetamab group and 17% of the BCMA BsAbs group (teclistamab and elranatamab). CNS disease was determined based on both imaging and CSF findings in 58%, imaging only in 33%, and CSF only in 8%. Site of CNS disease included 42% brain/cranial nerves, 13% spinal cord, or 46% with both. CNS disease was diagnosed prior to BsAb in 19 pts, with a median interval of 46 days (IQR 7-234), and 3 pts were identified within 2 weeks after BsAb initiation. Two pts identified at days 68 and 121 were included in the safety evaluation but excluded from the efficacy assessments. One pt received teclistamab and intrathecal chemotherapy (IT chemo) as a bridge to CAR-T and achieved a complete CNS response before CAR-T. CNS-directed therapy consisted of: 30% radiotherapy (RT), 30% IT chemo, 13% RT + IT chemo, 9% RT + surgery, and 4% steroids. CRS grade (G) 1-2 occurred in 50%, with no G3-4 CRS. ICANS G 1, 2, and 3 occurred in 13%, 21%, and 4%, respectively, with no G 4 ICANS. One pt developed delayed parkinsonism, and another developed leukoencephalopathy; both had CNS MM diagnosed pre-BsAbs and achieved a CNS response (1 complete, 1 partial). Infections occurred in 67% of pts, with 42% being severe, and 1 infection-related death. The systemic ORR of 18 evaluable pts was 67%, including 22% CR, 17% VGPR, and 28% PR. The overall CNS response of 19 evaluable pts was 58%, including 37% complete CNS response and 21% partial CNS response. Of 11 pts achieving a CNS response, 82% didn't have subsequent CNS progression. In 9 pts achieving CNS response after BsAb initiation, the median time to CNS response was 0.9 months (range 0.03-2.8), with an unreached median duration of CNS response. With a median follow-up of 11 months, the median PFS was 5.0 months (95% CI 2.5-NA) and OS was 12.2 months (95% CI 7.7-NA). No significant difference in median PFS (10.6 vs 4.6 months, p=0.11) or OS (20.2 vs 9.3 months, p=0.37) was observed between BCMA BsAbs (n=11) and talquetamab (n=11). Due to small sample limitation, no significant difference was observed in the median PFS (4.6 vs 8.2 months, p=0.48) or OS (20.2 vs 9.9 months, p=0.73) between BsAb monotherapy (n=19) and BsAb combination therapy (n=3). One pt who received teclistamab as a bridge to CAR-T achieved a complete CNS response and remains progression-free to date, demonstrating the best long-term outcome with a PFS of 674 days. Conclusions Our study demonstrates that BsAb use in pts with CNS MM is safe without increased incidence of ICANS. The use of BsAbs in combination with a multimodal CNS-directed approach led to an overall CNS response rate of 58% and an unreached median duration of CNS response. Previous studies (Gaballa et al., 2025) reported a 100% CNS response rate with CAR-T. In this study, 1 pt treated with BsAb as a bridge to CAR-T had the longest PFS, warranting further research to evaluate this combination's efficacy in this very high-risk population.

Abstract Background Talquetamab (talq) is a GPRC5D-directed bispecific antibody (BsAb) approved for the treatment of relapsed and refractory multiple myeloma (RRMM). The pivotal monumenTAL-1 clinical trial did not include patients with renal impairment (RI, creatinine clearance<40 mL/min) and therefore, data for the use of this agent in RI is lacking. Methods We examined the outcomes of patients with RRMM treated with standard of care (SOC) talq in a multicenter, retrospective cohort study. RI was defined as creatinine clearance (CrCl) <40 mL/min. For each patient we recorded demographics, disease characteristics, prior therapies, incidence and severity of adverse events of special interest, namely cytokine release syndrome (CRS) and immune-cell associated neurotoxicity syndrome (ICANS), along with response, progression-free (PFS) and overall survival (OS). We compared binary variables between different groups using Chi-squared test and assessed progression free survival (PFS) and overall survival (OS) using Kaplan Meier and Cox proportional hazards models. Patients who received talq as a bridge therapy prior to chimeric antigen receptor T-cells (CART cells) were censored for PFS analysis at the time of subsequent therapy. Results We included 417 patients who received SOC Talq and had complete datasets. 91 (22%) had RI, including 20 (5%) on dialysis. The median age was 68 and 65 years for patients with and without RI. Patients with RI were more likely to be female (64% vs. 51%), less likely to have prior CART cells (35% vs. 48%). There were no differences in performance status, race, presence of high-risk cytogenetic abnormalities [del17p, t(4;14), t(14;16), gain/amplification 1q], lines of prior therapy (median 6 vs. 6), prior ASCT (68% vs. 72%), presence of CNS disease (4% vs. 4%), prior plasma cell leukemia (8% vs 9%), prior BCMA therapy (54% vs. 61%) and triple class refractory disease (90% vs. 94%) among patients with and without RI. Rates of CRS (63% vs. 56%, P=0.21) were similar in the two groups, while severe CRS (grade ≥3: 6% vs 2%, P=0.02) was more common in patients with RI. Any grade (20% vs 14%, P=0.21) and high grade ICANS (grade ≥3: 4% vs 4%, P=0.97) were similar in patients with and without RI. There was no difference between groups on risk of infection (P=0.65) with cumulative risk at 6 months of 39% vs. 40%. With 11.1 months of median follow up, the overall response rate (60% vs 67%; P = 0.12), and progression-free survival (median 7.3 vs. 6.5 mo.; P = 0.9) were comparable between the two groups. There was no difference in outcomes according to RI in both patients previously treated with BCMA-directed therapy and BCMA-naïve. Conversely, among patients with RI, median PFS was 4.6 and 8.5 mo. for patients with and without prior BCMA therapy. Similarly, among patients without RI, median PFS was 6.5 and 6.2 mo, respectively. Among BCMA-naïve patients, there was no difference in OS between patients with and without RI (median not reached, 12 mo. OS rate 71% vs. 73%, P=0.53), while among patients with prior BCMA-directed therapy there was a trend towards better OS for patients without RI (median 8.9 vs. 13.8 mo; 12 mo. OS rate 43% vs 59%, P=0.06). Five patients (25%) became dialysis independent following talq therapy. On multivariable analysis, ECOG >1 (HR 1.62, 95% C.I. 1.25-2.10, P<0.001) and deletion of 17p (HR 1.55, 95% C.I. 1.17-2.06, P=0.003) but not RI or prior BCMA-directed therapy affected PFS. OS was affected by ECOG >1 (HR 2.37, 95% C.I 1.71-3.30, P<0.001), triple-class refractoriness (HR 3.03, 95% C.I. 1.12-8.21, P=0.03) and prior BCMA-directed therapy (HR 1.79, 95% C.I. 1.24-2.59, P=0.002) but not by RI. Conclusion Our findings support the feasibility of talq in patients with RI, including those on dialysis, with similar safety and efficacy profile to patients without RI. While neither prior BCMA-directed therapy nor RI affect PFS, refractoriness to conventional agents and prior exposure to BCMA-directed therapy adversely affects OS. This observation likely reflects better post progression survival following talq due to the availability of efficacious therapeutic options, including those directed at BCMA.

Abstract Introduction: VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is an aggressive auto-inflammatory disorder defined by somatic UBA1 mutations. UBA1 mutations arise in hematopoietic stem cells and bias differentiation toward myeloid lineages. Clonal involvement of monocytes and neutrophils in VEXAS is frequent. Recently, natural killer (NK) cells have been recognized within the UBA1 mutant clone; mutated NK cells have an exhausted phenotype and impaired cytotoxicity (Ganesan BioRxiv 2025; Breillat et al, Blood 2025). A unique NK-like T cell type (CD3+CD16+[CD56-] T cells) has a role in the immunopathogenesis of severe COVID-19, resulting in heightened cytotoxicity and tissue damage (Georg et all, Cell 2022). As NK cells do not typically express CD3, and as the activation of inflammatory pathways is not restricted to myeloid cells in VEXAS, (Mizumaki et al, Nat Comm 2025) we sought to assess the CD3+ cell populations for co-expression of CD16 using single-cell (sc) multiomic data from VEXAS patients. Methods: After IRB approval, we performed sc-proteogenomic sequencing using a custom-made gene panel (Tapestri, MissionBio) in 2 VEXAS patients. Libraries were sequenced on an Illumina NovaSeq instrument. In one case, we performed in parallel CITE-Seq in parallel and used canonical correlation analysis (CCA) to integrate these immunophenotypic and transcriptomic data with matching cell populations identified from proteogenomic sequencing. We used pathway analysis (IPA) and gene ontology enrichment (gProfiler), as well as differential gene expression (RNA-seq) to identify significant gene signatures. T-tests with Welch's correction were performed for statistical significance on surface markers from proteogenomic data which were transformed by center log ratio. Our observations were then validated in sc-proteogenomic data from two additional VEXAS patients profiled at the NIH. Results: We used a sc-multiomic strategy to study CD3+ T cell subsets in VEXAS patients. In the first UBA1 mutant (mt) sample, using clusters defined by UMAP overlay of CITE-Seq/proteogenomic data, we defined positive expression of CD3 expression in the non-UBA1mt T cell cluster. We then examined the proteogenomic data (n=700 cells) to identify CD3+ cells (n=89 UBA1mt, n=42 UBA1wt). We then divided the CD3+ fraction into CD56+ vs CD56- to obtain CD3+CD56+ (n=25 UBA1mt, n=12 UBA1wt) and CD3+CD56- (n=64 UBA1mt, n=0 UBA1wt) cells. The CD3+CD56- cells were not only entirely UBA1mt, but also co-expressed CD16, significantly elevated from CD3+CD56+ UBA1wt cells (p<0.0001; and no significance from granulocyte populations): 10% of UBA1mt cells were CD3+CD16+CD56-. This cell subset was detected in an additional 3 VEXAS samples, and, in each case, there was no significant difference between UBA1mt/UBA1wt CD3 expression (both were T cell subsets) and no significant difference in CD56 expression. There was a significant increase in CD16+ expression in UBA1mt over UBA1wt (p<0.0001) cells, but not between UBA1mt cells and other granulocytes. Finally, we assessed the CITEseq data from the first UBA1mt case and focussed on gene expression and pathway differences between CD3+ and CD3+CD16+(CD56-) cell populations. Using IPA, we found top differentially expressed pathways included neutrophil degranulation, inflammation, cell killing, and IL-8 activity. Differentially expressed genes included FCGR3B, TLR2, IL1R2, FCGR2A, CCR1, CXCL8, and CXCR1, some of these overlapping with what was reported in similar cells (CD3+CD16+) detected in COVID-19 (Georg et all, Cell 2022). Conclusion: We identify a unique NK-T cell like [CD3+CD16+(CD56] subset of cells within UBA1mt cells in patients with VEXAS. This cell type has been reported in patients with severe COVID-19 as having increased cytotoxic functions and associated with fatal outcomes. Rare or aberrant cell clusters defined by standard clustering analysis may mis-identify some cell types, especially if they aberrantly express CD3+CD16+, as either marker could be used to pre-gate cells into larger clusters of lymphoid or myeloid cells. Prospective and functional profiling of this cell type in VEXAS patients is ongoing.

Abstract Introduction: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening hematological disorder affecting ≈24 per 1,000,000 people in the US. Iptacopan, the first orally administered monotherapy for PNH, received US Food and Drug Administration approval in December 2023. APPRISE-PNH is a data platform designed to capture comprehensive real-world information on iptacopan-treated patients with PNH. The aim of this study was to describe patient profiles and assess treatment patterns and clinical outcomes among iptacopan-treated patients (age ≥18 years) with PNH in the US real-world setting. Methods: The present interim analysis of APPRISE-PNH includes data from patients enrolled between July 2, 2024, and June 13, 2025, with additional data collection expected through 2025. Duration of therapy was measured from the date of iptacopan initiation (index) until discontinuation or data cutoff, whichever occurred first. Treatment adherence was measured using the medication possession ratio (MPR; ratio of the total days' supply to days covered) and the proportion of days covered (PDC; ratio of days with supply to days covered). Clinical outcomes were assessed during follow-up including hemoglobin (Hb; change from pre-index to highest level post index, proportion of patients with Hb increase ≥2 g/dL, and proportion of patients with Hb normalization to ≥12 g/dL), lactate dehydrogenase (LDH) (change from pre-index to lowest level post index and proportion of patients with LDH reduction <1.5× upper limit of normal [ULN]), and number of red blood cell (RBC) transfusions. Results: Among 52 patients enrolled as of June 13, 2025, the median age was 53.7 years, 38% were male, and 60% were covered by commercial insurance. Overall, 25% of patients (n=13) were complement inhibitor (CI) naive at the time of iptacopan initiation, while 75% (n=39) were treatment experienced and had received ≥1 prior CI therapy for PNH (77% ravulizumab, 46% eculizumab, 26% pegcetacoplan). All patients received iptacopan 200 mg twice daily, per the product label; the median (IQR) duration of iptacopan therapy was 9.8 (5.0-12.8) months. At the time of data cutoff, 2 patients discontinued therapy (1 due to provider decision, 1 due to death). The median (IQR) MPR and PDC were 105.2% (100.6%-110.7%) and 97.3% (92.7%-99.5%), respectively. Among the 52 patients enrolled in APPRISE-PNH, 42 patients had medical records available at the time of data cutoff. Of the 23 of 42 patients (55%) with Hb values available pre- and post index at the time of data cutoff, 4 were CI treatment naive (median [IQR] pre-index Hb, 9.9 [9.1-10.2] g/dL) and 19 were CI treatment experienced (median [IQR] pre-index Hg, 10.7 [8.9-12.2] g/dL). The median (IQR) change from pre-index to highest value post-index was similar for both groups (1.6 [0.8-2.3] g/dL and 1.6 [0.6-3.4] g/dL, respectively). However, among the CI treatment–experienced patients, those with pre-index Hb <12 g/dL (n=11) experienced a greater improvement than those with pre-index Hb ≥12 g/dL (n=8), with median (IQR) of 3.3 (2.2-4.5) g/dL vs 0.4 (0.1-1.3) g/dL, respectively. Overall, 12 of 23 patients (52%) achieved a Hb increase ≥2 g/dL, and 17 of 23 (74%) achieved Hb normalization to ≥12 g/dL. Among the 18 of 42 patients (43%) with LDH values available pre- and post index, the median (IQR) change from pre-index to lowest post-index value was −41.5 (−155.8 to 2.5) U/L. Among those with clinical data, most patients (38 of 42; 90%) did not require RBC transfusions during follow-up and 4 had evidence of an RBC transfusion over the follow-up period; 2 of 4 patients requiring transfusions had aplastic anemia and/or myelodysplastic syndrome. At the time of data cutoff, no patients with clinical data available had evidence of a major adverse vascular event (including thrombosis, transient ischemic attack, stroke, and major bleeding) over the follow-up period. Conclusions: These data represent early insights into the real-world use of iptacopan and related Hb response in US patients with PNH. Adherence to iptacopan was high, and iptacopan treatment improved Hb and LDH parameters, providing comprehensive hemolysis control. Enrollment is currently ongoing; data on additional patients with longer follow-up are forthcoming.

Abstract Introduction: Iptacopan, the first oral complement inhibitor, offers an attractive alternative to parenteral complement blockers in paroxysmal nocturnal hemoglobinuria (PNH). While clinical trials have confirmed its efficacy vs terminal C5 inhibition, real-world data on breakthrough hemolysis (BTH), complement-activating conditions (CACs), and switching patients with satisfactory response to prior therapy (hemoglobin [Hgb] ≥10 g/dL) are limited. We studied a large multi-institutional PNH cohort treated with iptacopan. Methods: We performed a retrospective analysis of 62 patients with PNH who received iptacopan for ≥3 months between FDA approval in December 2023 and April 2025 (mean exposure, 1.01 years; 62 patient-years). Patients from the Cleveland Clinic network and Mayo Clinic were analyzed. Demographics, prior therapies, reasons for transition, Hgb, lactate dehydrogenase (LDH), platelet counts, thrombotic events, CACs, BTH, and adverse events were extracted. Efficacy was assessed separately for treatment-naive patients and treatment-experienced patients (sub-optimal responders [Hgb <10 g/dL] and optimal responders to prior therapy). Results: Overall, 12 of 62 patients were treatment naive and 50 switched from prior therapy (of whom 21 had sub-optimal responses and 29 had optimal responses). In the 50 patients who switched, 60% transitioned from ravulizumab, 30% from pegcetacoplan, 8% from eculizumab, and 2% from ravulizumab and danicopan. The primary reasons for switching were the convenience of oral medications (n=17), extravascular hemolysis or BTH (n=10), prior medication side effects (n=5), desire to further improve Hgb (n=6), and not documented (n=12). A total of 4 patients discontinued iptacopan (2 pregnancies, 1 insurance reversal, 1 intolerable gastrointestinal toxicity). Three patients reported headaches, and 1 reported abdominal pain; all resolved within 1 week from treatment start. Across the 62 patient-years, no thrombotic events occurred, 18 CAC episodes were managed with iptacopan 200 mg BID (10 infections, 1 heart-failure exacerbation, 2 minor surgeries, 1 traumatic brain injury, 2 pancreatitis, 2 pregnancies), and none triggered BTH. Overall, 3 clinically significant BTH events (in 3 patients; 4.8% annualized) were recorded: 2 infection-related (managed outpatient) and 1 alcoholic pancreatitis; all resolved with a 1- to 2-day increase to iptacopan 400 mg BID ± single-dose eculizumab. Two hemolytic events secondary to non-adherence were reported (4 days after stopping iptacopan). These resolved after resuming iptacopan 200 mg BID without need for hospitalization. In treatment-naive patients, mean Hgb increased significantly by 1.87 g/dL from iptacopan initiation (baseline) to 3 months (9.9±1.9 to 11.8±1.3 g/dL; P=.005), sustained until last follow-up at 12 months. LDH decreased by 369 U/L at 3 months (P=.058), sustained through 12 months. No significant change was seen in platelets, absolute neutrophil count (ANC), or white blood cell (WBC) count. In treatment-experienced sub-optimal responders, mean Hgb increased significantly by 2.16 g/dL from baseline to 3 months (8.6±.89 to 10.8±2.1; P<0.001). At 12 months, 85% of patients had increased Hgb compared with baseline (median increase: 3.31±1.62 g/dL). LDH decreased significantly from baseline to 3 months by 229 U/L (P=.03), with no significant changes noted in LDH from 3 to 12 months or in platelets, ANC, or WBC counts. In previously treated complement inhibitor responders, mean Hgb increased significantly by 0.75 g/dL from baseline to 3 months (12.0±1.3 to 12.8±1.7 g/dL; P=.004), with 79% showing improvements from baseline at 12-month follow-up (median increase: 1.16±0.82 g/dL). LDH decreased significantly by 45 U/L from baseline to 3 months (P=.03), with no further significant changes from 3 to 12 months. Conclusions: In this real-world cohort, iptacopan provided substantial and durable hemoglobin improvement across naive and previously treated patients with PNH, with meaningful reduction in hemolytic parameters, absence of thrombosis, and low BTH rate predominantly linked to infection. Patients with previous satisfactory responses also showed improved Hgb levels. The favorable safety profile and high treatment persistence underscore iptacopan's role as an effective first-line or switch therapy and support its incorporation into evidence-based sequencing algorithms in the evolving PNH treatment landscape.

Abstract Introduction: The therapeutic landscape for paroxysmal nocturnal hemoglobinuria (PNH) has rapidly evolved with multiple proximal complement inhibitors now available, including pegcetacoplan (C3 inhibitor) and iptacopan (oral factor B inhibitor). While clinical trials have established individual drug efficacy compared with terminal complement inhibitors, real-world evidence regarding therapeutic transitions between proximal complement inhibitors remains extremely limited. As patients and clinicians increasingly seek to optimize treatment through sequential therapy approaches, understanding the outcomes of transitioning from pegcetacoplan to iptacopan becomes critical for evidence-based treatment sequencing in this rare hematologic disorder. Methods: We conducted a retrospective multicenter analysis across 3 academic medical centers (Cleveland Clinic, Mayo Clinic, Levine Cancer Institute) that evaluated 15 consecutive patients with PNH who were considered for transition from pegcetacoplan to iptacopan. Patients had confirmed PNH by flow cytometry and ≥3 months pegcetacoplan exposure. After switching to iptacopan, we assessed treatment acceptance rates, demographic characteristics, clinical outcomes including hemoglobin and lactate dehydrogenase (LDH) levels, and safety parameters. Responses to iptacopan were classified as optimal (hemoglobin >10.5 g/dL with clinical improvement) or suboptimal. Statistical analysis used paired t tests for continuous variables. Results: Of the 15 patients evaluated (median age [range]: 53 [22-81] years; 73% female), 14 patients (93.3%) elected to transition to iptacopan, demonstrating high treatment acceptance. Disease subtypes included classic PNH (36%) and PNH (64%) in the setting of another bone marrow disorder (n=7), multiple myeloma (n=1), and myelofibrosis (n=1). Median (range) duration of pegcetacoplan treatment pre-switch was 3 months (2-7 months), and median (range) duration of iptacopan treatment was 24 months (6-36 months). Among patients who transitioned, 79% (11/14) achieved hemoglobin improvement, with a mean increase from 9.2±1.8 to 10.8±2.1 g/dL (P=.028). Overall, optimal response was achieved in 64% (9/14) of patients. Response rates varied significantly by disease subtype: 80% in patients with classic PNH vs 56% in patients with PNH and aplastic anemia, with particularly poor outcomes in patients with concurrent hematologic malignancies (0%). LDH levels improved in 86% of patients, decreasing from 400±152 to 310±95 U/L (P=.015). PNH clone sizes remained stable throughout transition (erythrocyte: 75.1%±9.2% vs 75.4%±9.4%, P=.62; granulocyte: 95.0%±3.9% versus 95.2%±4.0%, P=.45). Treatment was well tolerated with no serious adverse events, breakthrough hemolysis, thrombosis, or discontinuations required. Two patients experienced mild self-limited gastrointestinal symptoms. Conclusions: This first multicenter real-world analysis demonstrates that the pegcetacoplan-to-iptacopan transition provides clinical benefit in the majority of this initial set of patients with PNH, with significant improvements in hemoglobin and an excellent safety profile while maintaining clone stability. The high acceptance rate suggests that patients prefer oral therapy over subcutaneous administration. These findings address a critical knowledge gap in proximal complement inhibitor sequencing, suggesting that iptacopan is an effective therapeutic option for patients with inadequate pegcetacoplan response and supporting the development of evidence-based treatment algorithms for optimal PNH care in the era of multiple complement inhibitor options.

Abstract Introduction Mature T-cell lymphomas, including aggressive nodal PTCL, advanced stage CTCL, and extranodal cytotoxic lymphomas, are associated with poor outcomes. While karyotype (KT) abnormalities are frequently detected in these diseases, limited data exist on their prognostic significance. We evaluated the impact of KT abnormalities, including complex KT and specific chromosomal lesions, along with clinical and demographic factors, on overall survival (OS) in a single-center cohort. Methods We retrospectively reviewed 189 patients (pts) diagnosed with T-cell lymphoma who had successful metaphase KT at diagnosis from peripheral blood (PB), bone marrow (BM), or tumor tissue. T-cell lymphomas were classified according to WHO 2022 into nodal, extranodal/cytotoxic, and cutaneous subtypes. CTCLs were stratified into indolent (Early-stage CTCL, IA–IB) and aggressive (Sézary syndrome, transformed mycosis fungoides). KTs classified as normal, abnormal, and complex (≥3 abnormalities), and recurrent abnormalities were recorded. Baseline clinical and lab data were collected. OS was estimated using the Kaplan-Meier (KM) method with 95% confidence intervals (CI). Univariate Cox proportional hazards (CPH) model identified factors associated with OS, and significant variables were entered into multivariate CPH models. Results The median age was 66 years (IQR 55-74); 65% were male and 35% were female. Overall, 58% of pts were alive at analysis. Nodal PTCL was the most common subtype (113 pts, 60%), followed by early CTCL (30, 16%), aggressive CTCL (24, 13%), and extranodal lymphomas (22, 12%). KT was obtained from 166 BM (86%), 26 PB (13%), and 2 tissue (1%) specimens. Among abnormal KTs, 63% were from BM, 35% from PB, and 2% from tissue. Specific abnormalities included gain of chr1 (5%), gain of chr3 (5%), gain of chr7 (5%), gain of chr8 (5%), monosomy 5 or del(5q) (4%), monosomy 9 or del(9q13q22) (4%), Monosomy 10 (4%), loss of chrY (5%), and presence of marker chromosomes (5%).Of the 189 pts, 48 (25%) had an abnormal KT, while 141 (75%) had a normal KT. Complex KT was observed in 31 (16%) pts. Abnormal non-complex and complex KTs were seen respectively in: aggressive CTCL (8%, 42%), nodal PTCL (4%, 13%), extranodal (9%, 14%), and early CTCL (27%, 10%). KM survival analysis showed a median OS for the entire cohort of 95 months (95% CI: 65-245). Pts with a normal KT had a median OS of 143 months (95% CI: 81-inf) compared with 34 months (95% CI: 18-83) for those with an abnormal KT. Pts without a complex KT had a median OS of 144 months (95% CI: 85-inf), whereas those with a complex KT had 14 months (95% CI: 4-25). For specific abnormalities, pts with gain of chr7 had OS of 3 months, gain of chr8 had 19 months, monosomy 5 or del(5q) had 4 months, loss of chrY had 30 months, gain of chr1 had 4.5 months, gain of chr3 had 7.5 months, monosomy 9 or del(9q13q22) had 2 months, monosomy 10 had 17 months, and marker chromosome presence had 5.5 months. Univariate CPH identified complex KT (HR = 3.9, p < 0.001), gain of chr1 (HR = 5.7, p < 0.001), gain of chr3 (HR = 4.6, p < 0.001), monosomy 5 or del(5q) (HR = 4.6, p < 0.001), gain of chr7 (HR = 4.2, p < 0.001), gain of chr8 (HR = 3.3, p < 0.001), monosomy 9 or del(9q13q22) (HR = 4.9, p < 0.001), monosomy 10 (HR = 2.8, p = 0.008), and marker chromosomes (HR = 4.6, p < 0.001) as adverse factors. Higher platelet count was protective (HR = 0.9, p < 0.001), while greater number of abnormalities increased hazard (HR = 1.1, p < 0.001). In multivariate CPH model, complex KT (HR = 3.1, 95% CI: 1.2-8.2, p = 0.019), monosomy 9 or del(9q13q22) (HR = 4.4, 95% CI: 1.2-15.4, p = 0.022), gain of chr1 (HR = 3.5, 95% CI: 1.1-11.8, p = 0.042), and low platelet count (HR = 0.98, 95% CI: 0.97-0.99, p = 0.006) remained independent predictors of poor OS. Conclusion: We demonstrate that cytogenetic abnormalities detected in PB or BM, most notably complex KTs, confer a markedly poor prognosis in aggressive T-cell lymphomas. The integration of KT data with clinical parameters, such as platelet count, offers a powerful approach to refine risk stratification, identify biologically high-risk subgroups, and potentially guide personalized therapeutic strategies in this challenging disease spectrum. To our knowledge, this is one of the largest single-center studies assessing the prognostic significance of KT in mature T-cell lymphomas, providing novel insights into the role of specific chromosomal lesions in patient outcomes.

Abstract Marginal zone lymphoma (MZL) is an uncommon non-Hodgkin B-cell lymphoma accounting for 7-10% of lymphoma diagnoses. Extranodal MZL (EMZL) of mucosa-associated lymphoid tissue (MALT) is the most common subtype (61%) of MZL. While the mutational landscape, chromosomal aberrations and transcriptome of nodal and splenic MZL have been extensively evaluated, the mutational landscape of EMZL has only been evaluated in a small number of patients and mainly by targeted sequencing. Consequently, the comprehensive genomic landscape of EMZL remains largely uncharacterized. Herein, we performed whole exome sequencing followed by targeted sequencing of potential tumor driver genes, copy number and/or RNA transcriptome analyses in 165 patients with pretreatment EMZL tumors involving 16 anatomic locations. All samples were collected and underwent expert review as part of the Atlas of Blood Cancer Genomes consortium. The most common anatomic locations were ocular adnexa (OAMZL) (n=35), gastric (n=25, including 6 positive for Helicobacter pylori), salivary glands (n=25), and lungs (n=24). Using common criteria for variant mutation calling and significant focal copy number (CN), we identified 1218 variants (1030 missense and 188 truncation mutations) across 174 genes and 2837 CN focal alterations (1614 copy gains and 1223 copy number losses). Of these genes, 44 and 11 were mutated in >5% and >10% of specimens, respectively. We detected variants identified previously by targeted sequencing in EMZL from different locations (e.g. TNFAIP3 (A20) (12%), TBL1XR1 (13%), SPEN (10%), CARD11 (7%), TET2 (7%) and CREBBP (6%)). We detected mutations in KLF2 (10 mutations in 8 EMZL patients) and PTPRD (7 mutations in 7 EMZL patients) that were previously suggested to be specific for splenic and nodal MZL, respectively. We also detected variants not previously reported in EMZL, including a transcriptional factor ZEB2, LRP1B,and others. The most frequently mutated gene in our study (25% of tumors) was IGLL5. Some mutations were limited to specific locations (e.g. ZEB2 mutations seen exclusively in gastric and salivary gland EMZL), while most were observed across all anatomic locations. There was no association between specific mutations and clonal IGHV, in contrast to previous reports. Using Enrichr tool, we observed enrichment of mutations in genes belonging to the B cell receptor activation, NOTCH signaling, Wnt-beta catenin signaling, NF-kB signaling , PI3K AKT signaling, DNA repair and other pathways. Chromosomal and copy number changes were also commonly observed including previously reported trisomy of chromosomes 3 and 18. Combining DNA mutations and CN alterations, the number of genetic lesions per tumor sample in the 174 mutated genes ranged from 0 to 95, with an average load of 17 lesions per case. RNA sequencing was successful in 159 EMZL tumors from 16 distinct anatomic locations. Unsupervised clustering using all genes with a median log2-normalized gene expression value greater than 5 and a standard deviation greater than 1 (1323 genes) demonstrated that the majority of gastric EMZL with and without H. pylori infections clustered together on 2 dendrograms as did most of the samples of OAMZL. Since the clustering could be forced by organ-specific and not tumor-specific gene expression, we next focused on the expression of the 345 genes from the LM22 matrix that passed our transcriptomic row filtering. Unsupervised clustering resulted in clustering of most gastric EMZL irrespective of H. pylori positivity together in the same dendrogram branch, accompanied by few additional EMZL from other anatomic locations. Most of the EMZL samples from other locations did not show preferential co-clustering together. On comparison of gene expression between gastric and OAMZL, there was enrichment of the B-cell receptor signaling pathway, B-cell activation, B-cell naïve and B-cell memory cells, B-cell proliferation and NF-kB signaling in the latter. Immune microenvironment analysis showed a statistically significant increase in resting mast cells and decrease in M1 macrophages in gastric EMZL and increase in regulatory T cells in salivary EMZL. The broad genomic studies reported here underscore the biological similarity of EMZL across anatomical sites with the potential exceptions of gastric EMZL (regardless of H. Pylori status). These data provide valuable genomic and transcriptomic resources to inform future diagnostic and therapeutic strategies.

Abstract Diffuse Large B Cell Lymphoma (DLBCL), the most common subtype of aggressive B-cell Non-Hodgkin Lymphoma (NHL), accounts for 30-40% of newly diagnosed NHL cases. Despite recent progress improving our understanding of molecular features of DLBCL, there is still a high relapse rate (~45%) among patients who undergo standard treatment (R-CHOP). Several groups have identified reproducible molecular clusters of DLBCL although, the biologic significance of many of the specific gene mutations within these clusters is poorly understood. DTX1 mutations are a feature of the BN2/C1 DLBCL classifiers and are among the mutations with unknown significance. BN2/C1 DLBCL are a mixture of ABC, GCB, and Unclassified cell of origin (COO) with a common signature being the presence of genetic alterations in genes known to regulate the NOTCH pathway; yet, these tumors lack transcriptional signatures of traditional NOTCH activation, suggesting a unique and undefined biology driven through non-canonical NOTCH pathway activation. DTX1 is an E3 ubiquitin ligase which directly binds the intracellular domain of the NOTCH receptor (NICD), targeting it for degradation, resulting in suppression of NOTCH pathway activity. We therefore hypothesize that DTX1 mutations lead to NOTCH pathway dysregulation and are a critical driver for a subset of BN2/C1 DLBCLs. Using whole exome sequencing (WES) data from 404 newly diagnosed DLBCL patients, we found 8% of patients with mutations in DTX1. Alterations in DTX1 were localized to the NICD binding domain, WWE1. In silico Alphafold modeling of DTX1 WWE1-interaction with NICD revealed that patient mutations clustered within predicted interacting surfaces with NICD. These findings lead to the hypothesis that mutations in the DTX1 WWE1 domain suppress its ability to bind to and degrade NICD, enhancing NOTCH pathway activation in DLBCL. To address this question, we first compared DTX1 protein expression by immunoblot in DTX1 WWE1 mutant (OCI-Ly3 and SUDHL2) and wildtype (WT) (OCI-Ly7, OCI-Ly19, SUDHL6, and U2932) DLBCL cell lines. We found higher expression of NICD1 (p=0.03) in OCI-Ly3 and NICD2 (p<0.0001) in SUDHL2 cell lines compared to WT. This increase was accompanied by an increase in NOTCH surface expression with higher NOTCH1 (p<0.0001) and NOTCH2 (p<0.0001) expression on OCI-Ly3 and SUDHL2 cells, respectively, compared to WT. To remove variability across cell lines we next used CRISPR to generate DTX1 knock out (KO) models using WT DTX1 DLBCL cell lines U2932 and OCI-Ly19. Analysis of NICD and NOTCH receptor protein expression confirmed our initial finding, showing an 8.5 and 4.8-fold increase of NICD1 and a 6 and 2.5-fold increase of NICD2 expression in the U2932 and OCI-Ly19 DTX1 KO cell lines, respectively, compared to empty vector (EV) controls. An increase in surface NOTCH1, and to a lesser extent NOTCH2, was seen in U2932 (p=0.01 and p=0.07, respectively) and OCI-Ly19 (p=0.001 and p=0.2, respectively) KO cells compared to EV controls. To identify pathways affected by DTX1 mutations, we next performed RNAseq on U2932 EV and KO cell lines. Of interest, we did not detect any significant changes in classical NOTCH driven genes (Hes1, Hey1, etc.), supporting prior studies on BN2/C1 tumors. However, we did identify potential non-canonical NOTCH-target genes that may contribute to lymphomagenesis. Gene expression in KO cells showed upregulation of genes involved in germinal center (GC) processes (AICDA, IRF4; p<0.001) and cellular growth and survival (IL6R, CCND2, STAT5B, BCL2; p<0.0001). Measurement of IL6R by flow cytometry and CyclinD2 by immunoblot further verified DTX1-mediated upregulation of IL6R (p<0.01) and CyclinD2 (p<0.01) for U2932 KO cells compared to EV control. We also observed downregulation of genes contributing to cell death (ex. BAX, CASP8, FAS; p<0.05) in KO cells compared to EV. Together, these novel findings support our hypothesis that DTX1 WWE1 mutations lead to dysregulation of the NOTCH pathway by driving overexpression of NICD and NOTCH, resulting in dysregulated expression of proteins involved in cell cycle, GC reaction, and apoptosis. We further provide new biologic insight into BN2/C1 DLBCL, ultimately highlighting a path toward novel therapeutic targets and the advancement of personalized medicine, as patients harboring these mutations may benefit from new therapies targeting inflammatory pathways, such as CELMoDs.