Transfusion Independence Research Articles

Exagamglogene Autotemcel for Transfusion-Dependent β-Thalassemia

Background: Exagamglogene autotemcel (exa-cel) is a non-viral cell therapy designed to reactivate fetal hemoglobin (HbF) via ex vivo CRISPR-Cas9 gene-editing of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) at the erythroid-specific enhancer region of BCL11A in patients (pts) with transfusion-dependent β-thalassemia (TDT). Here we report that in a pre-specified interim analysis, the pivotal CLIMB THAL-111 trial of exa-cel met primary and key secondary endpoints. Methods: CLIMB THAL-111 is an ongoing, 24-month (mo), phase 3 trial of exa-cel in pts age 12-35y with TDT and a history of ≥100 mL/kg/y or ≥10 U/y packed red blood cell (RBC) transfusions in the 2y before screening. Primary endpoint is transfusion independence defined as proportion of pts maintaining a weighted average hemoglobin (Hb) ≥9 g/dL without RBC transfusion for ≥12 consecutive mos (TI12). Key secondary endpoint is proportion of pts maintaining a weighted average Hb ≥9 g/dL without RBC transfusion for ≥6 consecutive mos (TI6). Evaluable pts had ≥16 mos of follow-up after exa-cel infusion. Evaluation of TI12 and TI6 started 60 days after last RBC transfusion for post-transplant support or TDT management. Pts completing trial enrolled in long-term follow-up Study 131. Mean (SD) shown except where noted. Results: As of 16 Jan 2023, 52 pts (mean age 21.5[range 12-35]y; 18[34.6%] age ≥12 to <18y; 31[59.6%] with severe genotypes [β 0/β 0 or β 0/β 0-like], median annualized transfusion volume 201.0 mL/kg) received exa-cel; median follow-up 20.4 (range 2.1-48.1) mos. Following infusion, all pts engrafted neutrophils and platelets (median 29 and 44 days, respectively). Of the 35 pts evaluable for primary and key secondary endpoints, 32 (91.4%) achieved TI12 and TI6 (95% CI: 76.9%, 98.2%; P<0.0001). Pts achieving TI12 stopped transfusions 35.2 (SD, 18.5) days after exa-cel infusion and remained transfusion independent for 22.5 (range, 13.3, 45.1) mos (Fig). For 3 pts not achieving TI12, one had reductions in annualized RBC transfusion volume of 83.9%, while the others have been transfusion-free for 7.3 mos and 4.0 mos starting 60 days after the last transfusion. For all pts, total Hb was 11.4 g/dL at Month 3 (≥12g/dL Month 6 onward) and HbF was 7.7 g/dL at Month 3 (≥ 10 g/dL Month 6 onward) with pancellular distribution (≥95% RBCs expressing HbF Month 6 onward). Proportion of edited BCL11A alleles was stable over time in bone marrow CD34 + and peripheral blood nucleated cells. Pts not yet evaluable and with sufficient follow-up were also transfusion-free. Quality-of-life (QOL) measures showed clinically significant improvements. All pts had ≥1 adverse event (AE), most were Grade 1 or 2; 46 (88.5%) pts had AEs of Grade 3 or 4 severity. Most common AEs were febrile neutropenia (61.5%), headache (53.8%), and stomatitis (50.0%). Most AEs and serious AEs (SAEs) occurred within first 6 mos after infusion. Two pts had SAEs considered related to exa-cel: headache, hemophagocytic lymphohistiocytosis (HLH), acute respiratory distress syndrome and idiopathic pneumonia syndrome (latter also considered related to busulfan) all in the context of HLH (n=1) and delayed engraftment and thrombocytopenia (both also considered related to busulfan) (n=1), which all resolved. There were no deaths, discontinuations, or malignancies. Conclusions: The CLIMB THAL-111 trial met primary and key secondary endpoints, with exa-cel treatment resulting in early and sustained increases in Hb and HbF leading to transfusion independence in >90% of pts with TDT and improved QOL. Safety profile of exa-cel was generally consistent with myeloablative busulfan conditioning and autologous transplantation. These results show exa-cel has the potential to deliver a one-time functional cure to pts with TDT.

Clinical Safety and Efficacy of Narsoplimab in Pediatric and Adult Patients with Transplant-Associated Thrombotic Microangiopathy: A Real-World Experience

Introduction Transplant-associated thrombotic microangiopathy (TA-TMA) is a severe complication occurring after hematopoietic stem cell transplantation (HSCT), often resulting in high morbidity and mortality. There are currently no approved treatments for TA-TMA, but complement inhibition is increasingly recognized as an active treatment option in this setting. Narsoplimab (OMS721) is a fully human IgG4 antibody that binds MASP-2, the effector enzyme of the lectin pathway of the complement system. A recent pivotal trial demonstrated the safety and efficacy of narsoplimab in patients with TA-TMA. We report the results of a real-world experience with narsoplimab in a series of pediatric and adult patients with TA-TMA. Material and methods The diagnosis of TA-TMA was based on the following criteria (Schoettler ML, et al. Transplant Cell Ther. 2023 Mar;29(3):151-163): anemia (failure to achieve transfusion independence, hemoglobin decline by ≥1 g/dL or new-onset transfusion dependence); thrombocytopenia (failure to achieve platelet engraftment, transfusion dependence, or ≥50% reduction in baseline platelet count after full platelet engraftment); elevated lactate dehydrogenase (LDH); decreased serum haptoglobin; schistocytes in the peripheral blood smear; hypertension; and proteinuria (≥1 mg/mg random urine protein-to-creatinine ratio [rUPCR]). A positive direct Coombs test was an exclusion criterion. Narsoplimab was administered intravenously at the dose of 4 mg/kg (max 370 mg) twice weekly for at least eight doses. Response criteria were defined by improvement in both laboratory TMA markers and any clinical benefit (Khaled SK, et al. J Clin Oncol. 2022 Aug;1;40(22):2447-2457). Results Fifteen patients with a median age of 61 years (range, 6 - 71), 11 adults and 4 pediatrics, were treated under a compassionate use program, after ethical committee approval, between January 2018 and April 2023. All patients had previously undergone allogeneic HSCT (Table 1). All patients presented at least 4 of the 6 criteria for TA-TMA diagnosis. Fourteen patients (93%) were defined as high-risk TA-TMA for the presence of the following criteria: LDH > 2 times the ULN, rUPCR ≥ 1 mg/mg, multiorgan dysfunction, concurrent acute GvHD ≥ grade 2, or infection. Time from transplant to TA-TMA was 161 days (range, 30 - 452). Before TA-TMA, all patients had acute GvHD with a median of 116 days (range, 21 - 405) after transplant. Severe infection had been documented in 10 patients (67%) after transplant. CMV reactivation and BK virus hemorrhagic cystitis occurred in 5 and 4 patients, respectively. Twelve patients (80%) were on calcineurin inhibitors at TA-TMA onset. Fourteen patients (93%) were transfusion dependent at baseline. Patients received a median of 11 (range, 8-34) doses of narsoplimab. All infusions were well-tolerated, and no narsoplimab-related adverse events were reported. Eleven patients responded to treatment (73%), based on the achievement of transfusion independence (10 patients) as well as on clinical and laboratory improvement, which occurred in all responders. Before and after narsoplimab, the median hemoglobin values were 9,1 g/dL (range, 7,7 - 12,3) and 10,35 g/dL (range, 9,2 - 12,4); the median platelet count was 25.000/mmc (range, 10.000 - 62.000) and 76.000/mmc (range 32.000 - 367.000); the median LDH values were 497 U/L (range 271 - 1201) and 224 U/L (range 184 - 393), respectively. The median time to response was 50 days (range, 9 - 105). One-hundred-day survival was 80% in the study population and 100% for responders (Figure 1). After treatment completion, TA-TMA never reoccurred. Three of the four patients who failed to respond, eventually died with laboratory and clinical evidence of persisting TA-TMA. Conclusion In this study of high-risk TA-TMA patients, the inhibition of the lectin pathway of complement activation with narsoplimab was shown to be not only an effective but also a remarkably safe treatment option with no evidence of an increased risk of infectious complications in both children and adults.

Clinical Effectiveness and Safety of Momelotinib Compared with Continued Ruxolitinib or Best Available Therapy in Patients with Myelofibrosis Who Required RBC Transfusions: Subgroup Analysis of the Phase 3 Simplify-2 Study

Introduction: Splenomegaly, constitutional symptoms, and anemia are key clinical features of myelofibrosis (MF); approximately one-third of patients (pts) are anemic at diagnosis, and most develop anemia over time. While Janus kinase (JAK) inhibitors such as ruxolitinib (RUX) and fedratinib (FED) may address symptoms and splenomegaly, they do not manage and may exacerbate anemia. Treatments for anemia include erythropoiesis-stimulating agents (ESAs), often in combination with RUX or FED, and androgens such as danazol; however, these have shown limited efficacy. Red blood cell (RBC) transfusions are the mainstay of anemia management in MF, but transfusion dependency is associated with diminished quality of life and is a negative prognostic factor for survival. Treatments that address anemia as well as spleen volume and symptoms are needed. Momelotinib (MMB), a JAK1/JAK2/activin A receptor type 1 inhibitor, has demonstrated clinically meaningful and durable improvements in anemia, splenomegaly, and symptoms in pts with MF across 3 phase 3 trials. To evaluate outcomes in pts who switched to MMB vs continuing RUX or best available therapy (BAT) despite transfusion requirement, we present a descriptive subgroup analysis of pts enrolled in SIMPLIFY-2 (NCT02101268) who were considered transfusion dependent (TD; ≥4 units of RBC transfusions in the previous 8 wk or hemoglobin [Hb] level <8 g/dL) or transfusion requiring (TR; receiving transfusions but not meeting TD criteria) at baseline (BL). Methods: SIMPLIFY-2 was an international, multicenter, open-label, phase 3 clinical trial investigating the efficacy and safety of MMB vs BAT in pts with MF who had suboptimal responses or hematologic toxicities while receiving RUX. Pts (N=156) were randomized 2:1 to receive open-label MMB or BAT, which was RUX in 88.5% of pts. Treatment washout from prior RUX was not permitted before study enrollment. The primary endpoint was spleen volume reduction ≥35% (SVR35). Total Symptom Score (TSS) response rate (≥50% reduction; TSS50) and transfusion independence response (TI-R; no RBC transfusions for ≥12 wk immediately before the end of wk 24, with all Hb levels ≥8 g/dL) were key secondary endpoints. This post hoc, descriptive analysis focused on pts treated with either MMB or BAT, who were considered non-transfusion-independent (non-TI), defined as either TD or TR, at BL. Results: In SIMPLIFY-2, 72 of 104 pts (69%) in the MMB arm and 33 of 52 pts (63%) in the BAT arm were non-TI at BL, and BL characteristics were balanced between both patient groups. Mean duration of prior treatment with RUX was 64.6 and 59.5 wk in non-TI pts in the MMB and RUX arms, respectively. Average BL TSS for this subpopulation was 18.6. All pts randomized to the MMB arm received a starting dose of 200 mg daily. In the BAT arm, 29 of 33 pts (88%) were treated with RUX, with 59% receiving a BL dose of ≤20 mg daily. ESAs were administered to 5 pts in the BAT arm. At wk 24, SVR35 was observed in 7 of 72 pts (10%) treated with MMB and 1 of 33 pts (3%) treated with BAT. TSS50 was achieved in 21 of 72 pts (29%) treated with MMB, but there were no responses in the BAT arm. Additionally, TI-R was achieved in 25 of 72 pts (35%) treated with MMB compared with only 1 of 33 (3%) treated in the BAT arm on RUX. Many responders with MMB achieved 2 or all 3 endpoints (16 of 36 responders [44%]) (Figure); there were no dual or triple responses in the BAT arm. Of the 5 pts in the BAT arm who received ESAs, only 1 pt each (different pts per response) achieved SVR35, TSS50, or TI. Safety outcomes were consistent with those previously reported for the intent-to-treat (ITT) population. Conclusions: In RUX/BAT-treated pts with MF who required RBC transfusions, continued treatment with RUX/BAT in most pts resulted in poor treatment outcomes compared with MMB. Specifically, treatment with MMB demonstrated an ability to deliver higher SVR, TI, and TSS response rates. The lower SVR35 rate in both arms, similar to the overall ITT population, was likely a result of lack of washout from prior JAK inhibitor treatment. While pt numbers were limited, similar findings were observed compared with pts who received ESAs. Overall, these data support MMB as a potential alternative treatment option for pts with MF who require RBC transfusions. Figure. Responses at Week 24 for Non-TI Patients at Baseline

Phase 1/2 Study of the Activin Receptor-like Kinase-2 Inhibitor Zilurgisertib (INCB000928, LIMBER-104) As Monotherapy or with Ruxolitinib in Patients with Anemia Due to Myelofibrosis

Introduction:Elevated levels of the iron regulator hepcidin can cause functional iron deficiency anemia. Hepcidin dysregulation is central to anemia of chronic inflammation observed in several malignancies including myelofibrosis (MF). Activin receptor-like kinase-2 (ALK2 [ie, ACVR1]) contributes to MF-associated anemia via hepcidin upregulation. We evaluated the safety, efficacy, pharmacokinetics (PK), and pharmacodynamics (PD) of zilurgisertib-a potent and selective oral ALK2 inhibitor-in patients (pts) with anemia due to MF. Methods:This ongoing open-label, multicenter, phase 1/2 dose-escalation/expansion INCB 00928-104 study (NCT04455841) is evaluating zilurgisertib alone (treatment group A [TGA]) or with ruxolitinib (RUX; treatment group B [TGB]). Eligible pts are ≥18 years old with primary/secondary MF of intermediate (Int)-1 (TGB only) or Int-2/high-risk (TGA and TGB) per the Dynamic International Prognostic Scoring System (DIPSS) and with anemia, including pts who are transfusion dependent (≥4 units of red blood cell transfusions during the 28 days or 8 weeks before Cycle [C] 1 Day [D] 1 for hemoglobin [Hb] <8.5 g/dL in the absence of bleeding or treatment-induced anemia) or are nontransfusion dependent with symptomatic anemia (Hb <10 g/dL during screening on 3 separate occasions ≥7 days apart and not meeting criteria for transfusion dependence). The zilurgisertib starting dose in TGA was 50 mg once daily (qd), with dose increases of ≤2-fold performed until a grade ≥2 toxicity with reasonable probability of being related to the treatment group was observed; subsequent dose increases were limited to ≤50% until the maximum tolerated dose (MTD) was reached or the recommended doses(s) for expansion were identified. In TGB, pts were on a stable regimen of RUX for ≥12 weeks before initiating zilurgisertib at 100 mg qd. The primary endpoints are safety and tolerability, including determination of dose-limiting toxicities (DLTs) and MTD. Secondary endpoints include efficacy (per anemia response parameters), PK, and PD (hepcidin measurement). Results:A total of36 pts were enrolled at the time of analysis (data cutoff, February 15, 2023), with 20 in TGA and 16 in TGB. Median (range) age was 73 (53-84) years for TGA and 75.5 (54-85) years for TGB; 65% of TGA pts had received prior RUX therapy. Overall, 89% had Int-2 risk DIPSS, and the remainder had high-risk DIPSS (1 in TGA, 3 in TGB). In total, 55% of pts in TGA and 25% in TGB were transfusion dependent at time of enrollment. Median (range) baseline Hb was 7.7 (7-10) g/dL in TGA and 8.0 (5-9) g/dL in TGB. Baseline median (range) hepcidin was high in both cohorts (TGA, 171 [18-535] ng/mL; TGB, 126 [7-421] ng/mL; normal range, 0-50 ng/mL). At the time of analysis, dose escalation was ongoing in both treatment groups. No DLTs occurred in either treatment group, and the MTD had not been reached. Treatment-emergent adverse events (TEAEs) were mainly low grade without apparent dose dependence. Grade ≥3 TEAEs occurred in 11 pts, with thrombocytopenia the most common (n=4). The PK profile for zilurgisertib at steady state was consistent with that observed with previous healthy volunteer studies, with observed time of maximum concentration at 2-4 hours after administration and predicted half-life of approximately 24 hours. Maximum reduction in hepcidin following zilurgisertib dosing in C1D1 was observed at 6-8 hours postdose; the highest doses tested in both TGA and TGB demonstrated more effective maintenance of hepcidin suppression over time compared with lower doses. Among non-transfusion-dependent pts, anemia improvement (Hb increase of ≥1.5 g/dL vs baseline) was observed in both treatment groups (Figure). Among transfusion-dependent pts, anemia response of transfusion independence had not been observed at data cutoff. All pts with anemia improvement have maintained Hb increase in the absence of transfusion and remain on study. Conclusions:Treatment with zilurgisertib monotherapy or in combination with RUX in this pt population was generally well tolerated, with predominantly grade 1/2 TEAEs. Reduced hepcidin levels were observed at all dose levels with both monotherapy and in combination with RUX, with greater control of hepcidin over time observed at higher zilurgisertib doses. Preliminary improvements in anemia were observed in non-transfusion-dependent pts during dose escalation, suggesting potential for therapeutic activity.

Efficacy and Safety of Venetoclax in Combination with Azacitidine for the Treatment of Patients with Treatment-Naive, Higher-Risk Myelodysplastic Syndromes

Introduction: Azacitidine (Aza) has been shown to prolong survival in patients with treatment-naive, higher-risk myelodysplastic syndrome (HR MDS) compared to lower-intensity, conventional treatment regimens; however, improvement in clinical outcomes are needed. Clinical data on the synergy of Aza with venetoclax (Ven)-a selective, potent BCL-2 inhibitor-in the treatment of myeloid malignancies and the unmet need in HR MDS provide a rationale to evaluate Ven in combination with Aza in treatment-naive HR MDS. Here, we report efficacy and safety data in patients with treatment-naive HR MDS treated with Ven+Aza at the recommended Phase 2 dose (RP2D) in the safety expansion part of the Phase 1b study (NCT02942290). Methods: Adult patients were enrolled with de novo treatment-naive HR MDS defined by the Revised International Prognostic Scoring System (IPSS-R) score of >3 with an Eastern Cooperative Oncology Group performance status of ≤2, and bone marrow (BM) blasts <20% at baseline. Patients received Ven 400 mg orally daily on Days 1-14 and Aza 75 mg/m 2 intravenously or subcutaneously on Days 1-7 or on Days 1-5, 8, and 9 of each 28-day cycle (RP2D). The primary objective was to assess the complete remission (CR) rate. Key secondary objectives included determining marrow CR (mCR), overall response rate (ORR), hematologic improvement (HI), postbaseline red blood cell (RBC) and platelet transfusion independence (TI), overall survival (OS), duration of CR, time to next treatment (TTNT), transformation to acute myeloid leukemia (AML), and time to AML transformation. Responses were assessed by International Working Group 2006 criteria. Prophylactic antibiotics were mandated in Cycle 1 and recommended for Grade ≥3 neutropenia thereafter. Safety was analyzed in patients who received ≥1 dose of study treatment. Results: At thedata cutoff of May 31, 2023, 107 patients had received Ven+Aza at the RP2D. Key baseline characteristics for all treated patients are shown in Table 1A. Median age was 68 years (range, 26-87), 64% of patients had intermediate or poor cytogenetic risk, and >89% had ≥5% BM blasts. Median number of treatment cycles before transplantation was 3.0 (range, 1.0-11.0). At the median follow-up of 31.9 months (95% CI, 30.4-42.5), CR rate was 29.9% (95% CI, 21.4-39.5), with a median CR duration of 16.6 months (95% CI, 10.0-not reached [NR], Table 1B). Median OS was 26 months (95% CI, 18.1-51.5), with an estimated 12-month OS of 71.2% (95% CI, 61.4-78.9)and 24-month OS of 51.3% (95% CI, 41.2-60.5). Median OS for CR was NR. Median TTNT including transplantation was 6.8 months (95% CI, 5.6-8.3). Sixty-two (57.9%) patients received subsequent treatment, including transplantation in 42 (39.3%) patients; the median time to transplantation was 4.8 months (range, 1.4-16.8). Among patients who received transplantation post-study, 17 were transplant ineligible at study entry. Postbaseline TI rate was 61.7% for RBC and 72.0% for platelets. Median maximal duration of TI achieved was 5.4 months (range, 1.8-50.8) and 5.4 months (range, 1.9-56.0) for RBC and platelets, respectively. Postbaseline overall hematologic improvement (HI) was achieved in 51 (49.0%) of 104 evaluable patients, and specific responses included erythroid (40/93; 43.0%), platelet (32/74; 43.2%) and neutrophil (10/57; 17.5%) indices. All patients experienced ≥1 treatment-emergent adverse event (TEAE), with 94.4% of patients reporting grade ≥3 TEAEs. Serious adverse events (SAEs) occurred in 68.2% of patients. Common TEAEs of any grade were constipation (53.3%), nausea (49.5%), neutropenia (48.6%), thrombocytopenia (44.9%), febrile neutropenia (42.1%), diarrhea (41.1%), anemia (39.3%), vomiting (36.4%), and hypokalemia (26.2%). Grade ≥3 TEAEs reported in ≥20% of patients were neutropenia (48.6%), thrombocytopenia (43.0%), febrile neutropenia (42.1%), and anemia (34.6%). Infections were reported in 57% of patients, including SAEs in 40.2% of patients. Of the 59 deaths (55.1%) reported, 23 (21.5%) were due to disease progression and 7 (6.5%) to adverse events. Within 60 days after study start, 7 deaths (6.5%) were reported. Conclusion: Ven 400 mg for 14 days plus Aza combination was well tolerated with favorable responses of CR+PR+mCR in >80% and HI in nearly 50% of patients with treatment-naïve HR MDS. A separate Phase 3 study of this combination is ongoing to confirm survival benefit.

A Phase 2 Study of Canakinumab in Patients with Lower-Risk Myelodysplastic Syndromes or Chronic Myelomonocytic Leukemia

Background Myelodysplastic syndromes (MDS) lie on a continuum of myeloid neoplastic progression between clonal hematopoiesis (CH) and acute myeloid leukemia (AML). Interleukin 1 beta (IL-1β)-induced inflammasome activation is a mechanism of cancer initiation and progression. Given that IL-1β upregulation induces aberrant myeloid differentiation of hematopoietic stem and progenitor cells (HSPCs), we hypothesize that IL-1β plays a critical role in MDS pathogenesis, and targeting IL-1β signaling will overcome aberrant MDS HSPCs' myeloid skewing. Here, we report final results of a phase 2 study evaluating the safety and efficacy of canakinumab, an IL-1β inhibitor, in patients with lower-risk MDS or chronic myelomonocytic leukemia (CMML). Methods We conducted a single center, open-label phase 2 trial at The University of Texas MD Anderson Cancer Center (Houston, TX, USA). Patients aged ≥ 18 with IPSS-R ≤ 3.5 MDS/CMML who have previously been treated were included in the study. Patients received 300 mg of canakinumab on day 1 of a 4-week cycle. The primary objective was to determine the clinical activity of canakinumab in MDS/CMML patients. Response was assessed using the modified International Working Group 2006 criteria for MDS (Cheson et al. 2006). Secondary objectives were to evaluate the safety profile including rate of transfusion independence (TI), duration of response (DoR), progression-free survival (PFS), and overall survival (OS). All patients who received 1 dose of study drug were included in the analyses. This study is registered with ClinicalTrials.gov (NCT04239157). Findings Between August 2020 and May 2023, 27 patients were enrolled in the phase 2 portion of this study, and 2 patients failed screening. The median age was 74 years with 15 (60%) male patients; 20 patients (80%) were post-hypomethylating agent failure with a median number of prior lines of therapy of 2 (1-5). Transfusion dependency was observed in 24 patients (96%) prior to canakinumab initiation. Fourteen (56%) patients showed normal karyotype. IPSS-R stratification revealed an intermediate-2 risk in 12 (48%) patients and a high risk in one (4%). The most common mutations were SF3B1 (40%), TET2 (32%), DNMT3A (28%), and RUNX1 (24%). IPSS -M risk score was calculated for 24 cases showing one (4%) very low (VL), four (16%) low (L), 14 (16%) moderate low (ML), eight (32%) moderate high (MH), five (20%) high (H), and two (8%) very high (VH) risk categories. Canakinumab was well tolerated and no drug-related toxicities were observed. One death due to sepsis, which was deemed not treatment-related, occurred on the study drug. Out of 23 evaluable patients, the overall response rate was 17·4%, with erythroid and platelet hematological improvement (HI-E and HI-P, respectively) confirmed in 3 (13.0%) patients and 1 (4.3%) patient, respectively. Thirteen patients had stable disease (56·5%) and 6 (26·1%) progressed during therapy, 1 of which transformed to AML (Fig. 1). TI was achieved in 3 patients (median DoR 8·53 months (95% CI 0·41-16·1) and 2 of them maintained TI for over 12 months. With a median follow-up time of 22·6 months (95% CI 15·0-29·4), median OS was 17·3 months (95% CI 14·3-not estimable). We performed separate univariate analyses to evaluate any associations between the IPSS-M and OS/PFS. The median OS in patients with higher-risk MDS by IPSS-M (MH, H, VH) was 15·0 months vs 29·4 months in the lower-risk disease by IPSS-M (VL, L, ML) group (p=0·12). Interestingly, statistically significant findings were observed with 1-year PFS when stratifying patients into higher vs lower risk MDS by IPSS-M (64·3% vs 100·0%, respectively; p=0·022, Fig. 2). Conclusion In this cohort of MDS patients who had experienced multiple lines of prior therapy and exhibited high-molecular-complexity, canakinumab showed limited efficacy (HI 17.3%). Nevertheless, canakinumab showed a good safety profile and yielded sustained long-term responses in patients with single somatic driver mutation in TET2 or DNMT3A. This suggests that clonal complexity, and therefore disease burden, may be a determining factor in response to canakinumab. Therefore, we have amended the protocol of a phase 1/2 clinical trial evaluating the safety and activity of canakinumab in clonal cytopenia of unknown significance (CCUS) and low-molecular complexity MDS patients. Our results will clarify the role of IL-1β signaling in MDS initiation and progression.

Real-World Retrospective Study of Non-Transfusion Dependent Patients with Myelodysplastic Syndromes Treated with Luspatercept: A Healthcare Claims Database Study

Background: Myelodysplastic syndromes (MDS) are common hematologic malignancies in older adults that are characterized by abnormal bone marrow function leading to reduced blood cell production, persistent cytopenias, with a risk that patients may progress to acute myeloid leukemia (AML). Due to the high rate of anemia, many patients with MDS require red blood cell transfusions (RBCT), which, in turn, are associated with a high clinical and economic burden. In the phase 3 randomized COMMANDS and MEDALIST clinical trials, luspatercept reduced the severity of anemia among transfusion-dependent (TD), erythropoiesis-stimulating agent (ESA)-refractory and ESA-naive patients with lower-risk (LR)-MDS (Platzbecker U, et al. Lancet 2023. doi:10.1016/S0140-6736(23)00874-7, Fenaux P, et al. N Engl J Med 2020;382:140-151). However, there are limited real-world data on the use of luspatercept in patients who are non-transfusion dependent (NTD) or have a low transfusion burden. This study aims to describe the real-world clinical outcomes and treatment patterns before and after the initiation of luspatercept in patients with LR-MDS who were NTD before luspatercept initiation, in the USA. Methods:In this retrospective claims-based cohort study, data from the Symphony Health database (Jan 1, 2010 to June 30, 2022) were used to identify adults with a diagnosis of MDS (initial diagnosis on or after Jan 1, 2015) before the first claim for luspatercept (index date). Patients were considered NTD if they had no unique dates with a claim for RBCT during the 8-week period before or on the index date. Patients were excluded if they received chemotherapy or had a diagnosis of refractory anemia with excess blasts or AML during the study period, as they were presumed to have higher-risk MDS. Patients were also excluded if they had a diagnosis of β-thalassemia, myelofibrosis, aplastic anemia, or breast cancer in the 6 months pre-index (baseline period) or prior use of hypomethylating agents (HMAs). Patient demographics and clinical characteristics were assessed during the baseline period, and patients' RBCT status (NTD or TD) was measured for 6 months after the index date. A patient was considered 8-week NTD if they had no RBCT in ≥ 1 rolling 8-week period; 12-week, 16-week, and 24-week NTD patients were defined similarly, using increasing durations of NTD. Administration of other MDS therapies (ie, chemotherapy, ESA, granulocyte colony stimulating factor [G-CSF], HMA, and immunomodulatory imide drug [IMiD ®] agent) was measured pre-index and post-index until the end of clinical activity or data availability (follow-up). Results: Of the 871 eligible patients who received luspatercept 589 (67.6%) were NTD before luspatercept initiation. Among this NTD population, the mean (standard deviation [SD]) age was 74.7 (6.3) years and 57.2% were male. Before luspatercept initiation, 15.3% of patients received 2 treatment classes and 0.8% received ≥ 3 treatment classes. Almost all patients (98.5%) maintained 8-week NTD status in the 6 months after luspatercept initiation. Similarly, 96.8%, 94.1%, and 88.6% of patients maintained NTD status for at least 12, 16, and 24 weeks in the 6 months after luspatercept initiation, respectively (Figure 1). Most patients (64.7%) did not require any additional MDS-related treatments during the study follow-up period, (median [SD] 15.7 [7.4] months). Overall, 77.1% of patients were treated with luspatercept for > 6 months and 68.4% for > 12 months. After luspatercept initiation, patients most commonly received treatment with ESAs or HMAs (14.9%; Figure 2). Conclusion:This is the first real-world evidence study to address luspatercept treatment in patients who were NTD prior to luspatercept treatment, which resulted in positive clinical outcomes and few RBCTs.Almost all patients with LR-MDS who were NTD at luspatercept initiation maintained 8-week NTD status during the 6 months after luspatercept initiation. The majority of patients did not receive a RBCT for a 24-week period after luspatercept initiation. Finally, over three-quarters of the patients remained on luspatercept and two-thirds of patients did not receive additional MDS-related treatments after a median follow-up of 15.7 months.

Retrospective Analysis of the Relationship between Transfusion Independence and Bone Marrow Fibrosis Reduction in Patients with Myelofibrosis Treated with Pacritinib Versus Ruxolitinib

Background Pacritinib is a JAK1-sparing JAK2/IRAK1/ACVR1 inhibitor for treatment of myelofibrosis (MF). In addition to improving spleen volume and symptoms, pacritinib is associated with anemia benefit in MF patients. Recent in vivo studies have shown that dual JAK2/IRAK1 inhibition is associated with improvement in both cytopenias and bone marrow reticulin fibrosis (BMF) in an inflammation-driven murine MF model ( Cuenca Zamora E, et al. EHA 2023; P987 and P990). Here, we retrospectively analyzed the relationship between achieving transfusion independence and reduction in BMF in MF patients treated with pacritinib 200 mg twice daily (BID) vs ruxolitinib (RUX) on the phase 3 PERSIST-2 study. Methods: PERSIST-2 enrolled patients with platelet counts ≤100 x 10 9/L. This analysis focused on pacritinib 200 mg BID and on patients who received RUX as best available therapy (BAT) who enrolled ≥12 weeks prior to study termination and who required red blood cell (RBC) transfusions at baseline. The proportion of patients who achieved transfusion independence response (TI-R, any 12-week interval with no RBC transfusions) was ascertained for pacritinib vs RUX. The proportion of patients with BMF reduction (≥1 grade decrease in reticulin fibrosis from baseline at week 24) was reported among patients on pacritinib achieving TI-R vs. non-response (NR). Results: The analysis included 41 patients on pacritinib (median dose intensity 100% through week 24) and 18 on RUX (median daily dose 10mg at week 24). Baseline characteristics were similar between the groups, including median platelet count (41 vs 38 x 10 9/L) and median hemoglobin (8.7 vs 8.6 g/dL). All patients required RBC transfusion at baseline. A significantly greater proportion of patients treated with pacritinib vs RUX achieved TI through week 24: 37% (n=15/41) vs 6% (n=1/18), P=0.023. Nominally, this trend held for those with baseline platelets <50 x 10 9/L: 28% vs 8%, P=0.222. In addition, a greater percentage achieved a 50% reduction in RBC transfusions over any 12 weeks (49% vs 6%, P=0.001). Paired bone marrow assessments at baseline and week 24 were available for 18/41 of patients on pacritinib, of whom 44% (8/18) achieved TI-R on study. The proportion of patients who experienced BMF reduction (>=1 grade at any point) was significantly greater among TI-R (62.5%, n=5/8) compared to TI-NR (10%, n=1/10) on pacritinib ( P=0.043). Of the 5 patients who achieved TI-R and BMF reduction, all had grade 2-3 fibrosis at baseline, and 2 experienced a reduction from grade 3 to grade 1 ( Figure 1). By contrast, paired bone marrow biopsies were available for 5 patients on RUX, and there was no association between fibrosis reduction in TI-R (0%, n=0/1) and TI-NR (25%, n=1/4). Conclusions: In cytopenic MF patients from PERSIST-2, TI-R on pacritinib was associated with BMF improvement. Though these results are based on a small sample size, they contrast with recent data suggesting no correlation between BMF reduction and TI-R on the JAK1/2 inhibitors momelotinib and ruxolitinib ( Oh ST, et al. Blood 2022;140 (Supp 1):821-23). While differences in study design could have impacted these results, these findings suggest that distinct inhibitory profiles may further distinguish the clinical impact of these treatments. Further studies are warranted to confirm the relationship between BMF reduction and anemia benefit in patients treated with pacritinib. Study funded by CTI BioPharma Corp., a Sobi company

AsCas12a Gene Editing of HBG1/2 Promoters with EDIT-301 Results in Rapid and Sustained Normalization of Hemoglobin and Increased Fetal Hemoglobin in Patients with Severe Sickle Cell Disease and Transfusion-Dependent Beta-Thalassemia

Background: Sickle cell disease (SCD) and transfusion-dependent β-thalassemia (TDT) are hereditary blood disorders caused by mutations in the β-globin gene. Clinical evidence has demonstrated that increased fetal hemoglobin (HbF, α2γ2) can reduce or eliminate SCD and TDT complications. EDIT-301, an investigational gene-edited autologous hematopoietic stem cell medicine, has a unique genomic modification that mimics naturally occurring mutations of hereditary persistence of fetal hemoglobin in the γ-globin gene ( HBG1/2) promoters. These mutations reactivate γ-globin expression and increase HbF production. EDIT-301 is manufactured with a highly efficient and specific, proprietary gene editing nuclease, AsCas12a. In preclinical studies, edited CD34 + cells from patients with SCD or TDT increased HbF production in red blood cells (RBCs) sufficient for a therapeutic effect, including reduced sickling (SCD) and improved erythropoiesis (TDT). Aim: RUBY (NCT04853576) and EdiThal (NCT05444894) are Phase I/II, multicenter, open-label, single-arm studies evaluating the safety, efficacy, and tolerability of EDIT-301 in patients with severe SCD and TDT, respectively. As of June 28, 2023, 7 SCD patients and 2 TDT patients have received EDIT-301 treatment. Preliminary clinical efficacy and safety data are reported. Methods: Patients aged 18-50 years with severe SCD (defined as ≥2 severe vaso-occlusive events [VOEs] per year in the 2 years prior to informed consent [IC]) and patients aged 18-35 years with TDT (defined as at least 100 mL/kg/year or 10 U/year of packed RBC transfusions in the 2 years prior to IC) were eligible to enroll in RUBY and EdiThal, respectively. Autologous CD34 + hematopoietic stem and progenitor cells collected by apheresis after plerixafor (RUBY) or plerixafor + filgrastim (EdiThal) mobilization were edited at the HBG1/2 promoters with AsCas12a. After myeloablative conditioning with busulfan, patients received a single infusion of EDIT-301 (a minimum of 3 × 10 6 CD34 + cells/kg), and were monitored for engraftment, total hemoglobin (Hb), HbF, mean HbF concentration/F-cell (MCH-F/F-cell), percentage of F-cells, markers of hemolysis, transfusion requirement, VOEs (SCD only), and adverse events (AEs) for 24 months. Results: Based on a data cut of June 28, 2023, Patients 1-4 with SCD were 12-, 9-, 4-, and 4-months post-EDIT-301 infusion, respectively. Patients 5-7 with SCD were <1-month post-EDIT-301 infusion. Patients 1-2 with TDT were 3- and <1-months post-EDIT-301 infusion, respectively. Neutrophil and platelet engraftment were achieved after a mean (range) of 25 (23-29) and 27 (19-37) days in Patients 1-4 with SCD and on Day 23 and 26 in Patient 1 with TDT, respectively. There were no VOEs in SCD patients post-EDIT-301 infusion, compared with a mean (range) of 4.2 (3.0-5.5) VOEs/year in the 2 years before enrollment (n=6). Following EDIT-301 infusion, Hb levels rapidly increased to 14.2 (12.4-15.7) g/dL by Month 4 (n=4), reaching the normal physiological range, from a mean (range) of 10.5 (8.5-11.9) g/dL at baseline (n=5). By Month 4, the mean (range) HbF concentration was 6.8 (5.7-7.6) g/dL and HbF was >40% (n=4); Patients 3 and 4 had >50% HbF. Percentage of F-cells and MCH-F/F-cell also increased. Key markers of hemolysis improved or normalized in all patients with SCD. Patient 1 with TDT had a HbF concentration of 7.2 g/dL by Month 3, stopped receiving RBC transfusions 20 days after EDIT-301 infusion, and remained transfusion free through the 3-month period. Patient 2 with TDT also showed early improvements. The safety profile of EDIT-301 in both SCD and TDT was consistent with myeloablative conditioning with busulfan. No serious AEs were reported after EDIT-301 infusion. Conclusion: These data demonstrated successful engraftment, a rapid and sustained normalization of Hb as early as 4 months after infusion, an increase in HbF and percentage of F-cells, resolution of VOEs (SCD) and transfusion independence (TDT). In addition, there were improvements in key markers of hemolysis (SCD) and a favorable safety profile in EDIT-301-treated patients. EDIT-301 treatment showed promising results for the first clinical use of AsCas12a in both SCD and TDT patients after gene editing of the γ-globin gene ( HBG1/2) promoters. These findings support further investigation of EDIT-301 in the RUBY and EdiThal trials. Updated data with additional outcomes will be presented.

Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH) Treated with Pegcetacoplan: Real Life Experience

Introduction: C5 inhibitors (C5i) treatment has dramatically improved the management of intravascular hemolysis (IVH) in PNH patients. However, a significant proportion of patients remain anemic due to suboptimal control of IVH and the development of extravascular hemolysis (EVH), consequence of C5i treatment. Pegcetacoplan (PEG) is the first proximal inhibitor of the complement system, through the inhibition of C3, allowing to control both IVH and EVH. PEG has recently been marketed in Spain for use in adult PNH patients who remain anemic after treatment with an C5i for at least 3 months. The objective of this work is to analyze the response of the first patients treated with PEG in real life in Spain. Patients and methods: clinical and analytical variables were collected from a series of 10 patients diagnosed with PNH who received treatment with PEG through an early access program. PEG was self-administered subcutaneously at 1080 mg twice a week. See Table 1. Transfusion needs and the adverse effects that occurred were also collected. Results: median (range) duration of treatment with PEG at the time of the analysis was 4 (2-8) months. Hemoglobin (Hb) values increased a median of 2.4 g/dL after PEG treatment. This improvement was rapidly observed since the beginning of the treatment (median increase at 1 week was 1.3 g/dL and at 2 weeks 2.4 g/dL). All patients reached Hb levels of >8 g/dL, 80% >10 g/dL and 40% >12 g/dL. An increased in Hb >2 g/dL was observed in 60% of the patients. Median values of parameters of hemolysis (absolute reticulocyte counts, bilirubin, LDH) became normal. See Table 2. The direct antiglobulin test turned into negative in all positive cases pre-PEG (4 out of 4). No patient suffered from acute hemolytic events, thrombosis, or required PRBC transfusion once PEG had been initiated. On a 5-point scale (0: nothing; 5: very much), subjective improvement of patient quality of life and physician satisfaction were 4 (3-5), and 5 (3-5) [median (range)]. PEG-related adverse events were just reported in one patient (10%): mild post-infusion nausea. At the end of the analysis, all patients continue on PEG. Conclusions: the results observed in the first patients treated with PEG in real life in Spain, although with a limited follow-up, confirm those reported in phase 3 clinical trials, with significant improvement in the Hb levels and hemolysis parameters, which results in transfusion independence. PEG was also shown to act quickly from the start of treatment, to significantly improve quality of life, and to present an excellent safety profile. PEG, the first approved proximal complement inhibitor, can therefore be considered as a relevant therapeutic option in the current management of PNH.

Long-Term Evaluation of Luspatercept in Erythropoiesis-Stimulating Agent (ESA)-Intolerant/Refractory Patients (pts) with Lower-Risk Myelodysplastic Syndromes (LR-MDS) in the Phase 3 MEDALIST Study

Background: Pts with LR-MDS receiving luspatercept in the phase 3 MEDALIST trial previously reported durable, long-term red blood cell (RBC) transfusion independence (RBC-TI) (Fenaux P, et al. J Clin Oncol 2022;40[suppl 16]. Abstract 7056). MEDALIST pts were eligible to enroll in a follow-up study to evaluate long-term efficacy and safety. Aims: To report long-term efficacy and safety outcomes in ESA-refractory/intolerant pts with LR-MDS treated with luspatercept in the MEDALIST trial with an additional 26 mo of follow-up from the final MEDALIST data cutoff. Methods: Eligible pts were ≥ 18 y of age; IPSS-R-defined Very low-, Low-, or Intermediate-risk MDS with ring sideroblasts; were refractory, intolerant, or unlikely to respond to ESAs, and required regular RBC transfusions. Pts were randomized 2:1 to luspatercept (starting dose 1.0 mg/kg, with titration up to 1.75 mg/kg) or placebo. Efficacy outcomes include RBC-TI ≥ 8 wk and ≥ 16 wk. Cumulative duration of response was determined by Kaplan-Meier (KM) analysis. Rates of longest single and cumulative duration of RBC-TI ≥ 1 y and exposure-adjusted incidence rates (EAIR) of treatment-emergent adverse events (TEAEs) and AEs of special interest (AESIs) were calculated. Rates of high-risk (HR)-MDS and acute myeloid leukemia (AML) progression were calculated from LR-MDS diagnosis to HR-MDS/AML diagnosis, or to last HR-MDS/AML follow-up date for pts who did not progress. Results: As of January 2, 2023, 11 pts remained on luspatercept treatment; 8 pts randomized to luspatercept and none from placebo continued in post-treatment follow-up. The median (range) follow-up time was 39.9 (2.8-76.0) mo for luspatercept arm pts and 38.7 (1.7-68.6) mo for placebo arm pts. The median (range) duration of treatment was 50.9 (5.9-332.9) wk for luspatercept pts and 24.0 (9.0-103.0) wk for placebo pts. Seventy-five of 153 (49.0%) luspatercept pts achieved RBC-TI ≥ 8 wk during the entire treatment period and 53/75 (70.7%) had ≥ 2 response periods with a median cumulative duration of 110.14 wk (95% confidence interval [CI], 53.71-154.14; Figure A). Overall, 31/75 (41.3%) luspatercept pts had the longest RBC-TI duration ≥ 1 y, and 44/75 (58.7%) had a cumulative RBC-TI duration ≥ 1 y. In total, of the 48/153 (31.4%) pts receiving luspatercept who achieved RBC-TI ≥ 16 wk during the entire treatment period, 32/48 (66.7%) had ≥ 2 response periods with a median cumulative duration of 129.29 wk (95% CI, 79.86-240.43). Grade 3/4 treatment-related TEAEs were reported in 14/153 (9.2%; EAIR, 5.3 per 100 pt-y [PYs]) and 3/76 (3.9%; EAIR, 6.6 per 100 PYs) luspatercept and placebo pts, respectively; TEAEs of any grade leading to permanent treatment discontinuation were reported in 24/153 (15.7%; EAIR, 8.6 per 100 PYs) luspatercept and 6/76 placebo pts (7.9%; EAIR, 13.0 per 100 PYs). The most common TEAEs of any grade reported in > 5% of luspatercept pts were fatigue (47/153 [30.7%]; EAIR, 22.1 per 100 PYs; vs placebo, 11/76 [14.5%]; EAIR, 27.1 per 100 PYs), diarrhea (47/153 [30.7%]; EAIR, 23.5 per 100 PYs; vs placebo, 8/76 [10.5%]; EAIR, 18.4 per 100 PYs), asthenia (41/153 [26.8%]; EAIR, 18.8 per 100 PYs; vs placebo, 9/76 [11.8%]; EAIR, 21.5 per 100 PYs), peripheral edema (40/153 [26.1%], EAIR, 17.6 per 100 PYs; vs placebo, 13/76 [17.1%]; EAIR, 32.0 per 100 PYs), and back pain (38/154 [24.7%]; EAIR, 16.8 per 100 PYs; vs placebo, 5/76 [6.6%]; EAIR, 11.7 per 100 PYs; Figure B). During the entire treatment period, 26/44 (59.1%), 9/23 (39.1%), and 12/86 (14.0%) pts who received ≤ 1 mg/kg, 1.33 mg/kg, and 1.75 mg/kg luspatercept, respectively, reported fatigue of any grade. No new progression to HR-MDS or AML events have been reported since the last data cutoff (Santini V et al. Blood 2022;140[suppl 1]:4079-4081). Conclusions: Pts with LR-MDS who received luspatercept for > 2 years longer than in the original MEDALIST study, continued to experience sustained periods of RBC-TI with more than half of pts experiencing cumulative RBC-TI for ≥ 1 year. The long-term safety profile of luspatercept is consistent with previous shorter-term reports, and AEs were mostly lower grade with rates of fatigue decreasing with increasing luspatercept dose. These data demonstrate the long-term efficacy and safety of luspatercept in pts with LR-MDS intolerant/ineligible for ESA treatment.

Efficacy and Safety of Single Agent Proximal Complement Inhibitors in Paroxysmal Nocturnal Hemoglobinuria (PNH) Patients with Residual Anemia Despite of Adequate Terminal Complement Inhibitor Use

Background: Introduction of C5 inhibitors is a major advancement in the treatment of Paroxysmal Nocturnal Hemoglobinuria (PNH) patients. First Eculizumab and then Ravulizumab significantly improved anemia by controlling intravascular hemolysis (IVH), reduced thrombosis risk, improved quality of life and prolonged survival. However, a significant proportion of PNH patients remain anemic with transfusion dependence despite maximal C5 inhibition due to C3 mediated residual extravascular hemolysis (EVH). Recently two randomized, open label, controlled trials with proximal complement inhibitors were studied in this patient population comparing against C5 inhibitors as single agents with excellent results. Here we compare efficacy and safety data of proximal complement inhibitors pegcetacoplan (C3 inhibitor), Iptacopan (factor b inhibitor) based on published or presented data. Methods: We compared the efficacy and safety data of randomized portion of PEGASUS and APPLY-PNH trials. PEGASUS trial is a phase 3, randomized, open label, active-comparator controlled trial with Pegcetacoplan (a pegylated pentadecapeptide that targets C3) compared efficacy and safety against eculizumab in PNH patients with Hb <10.5 despite of treatment with Eculizumab (Hillerman, et al NEJM 2021;384). Primary end point of the study was mean change in Hb level from baseline to week 16. APPLY-PNH is an open label randomized, multicenter phase 3 trial compared Iptacopan 200 mg BID (oral factor b inhibitor) monotherapy with standard of care C5 inhibition therapy. (Regis P. de Latour et al. Blood (2022) 140 (Suppl 2): LBA-2). Primary end points of the trial were Hematological response defined as an increase in Hb of ≥ 2 g/dL from baseline and Hb ≥ 12 g/dL in absence of transfusions. Secondary end points included number of clinical and hematological markers of hemolysis and safety. Results: Summarized in table 1. PEGASUS trial included 80 patients with 41 in pegcetacoplan arm and 39 in Eculizumab arm. APPLY-PNH included 97 patients with 62 in Iptacopan arm compared to 35 in standard of care anti C5 therapy. Majority of baseline characteristics were similar between two studies. Mean age in both studies was around 50 years and close to 2/3rd of patients in each study were females. Median duration of prior C5 therapy was between 3-4 years in both studies. More than half of patients in both studies required PRBC transfusions in preceding months prior to enrollment. Baseline mean Hb was between 8-9 g/dL, LDH between 250-300 U/L, mean absolute retic count (ARC) 190-200x109/L. Both studies showed superiority in change from baseline Hb with +2.69 g/dL in PEGASUS trial with all available data regardless of transfusion events and +3.63 in APPLY-PNH trial. Both studies showed either noninferiority or superiority in freedom from transfusions and change in ARC. Interestingly, LDH change was not significant in both studies. Change from baseline fatigue FACIT-score was numerically better but not tested in PEGASUS trial and was superior in APPLY-PNH. No major vascular events or serious infections by encapsulated bacteria were reported in either study. Breakthrough hemolysis was reported in 4 out of 40 patients in PEGASUS trial that led to treatment discontinuation in 3 patients and 2 out of 62 patients in APPLY-PNH trial, however none of them required treatment discontinuation. Conclusions: PEGASUS and APPLY-PNH trials showed that in patients with persistent anemia despite C5 inhibitor therapy, proximal complement inhibition with either pegcetacoplan (C3 inhibitor) or Iptacopan (factor b inhibitor) as a single agent showed significant improvement in Hemoglobin with higher rate of transfusion independence with control of extra vascular hemolysis while maintaining intravascular hemolysis control with no serious infections. These studies represent another major advancement in the management of PNH patients. Long term follow up is needed regarding safety and to identify better ways to manage breakthrough hemolysis in patients on proximal complement inhibitors.

Meter: A Multi-Country, Real-World Chart Review Study to Explore Treatment Patterns, Effectiveness and Healthcare Resource Utilization for Patients with Myelofibrosis

Background : Myelofibrosis (MF) is a rare myeloproliferative disorder associated with significant morbidity and mortality. The hallmarks of MF pathobiology include aberrant myeloproliferation, cytokine-induced inflammation, bone marrow reticulin fibrosis, extramedullary hematopoiesis, cytopenias, and constitutional symptoms. Hydroxyurea was the most commonly used drug in patients with MF prior to the approval of ruxolitinib (RUX), a first-in-class Janus kinase 1/2 inhibitor (JAKi) that is widely approved for symptomatic patients with MF. In addition to RUX, the JAKis fedratinib and, more recently, pacritinib have also been approved by the US Food and Drug Administration. Real-world treatment patterns and impact of currently available JAKis on patients with MF are not well understood. Several novel agents are in advanced development and will further reshape the treatment landscape of MF. A better understanding of current treatment patterns will assist in positioning novel treatments within the MF therapeutic landscape. Methods : The METER study (NCT05444972) is an ongoing multicountry noninterventional retrospective chart review assessing treatment patterns, effectiveness, and healthcare resource utilization (HCRU) in patients diagnosed with MF. Data from patients aged ≥18 years with primary or secondary MF treated on or after the local first date of RUX approval until December 31 , 2021 were assessed. Patients who received treatment for MF in a clinical trial were excluded. The primary objective is to describe real-world MF treatment patterns, including patient characteristics, time from MF diagnosis to first-line (1L) therapy, choice, duration and reason for change/discontinuation of initial and subsequent treatments for MF, and treatment procedures. Secondary objectives include assessments of days hospitalized as part of HCRU. Results : As of June 1, 2023, 928 patient charts were included, met eligibility criteria, and had initial treatment information available. Most patients were male (54%) and White (65%), and the median (range) age for patients ≤89 years of age was 66 (58-73) years; the most common geographic locations were Europe (53%), Latin America (23%), and North America (13%). Of patients, 66% (614/928) had primary MF, and 10% (97/928) were transfusion-dependent. Of patients tested for high molecular risk mutations, 50% (81/162) were positive. Of patients with available bone marrow fibrosis data, 82% (554/680) had grade ≥2 bone marrow fibrosis at diagnosis. The average interval from MF diagnosis to start of initial treatment (index date) was approximately 8.5 months. RUX was the most commonly used 1L therapy (47%; 437/928) followed by hydroxyurea (41%; 380/928). RUX was also the most common therapy used in second-line (2L), third-line, fourth-line, and fifth-line treatment for 62% (217/353), 63% (107/171), 66% (56/85), and 59% (24/41) of patients, respectively. Mean (SD) time from index date to procedural intervention was 556 (519) days; the most common procedure was stem cell transplant (n = 71) followed by splenectomy (n = 20). Of the 927 patients who received 1L therapy, 98% remained on 1L therapy through Week 24, and 66% did not initiate 2L therapy until Week 156. Median (95% CI) duration of 1L therapy was 48 (45-52) months (Figure). Median (95% CI) survival from the start of 1L therapy was 79 (71-NR) months. The estimated survival rate (95% CI) was 76% (73-79) at Week 156. Median (95% CI) overall survival was 120 (93-147) months. Median (Q1-Q3) total number of days hospitalized after the index date was 2 (0-19), and median (Q1, Q3) total number of days in the intensive care unit after the index date was 0 (0, 0). Analyses will be updated for presentation. Conclusions : In patients with MF, RUX was the most commonly used agent in all lines of therapy. The greatest reduction in duration of MF treatment occurred from 1L to 2L. Most patients remained on 1L therapy through Week 24 and did not initiate 2L therapy until Week 156. Median survival time from start of 1L therapy to death was 79 months (approximately 6 years). There was a high degree of advanced bone marrow fibrosis as well as transfusion dependence among this real-world patient population. Together, these results highlight the importance of optimizing 1L therapy.

Efficacy and Safety of Luspatercept in Patients Enrolled in the BELIEVE Trial: Data from the Phase 3b Long-Term Rollover Study

Background: Ineffective erythropoiesis and anemia are pathognomonic features of β-thalassemia, leading to red blood cell (RBC) transfusion dependence in patients with more severe genotypes and consequently increased morbidity and mortality. The phase 3 BELIEVE study showed that luspatercept reduces transfusion burden in transfusion-dependent patients with a manageable safety profile (Cappellini MD, et al. HemaSphere 2022;6[S3]:171-172; Viprakasit V, et al. HemaSphere 2022;6[S3]:2664-2665). Patients who continued to benefit from luspatercept at completion of the BELIEVE study or who needed to complete post-treatment follow-up could roll over to the phase 3b long-term follow-up study (LTFU; NCT04064060) to continue receiving treatment or complete post-treatment follow-up, respectively. Patients receiving luspatercept were monitored for continued efficacy and safety. Methods: The aim of this analysis was to evaluate long-term safety and efficacy of luspatercept in patients who rolled over to the LTFU study. This analysis included patients randomized to luspatercept during BELIEVE (luspatercept group) and those randomized to placebo who crossed over to receive luspatercept after unblinding (crossover group). Response was defined as ≥ 33% reduction from baseline in RBC transfusion burden during any 12-week interval over the entire treatment period of the combined studies. The data cutoff was Jan 2, 2023. Results: At the closure of the BELIEVE trial, 127/224 (56.7%) patients from the luspatercept group and 67/92 (72.8%) patients from the crossover group had transitioned to the LTFU study with the intention to continue luspatercept. At data cutoff, treatment was ongoing for 138 patients, 90 in the luspatercept group and 48 in the crossover group. Median (range) total treatment duration over the combined studies was 229.1 (1.7-336.1) weeks for the luspatercept group and 221.2 (6.1-230.7) weeks for the crossover group; 98 patients had completed 288 weeks (> 5 years) of treatment at data cutoff, all of whom had been randomized to luspatercept. In the luspatercept group, 180/224 (80.4%) patients had achieved response, continuing the trend showing an increasing proportion of responders with longer duration of treatment observed at previous data cutoffs (Figure A). Response in the crossover group was similar with 71/92 (77.2%) responders. Patients in the luspatercept and crossover groups had median (range) reductions in transfusion burden of −17.75% (−100.0 to 33.3) and −19.05% (−100.0 to 20.8), respectively, from baseline to week 145-192, equating to mean reductions of 6.78 RBC units (SD 7.27; n = 120) and 6.85 RBC units (SD 6.78; n = 50), respectively. Liver iron concentration in the luspatercept group was reduced with long-term treatment at each timepoint compared with the baseline (mean decrease of 2.80 mg/g dry weight [dw] at week 144 from median 8.97 [range, 1.1-31.9] at baseline [n = 24]; mean decrease of 0.45 mg/g dw at week 192 from median 7.75 [1.4-35.5] at baseline [n = 27]; mean decrease of 1.48 mg/g dw at week 240 from median 5.65 [1.0-42.0] at baseline [n = 20]). Mean changes from baseline in overall serum ferritin levels (last 24-week level for each patient prior to their efficacy cutoff) were −376.27 μg/L for luspatercept and +43.09 μg/L for crossover. In the combined studies up to data cutoff, 59.4% of luspatercept patients and 47.8% of crossover patients discontinued treatment. The most frequent reason for treatment discontinuation was the patient's personal decision to withdraw (luspatercept: 23.7% in BELIEVE and 33.5% in the combined studies; crossover: 14.1% in BELIEVE and 28.3% in the combined). Discontinuation due to an adverse event (AE) in the combined studies was similar to experience from BELIEVE (luspatercept: 10.3% BELIEVE and 12.5% combined; crossover: 4.3% BELIEVE and 7.6% combined). One patient (0.4%) discontinued luspatercept and transitioned to a commercially available treatment. The frequency of treatment-emergent AEs in the combined studies was also consistent with previous experience from the BELIEVE trial (Figure B). Summary: These long-term data from the LTFU study show that erythroid responses and safety results in both the luspatercept and crossover groups were consistent with previous clinical experience from the BELIEVE trial. Patients receiving long-term luspatercept treatment experience durable clinical benefit with no new safety concerns.

Applying the Novel EHA/EBMT Grading System for Icaht Following CAR-T Therapy: Comparative Incidence across Disease Entities and Association with Infections and Mortality

Background: Hematological toxicity is a frequent side effect of CAR-T therapy and predisposes for severe infectious complications. Recently, the EHA/EBMT consensus grading for Immune Effector Cell Associated HematoToxicity (ICAHT) was developed ( Rejeski et al. Blood 2023). In contrast to existing grading systems such as the CTCAE, the novel ICAHT grading integrates both the depth and duration of neutropenia. We hypothesized that ICAHT severity is associated with key clinical sequelae such as transfusion requirements, hospitalization, severe infections, and adverse treatment outcomes. Methods: We applied the novel grading of early ICAHT (day 0-30) to a multicenter retrospective real-world cohort of 549 patients treated with BCMA- or CD19-directed CAR T-cells for relapsed/refractory B-cell malignancies (334 large B-cell lymphoma [LBCL], 112 multiple myeloma [MM], 103 mantle cell lymphoma [MCL]) across twelve international sites (Germany, France, Spain, USA). Hematotoxicity endpoints included the total cumulative duration of severe neutropenia (ANC <500/µL, day 0-60) and phenotypes of neutrophil recovery ( Rejeski et al. Blood 2021). Infections were studied until day +90 after CAR-T and were graded on a 5-grade scale as mild, moderate, severe, life-threatening, or fatal. Non-relapse mortality (NRM) was defined as death following CAR-T without evidence of relapse or progression. Kaplan-Meier estimates of progression-free (PFS) and overall survival (OS) were compared using log-rank test. Results: Our study cohort included 424 patients without severe ICAHT (absent or grade 1-2) and 125 patients with severe ICAHT (grade 3-4). The distribution of mild (1°), moderate (2°), severe (3°) and life-threatening (4°) ICAHT was 36%, 29%, 17%, and 5%. Seventy patients (13%) did not develop ICAHT of any grade. When comparing ICAHT grades across disease entities, we noted a numeric trend towards increased severe ICAHT in MCL compared to LBCL or MM patients (Grade ≥3: 28% vs. 23% vs. 15%). Patients that subsequently developed severe ICAHT displayed elevated serum inflammatory markers and pronounced cytopenia at baseline - reflected by increased CAR-HEMATOTOX scores (median 3 vs. 1, p<0.0001). On multivariate binary logistic regression, co-stimulatory domain (CD28z), low platelet count, low ANC, low hemoglobin, increased serum ferritin, and the presence of bone marrow infiltration were independent risk factors for severe ICAHT. We noted a strong positive correlation between ICAHT severity and the cumulative duration of severe neutropenia (r=0.92, p<0.0001). The aplastic phenotype of neutrophil recovery was enriched in patients with grade 3 (73%) and especially grade 4 ICAHT (100%). Severe ICAHT was also associated with coincident multilineage cytopenias, resulting in increased transfusion requirements for both platelets (85% vs. 21%, p<0.0001) and red blood cells (86% vs. 41%, p<0.0001). In terms of management of hematotoxicity, the severe ICAHT group more commonly received G-CSF (72% vs. 44%, p=0.01), TPO mimetics (12% vs. 2%, p<0.0001) and hematopoietic stem cell boosts (6% vs. 0.2%, p<0.0001). Importantly, patients with severe ICAHT displayed a significantly increased rate of severe infections (49% vs. 13%, p<0.0001, Fig. 1a) and severe bacterial infections (36% vs. 8%, p<0.0001). This translated into a markedly increased 1-year NRM rate (14% vs. 4.5%, logrank p<0.0001, Fig. 1b), which was primarily attributed to fatal infections of fungal or bacterial origin. Of note, the ICAHT grading showed superior discrimination for severe infections (C-index 0.73, 95%CI: 0.67-0.78) compared to CTCAE grading (C-index 0.55, n.s.). Prolonged hospitalization was noted in case of severe ICAHT (median 21 vs. 16 days, p<0.0001) and intensive care admission was more common (23% vs. 4%, p<0.001). Finally, we observed inferior PFS (1-year PFS 35% vs. 51%, median 4 vs. 14 months, p<0.0001) and inferior OS (1-year OS 52% vs. 73%, median 12 months vs. not-reached, p<0.0001) in the patients that developed severe ICAHT. Conclusions: These data highlight the clinical relevance of the novel EHA/EBMT ICAHT grading system. Importantly, ICAHT severity was closely associated with transfusion dependence, increased infection incidence, and adverse treatment outcomes with high NRM. Taken together, these findings argue for reporting ICAHT grades in clinical trials evaluating established and novel CAR constructs.

Machine Learning-Based Time-Series Clustering Identifies Archetypal Trajectories of Hematotoxicity after CAR T-Cell Therapy

BACKGROUND Severe hematotoxicity has been reported in a subset of patients (pts) after chimeric antigen receptor (CAR) T-cell therapy, leading to severe infections, transfusion dependency, and worse outcomes. Early identification of pts at risk for severe hematotoxicity could inform the consideration of an autologous stem cell boost, allogeneic HCT, and/or additional infectious prophylaxis. While distinct archetypal trajectories of blood count recovery have been proposed (e.g., quick vs. intermittent vs. aplastic), manual trajectory classification is subjective and labor-intensive. To address these limitations, we automated the identification of distinct trajectories of hematotoxicity by applying time-series clustering to longitudinal absolute neutrophil count (ANC) data from >400 pts treated with CAR T-cell therapy. Next, we sought to identify factors associated with the identified trajectories and to assess the predictive ability of the CAR-HEMATOTOX score (Rejeski, Blood 2021). STUDY DESIGN AND METHODS Adults ≥18 years of age who received their first infusion of CAR T cells for hematologic malignancies with commercial or investigational products at the Fred Hutchinson Cancer Center (2013-2023) were included. ANC trajectories were clustered using non-supervised longitudinal k-means based on Euclidean distances using the latrend and kml packages in R 4.1.3. We applied logistic regression to pre-lymphodepletion (pre-LD) variables to predict poor/very poor ANC recovery. Sensitivity and specificity were computed using a probability threshold based on the Youden criteria. RESULTS A total of 509 pts were identified; 106 were excluded due to insufficient data, with 403 pts included for the analysis. The most common disease types were aggressive NHL (n = 161; 40%), indolent NHL (n = 82; 20%), and ALL (n = 74; 18%). CAR T-cell products were axi-cel, n= 101 (25%); brexu-cel, n = 24 (6%); cilta-cel, n = 21 (5%); liso-cel, n = 46 (11%); ide-cel, n = 25 (6%); tisa-cel, 12 (3%); and investigational CD19 or CD20 CAR T-cell products, n = 174 (43%). As shown in Figure 1A, the ANC longitudinal data clustered into four distinct trajectories as follows: 1) high nadir followed by rapid recovery (“very good recovery”), n = 294 (73%); 2) low nadir followed by rapid recovery (“good recovery”), n = 87 (22%); 3) low nadir followed by intermittent recovery (“poor recovery”), n = 13 (3%); 4) aplastic phenotype (“very poor recovery”), n = 9 (2%). In univariate logistic regression, ALL (reference: aggressive NHL; OR = 5.43, 95% CI, 1.71-20.6, p = 0.006), pre-LD lower ANC (OR = 3.33 per log 10 , 95% CI, 1.82-6.25, p < 0.001), lower pre-LD platelet count (OR = 10 per log 10, 95% CI, 3.70-33.3), p < 0.001), and higher pre-LD disease burden as measured by lactate dehydrogenase (LDH) were associated with poor/very poor ANC recovery (OR = 16.6 per log 10, 95% CI, 4.79-59.3, p < 0.001). Next, we assessed the predictive ability of CAR-HEMATOTOX to identify poor/very poor ANC recovery in n = 356 pts with a calculable score. The CAR-HEMATOTOX score high/low showed modest discrimination (C-index: 0.65), which improved when used as a continuous variable (C-index: 0.85). As previously reported, these models had high sensitivity (>90%) but low specificity (high/low: 31%, continuous: 58%). To improve risk prediction of poor/very poor ANC recovery, we built a logistic regression model using restricted cubic splines - allowing for non-linear effects - including pre-LD ANC, platelet, Hb, LDH, CRP, and ferritin, which showed higher discrimination (C-index: 0.91), high sensitivity (88%), and higher specificity (79%) ( Figure 1B). CONCLUSION We introduce an automated, scalable, and disease-agnostic framework to analyze hematologic toxicity after CAR T-cell therapy. K-means clustering of longitudinal ANC data categorized pts into archetypal trajectories of hematologic recovery. A logistic regression model using pre-LD ANC, platelet, Hb, LDH, CRP, and ferritin showed improved discrimination and sensitivity compared to CAR-HEMATOTOX in our training set, but both models had low specificity (poor ability to “rule in” pts at risk of severe hematotoxicity) and thus low clinical utility at this time. We plan to further improve our predictive models by incorporating post-infusion biomarkers of systemic inflammation that we have previously shown to be associated with delayed count recovery after CAR T-cell therapy (Juluri, Blood Advances 2022).

Erythrocyte Disorders Mimicking Congenital Dyserythropoietic Anemia Based on Bone Marrow Pathology Exposed By Genetic Evaluation

Congenital dyserythropoietic anemias (CDAs) are a rare group of heterogeneous genetic diseases characterized by hemolysis, ineffective erythropoiesis predisposing to iron overload, and the pathologic finding of bi- and multinucleated erythroblasts in the bone marrow (BM). With the identification of causative genetic mutations over the last two decades, the current classification includes the following types with the causative gene in parenthesis: Ia ( CDAN1), Ib ( CDIN1); II ( SEC23B); IIIa ( KIF23), IIIb ( RACGAP1); IV ( KLF1) ; and XLTD ( GATA1). Clinical presentation can vary widely even within the same type, ranging from mild cases of anemia to severe cases in which patients are subject to lifelong transfusion dependency. The CDA registry (CDAR) in North America (NCT02964494) was established to allow natural history studies on patients with CDA. Participants without a genetic diagnosis are offered whole genome sequencing (WGS) for patients and parents and may elect to provide samples to the CDAR biorepository to support collaborative mechanistic studies. Currently 169 subjects from 73 different families are enrolled in CDAR (85 patients, 84 unaffected family members). After genetic evaluation, 13 patients were found to be affected not by CDA, but rather by other causes of hereditary hemolytic anemia with secondary dyserythropoiesis. Three patients were diagnosed with pyruvate kinase deficiency (PKD). Patient (pt) 1 had a history of chronic anemia requiring sporadic transfusions since birth and was diagnosed with CDA-II based on BM studies. WGS revealed that the patient was heterozygous for a known PKLR pathogenic variant c.1022G>C p.(Gly341Ala)and for a novel variant of uncertain significance (c.695-3C>G).PK activity assay confirmed the diagnosis of PKD and the patient is now treated with the PK activator mitapivat. Pt 2 had severe transfusion dependent anemia since birth and iron overload. The patient underwent splenectomy at the age of 4 with mild improvement of symptoms. He was diagnosed with CDA II based on BM pathology. Genetic testing was performed and he was found to be compound heterozygous for 2 pathogenic variants in PKLR: c.644dup p.(Arg216fs) and c.994_1003dup p.(Val335fs). Pt 3 had a history of anemia and jaundice since birth; she has not had frequent transfusions but was splenectomized at age 17. The patient was found to be homozygous for c.1436G>A p.(Arg510Gln), a known pathogenic variant in PKLR. Four patients were diagnosed with HBB pathogenic variants causing frameshift and transcription of an elongated β-globin chain, i.e. unstable hemoglobinopathy. Pt 4 was first diagnosed with CDA II at 12 years of age based on BM studies performed due to chronic hemolytic anemia. After enrolling in CDAR, WES revealed heterozygous HBB p.(Lys96Asnfs*63). Pts 5, 6, and 7 are all symptomatic participants from the same family (mother and children). The mother (Pt 5) had frequent transfusion requirement, misdiagnosed in childhood as CDA IV due to BM dyserythropoiesis and the finding of high fetal hemoglobin. Her children had a similar phenotype requiring episodic transfusions initially, transitioning to scheduled transfusions by 8 y.o. WES in pt 5 revealed heterozygous HBB c.348_349delinsG (Hb Grand Junction) with follow-up HBB sequencing confirming that the children also carry the same variant . Three more patients were diagnosed with SPTA1 variants causing RBC membrane disorders. Pt 8 was found to have homozygous c.4339-99C>T (alpha-LEPRA) and heterozygous c.4347G>T p.(Lys1449Asn) with a phenotype of hereditary spherocytosis. Pts 9 and 10 are sisters, who presented with chronic, transfusion-dependent anemia since birth. They were diagnosed with CDA-II based on binucleated erythroblasts in BM studies performed in early childhood. They had splenectomy at 5 years of age and became transfusion-independent but continued to have mild anemia and reticulocytosis. WGS performed for them and their parents revealed a novel homozygous intronic variant in SPTA1 c.5834-18A>G. Phenotypic analysis was compatible with hereditary spherocytic pyropoikilocytosis. Hemolytic anemias with stress erythropoiesis may mimic the clinical presentation and pathologic findings of CDAs, making the phenotypic diagnosis challenging. Including genetic evaluation in the diagnostic workup of these patients can improve accuracy, timing of diagnosis, and management by specific therapy, if available.

A Phase 1b Trial of DISC-0974, an Anti-Hemojuvelin Antibody, in Patients with Myelofibrosis and Anemia

Hepcidin, a central regulator of iron homeostasis, is pathologically elevated in patients with myelofibrosis (MF) and anemia. Chronic elevations in hepcidin contribute to the onset and severity of anemia. DISC-0974 is an investigational, first-in-class, monoclonal antibody that blocks hemojuvelin, a co-receptor in the bone morphogenetic protein-signaling pathway driving hepcidin expression. Preclinical studies have shown that DISC-0974 suppresses hepcidin and increases serum iron. A healthy volunteer study has demonstrated dose-dependent reductions in serum hepcidin, increases in serum iron with doses up to 56 mg administered subcutaneously, and increasing trends in reticulocyte count, reticulocyte hemoglobin, mean corpuscular hemoglobin, total hemoglobin (Hgb), and red blood cell count. In this Phase 1b/2a, open-label, multiple-ascending dose study (NCT05320198), we are assessing the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of DISC-0974 in patients with MF and anemia. Eligible participants include patients over 18 years of age with intermediate-2 or higher-risk MF and anemia. MF is required to be confirmed using the World Health Organization 2016 criteria. Anemia is defined per protocol as Hgb < 10 g/dL or transfusion dependence, as defined by the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT). A stable dose of hydroxyurea and/or Janus kinase (JAK) inhibitor is allowed on trial. Major exclusion criteria include: liver iron concentration ≥ 7 mg/g dry weight; splenectomy; nutritional, genetic, infectious, or autoimmune causes of anemia. Dose escalation is based on a Bayesian optimal interval design with accelerated titration. Safety Review Committee assessments gate escalation decisions. Dosing occurs monthly for a total of 6 doses. Primary endpoints include safety and tolerability assessments of adverse events (AEs), clinical laboratory assessments, vital signs, physical examinations, and electrocardiograms. Secondary endpoints include anemia response as defined by the IWG-MRT, transfusion response as defined by a decrease of 50% in transfusion requirement over any 8-week period, standard PK parameters and PD metrics including serum hepcidin-25, iron, transferrin saturation, ferritin, and hematology biomarkers. All data are summarized using descriptive statistics. Initial data show a dose-related increase in pharmacokinetic parameters. DISC-0974 treatment led to dose-dependent reductions in serum hepcidin-25 and increases in serum iron levels. There have been no serious AEs or AEs leading to study withdrawal. Most AEs were mild, transient, and unrelated to DISC-0974. As of August 1, 2023, enrollment and dose escalation are ongoing. Safety, PK, and PD data from at least the first two cohorts will be presented.

Venetoclax Plus Azacitidine, Low Dose Cytarabine, Aclarubicin and G-CSF (VA-CAG Regimen) for Newly Diagnosed Young Patients with Acute Myeloid Leukemia: A Prospective, Multicenter, Single-Arm Phase 2 Clinical Trial

Background: Venetoclax, in combination with hypomethylating agents or low-dose cytarabine, is approved for newly diagnosed acute myeloid leukemia (AML) patients who are over 75 years of age or not eligible for intensive chemotherapy, while the efficacy of venetoclax-based regimens in young fit AML patients still needs to be further explored. Although the combination of anthracycline and cytarabine has achieved a remission rate of about 70% in these patients, the low complete response rate in adverse-risk patients, strong adverse reactions, and long duration of myelosuppression limited the clinical benefit. We presumed that venetoclax plus azacitidine in combination with low-intensity regimens CAG (G-CSF priming, low dose cytarabine, and aclarubicin) could have a better composite complete remission with an acceptable safety profile. Methods: Patients who were newly diagnosed with AML aged from 18 to 65 years without active infection, bleeding and severe cardiopulmonary insufficiency were enrolled. Participants received induction as azacitidine 75 mg/m 2 subcutaneously once daily on days 1-7, cytarabine 10mg/m 2 subcutaneously q12h on days 1-7, aclacinomycin 12 mg/m 2 on days 1,3,5,7, granulocyte colony-stimulating factor 5µg/kg on days 1-7, and venetoclax orally once daily (100 mg d1, 200 mg d2, 400 mg d3-21). Venetoclax dose was adjusted based on concomitant CYP3A inhibitors. The efficacy were evaluated by bone marrow morphology and flow cytometry on day 28 cycle 1. The primary endpoints were safety and the composite complete remission rate. This study was approved for ethical review and registered with ClinicalTrials.gov (NCT05662956). Results: Twenty-six patients from eight sites were enrolled between January 1, 2023, and June 20, 2023. The median age was 52 years (range, 18-63years). Thirteen patients (50.0%) had adverse risk, 7 patients (26.9%) had intermediate risk, and 6 patients (23.1%) had favorable risk. All 26 patients (100%) achieved complete remission after cycle 1, and 21 patients (80.8%) was MRD negative by flow cytometry. Two patients (7.7%) were treated with venetoclax for 14 days due to ineffective platelet transfusion and severe infection during treatment. Twenty-two patients (84%) used azole drugs to prevent fungal infection. The median myelosuppression time was 13 days (range, 5-22days), and the median red blood cell and platelet transfusions were 5.5u (range, 0-11.5u) and 30u (range, 0-170u), respectively. Eleven patients (42.3%) experienced infection (including pulmonary fungal infection, oral cold herpes, novel coronavirus infection, etc.), and two of them (7.7%) had a breakthrough invasive fungal infection, but with good management. The most common grade 3/4 adverse events included bone marrow suppression (92.3%), liver injury (19.2%), gastrointestinal reaction (11.5%) and coagulation dysfunction (3.8%).No treatment-related death occurred. Conclusion: VA-CAG regimen achieved high rates of complete remission and MRD negative in young adult fit patients with newly diagnosed AML. This combined regimen has an acceptable safety profile, with low incidence of infection and transfusion dependence.

Prognostic Significance and Clinical Correlations of Myeloid Mutations in Myelofibrosis Based on Their Functional Class

Background: In addition to the driver mutations JAK2, CALR and MPL, patients (pts) with primary myelofibrosis (PMF) may also express mutations in a number of genes frequently associated with myeloid neoplasms. These genes encode regulators of chromatin modification and DNA methylation, RNA splicing and transcription, as well as oncogenes and signal transduction. In pts with PMF, including those with prefibrotic (pre-)-PMF, selected mutations were shown to deserve prognostic relevance, and led to the development of molecular integrated, or exclusive, scores (such as MIPSS70, MIPSS70-plus, GIPSS and others). Aim: The aim of the study was to correlate the type of mutations, clustered in relation to their known functional classes, with hematological and clinical correlates, and outcome in a large population of molecularly annotated pts with PMF. Patients and Methods: All pts with a confirmed ICC 2022 diagnosis of PMF from the database at CRIMM (Florence), for whom mutation analysis of a panel of 40 myeloid neoplasm-associated genes performed by NGS (Oncomine, ThermoFisher) was available, were included in the study. Pts were stratified in 6 categories based on known function of mutated gene: spliceosome (cat. 1: SF3B1, U2AF1, SRSF2, ZRSR2), DNA methylation gene (cat. 2: TET2, DNMT3A, IDH1, IDH2, SETBP1), histone modification gene (cat. 3: ASXL1, EZH2), RAS pathway (cat. 4: NRAS, KRAS, CBL, NF1, PTPN11), transcription factor (cat. 5: RUNX1, NFE2, TP53) and “other” gene mutations (cat. 6: LNK/SH2B3). Results: A total of 286 pts with at least 1 myeloid neoplasm-associated gene mutation were included (110 prePMF, 38.5%; 176 overt PMF, 61.5%). Of these, 69 have mutations in spliceosome genes, 81 in DNA methylation genes, 95 in histone modification genes, 19 in the RAS pathway, 13 in transcription factor genes and 9 in “other” gene category. Analysis of clinical characteristics (Table) showed that Cat. 1 pts were significantly older (80.6% aged >60y, P=0.003), no difference regarding gender. There was no difference in blood counts but circulating blasts >1%, that were higher in cat 3 and 1 compared to the others (P=0.009). A G3 fibrosis was more common in cat 3 and 5 (43.5% and 50%, p<0.001). No significant difference was noticed as regarded driver mutations and karyotype abnormalities. Splenomegaly was more common in cat 3 and cat 6 (86.5% and 88.9%, respectively, p=0.015), while constitutional symptoms were enriched in cat 5 (69.2%, p=0.015). The proportion of pts with transfusion dependency was lower among those with mutations in DNA methylation genes (cat. 2) and “other” mutations (cat. 6) (21% and 22.2%, respectively, p=0.014). There was no significant difference among gene categories as regarded IPSS score, MIPSS70 score, thrombosis and bleeding events, progression to overt MF (in case of pre-PMF), transformation to AML and rate of secondary neoplasms. The median overall survival (OS) for all pts was 7.1 years (IC: 5.7-8.5), with categories 2, 4 and 5 showing the longest survival (10.7y (6.3-15.1), 11.5y (4.4-18.7), and 10.5y (2-18.9) respectively). In particular, pts in cat 2 showed significantly longer OS than pts in cat 1 (5.4y; HR 1.7, 95% CI, 1.1-2.6; p=0.021) and cat 3 (10.7 vs 6.1y; HR 1.5, 95% CI, 1-2.3). Considering that cat 1, 3, and 6 on one side, and cat 2, 4, 5 on the other, did not differ significant each to the other, we combined those categories to assess respective impact on survival. We found a statistically significant difference between the 2 groups, with pts harboring mutations in spliceosome, histone modifiers and “other” genes having significantly shortened survival (5.8y, CI 4.1-7.5; HR 1.57, CI 1.13-2.18) compared to the other categories (median survival, 10.8y, CI 7.2-14.3) (P=.007). Conclusion: Current analysis revealed distinctive clinical characteristics and survival outcomes associated with specific categories of mutated myeloid genes in pts with PMF, largely overlapping with the ICC defined “myelodysplasia-related gene mutations” category.