Citations

Abstract Despite the remarkable efficacy of chimeric antigen receptor T -cell therapy (CART) for the treatment of B-cell malignancies, durable remission remains limited often due to tumor relapse. We have previously demonstrated that tumor-derived extracellular vesicles (EVs) induced CART cell failure in preclinical models. To characterize the impact of tumor EV induced CART cell dysfunction, we assessed microRNA (miRNA) profiles contained within tumor EVs from two independent patient cohorts and studied how they contributed to CART dysfunction. Our first cohort included patients with chronic lymphocytic leukemia (n=50). We previously showed that CLL patient derived EVs induce a state of CART cell dysfunction. To understand this dysfunction, we interrogated the miRNA cargo significantly enriched in CLL EVs and how their coculture impacts CART signaling by RNAseq. Here, we found a significant enrichment in miR-125a within CLL EVs as compared to healthy donor controls (p=.0001). CART cocultured with CLL EVs showed alterations in T cell activation pathways, where miR-125a targets TNFAIP3 and NFkB pathways were activated. These findings implicate miR-125a from CLL EVs in CART dysfunction. Next, we aimed to validate the impact of miRNA on CART cell outcomes in the clinic. We interrogated miRNA profiles from patients with diffuse large B cell lymphoma (DLBCL) treated with CART cell therapy (CART19-28ζ, axicabtagene ciloleucel). EV miRNA cargo was compared between responders (complete remission at 6 months, n=10) and non-responders (no response 1 month post CART19, n=10) to identify differentially enriched miRNAs across groups. miR-125a was again significantly upregulated in EVs of non-responders as compared to responders to CART19 treatment (fold change=3.28, padj=.018). To study the direct effect of miR-125a on CART cell functions, we generated and studied the effector functions of CART19-28z following transfection with miR-125a or negative miR control. CART19 cells transfected with miR-125a showed a dose dependent decrease in killing of lymphoma cells as compared to miR-control (p=.0001). miR-125a also significantly increased the rate of apoptosis in CART19 cells (fold change=1.95, p=.024) and decreased the level of CART proliferation (fold change=.71, p=.013) as compared to controls. Notably, miR-125a did not impact tumor cell growth, further verifying a direct CART effect. In summary, our studies demonstrate the impact of tumor derived miRNAs on CART cell outcomes. They identify that miR-125a is 1) associated with CLL EV induced CART dysfunction, 2) significantly elevated in non-responders to CART therapy in the clinic, and 3) able to decrease CART19 efficacy through reduced CART killing/proliferation and increased apoptosis. These results highlight a novel mechanism of CART19 failure induced through miRNA cargo delivery by tumor-derived EVs and the role of miR-125a in inducing CART19 dysfunction. Citation Format: Olivia Sirpilla, R. Leo Sakemura, Ismail Can, Truc N. Huynh, James H. GIrsch, Claudia Manriquez Roman, Carli M. Stewart, Kun Yun, Ekene J. Ogbodo, Long Mai, Omar Gutierrez Ruiz, Makena Rodriguez, Brooke Kimball, Hong Xia, Jose C. Villasboas, Stephen Ansell, Nora Bennani, Patrick B. Johnston, Jonas Paludo, Januario Castro, Mohamed Kharfandabaja, Sameer Parikh, Neil Kay, Yi Lin, Elizabeth Siegler, Saad Kenderian. Tumor-derived microRNA125a induces CART cell apoptosis and failure in B cell malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3841.

Background: CD19 CAR T-cell therapy is a novel cancer treatment for B-cell malignancies. Systemic inflammation due to Cytokine Release Syndrome (CRS) can occur. Elevated levels of cytokines have been linked to valve damage. Hypothesis: Evaluate changes in valve morphology or progression of valvular heart disease in adult patients after CD19 CAR T-cell therapy and by clinical CRS grade. Methods: Patients that underwent CD19 CAR T-cell therapy with both a baseline and a post-treatment transthoracic echocardiogram (TTE) were included. Patient characteristics and outcomes were abstracted from the electronic medical record. CRS was categorized as CRS<2 and CRS ≥2 for all patients using the ASTCT 2019 criteria. Valve thickening was graded as a dichotomous variable. Valve disease (regurgitation or stenosis) was ranked on a 1-to-6-point numeric scale (none, mild, mild-moderate, moderate, moderate-severe, severe) and grade point value difference was calculated. Variables were compared by Chi Squared and Student’s t tests. Results: 114 patients were included with a median TTE follow-up of 44 days, 54% developed CRS ≥2 (Table 1a). Overall, no statistically significant changes in valve morphology and valve disease progression were observed in the cohort (Figure 1a, 1b). Among CRS groups, valve morphology changes and valve disease progression were similarly distributed (21% in CRS <2 vs 19% in CRS ≥2, p=0.623 and 28% in CRS <2 vs 24% in CRS ≥2, p=0.62 respectively) (Fig. 1a). In the cases that progression was observed, it was mostly mild, and regurgitation was the most common pattern (Fig. 1c). Conclusions: This is the first study to evaluate the incidence of cardiac valve disease progression or thickening in patients treated with CD19 CAR T therapies. We can conclude that no progression of valve disease or changes in valve morphology were observed in its entirety or by CRS groups. Longer follow up is needed to validate these findings.

AbstractIntroductionThe infusion of autograft Natural Killer Cells (NKC)/CD14+HLA‐DRDIM ratio is a predictor of survival in lymphoma patients undergoing autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT). This study evaluated if the Day 100 NKC/CD14+HLA‐DRDIM ratio still functions as a prognostic immune‐biomarker.MethodsThis was a retrospective, single‐institution, cohort analysis including 107 patients in this study that had clinical assessment at Day 100 post‐APBHSCT from our prior phase III trial. We evaluated the prognostic ability of the Day 100 NKC/CD14+HLA‐DRDIM ratio to predict overall survival (OS) and progression‐free survival (PFS) using Cox regression model for outcome analysis and survival by Kaplan–Meier method.ResultsThe median follow‐up from day 100 was 94.7 months (range 4.83–158.1 months) for the entire cohort. Patients with a Day 100 NKC/CD14+HLA‐DRDIM ratio ≥1.67 experienced better OS and PFS versus those with a Day 100 NKC/CD14+HLA‐DRDIM ratio <1.67: median OS was not reached versus 49.7 months, the 5‐year OS rates were 91% (95% CI, 81%–96%) versus 40% (95% CI, 27%–55%), p < .0001, respectively; and median PFS was not reached versus 23.5 months, the 5‐year PFS rates were 66% (95% CI, 55%–81%) versus 21% (95% CI, 15%–40%), p < .0001, respectively. Day 100 NKC/CD14+HLA‐DRDIM ratio was an independent predictor for OS and PFS in the multivariate analysis.ConclusionsDay 100 NKC/CD14+HLA‐DRDIM ratio is a prognostic immune‐biomarker in lymphoma patients post‐ APBHSCT.

Introduction: In Cohorts 1+2 of the ZUMA-1 Phase 1/2 study of axi-cel in R/R LBCL, 11% and 31% of patients (pts) experienced Grade ≥3 cytokine release syndrome (CRS) or neurologic evenets), respectively. To minimize the toxicities seen with axi-cel, a safety management cohort, Cohort 6 (N=40), was added to evaluate whether prophylactic (ppx) corticosteroids (CS) could decrease grade ≥ 3 CRS or ICANS. The 2-year update of ZUMA-1 Cohort 6 showed no grade ≥3 CRS and 15% grade ≥3 ICANS without any difference in objective response rate (ORR) or complete response rate (CR) when compared to cohorts 1+2 (Oluwole Blood 2022). The FDA had previously approved an update to the prescribing information for axi-cel to include use of ppx CS across all approved indications in January 2022. However, ppx CS is not a mandatory standard treatment and we sought to establish the clinical outcomes in the real-world practice. Methods: To assess the clinical outcomes of pts receiving ppx CS, we conducted a multicenter retrospective analysis of pts with R/R LBCL who were treated with axi-cel since the FDA approval of ppx CS in January 2022. Baseline characteristics, toxicities, and efficacy were compared between the no ppx and ppx CS groups. CRS and ICANS were graded based on ASTCT 2019 guidelines. Event-free survival (EFS) was defined as time from axi-cel infusion to progression, re-treatment, or death. Overall survival (OS) was defined as time from axi-cel infusion to death due to any cause. Results: A total of 66 pts at 5 centers received axi-cel between Jan 31, 2022, and June 20, 2023. Thirty-five (52%) pts received ppx CS, with a median age of 63 years (26-85 years). By histology, 75% (n=50) of the pts had DLBCL, 13.6% (n=9) had high grade B-cell lymphoma (HGBL), 9.1% (n=6) had transformed follicular lymphoma (TFL) and 1.5% (n=1) primary mediastinal LBCL (PMBCL). 59% of the pts (n=37) had IPI &gt;2 and 66% (n=43) had stage III/IV disease. The baseline characteristics at the time of apheresis are shown in Table 1 and were comparable between the 2 groups, except for more HGBL, fewer prior lines of therapy and longer median time from apheresis to axi-cel infusion in the ppx CS group. Among the entire cohort, only 37% (n=25) met ZUMA-1 eligibility criteria at the time of lymphodepletion, and 67% (n=44) needed bridging therapy. Any grade CRS occurred in 88% (n=58) of the pts, with grade ≥2 CRS in 38% (n=25). Any grade ICANS occurred in 55% (n=37) of the pts, with grade ≥2 ICANS in 41% (n=27). Any grade ICANS was significantly lower in the ppx CS group than the no ppx group (45.7% vs 65.5%). The rates of any grade CRS, grade ≥2 CRS, grade ≥2 ICANS, the median time to CRS onset, ICANS onset, CRS duration, and ICANS duration were comparable between the 2 groups. Tocilizumab and steroids use was similar between two groups with a trend towards less ICU admission in patients in the ppx CS group. Overall, 14 (21%) pts developed infectious complications within 30 days of axi-cel infusion. The day 30 ORR was 84% and was comparable between the 2 groups (77% in the ppx group vs 93% in the no ppx group). The CR was 45.7% in ppx CS group compared to 65.5% in no ppx group. At a median follow up of 219 days (27-1178), 37 (56.1%) pts had progressed and 25 (37.9%) pts had died. The number of days to progress was significantly lower in the ppx CS arm. The median EFS and OS were not significant between the 2 groups. Conclusions: This multicenter retrospective study showed that the efficacy of treatment with axi-cel in R/R LBCL did not decrease with the use of ppx CS. No significant differences in efficacy or CAR-T-associated toxicities were noted in the 2 groups, potentially due to selective use with patients at presumed higher risk of severe CRS and ICANS. A larger dataset and longer follow-up is needed for risk-stratified analysis and the study is ongoing.

Background: A pivotal clinical trial comparing the efficacy and safety of ibrutinib with zanubrutinib in patients with Waldenström macroglobulinemia (WM) did not achieve its primary endpoint of complete response or very good partial response. In addition, median progression-free survival was not reached in either treatment arm. In the absence of treatment effectiveness differentiation based on clinical trial evidence, we conducted a real-world study to assess patient characteristics, treatment patterns, and all-cause healthcare resource utilization (HRU) in patients with WM who received ibrutinib or zanubrutinib as first-line (1L) therapy. Methods: In this retrospective cohort study, we used the ConcertAI Database to collect claims data of patients with WM aged ≥18 years who initiated single-agent ibrutinib (420 mg/day) or zanubrutinib (320 mg/day) as 1L therapy on or after 9/1/2021 (index date). A 6-month washout period of guideline-recommended WM antineoplastic agents was required to confirm 1L status. Patients were excluded if they were receiving ibrutinib and zanubrutinib concurrently, died within 30 days of the index date, had a record of hematopoietic stem cell transplant, had a record of other ibrutinib indications in the 6 months before index, or were participating in a clinical trial. Baseline demographics and clinical characteristics, therapy duration (number of days between the first and last day of the medication supply), and HRU (all-cause and WM-specific) per-patient-per-month (PPPM) were assessed. Results: The study included 51 patients (ibrutinib, n=30; zanubrutinib, n=21). In both cohorts, most participants were male (ibrutinib, n=20 [67%]; zanubrutinib, n=16 [76%]), and the mean age at baseline was 73 years and 75 years, respectively. At baseline, the median Charlson Comorbidity Index was 0, and the WM-related and ibrutinib/zanubrutinib-related clinical events were similar between the two cohorts. While the zanubrutinib cohort had a higher prevalence of infections (33% vs 3%) and musculoskeletal pain (24% vs 7%) at baseline, the ibrutinib cohort had a higher prevalence of hypertension (20% vs 14%). The baseline prevalence of anemia was similar in both cohorts (ibrutinib, 27%; zanubrutinib, 29%). Mean follow-up was 6.9 months (ibrutinib) and 6.3 months (zanubrutinib). The mean ± SD duration of therapy was 152 ± 112 days (ibrutinib) and 113 ± 99 days (zanubrutinib; p=0.195). The ibrutinib cohort had a significantly lower all-cause HRU PPPM (4.53 ± 3.96 vs 8.53 ± 6.66, p=0.020) and lower WM-specific HRU PPPM (0.11 ± 0.26 vs 0.54 ± 1.14, p=0.104). Conclusions: In this real-world analysis, patients with WM treated with 1L ibrutinib had a numerically longer duration of therapy and lower all-cause and WM-specific HRU PPPM, compared to those treated with 1L zanubrutinib. Due to a small sample size and short follow-up, these findings should be interpreted cautiously.

Introduction: Chimeric antigen receptor T-cell therapy (CAR-T) has revolutionized the treatment of non-Hodgkin lymphoma (NHL). Despite having an increased risk of NHL, patients with pre-existing autoimmune disease (AID) were excluded from pivotal CAR-T trials due to concerns that CAR-T may exacerbate AID. As a result, there are limited data on the safety and efficacy of CAR-T for NHL in patients with AID. Interestingly, there is also growing evidence that CAR-T can be therapeutically effective for AID, such as in the treatment of systemic lupus erythematosus (SLE). As CAR-T utilization for NHL increases, it is essential to characterize the safety and efficacy of this potentially curative therapy in patients with AID. This study aimed to evaluate the impact of AID on outcomes in patients treated with commercial CD19-targeted CAR-T for NHL. Methods: Following Institutional Review Board approval, we conducted a retrospective analysis of all patients who were treated with commercial CD19-targeted CAR-T for NHL and had a pre-existing AID across the Mayo Clinic Enterprise (Arizona, Florida, and Minnesota) between January 2018 and May 2023. Variables collected included age, gender, NHL type, AID type, and CAR-T product. Efficacy outcomes, including response rates at 6 and 12 months after CAR-T, were collected. Toxicities, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), were collected and analyzed. Our chart review for AID included SLE, sarcoidosis, ulcerative colitis, celiac disease, pernicious anemia, Crohn's disease, psoriasis, Sjogren's syndrome, hypothyroidism (Hashimoto's disease), hyperthyroidism (Graves' disease), rheumatoid arthritis (RA), vasculitis, scleroderma, and mixed connective tissue disease (MCTD). Results: A total of 235 patients who received commercial CD19-targeted CAR-T for NHL across the Mayo Clinic Enterprise were identified (Table 1). Of these 235 patients, 27 had a pre-existing AID and 208 did not. The median age was 66 years (range 39-81) for patients with AID and 59 years (range 18-88) for patients without AID. Over half of the patients were male (59% of patients with AID and 51% of patients without AID). The most common NHL type was diffuse large B cell lymphoma (41% of patients with AID and 56% of patients without AID). Most patients received axicabtagene ciloleucel (85% of patients with AID and 84% of patients without AID). The most common AID was hypothyroidism (81%, n=22), although other conditions were also identified, including RA (11%, n=3), SLE (4%, n=1), pulmonary sarcoidosis (4%, n=1), psoriasis (4%, n=1), and MCTD (4%, n=1). Two patients had more than one AID. Median follow-up was 18 months (range 1-36) for patients with AID and 14 months (range 2-49) for patients without AID. Six months after CAR-T, the complete response (CR) rate was 77.2% and 45.1% in patients with AID and without AID, respectively (p=0.0042). Twelve months after CAR-T, the CR rate was 50% and 31.4% in patients with AID and without AID, respectively (p=0.0801). CRS of any grade occurred in 78% and 88% of patients with and without AID, respectively. ICANS of any grade occurred in 41% and 54% of patients with and without AID, respectively. Conclusion: AID did not appear to adversely impact the safety or efficacy of CAR-T for NHL. Limitations of our study include the small number of patients with AID and the fact that the most common AID was hypothyroidism. Larger studies are warranted to confirm these findings. Additional data are needed to characterize the impact of CAR-T for NHL on AID outcomes and to describe the effect of disease-modifying antirheumatic drugs on NHL outcomes after CAR-T.

Background: The new standard of care for fit patients with refractory or early relapse of diffuse large B-cell lymphoma (DLBCL) is chimeric antigen receptor T-cell (CAR-T) therapy. However, for patients with a relapse ≥12 months after completing frontline therapy, salvage chemotherapy followed by high-dose chemotherapy and autologous stem cell transplant (ASCT) remains the standard of care. There is a need to characterize such patients and their survival in view of the recent shift in treatment paradigm. Methods: Patients with DLBCL that relapsed ≥12 months after R-CHOP or R-CHOP-like frontline therapy who underwent salvage therapy and ASCT at Mayo Clinic or University of Iowa between 07/2000 and 4/2020 were identified from institutional lymphoma and transplant databases. Clinical characteristics, treatment information, and outcome data were abstracted. Progression-free survival (PFS) and overall survival (OS) from the time of ASCT were analyzed using Kaplan-Meier method and Cox proportional hazards models. Statistical analyses were performed in JMP v15. Results: A total of 158 patients with late relapsed DLBCL who underwent salvage chemotherapy and ASCT were identified. Baseline characteristics at relapse/ASCT are shown in Table 1. Median time from frontline therapy completion to 1st relapse was 26.4 months (range 12.0-152.4). Median age at relapse was 63 years (range 19-77), and 96 (61%) patients were male. A minority (3; 3%) had ECOG PS ≥2. 43 (52%) patients had an elevated serum LDH level, 70 (65%) had advanced stage disease, and 12 (11%) had &gt;1 extranodal involvement. Median line of salvage therapy was 1 (range 1-3), and 17 (11%) patients required &gt;1 line of salvage therapy. Best response before ASCT was complete response (CR) in 97 (61%) and partial response (PR) in 61 (39%). Median age at ASCT was 64 years (range 19-78). Median follow-up after ASCT was 91.5 months (95% CI 74.0-103.3). Median PFS and OS were 54.5 (95% CI 31.9-77.8) and 99.8 (95% CI 60.3-144.5) months, respectively. The 2-year PFS and OS rates were 64% (95% CI 56-71) and 81% (95% CI 74-87), respectively. No statistically significant difference in PFS was seen based on age at ASCT, sex, serum LDH, stage, or extranodal site involvement of &gt;1 at relapse (Table 2). However, patients who required &gt; 1 line of salvage therapy, compared to those requiring 1 line of salvage therapy, had significantly inferior PFS (median 6.1 vs 61.8 months, P &lt;0.0001) and OS (17.8 vs 111.7 months, P &lt;0.0004). There was no statistically significant difference in survival in patients who achieved CR vs PR prior to ASCT, with a median PFS of 61.8 vs 37.8 months( P=0.21) and a median OS of 111.7 vs 78.3 months ( P=0.62). Patients who achieved CR after 1 line of salvage therapy had the most favorable PFS and OS, with a median PFS of 65.6 vs 45.4 vs 6.1 vs 7.6 months ( P=0.0004) and a median OS of 133.0 vs 88.9 vs 24.2 vs 17.6 months ( P=0.004) in patients achieving CR after 1 line of salvage therapy vs PR after 1 line of salvage therapy vs CR after &gt;1 line of salvage therapy vs PR after &gt;1 line of salvage therapy, respectively (Table 2). In multivariate Cox regression models adjusted for age at ASCT and sex, patients requiring &gt; 1 line of salvage therapy, compared to those who required 1 line of salvage therapy, had significantly inferior PFS with a hazard ratio (HR) of 3.25 (95% CI 1.82-5.78, P &lt;0.0001) and OS with a HR of 3.50 (95% CI 1.86-6.60, P=0.0001). However, there remained no significant difference in survival based on response status (CR vs PR) with a HR for PFS 0.78 (95% CI 0.52-1.17, P=0.23) and OS 0.93 (95% CI 0.58-1.47, P=0.74). Conclusions: Survival after ASCT was excellent in patients with late relapsed DLBCL achieving CR after 1 line of salvage chemotherapy. Favorable survival outcomes were seen in patients who achieved PR after 1 line of salvage therapy. These data support the current clinical practice of ASCT consolidation in these patients. However, post-ASCT survival was poor in patients who required more than 1 line of salvage chemotherapy, despite achieving a satisfactory response to subsequent lines of salvage therapy. Alternative treatment strategies such as CAR-T therapy should be considered in such patients.

Background: Waldenström Macroglobulinemia (WM) is an indolent lymphoma with heterogeneous outcomes. The recently developed, Revised International Prognostic Scoring System for WM (rIPSS-WM) did not examine the prognostic impact of MYD88L265P, a somatic alteration present in most patients with WM. Moreover, rIPSS-WM could only be partially validated in an external cohort. Here, we report the performance of rIPSS-WM and propose a refined prognostic model with external validation. Methods: We reviewed medical records of treatment-naïve patients with active WM consecutively seen at Mayo Clinic, Rochester (MCR) between 01/01/1996 and 12/31/2017. We applied the rIPSS-WM model in patients with data available for all required parameters, including age, serum beta-2 microglobulin (β2M), serum lactate dehydrogenase (LDH) and serum albumin at diagnosis to assess the prognostic utility of this model. We then identified the dichotomized clinical and laboratory parameters prognostic for overall survival (OS) by univariate analyses (UVA) in our cohort. The significant parameters were analyzed to independently predict OS in a multivariable analysis (MVA) and to create a prognostic model, which was subsequently validated in an independent multi-institutional cohort. Results: We identified 889 patients with active WM at MCR, with a median follow-up of 8.2 [95% confidence interval (CI): 7.5-9] years. The estimated median OS for this cohort was 10.6 (95%CI: 9.7-11.4) years. Patients with available data in this cohort for the validation of rIPSS-WM (n=241) were risk stratified into very low (n=46), low (n=64), intermediate (n=58), high (n=46) and very-high risk groups (n=27) per rIPSS-WM, with the respective 5-year OS rates of 96%, 76%, 72%, 77% and 32%, demonstrating overlapping survival curves for the low, intermediate and the high-risk groups. Because rIPSS-WM could not be validated, we used the data from the MCR cohort and identified age at diagnosis of active WM, LDH &gt;upper limit of normal (ULN), β2M &gt;3µg/mL and albumin &lt;3.5g/dL as statistically significant prognostic markers for OS on UVA. Notably, the presence of MYD88 L265P did not impact OS [median 11.4 years (95%CI: 10.1-not reached (NR) for MYD88 L265P genotype (n=231) versus 10 years (95% CI: 8.1-NR) for MYD88 WT genotype (n=65); p=0.33]. On MVA, LDH &gt;ULN (HR 2.34), serum albumin &lt;3.5 g/dL (HR 1.5) and age groups 65-75 years (HR 1.4) and &gt;75 years (HR 2.6) were independently prognostic. Based on comparable HRs, we assigned a score of 1 point each to serum albumin &lt;3.5 g/dL and age group 66-75 years and similarly, 2 points each for age &gt;75 years and serum LDH &gt;ULN per their impact on OS. Patients with the composite scores of 0, 1 and 2 were categorized as low risk, low- intermediate risk and intermediate risk, respectively. Due to similar OS for the scores of 3 to 5, these were combined to form the high-risk group of our proposed model: Modified Staging System for WM (MSS-WM). The median OS was 14.6 years [95%CI: 9.1 years-NR] for low-risk (score 0, n=71, 21%), 11.2 years (95% CI: 9.1-15.2 years) for low-intermediate risk (score 1, n=110, 32%), 8.1 years (95% CI: 6.4-12.2) for intermediate risk (score 2, n=81, 24%) and 5.5 years (95 % CI: 3.9-11 years) for the high-risk group (score ≥3, n=79, 23%); p&lt;0.0001. In this derivation cohort, the 5-year OS rate was 93%, 82%, 69% and 55% and 10-year OS rate was 60%, 53%, 45% and 30% for the low, low-intermediate, intermediate, and high-risk cohort, respectively ( Figure 1A). We also validated MSS-WM using competing risk analysis (p=0.001) and in the cohort of rituximab treated patients (p&lt;0.0001). We then used data from an independent series of 335 treatment-naïve symptomatic patients from academic institutions (n=5) across the US and Europe for external validation of the MSS-WM model. The median follow-up for the validation cohort was 6.3 years (95% CI: 5.5-7.2 years). The 5-year OS was 93%, 90%, 75% and 57% and the estimated 10-year OS was 91%, 80%, 64% and 35% for the low risk (n= 86, 26%), low-intermediate (n=107, 32%), intermediate (n=86, 26%) and high-risk (n=59, 18%) cohorts, respectively (p&lt;0.0001, Figure 1B). Conclusions: Our proposed model, MSS-WM, is a simple, clinically useful, externally validated model that reliably risk stratifies previously untreated patients with active WM into four groups that have distinct outcomes based on the composite scores derived from the patients' age, serum albumin and serum LDH at diagnosis.

Introduction While chimeric antigen receptor (CAR)-T cell therapy has transformed the management of hematologic malignancies, it requires frequent monitoring for acute toxicities, almost universally achieved through mandatory hospitalizations, therefore utilizing a significant amount of healthcare resources. At Mayo Clinic in Rochester, MN, our standard practice is administering CAR-T cell therapy in the outpatient setting through a multi-disciplinary hospital-based outpatient (HBO) unit and remote patient monitoring (RPM) program. Our CAR-T RPM program consists of in-home, electronic health record-integrated technology to monitor vital signs and neurologic symptoms for 30 days post CAR-T infusion. Here we report the healthcare utilization outcomes of CAR-T patients managed in the outpatient setting enrolled in the RPM program. Methods Patients undergoing FDA-approved CAR-T cell treatment in the outpatient setting and participating in the CAR-T RPM program at Mayo Clinic Rochester were included in this IRB-approved study. Patient characteristics, healthcare utilization metrics, inpatient interventions, and patient satisfaction data regarding the RPM program were reviewed. Length of stay (LOS) includes any hospitalizations for which the admission date falls within the RPM monitoring period (CAR-T cell infusion to day +30), even if the hospitalization continued past day +30. Results A total of 123 patients participated in the CAR-T RPM program and underwent treatment in the outpatient setting. Median age at CAR-T infusion was 63 years (range 22 - 83), and most patients were male (n=78, 63%). Non-Hodgkin lymphoma was the most common diagnosis (n=74, 60%), followed by multiple myeloma (n=47, 38%), ALL (n=1, 1%) and other (n=1, 1%). During the PRM monitoring period, 19 (16%) patients were managed entirely in the outpatient setting. The remaining 104 (84%) patients required at least one hospitalization, with most patients (n=70, 57%) hospitalized only once [26 (21%) patients were hospitalized twice, and 7 (6%) patients were hospitalized 3 times, and 1 (1%) patient hospitalized 4 times during the monitoring period]. When considering the first hospitalization post CAR-T infusion, the median LOS was 6 days (range 2 - 47). When considering all hospitalizations post CAR-T, the median LOS was 8 days (range 2 - 47). Only 7 (6%) patients required an ICU stay, with a mean ICU stay of 0.2 days (standard deviation 0.9). Cytokine release syndrome (CRS) was noted in 92 (75%) of patients at a median of 3 days (range 0 - 18) post CAR-T infusion. All patients with CRS received tocilizumab, at a median of 4 days post CAR-T infusion. Steroids for CRS were administered in 63 (68%) of these patients. Neurotoxicity was reported in 45 (37%) patients at a median of 7 days (range 1 - 19) post CAR-T infusion. During the RPM monitoring period, patients were seen in our HBO unit with a median of 18 outpatient visits (range 4 - 30). Patient survey data, obtained at the end of the RPM monitoring period, were available from 37 patients. The majority of patients felt that the RPM program helped them feel comfortable managing their health at home, were able to reach a team member, and receive an appropriate response promptly. The majority of patients felt comfortable using the RPM equipment and interacting with providers virtually. Overall, 83% of patients were satisfied with the RPM program and 6% were neither satisfied nor dissatisfied. When asked about the reason for disappointment, technical difficulties/issues with the devices were the themes mentioned by the few patients (11%) who were unsatisfied with the RPM program. Conclusion: Despite the complexities and frequent monitoring associated with CAR-T cell therapy, outpatient CAR-T cell treatment is a feasible model of care. As the standard practice at our institution, the CAR-T RPM program was part of the management of nearly all patients undergoing an FDA-approved CAR-T product in the outpatient setting. RPM in the acute setting post CAR-T infusion is a well-received practice initiative by the majority of patients, including a high level of comfort utilizing the RPM equipment and virtual interaction with the RPM providers.