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Introduction: Risk stratification approaches using clinical criteria or biomarkers in acute graft-versus-host disease (GVHD) have traditionally been implemented at diagnosis or initiation systemic treatment with corticosteroids. For patients who require second-line treatment, the significance of biomarkers at salvage therapy and the relationship between biomarker risk and choice of therapy are unknown. Methods: We studied adult patients who received second-line treatment for acute GVHD between January 2016 and December 2021 in the Mount Sinai Acute GVHD Consortium (MAGIC) database, which collects clinical data and longitudinal serum samples from allogeneic HCT recipients using a rigorous PRoBE study design. Exclusion criteria included relapse of underlying malignant disease prior to second-line therapy, missing response data, or missing serum sample. Serum samples collected from 7 days prior to 3 days after initiation of second-line therapy met criteria for biomarker analysis. The MAGIC algorithm probability (MAP) was calculated as a single value based on concentrations of ST2 and REG3α and was stratified at a threshold of 0.290 to define high MAP and low MAP groups. The primary objective evaluated the association between MAP and survival for patients receiving second-line therapy for acute GVHD. The key secondary objective was to investigate the MAP and choice of second-line systemic agent on Day 28 overall response rate (ORR) and survival. Results: In total, 316 adult patients received second-line treatment for acute GVHD; 149 patients (47%) were excluded for disease relapse (n=27), missing response data (n=48), or missing sample (n=74).Of the 167 evaluable patients, most had steroid-refractory acute GVHD (n=146, 87%), rather than steroid-dependent (n=8, 5%) or steroid-sensitive (n=14, 8%) disease. 62 patients received ruxolitinib while 102 received other systemic agents (best available therapy: BAT). Baseline clinical characteristics of the study population according to treatment choice were similar, except for donor type (Rux: MRD 15%, MUD 74%, haplo 11%; BAT: MRD 30%, MUD 67%, haplo 3%; P=0.014) and median days from corticosteroids to second-line treatment (Rux: 18, BAT: 12; P=0.02).In total, 81 patients had high MAPs and 86 patients had low MAPs, with similar distribution in each treatment cohort (P=0.53). For the entire cohort, the median follow-up for survivors was 22 months (range, 1.5-27).The MAP separated patients into 2 groups (high vs low) with significantly different mortality (NRM at 2 years, 76% vs 29%, P<.0001) and survival (OS at 2 years, 12% vs 63%, P<.0001). Patients who received ruxolitinib as second-line therapy had lower mortality (NRM at 2 years, 35% vs 60%, P<.002) and improved survival (OS at 2 years, 51% vs 32%, P<.008), compared to those who received other systemic agents. However, the outcomes of patients with high MAP were poor, regardless of second-line treatment choice ( Figure 1A). The MAP (low vs high), time from corticosteroids to second-line treatment (≥14 days vs < 14 days), GVHD grade at second-line (0-2 vs 3-4), and choice of second-line therapy (Rux vs BAT) were all significant (P<0.05) predictors of lower NRM and higher OS in multivariate analysis. The MAP also separated patients into 2 groups with significantly different D28 ORR (low: 49%, high: 30%, P<.0001). In agreement with prospective trials, ruxolitinib resulted in higher D28 response rates compared to other systemic therapies (ORR 54.9% vs 30.5%, P=0.005), which was observed in both low MAP (ORR, 64.5% vs 38.5%, P=0.017) and high MAP cohorts (ORR, 42.9% vs 22.6%, P=0.06) ( Figure 1B). The MAP (low vs high), GVHD grade at second line (0-2 vs 3-4), and choice of second-line therapy (Rux vs BAT) were significant predictors (P<0.05) of higher D28 ORR in multivariate analysis. Conclusion: The MAP measured at the initiation of second-line systemic treatment for acute GVHD predicts NRM and OS, as well as treatment response. The outcomes of patients with high MAP are poor, regardless of second-line treatment choice, and the higher CR rate in low MAP patients may drive higher survival rates. Incorporation of MAP into clinical trials in this setting warrants investigation. The results also support the current use of ruxolitinib as second-line treatment for acute GVHD, particularly in patients with low MAP.

Background ABBV-383 is an off-the-shelf, fully human B-cell maturation antigen (BMCA) X CD3 bispecific antibody with bivalent BCMA domain and low CD3 affinity that targets both BCMA-expressing multiple myeloma (MM) cells and CD3-expressing T cells. ABBV-383 has shown promising activity in an ongoing phase 1 study in patients (pts) with relapsed/refractory (RR) MM ( Voorhees et al. ASH 2022; Weisel et al. EHA 2023). Here, we report the safety and efficacy results from the ABBV-383 IV Q3W at 20 mg, 40 mg and 60 mg dose levels. Methods The phase 1 dose escalation (ESC) and expansion (EXP) study (NCT03933735) of ABBV-383 enrolled pts with RRMM with ≥3 prior lines of therapy (LOT), including a PI, IMiD, and an anti-CD38 mAb with no prior BCMA exposure. After exploring 14 dose levels in dose ESC, 3 dose levels were further explored in dose EXP including ABBV-383 Q3W IV 20 mg, 40 mg, and 60 mg, until disease progression/unacceptable toxicity. The primary objectives were to determine safety/tolerability, PK/PD, and RP2D. The secondary objective was to evaluate clinical activity. Responses were investigator assessed per IMWG 2016 criteria and adverse events (AEs) by CTCAE v5.0. Results As of 17May2023, 220 pts were treated with ABBV-383, 73 pts in the dose ESC and 147 in the dose EXP with 32 pts at 20 mg, 55 pts at 40 mg, and 61 pts at 60 mg Q3W. Median duration of follow up was 7.1 (0.8-36.9), 12.2 (1.3-34.4) and 24.2 (0.6-33.4) months (mo) in the 20 mg, 40 mg and 60 mg dose levels with 25%, 36% and 21% pts continuing treatment (tx), respectively. Median age for all pts was 68 yrs (range, 35-92 yrs), Median prior LOT was 5 (range, 3-23), and 80% were triple-class refractory. Baseline characteristics are summarized in Table 1 by dose level. Treatment-emergent (TE) AEs were reported in 97% (78% ≥G3) of pts at 20 mg, 100% (84% ≥G3) of pts at 40 mg, and 100% (82% ≥G3) of pts at 60 mg. CRS, the most common TEAE, occurred in 50% (34% G1/13% G2/3% G3) of pts at 20 mg, 71%(45% G1/25% G2/0% ≥G3) of pts at 40 mg, and 70%(51% G1/18% G2/2% G3) of pts at 60mg. At the 3 dose levels, CRS occurring after the first dose had median time to onset of 1 day (range, 1-2) and median duration was 2 days (range, 1-10). ICANS occurred in 3% (3% G1/0% ≥G2) of pts at 20 mg, 5% (2 % G1/4% G2/0% ≥G3) of pts at 40 mg, and 5% (3% G2/2% G3) of pts at 60 mg. No G4/5 CRS or ICANS occurred. Infections occurred in 56% (25% ≥G3) of pts at 20 mg, 71% (26% ≥G3) of pts at 40 mg, and 57% (34% ≥G3) of pts at 60 mg; most frequently (≥10%) reported were upper respiratory tract infections (15%, G3/4 1%), pneumonia (14%, G3/4 12%), urinary tract infections (12%, G3/4 3%), and COVID-19 (11%, G3/4 1%). At 20 mg, 40 mg, and 60 mg, the incidence of neutropenia was 41% (25% ≥G3), 42% (31% ≥G3), and 43% (34% ≥G3); anemia 50% (25% ≥G3), 55% (31% ≥G3), and 38% (13% ≥G3); thrombocytopenia 44% (28% ≥G3), 36% (16% ≥G3) and 26% (13% ≥G3), respectively. The tx discontinuation due to AEs was 6%, 11%, 10% in 20 mg, 40 mg and 60 mg, respectively, with no single PT reported in >2 pts. Clinical responses are shown in Figure 1. The median time to ≥VGPR was 0.7mo (0.7-5.8) at 20 mg, 1.0mo (0.7-10.4) at 40 mg, and 1.4 mo (0.7-7.8) at 60 mg. The median DOR was 9.7 mo (3.5-not reached (NR)) at 20 mg, and NR at 40 mg and 60 mg. The Kaplan-Meier (KM) estimates for DOR at 12 mo was 42% at 20 mg, 70% at 40 mg, 66% at 60 mg. The mPFS was 3.8 mo (2.4-7.9) at 20mg, 13.7mo (5.0-NR) at 40 mg, and 11.2 mo (4.8-NR) at 60 mg. The KM estimates for PFS at 12 mo was 19% at 20 mg, 51% at 40 mg, 49% at 60 mg. The median OS was 21.6 mo (7.9-NR) at 20 mg, and NR at 40 mg and 60 mg. ABBV-383 at 20 mg, 40 mg, and 60 mg led to rapid and transient production of key proinflammatory cytokines (IL-6, IL8, IFN-γ, and TNF-α), and reduction of soluble BCMA levels over time that were associated with disease response. ABBV-383 also promoted T-cell activation and proliferation with upregulation of CD69 and KI67 markers on peripheral CD4 and CD8 T cells in evaluable pts. Conclusions ABBV-383 showed a manageable safety profile at dosages of 20 mg, 40 mg, and 60 mg IV Q3W, with low incidence of TEAEs leading to discontinuation. Also, extended Q3W dosing interval with no step-up dosing schedule of ABBV-383 may provide enhanced convenience. However, 20 mg yielded numerically lower responses when compared to 40 mg and 60 mg. At 40 mg and 60 mg, ABBV-383 monotherapy yielded deep and durable responses with mPFS of 13.7 mo and 11.2 mo, and 12-month DOR of 70% and 66% (mDOR NR in pts with ≥CR), respectively. These results in heavily pretreated RRMM pts support further clinical evaluation.

[Background] The current standard first-line treatment for acute graft-versus-host disease (GVHD), systemic high-dose steroids, induces clinical responses in a majority of patients. Flares of GVHD after initial improvement often occur during tapering or discontinuation of immunosuppression. There is no consensus regarding the definition of GVHD flare and little has been published regarding its natural history. [Methods] We retrospectively evaluated clinical data and blood samples from 968 allogeneic hematopoietic cell transplantation (HCT) recipients from 23 Mount Sinai Acute GVHD International Consortium (MAGIC) transplant centers who achieved complete response (CR) or very good partial response (VGPR) within 4 weeks of acute GVHD treatment between 2014 and 2021. VGPR was defined as the complete resolution of acute GVHD manifestations except residual stage 1 skin disease. Flares were defined as a recurrence of acute GVHD after achievement of CR/VGPR if (1) patients had an increased symptom severity of at least 1 organ stage; (2) received intensified treatment (increase in steroid dose ≥ 0.25 mg/kg or initiation of additional systemic immunosuppression); and (3) had no prior history of primary disease relapse or donor lymphocyte infusion preceding the flare. Serum samples obtained at the time of CR/VGPR and at the time of flares were analyzed for ST2 and REG3α concentrations that generated MAGIC algorithm probabilities (MAPs) resulting in previously validated Ann Arbor (AA) scores (1, 2, and 3). [Results] The median recipient age at HCT was 55 years (range: 0 to 79); 18.6% of patients had grades III-IV acute GVHD before CR/VGPR. The median maximum daily dose of corticosteroids before CR/VGPR was 1 mg/kg methylprednisolone equivalent (range, 0.1 to 3.2 mg/kg). Flares developed within 6 months following CR/VGPR in 210/968 (21.7%) patients with a median onset of 28 days (range: 2 to 448). Symptom severity at the onset of flare symptoms varied widely (grade I: 22%; grade II: 38%; grade III-IV: 41%) and the development of a flare was associated with a five-fold increase in NRM (hazard ratio [HR], 4.84 [95% CI, 3.19-7.36], P < 0.001) when considered as a time-dependent covariate in a multivariate regression model. The large majority of non-relapse deaths after flares (54/71, 76%) were due to acute GVHD or complications from its treatment. The AA scores at the time of first CR/VGPR successfully stratified patients for risk of six-month NRM (AA1: 5%, AA2: 11%, AA3: 34%, P < 0.001) (Figure A). Increasing AA score at CR/VGPR was also associated with significantly increased risk of GVHD flares (Figure B). Not only did the risk of flare increase with each rising AA score, but the number of patients with severe (grade III/IV) symptoms at flare onset also increased (AA1: 34%, AA2: 43%, AA3: 54%). We next generated a multivariate regression model of risk factors for the development of flares. High AA scores at the time of CR/VGPR (AA2: HR, 1.81 [95% CI, 1.32-2.48], P = 0.001; AA3: HR, 3.14 [95% CI, 1.98-4.98], P < 0.001), HCT from HLA mismatched unrelated donor (HR, 1.74 [95% CI, 1.00-3.02], P = 0.049), and interestingly, rapid achievement of CR/VGPR from the time of initial treatment (≤14 days) (HR, 1.84 [95% CI, 1.21-2.80], P = 0.004) were all identified as significant risk factors. Meanwhile, no other transplant, GVHD, or treatment characteristics associated with the development of flares including maximum GVHD severity, maximum steroid dose, and use of additional immunosuppressive agents other than steroids before CR/VGPR. AA scores measured at the onset of flare symptoms in 98 patients also predicted six-month NRM (AA1, 6%; AA2, 19%; AA3 42%, P = 0.01). [Conclusion] Despite advances in treatment, flares of GVHD symptoms following excellent (CR/VGPR) responses still occur in over one fifth of patients in current practice and are associated with a five-fold increase in six-month NRM. AA scores from serum biomarkers predict outcomes despite the absence of symptoms, suggesting that MAGIC biomarkers detect subclinical damage to GI crypts that can drive later recrudescence of clinical GVHD. Measurement of the MAP at the time of response to GVHD treatment may thus help to risk-stratify tapering strategies of immunosuppressive therapy.

The overall response rate (ORR) 28 days (D28) after treatment has been adopted as the primary endpoint for clinical trials of acute graft versus host disease (GVHD). ORR combines complete response (CR) and partial response (PR) because CR and PR have very similar non relapse mortality (NRM). D28 ORR has some disadvantages: first, physicians usually decide to modify immunosuppression much earlier than D28, and second, NRM does not always correlate well with ORR at D28, particularly for patients who present with intermediate risk or low risk disease. MAGIC serum biomarkers at day 14 (D14) of GVHD treatment have been shown to correlate better with NRM than clinical symptom response (Srinagesh et al, Blood Advances, 2019). We therefore hypothesized that a combination of clinical symptom severity and biomarkers at D14 of treatment would predict NRM at least as well and possibly better than clinical response at D28. We studied 1144 patients from 23 MAGIC sites who were systemically treated with at least 0.25 mg/kg/day of systemic steroids (prednisone equivalents) and had clinical data and serum samples available in the MAGIC database and biorepository. We divided the patients into a training set (n=764) and a validation set (n=380). We used 12-month NRM from the time of acute GVHD onset as the primary outcome of interest. We first trained a recursive partitioning algorithm in the training set to create a response model (MAGIC D14 clinical response) according to overall GVHD grade at both onset and D14 that predicted 12-month NRM and then applied it to the validation set. Patients that either progressed to grade III/IV GVHD, continued having grade III/IV GVHD, or only improved to grade II at D14 from grade III/IV at D0 had high NRM and were classified as non-responders. Patients with grade I/II GVHD at day 0 who had grade 0-II GVHD at day 14 and patients who improved to grade 0/I at day 14 from grade III/IV at day 0 had low NRM and were classified as responders. Although counterintuitive, responders included patients whose GVHD remained at grade II because the 12 month NRM of this group was only 20%. The new clinical model predicted NRM as well as the D28 standard response model in the validation set. When we integrated the D14 MAP biomarker score (low: ≤ 0.290 vs high: >0.290) with the new D14 clinical response (D14 MAGIC integrated response), we observed three response groups of integrated response with strikingly different 12 month NRM (8%, 35%, 76%, p<0.001), in contrast to the D28 standard response (Figure 1A, 1B). D14 complete response required MAGIC clinical response with low MAP; D14 partial response required either MAGIC clinical response with high MAP or MAGIC clinical non-response with low MAP; and D14 non-response required MAGIC clinical non-response with high MAP. The D14 response groups also displayed significant differences in 12 month OS (82%, 58%, 14% respectively, p<0.001) We then compared the D14 integrated response with the D28 standard response for 12 month NRM prediction. This D14 integrated response model was superior for time-dependent AUC (0.78 vs 0.71, P=0.03), sensitivity (0.71 vs 0.54), positive predictive value (0.52 vs 0.48) and negative predictive value (0.92 vs 0.89), with minimal loss in specificity (0.85 vs 0.87) in the prediction of 12-month NRM compared to the D28 standard response model. Using decision curve analysis, the D14 integrated response displayed higher net benefit (correct identification of patients that will experience NRM by 12 months) over the whole range of threshold probabilities/preferences for changing immunosuppression when 12-month NRM was used as the outcome. We conclude first, that the definition of response that uses onset and D14 grades is as accurate as D28 ORR model; and second, that a model using clinical grades and biomarkers on D14 more accurately predicts long term NRM than the standard D28 definition and may be useful as a clinical trial endpoint.

Background: Acute myeloid leukemia (AML) therapy in older patients (age ≥ 60) has undergone a transformation with the introduction of multiple targeted therapies, which has allowed more patients to receive therapy than before. The most successful has been the combination of venetoclax + azacitidine (VA) which generated higher overall complete response rates in phase 2 studies than would be expected with azacitidine alone, leading to accelerated FDA approval on 21Nov2018. The VIALE-A phase 3 study confirmed the improved overall survival (OS, median 14.7 versus 9.6 months) of VA, leading to full FDA approval for marketing. This retrospective analysis provides real world data on the impact of baseline clinical and genomic markers of individuals receiving intensive chemotherapy versus VA. Methods: The precision medicine Beat AML Master Trial (NCT03013998) assigns patients to biomarker specific sub-study treatments based on targeted DNA sequencing and cytogenetics. However, a large subset of patients did not enroll on a sub-study, but were followed for off-study treatment and OS. From this subset, patients enrolled onward from 21Nov2018, when VA received accelerated approval, were examined for differences in clinical/genetic characteristics and OS in those receiving venetoclax + hypomethylating agent (V/HMA), any form of intensive chemotherapy (IC), alternative non-intensive therapy (NIT), or no therapy. The genetic mutations identified in this study are characterized by a variant allele frequency of 20%+, as defined in the trial for determining the dominant clone. The method of Kaplan-Meier was used to estimate OS, and the Cox model was fit to associate patient characteristics with OS. Results: From 21Nov2018, a total of 468 AML patients consented to the Beat AML trial and did not enroll to a sub-study. Treatment was chosen by the investigator based upon available clinical and genomic data. Of these 468 patients, 62 did not receive treatment, 2 had treatment data missing, 226 were treated with V/HMA, 112 with IC, and 66 with NIT. Demographics for all patients include median age 71 (60-90), 40% female, performance status (PS) (0-20%; 1-55%; 2-22%; 3-3%), median white blood cell (WBC) 4.1 (range 0.3-298.6), complex karyotype (CK) 20.6%, core binding factor (CBF) 7.8%, KMT2A-rearranged 3.6%, NPM1-mutated (m) 15.6%, IDH2m 14.6%, TP53m 13.2%, FLT3-ITD/TKD 12.9%, and NRASm/ PTPN11m/ KRASm/ NF1m/ CBLm 23.6%. Demographics that were significantly different (p<0.01) among the three groups (V/HMA, IC, and NIT) include age (younger in IC), PS (worse in NIT), AST/ALT (worse in NIT), CBF (more in IC), CK and TP53m (less in IC). Of the 404 patients who underwent treatment with V/HMA, IC, or NIT, 208 have died with those surviving having a median follow-up of 22.3 months. Figure 1 summarizes the OS of each treatment group. The median OS (95% CI) from time of initiating therapy is 13.6 (10.9-16.8) for V/HMA, 33.8 (20.7-not reached) for IC, and 11.6 (5.2-21.3) months for NIT. Univariable analysis for OS was significant at p<0.05 for increased age, WBC, PS, hemoglobin, CBF, CK, NPM1m, TP53m, TET2m and IC versus V/HMA. Multivariable analysis was significant at p<0.05 (hazard ratio) for increased age (1.14), PS (1.83), WBC (1.08), hemoglobin (0.91), and select genomic aberrations including CBF (0.37), NPM1m (0.35), and TP53m (2.1). Conclusions: These results from a large cohort of older AML patients treated with V/HMA, IC, or NIT show that their outcome is best defined by pre-treatment clinical features previously identified including age, performance status, WBC and hemoglobin along with limited genomic characteristics including CBF, NPM1m, and TP53m. While univariate analysis of OS favored IC over V/HMA and NIT, multivariable analysis supports that this advantage was most likely due to the favorable clinical and genomic features. The OS of V/HMA patients in this cohort is similar to that in the VIALE-A registration study of VA, providing further justification for this treatment for older AML patients deemed ineligible for intensive chemotherapy. Additionally, this data supports use of the patient cohort in this study for ongoing work in understanding and/or validating biomarkers associated with survival with V/HMA.

Introduction: Allogeneic hematopoietic cell transplantation (HCT) remains the only therapy for long-term disease control for many high-risk hematologic malignancies (HM). HCT use in older HM patients (pts) continues to increase. However, concerns of excessive transplant-related morbidity and non-relapse mortality (NRM) limit referrals and broader application of curative intent HCT. The HCT-comorbidity index (HCT-CI) was initially developed to improve risk-stratification of NRM. More recently, geriatric assessment (GA) and biomarkers have emerged as promising additional tools that may refine estimates of these risks. We hypothesized that a combination of health assessments by GA and biomarkers would constitute a robust and valid model, CHARM, for accurate personalized estimation of one-year (1-yr) NRM. Here, we report the results of the largest, first of its kind, prospective study of older recipients of HCT through the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) 1704 study (NCT03992352). Patients and Methods: Adults aged ≥60 years (yrs) with HM institutionally eligible for HCT were enrolled (n=1226) from 49 centers in the US between 2019 - 2021. Within 21 days of conditioning, 13 prospectively identified older pt.-specific health variables, informed from prior studies, were collected: age, HCT-CI, % of weight loss over the past yr, pt reported Karnofsky performance status, PROMIS physical function scale, instrumental activities of daily living (IADL), number of falls, PROMIS depression scale, number of prescribed medications, 4-meter walk speed, cognition by the Montreal Cognitive Assessment (MoCA), C-reactive protein (CRP) and albumin. The CHARM score to predict NRM within 1 yr was built using a multivariable (MVA) Fine-Gray model, with multiple imputation to handle modest missingness in covariates and grouped penalized variable selection using SCAD to identify variables to retain in the model. Final variables were used as continuous. The model further considered adjustment for conditioning intensity, CMV serostatus, and donor type. Area under the ROC curve (AUC) was calculated to validate the CHARM and compare to HCT-CI alone, with bootstrap sampling to correct for optimism in the within-sample AUC. MVA of overall survival (OS) within 1 yr used the CHARM score and adjusted for other significant variables derived from stepwise regression. Results: The primary analysis included 1105 pts who were confirmed eligible and proceeded to transplant. Median age was 67 (range 60-82) and 32% were ≥ 70 yrs. AML (45%) and MDS (30%) were the most common indications and matched donors the most frequent donor type at 72%. Reduced intensity conditioning with fludarabine (flu)-melphalan (38%) and flu-busulfan (20%) were the most common regimens. Baseline geriatric vulnerabilities among evaluable pts were frequent including slow walk speed (<0.8 meter/second) in 22%, any IADL limitation in 37%, and cognitive impairment (MoCA < 23) in 12%. 1-yr NRM was lower than expected at 14.4% with 1-yr OS of 72%. In the MVA model, albumin, CRP, HCT-CI, and weight loss were independently associated with NRM (Table) and comprised the CHARM. Of note, increasing age did not significantly affect NRM. The CHARM had within sample and bootstrap corrected AUC of 0.641 and 0.607 whereas the HCT-CI alone achieved corresponding AUC values of 0.601 and 0.598. NRM by tertiles is shown in Figure. Each point increase in the CHARM (median -2.2504, range -3.6327 to 0.1381), was associated with a hazard ratio (HR) of 2.83 (95% CI 2.12 - 3.78, p < 0.0001) for NRM. The CHARM also predicted overall mortality within 1-yr with a HR of 2.04 (1.65- 2.53, p <0.0001) per one point increase, independent of the disease risk index, which had a HR of 1.5 (95% CI 1.12 - 1.99, p =0.0059) for high/very high vs low/intermediate categories. Conclusions: We report on the first prospectively established tool, CHARM, to risk-stratify older adult HCT comprised of simple and readily available parameters in transplant and oncology clinics. Adopting CHARM in practice may promote HCT referrals and access for older pts, given low risks of NRM among CHARM lower 2/3 rd tertiles. Identifying high-risk CHARM pts pre-HCT will promote developing novel strategies to reduce NRM. Further analysis of the impacts of the 13 health assessment variables on geriatric morbidity such as disability trajectories is in-process.

Introduction: Lymphodepletion (LD) chemotherapy is critical for the efficacy of CAR-T therapy by eradicating immunosuppressive cells, inducing costimulatory molecules, and promoting expansion and persistence of CAR-T cells. It also can contribute to an increased risk of infections, cytopenia, and other toxicities. We evaluated the utilization of varying LD regimens used in standard-of-care (SOC) autologous B-cell maturation antigen-directed (BCMA) CAR-T therapy with ide-cel or cilta-cel for relapsed/refractory multiple myeloma (RRMM) and the effect on outcomes and toxicity. Methods: Data were retrospectively collected from patients with RRMM who underwent LD and CAR-T cell infusion by December 31, 2022, from 13 US academic institutions with SOC ide-cel or cilta-cel. Response rates and other categorical variables, specifically LD regimen, were tested for association using Wilcoxon rank-sum (or Kruskal-Wallis for three or more groups) or Fisher's exact tests, respectively. Results: A total of 523 patients were infused at the time of data cut-off with 489 patients evaluable for safety and survival analyses; 368 (75%) were infused with ide-cel and 121 (25%) with cilta-cel. The median age was 65 years old (range 30-90) with 206 females (42%) and 283 males (58%), and 13% with ECOG performance status ≥ 2 at time of LD. Fludarabine and cyclophosphamide (Flu/Cy) LD was used in 422 patients while 67 patients received other LD regimens including bendamustine-based (n = 35, 52%), cladribine-based (n = 25, 37%) or cyclophosphamide alone (n = 7, 10%). The primary reason for use of Flu/Cy LD was institutional guidance or SOC in 378 patients (90%), while the primary reason for use of other LD regimens was due to the fludarabine shortage in 65 patients (97%) with 3% citing physician's choice or institutional guidance. No significant difference was identified among response outcomes, with those receiving Flu/Cy LD achieving an ORR of 84% compared to 81% with other LD regimens (p = 0.59) and no difference observed in rates of ≥ VGPR (66% Flu/Cy LD vs 60% other LD; p = 0.48). Of those evaluable for MRD at 1 and 3 months, the MRD negative rate at 10 -6 for those with Flu/Cy LD was 77% (n= 137) and 77% (n=113) and with other LD regimens was 66% (n=35) and 79% (n=28), respectively. At a median follow-up of 9.7 months, no statistically significant difference was noted in median progression free survival (mPFS) with Flu/Cy vs other LD regimens (9.3 mos vs NR) or overall survival (OS) (19.4 mos vs NR). When stratified by type of CAR-T therapy, treatment with bendamustine-based LD was associated with an inferior mPFS compared to those receiving Flu/Cy LD in patients treated with ide-cel (3.8 vs 8.5 mos; p=0.0056), though not by multivariate analysis. Univariate analysis of patients treated with ide-cel between Flu/Cy and bendamustine LD did not reveal any significant differences in age, gender, ECOG, R-ISS stage, extramedullary disease, high-risk cytogenetics or renal dysfunction (Cr < 45 ml/min). LD regimen was not a predictor for PFS on multivariable analyses amongst patients treated with ide-cel, while ECOG ≥ 3 (hazard ratio [HR]= 4.44, 95% confidence interval [CI]= 1.40, 14.08) and t(4,14) (HR= 2.02, 95% CI=1.14, 3.59) were associated with worse PFS. No difference in mPFS by LD regimen was observed in patients receiving cilta-cel, which was a smaller cohort (mPFS: Flu/Cy 11.7 mos, bendamustine-based NR, cladribine-based NR, cyclophosphamide NR). Rates of all grade CRS (81% vs 70%), Grade ≥ 3 CRS (3% vs 3%), all grade ICANS (19% vs 12%, and Grade ≥ 3 ICANS (4% vs 2%) were similar among those receiving Flu/Cy or other LD regimens, respectively. Patients receiving Flu/Cy LD were less likely to have any grade cytopenia at 1 month (33% vs 55%, p < 0.001) and 3 months (52% vs 69%, p < 0.001), with no observed difference in infection rate. Conclusions: The fludarabine shortage experienced in the US in late 2022 necessitated the use of alternative LD regimens with BCMA-directed CAR-T therapy with most centers relying on bendamustine- or cladribine-based regimens. Use of bendamustine-based LD was associated with inferior PFS in patients receiving ide-cel on univariate analysis, but not on multivariate analysis after adjusting for other prognostic factors. In summary, there is no clear difference in efficacy or safety between Flu/Cy and non-Flu/Cy LD in patients receiving BCMA-directed CAR-T therapy. *Authors contributed equally

Background. Acute myeloid leukemia (AML) is a heterogenous disease that occurs primarily in older adults with a median age of 69 years at diagnosis. Most studies that characterize the genomic landscape of AML include younger adults with the majority of patients being younger than 60 years of age. We aimed to study the mutational landscape of newly diagnosed AML patients aged 60 years or older. Methods.Samples were collected from the multi-center Beat AML Master Trial (Burd, Nat Med 2020). Patients were enrolled between 2016 and 2023. Informed consent was obtained according to the Declaration of Helsinki. Patients diagnosed with non-APL AML and who were aged ≥ 60 years old were included. Patients underwent bone marrow aspiration and biopsy, cytogenetic analysis, FLT3-ITD ratio assessment (LeukoStrat CDx FLT3 Mutation Assay, Invivoscribe) and next generation sequencing (NGS) using FoundationOne®Heme(Foundation Medicine) to interrogate the entire coding region of 406 genes and select introns of 31 genes involved in rearrangements, as well as RNA sequencing to interrogate 265 genes known to be somatically altered in human hematological malignancies. The presence of multiple hotspot mutations within one gene in an individual patient was counted as one gene mutation. Patterns of co-occurrence between gene mutations were calculated using the Phi correlation coefficient. Statistical analyses were performed using R statistical software. P<0.01 was considered statistically significant. Results. A total of 1088 newly diagnosed AML patients were identified, of whom 1032 were 60 years or older. Patients had a median age of 72 years at time of diagnosis (range 60-92 years). Forty-two percent of the patients were female, most patients were non-Hispanic and 79% were Caucasian. NGS data were available for 1024 patients and mutations were identified in 461 different genes. Patients had a median number of 11.0 mutations (range 3.0 to 28.0). The most frequently mutated genes were DNMT3A (n=257; 25.1%), TP53(n=255; 24.9%), TET2 (n=243; 23.7%), RUNX1 (n=225; 22.0%), SRSF2 (n=221; 21.6%), ASXL1 (n=216; 21.1%), NPM1 (n=206; 20.1%), FLT3 (n=205; 20.0%), IDH2 (n=190; 18.6%), NRAS (n=208; 16.9%), PTPN11(n=104; 10.2%), STAG2 (n=101, 9.9% and IDH1 (n=99; 9.7%) (Figure 1A). FLT3-ITD was present in 98 (12.1%) of the 810 patients who were tested. Strongest significant co-occurrence was found between FLT3and NPM1 (n=103), STAG2 and ASXL1 (n=63), ASXL1 and RUNX1 (n=92), ASXL1 and SRSF2 (n=88), RUNX1 and SRSF2 (n=94), STAG2 and SRSF2 (n=51) and DNMT3A and NPM1 (n=92) (p<0.01). Pairwise negative correlations were observed between TP53 and NPM1 (n=6), TP53 and SRSF2 (n=17), and between NPM1 and RUNX1 (n=6) (p<0.01) (Figure 1B). The cytogenetic profiles and the full genomic landscape will be presented during the ASH meeting. Discussion. This is the largest study investigating the mutational profile in older adults with AML aged 60 years and older. Due to the 7-day screening period of the Beat AML study, patient selection was biased towards less-rapidly proliferative AML. We showed that the pattern of gene mutations was markedly different from other studies in AML that mainly included younger AML patients (Papaemmanuil, NEJM 2016; TCGA, NEJM 2013 ). The frequency of mutated TP53 was substantially higher in older AML patients, as was the occurrence of myelodysplasia-related gene mutations (e.g., SRSF2, RUNX1, ASXL1, STAG2, U2AF1, and SF3B1) and gene mutations in IDH1, IDH2 and TET2. In contrast, NPM1 mutation was less frequently mutated in older AML patients. Furthermore, we demonstrated that a large proportion (46%) of the AML patients older than 60 years of age do have a mutation that is potentially targetable for treatment ( FLT3 IDH1 IDH2 and NPM1). The high incidence of mutated TP53 and MDS-related gene mutations underscores the increased incidence of high-risk AML and the need for innovative personalized therapies in this older age group. Figure 1. A. Co-occurrence of the 15 most frequently mutated genes, and B. co-correlation between the 15 most frequently mutated genes. Blue indicates positive correlation, red indicated negative correlation. Only significant correlations (p<0.01) are shown.

Progression of myeloproliferative neoplasms to blast phase (BPMPN) is associated with lack of response to conventional therapies and dire clinical outcomes. Consequently, there is a major unmet need to develop new therapies for BPMPN. Chromothripsis, the process of catastrophic shattering and haphazard repair of chromosomes, is a key contributor to somatic variation in cancer, but this phenomenon has not yet been described in BPMPN. More broadly, whether chromothripsis might result in actionable molecular events that are amenable to targeting remains an open question. To characterise the contribution of structural variants to BPMPN, we first performed integrated copy number and mutation profiling in 64 BPMPN patients by SNP karyotyping and targeted next generation sequencing. We observed a recurrent pattern of chromothripsis that involved chromosome 21, which together with other structural variants led to amplification of a common region of chromosome 21 (‘chr21amp‘) in ~25% of patients (GISTIC q-val<0.01, Fig 1A). Chr21amp was associated with TP53 mutations and a higher number of copy number alterations. Patients with chr21amp had a particularly aggressive and treatment-resistant phenotype, with 0% surviving 12 months compared to 46% in the non-chr21amp pts ( p=0.0007), retaining significance in multivariate analysis including after correction for TP53 mutation status. Whole genome sequencing confirmed that the chromosomal rearrangements resulting in chr21amp occurred by different mechanisms, ranging from simple amplification to highly complex chromothriptic events involving multiple chromosomes. There were no recurrent translocation partners or mutations. The minimally amplified region (MAR) spanned 2.7Mb and contained 24 genes, with a median copy number of 3.5 (range 2.7-8.3) Single-cell transcriptomics combined with allelic resolution genotyping revealed that chr21amp was present in the dominant subclone and occurred subsequent to JAK2V617F and mut TP53 acquisition. Chr21amp was detectable in phenotypic HSCs and throughout early stages of hematopoiesis, but not in mature erythroid cells, consistent with a differentiation block. Of the 24 genes in the minimally amplified region, only one gene, DYRK1A, a serine threonine kinase linked to cell proliferation and survival, was both differentially expressed (single-cell and bulk RNAseq) and differentially accessible (ATACseq). To explore the functional role of DYRK1A in BPMPN we performed shRNA and CRISPR-mediated DYRK1A-knockdown and knockout (KO) in BPMPN cell lines (HEL and SET-2), which led to impaired cell proliferation. The DYRK1A inhibitors EHT1610 and GNF2133 also led to dose-dependent growth inhibition. DYRK1A-KO BPMPN HEL or SET2 cell clones showed a reduced ability to propagate leukemia in vivo with a significant survival advantage vs. wild type control mice. BPMPN chr21amp+ primary patient CD34+ cells were highly sensitive toDYRK1A inhibitors, while healthy control CD34+ cells were unaffected Prior studies have shown that DYRK1A activates the DREAM complex, a transcriptional repressor of DNA-repair pathways. In chr21amp patient cells, the DREAM DNA repair gene signature was significantly downregulated (NES -1.74, q-val <0.001), while conversely in CRISPR DYRK1A KO SET2 cells the transcriptional DNA repair signature was upregulated (NES 1.76, q-val <0.001). In functional assays, CRISPR DYRK1A KO was protective against DNA damage, with a reduction in γ-H2AX foci after etoposide treatment or irradiation ( p<0.01 for both). A second mechanism of leukemogenesis emerged from geneset enrichment analyses, which suggested enhanced JAK-STAT signaling in chr21amp BPMPN cells and downregulation in the CRISPR DYRK1A KO context. We validated this by showing that DYRK1A overexpression activates and potentiates STAT5B transcriptional activity in a luciferase reporter assay. Finally, we noted that the STAT target BCL2 was selectively upregulated in chr21amp cells. BCL2 inhibition showed strong synergy with DYRK1A inhibitors for induction of BPMPN cell apoptosis (Bliss synergy score 15). Collectively, these findings define the chr21amp event as a novel prognostic biomarker in BPMPN. We pinpoint DYRK1A amplification as a central driver of genomic instability and exacerbated JAK-STAT signalling, for the first time linking chromothripsis to a specific druggable target ( Fig 1B).

Background: Although recently available immune-based approaches in multiple myeloma produce high response rates, curative outcomes have not yet been achieved, which highlights the need for new agents that further activate the immune system without increasing toxicity. ORIC-533 is a highly potent and selective, orally bioavailable, small molecule inhibitor of CD73, an enzyme expressed by various cell types, including immune cells and which catalyzes the generation of adenosine from adenosine monophosphate (AMP) (Allard 2019). Adenosine itself is highly immunosuppressive, diminishing activity of a range of immune cell types, including T, NK, and dendritic cells (Young 2014). By blocking adenosine production from AMP via inhibition of CD73, ORIC-533 has demonstrated the ability to restore and enhance immune function. Multiple myeloma (MM) patient bone marrow (BM) contains multiple cell types that also express CD73, including immune cells, cancer-associated fibroblasts, mesenchymal stem cells, and endothelial cells (Allard 2019). Moreover, elevated adenosine levels in the MM BM niche correlate with disease progression (Horenstein 2016; Yang 2020). We have previously observed that CD73-mediated adenosine activity suppresses the cytolytic antitumor immune function in the MM BM milieu (Ray 2022). ORIC-533 treatment reduced adenosine production, overcame this immune suppression with evidence of restored DC-mediated priming and activated cytotoxic CD8 + T-cell function, and significantly enhanced immune cell cytolytic behavior against RRMM tumor cells in autologous patient ex vivo experiments (Junttila 2022), making ORIC-533 a potential immunotherapy for patients with MM. Methods: ORIC-533-01 (NCT05227144) is an ongoing i3+3 Phase 1b dose escalation study in patients with RRMM. The primary objectives are to determine single agent safety/tolerability and pharmacokinetics (PK) of ORIC-533 to select the RP2D. Pharmacodynamic assessments include measurement of CD73 functional activity in serum and BM, as well as enumeration of immune cell subsets and activation state in blood and BM. Patients are also evaluated for clinical efficacy using IMWG criteria. Results: As of 23 June 2023, 17 patients received ORIC-533 once daily across 4 dose levels (400 mg to 1600 mg). All patients were triple-class refractory, 88% were penta-refractory, and 59% also received prior anti-BCMA/CD3 bispecific therapy or anti-BCMA CAR-T therapy. Overall, ORIC-533 was very well tolerated, with 5 patients experiencing a total of 10 treatment-related adverse events (TRAEs). Fatigue was the only G3 AE and the only TRAE seen in more than 1 patient (1 event each of G3 and G2); all other events seen in 1 patient each, were G1 or G2 in severity, and of no specific system organ class. No dose limiting toxicities, no Grade ≥4 TRAEs, and no treatment-related serious adverse events have been observed. PK showed increased exposure with dose with a plasma half-life of ~24 hrs. Soluble CD73 enzymatic activity was nearly completely inhibited by C1D15 in serum of all patients across all dose levels, while the largest relative suppression in surface CD73 activity in BM cells was observed at the highest dose level. There was also evidence for increases in the abundance of circulating NK and CD8+ T cells after 1 treatment cycle, with preliminary evidence of enhanced CD8+ T-cell activation at the highest dose levels tested in both peripheral blood and BM. In addition, early evidence of single agent clinical activity was observed. Conclusions: ORIC-533 has demonstrated an acceptable safety profile and preliminary evidence of immune activation in a heavily pretreated RRMM patient population. Enrollment is ongoing and updated data will be presented.