Hampel, Paul J.

Abstract Background: Although CAR T-cell therapy has achieved remarkable response rates in adult patients (pts) with relapsed and refractory B-cell non-Hodgkin’s lymphoma (NHL), 20-30% of pts still have primary refractory disease, and 30-40% of pts relapse, often within 6 months of therapy. Given that durable clinical response can be achieved without CAR T cell persistence, we hypothesized that durable remission is correlated with the expansion of tumor-reactive T-cell receptor (TCR) clones following CAR T-cell infusion. To assess this, we examined the TCR repertoire of adult pts with B-NHL who received CD19 CAR T-cell (axi-cel) therapy to identify correlates of clinical response. Methods: Single-cell (sc) RNA sequencing (seq) and scTCR-seq were performed on peripheral blood mononuclear cells from B-NHL pts before lymphodepletion chemotherapy (pre), at peak CAR-T expansion (peak), and one month following CAR-T (M1). scRNAseq and scTCR-seq data were processed using CellRanger v7.0.1, which were then analyzed using Immunarch (v0.9.0) for TCR clonality and sample diversity. Diversity was assessed using the Gini coefficient to indicate clone size inequality (0 = maximum diversity). TCR diversity and phenotype of expanded and emerged TCR clones post CAR-T were compared across clinical response categories: CR (complete remission for at least 6 months), PD1 (primary refractory), and PD2 (relapsed after partial or complete response). Results: We analyzed 107,035 T cells from 77 serial samples of 32 pts (16 CR, 4 PD1, 12 PD2) and 5 healthy controls. Compared to pts with PD1 and PD2, pts with CR had a larger Gini coefficient for TCR clones at M1 relative to Pre and Peak. The Gini coefficient was the largest for tumor recirculating CD8 T effector memory (Tem) and activated CD8 peripheral memory (Tpm) cells at M1 for pts with CR. Examining the repertoire of emerged and expanded TCR clones at Peak and M1 from Pre, pts with PD2, compared to pts with CR, had a higher percentage of activated CD8 T peripheral memory (Tpm) and T regulatory cells (Treg) among the emerged clones and activated CD8 Tpm among the expanded clones. Patients with PD1, relative to patients with CR, had more proliferating and non-activated CD8 Tpm among the expanded and emerged clones. Conclusion: NHL pts with CR after CAR-T had more robust clonal expansion of T cells, particularly tumor recirculating CD8 Tem and activated CD8 Tpm, compared to pts with relapsed or refractory disease. In contrast, pts with relapsed or refractory disease had an expansion of TCR clones with a larger proportion of CD8 Tpm and Tregs. Endogenous tumor-reactive TCR expansion may help predict favorable clinical response following CAR T-cell therapy. Citation Format: Aiman J. Faruqi, Panwen Wang, Radhika Bansal, Andre De Menezes Silva Corraes, Henan Zhang, Zuoyi Shao, Kevin Regan, Eider Moreno Cortes, Arushi Khurana, Nora Bennani, Yucai Wang, Paul Hampel, Jonas Paludo, Patrick Johnston, Hemant Murthy, Madiha Iqbal, Stephen Ansell, Javier Munoz, Allison Rosenthal, Mohamed Kharfan Dabaja, Januario E. Castro, Saad Kenderian, Haidong Dong, Ying Li, Yi Lin. T-cell receptor repertoire changes associated with clinical response in patients with B-cell non-Hodgkin’s lymphoma receiving CD19 CAR-T therapy [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 53.

Abstract Background: The impact of a prior history of non-hematologic malignancy (NHM) on clinical outcomes among individuals with newly diagnosed chronic lymphocytic leukemia (CLL) or monoclonal B-cell lymphocytosis (MBL), the precursor to CLL, is not well known. Methods: In this prospective study, we identified individuals with CLL/MBL who were seen in the Division of Hematology at the Mayo Clinic, Rochester. Participants provided consent within nine months of diagnosis, had no prior history of hematological malignancy, and completed a self-reported risk-factor questionnaire, including a prior history of NHM. Time to first treatment (TTFT) was defined as the time between the date of diagnosis and the earliest date of the first CLL treatment, death, or the last known treatment-free follow-up date. Overall survival (OS) was defined as the time from diagnosis to death or the last follow-up. We used Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between a prior history of a NHM with OS and TTFT. We adjusted for sex and the CLL International Prognostic Index (CLL-IPI), a score comprised of five key CLL prognostic factors, including age and Rai stage. Results: Among the 1,090 CLL/MBL individuals, 833 (76%) had CLL. The median age at diagnosis was 64 years (range 24-89), with 65% being men, and 230 (21%) reported a prior history of NHM. The most common tumor was non-melanoma skin cancer (NMSC, 8.9%, 96 individuals), followed by prostate, testicular, and penile tumors (7.3%, 51 individuals), and melanoma (1.9%, 20 individuals). CLL/MBL patients with a prior history of a NHM were more likely to be over 65 years old (29%) than under 65 years old (14%, p < 0.0001). After a median follow-up of 2.9 years (range 0-21), 470 CLL/MBL patients progressed, requiring CLL treatment. CLL/MBL individuals with a prior history of NHM had a longer TTFT compared to those without (HR=0.69; 95% CI: 0.53-0.90; p=0.006). Individuals with a prior history of NHM who had either intermediate or high-very high CLL-IPI score had significantly longer TTFT (HR= 0.55; 95% CI: 0.33-0.92; p=0.02, and HR=0.65; 95% CI: 0.43-0.97; p=0.03, respectively) compared to those without NHM. After a median follow-up of 8.6 years (range 0-21), 359 individuals died. CLL/MBL patients with a prior history of NHM also experienced reduced OS compared to those without (HR=1.46; 95% CI: 1.08-1.97, p=0.013), particularly among those with low (HR=1.70; 95% CI: 0.96-3.00, p=0.07) or intermediate-risk (HR=2.08; 95% CI: 1.24-3.51, p=0.006), according to CLL-IPI. After excluding NMSC, results remained constant. Conclusions: At the time of diagnosis, one out of five CLL/MBL individuals had a prior history of a NHM. These individuals had a longer time to first CLL directed treatment and reduced OS, even after accounting for other important CLL prognostic factors, which deserves additional studies. Citation Format: Bryan A. Vallejo, Cristine Allmer, Kari G. Rabe, Dennis P. Robinson, Yucai Wang, Paul J. Hampel, Esteban D. Braggio, Neil E. Kay, James R. Cerhan, Sameer A. Parikh, Susan L. Slager. The impact of prior history of non-hematologic malignancies on time to first treatment and overall survival among individuals with CLL or MBL [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 7450.

PURPOSE Limited evidence exists regarding methotrexate (MTX) resumption after patients with lymphoma receive glucarpidase for toxic MTX levels and acute kidney injury (AKI). METHODS This retrospective review included adults with lymphoma treated with glucarpidase after MTX at Mayo Clinic between January 31, 2020, and October 10, 2022. Descriptive statistics summarize patient characteristics and clinical outcomes. RESULTS Of 11 patients treated with glucarpidase after MTX, seven (64%) were rechallenged with MTX. Indications for MTX rechallenge included confirmed CNS disease (n = 6, 86%) and intravascular lymphoma (n = 1, 14%). Compared with the nonrechallenged subgroup, before receiving MTX that required glucarpidase rescue, the rechallenged patients had lower median pretreatment serum creatinine (Scr; 0.7 v 1.2 mg/dL), and none had AKI with previous MTX doses, n = 0 (0%) versus n = 2 (50%). During the MTX dose requiring glucarpidase rescue, the rechallenged group had lower median peak Scr (1.26 v 3.32 mg/dL) and lower incidence of AKI stage III (n = 1 [14%] v n = 3 [75%]), and none of the rechallenged patients required renal replacement therapy (RRT; n = 0 [0%] v n = 1 [25%]). At the first rechallenge after glucarpidase administration, the median MTX dose reduction was 56% (range, 46%-75%), and the lowest used dose when prescribed according to each treatment protocol schedule was 1.5 g/m2. Two (29%) patients experienced AKI (n = 1 stage I, n = 1 stage II) after MTX rechallenge. Zero patients required RRT, and zero required another glucarpidase administration. Six (86%) patients completed all recommended MTX doses. CONCLUSION In selected adults with lymphoma who required glucarpidase for toxic MTX levels after administration of high-dose MTX, resumption of MTX therapy at lower doses is safe. Patients selected for MTX resumption had experienced less severe AKI during the previous cycle compared with those not selected for MTX resumption.

Abstract Monoclonal B-cell lymphocytosis (MBL) progresses to chronic lymphocytic leukemia (CLL) requiring therapy at 1% to 5% per year. Improved prediction of progression would greatly benefit individuals with MBL. Patients with CLL separate into 3 distinct epigenetic subtypes (epitypes) with high prognostic significance, and recently the intermediate epitype has been shown to be enriched for high-risk immunoglobulin lambda variable (IGLV) 3-21 rearrangements, impacting outcomes for these patients. Here, we employed this combined strategy to generate the epigenetic and light chain immunoglobulin (ELCLV3-21) signature to classify 219 individuals with MBL. The ELCLV3-21 high-risk signature distinguished MBL individuals with a high probability of progression (39.9% and 71.1% at 5 and 10 years, respectively). ELCLV3-21 improved the accuracy of predicting time to therapy for individuals with MBL compared with other established prognostic indicators, including the CLL international prognostic index (c-statistic, 0.767 vs 0.668, respectively). Comparing ELCLV3-21 risk groups in MBL vs a cohort of 226 patients with CLL revealed ELCLV3-21 high-risk individuals with MBL had significantly shorter time to therapy (P = .003) and reduced overall survival (P = .03) compared with ELCLV3-21 low-risk individuals with CLL. These results highlight the power of the ELCLV3-21 approach to identify individuals with a higher likelihood of adverse clinical outcome and may provide a more accurate approach to classify individuals with small B-cell clones.

INTRODUCTION Richter transformation (RT) is the histologic transformation of CLL/SLL into an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). We previously reported an incidence of 0.5% per year of RT in patients with newly diagnosed CLL and an incidence of 1% per year following initiation of therapy (Parikh, BJH, 2013). It is unknown whether these incidences have changed in the novel agent era. METHODS We identified patients with previously untreated CLL/SLL in the Mayo Clinic CLL Database who were seen within 12 months of diagnosis. Only patients with biopsy-proven DLBCL with histopathology confirmation at Mayo Clinic were included. Cumulative incidence methodology was used to display the time to development of RT with death as a competing risk (both from time of initial CLL/SLL diagnosis, and from start of CLL directed therapy). We defined the time period prior to February 2014 (FDA approval of ibrutinib for CLL) as the pre-novel agent era and the time period starting February 2014 as the novel agent era. Using Cox regression analysis, we compared the incidence of RT, both after initial CLL diagnosis and after initiation of CLL therapy, between patients diagnosed with CLL in the pre-novel agent era versus the novel agent era. RESULTS Between 1/2000 and 4/2023, 3347 patients were seen at Mayo Clinic. The median age at diagnosis was 65 years (range 21-97 years), and 66% patients were male. Baseline characteristics of patients at the time of CLL and RT diagnoses between the two treatment eras were similar, including distance in miles of primary residence from Mayo Clinic ( Table 1). The median follow-up for the entire cohort was 5.6 years (9.5 years for the pre-novel agent era cohort and 3.2 years for the novel agent era cohort). A total of 82 patients were diagnosed with RT (69 in the pre-novel agent era and 13 in the novel agent era). Overall, the 1-, 5- and 10-year cumulative incidence rates for RT from the time of CLL/SLL diagnosis were 0.6% (95% CI: 0.4-0.9%), 1.8% (95% CI: 1.3-2.3%), and 3.0% (95% CI: 2.4-3.8%), respectively. Among the patients who received CLL/SLL therapy (n=1382), the 1-, 5-, and 10-year incidence rates for RT from the time of treatment start were 0.3% (95% CI: 0.1-0.8%), 3.3% (95% CI: 2.4-4.5%), and 4.9% (95% CI: 3.7-6.5%), respectively. Among 1981 patients diagnosed with CLL/SLL in the pre-novel agent era, the 1- and 5-year incidence rates for RT from the time of diagnosis were 0.6% (95% CI: 0.4-1.1%) and 2.1% (95% CI: 1.5-2.8%), respectively. Among 1366 patients diagnosed with CLL/SLL in the novel agent era, the 1- and 5-year incidence rates following CLL/SLL diagnosis were 0.5% (95% CI: 0.2-1.1%) and 1.1% (95% CI: 0.6-2.2%), respectively. The RT incidence from time of CLL/SLL diagnosis was not significantly different between the pre-novel agent and novel agent era patients (hazard ratio [HR] 1.6, 95%CI 0.9-3.0, p=0.13). Patients who received CLL/SLL treatment in the pre-novel agent era (n=926) and novel agent era (n=456) had subsequent 1-year incidence rates of RT of 0.3% (95% CI: 0.1-1.0%) and 0.2% (95% CI: 0.0-1.8%), respectively. The 5-year incidence rates for these groups were 3.7% (95% CI: 2.6-5.2%) and 1.9% (95% CI: 0.7-5.0%), respectively. Although an increased risk of RT after CLL/SLL directed therapy was observed in the pre-novel agent era compared to the novel agent era (HR 2.4, 95%CI: 0.9-6.1, p=0.07; Figure 1), this did not cross the threshold of statistial significance. Among patients diagnosed in the pre-novel agent era who developed RT (n=69), CLL treatment prior to RT included: none, n=19 (28%); chemoimmunotherapy only, n=36 (52%); and novel agent, n=14 (20%; includes 11 treated with prior chemoimmunotherapy also). In contrast, among patients diagnosed in the novel agent era who developed RT (n=13), CLL treatment prior to RT included: none, n=8 (62%); and novel agent, n=5 (38%). CONCLUSIONS Patients who received CLL/SLL directed treatment appear to have a lower risk of RT in the novel agent era. This may be driven by the fact that none of the patients who developed RT in the novel agent era received chemoimmunotherapy. Whether novel agent use for CLL/SLL suppresses the development of RT or avoids the risk associated with cytotoxic chemotherapy-induced clonal evolution requires further study. Although limited by length of follow-up, our findings challenge the notion that RT incidence will increase in parallel with CLL patients living longer with novel agent treatments.

Background: Monoclonal B-cell lymphocytosis (MBL) is a precursor condition to chronic lymphocytic leukemia (CLL) characterized by the presence of circulating monoclonal B-cell populations in the peripheral blood of otherwise healthy individuals. MBL increases risk of several adverse clinical outcomes, including development of hematological malignancies. Mosaic chromosomal alterations (mCAs) are a form of clonal hematopoiesis which affect large segments of DNA and include gains, losses, and copy number neutral loss of heterozygosity events. mCAs can be detected from SNP-array genotyping. Prior work has suggested mCAs as a potent risk factor for hematological malignancies. However, the nature of the relationship between mCAs and MBL is unknown. We sought to determine 1) the association between mCAs and MBL and 2) their combined effect on risk of hematological malignancies, in a large, prospectively collected, and well-annotated cohort of individuals with known MBL, mCA, and clinical outcomes. Methods: We examined the prevalence of mCA in a cohort of individuals from the Mayo Clinic Biobank who were screened for MBL using a sensitive eight-color flow cytometry assay. We classified MBL by the size of the clone relative to total B-cells, with high count (HC) defined as those individuals who had a percent clonal B-cell count ≥85% out of total B-cell count and low-count (LC) otherwise. Autosomal mCAs were detected from whole blood DNA collected at the time of MBL screening using a SNP-array-based assay. The MoChA pipeline was used to identify mCA events. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CIs). To examine incident hematological cancers, we identified and validated all hematological cancers through medical record abstraction using the International Statistical Classification of Diseases codes. Cox regression was used to calculate hazard ratios (HR) and 95% CIs, stratified by MBL status or autosomal mCA status. All models were adjusted for age and sex. Results: We evaluated the prevalence of autosomal mCA in 3,764 individuals (792 individuals with MBL of whom 64 had HC-MBL and 2,972 without MBL). The prevalence of autosomal mCA was 7.7% ( n=288) with a median mCA cell fraction of 0.09 (range 0.01-1). Among those with and without MBL overall, the prevalence of mCA was 15.5% ( n=123) and 5.6% ( n=165), respectively (Figure 1). Compared to those without an autosomal mCA, individuals with an autosomal mCA were 2.4-fold more likely to have MBL (95% CI 1.9-3.2; P =2.0x10 -11; Figure 1). CLL-associated mCA (i.e., those commonly altered in CLL including trisomy 12 and deletion of 6q, 11q, 13q, and 17p) were present in 42 individuals, of whom 38 (90.5%) had MBL overall and 30 (71.4%) individuals had HC-MBL. Compared to those without a CLL-associated mCA, individuals with a CLL-associated mCA were 539.39-fold more likely to have HC-MBL (95% CI 190.3-1975.9; P <2.0x10 -16) and 6.7-fold more likely to have LC-MBL (95% CI 2.0-26.5; P =0.0031; Figure 1). Next, we evaluated the relationship between MBL and mCA with risk of developing a hematologic malignancy in 3,009 individuals with follow-up data (median 10 years). Forty-one individuals developed an incident hematological malignancy (68.3% lymphoid). When we evaluated the effect of autosomal mCA stratified by MBL status we observed elevated but non-significant risk of hematological malignancies (Figure 2). When we evaluated the effect of MBL stratified by autosomal mCA status we observed elevated and significant increased risk of developing a hematological malignancy (Figure 2). Conclusions: We found that the presence of an autosomal mCA is highly associated with having MBL. In particular, >90% of CLL-associated mCA carriers had MBL with ~7- and ~540-fold increased association for LC- and HC-MBL, respectively. These results suggest that almost all individuals in large biobanks with CLL-associated mCAs have undiagnosed MBL. However, not all individuals with MBL have an mCA. When evaluating risk of hematological malignancies, we found autosomal mCAs had >2-fold elevated but non-significant effects when stratified by MBL status while MBL remained a significant risk factor regardless of autosomal mCA status. Collectively these results support that MBL remains an important risk factor and suggests that mCAs hold potential to identify a subgroup of individuals at greater risk of developing a hematological malignancy.

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.

INTRODUCTION We aim to identify factors that impact outcomes of venetoclax for patients with CLL treated in routine practice at a tertiary center. We report on the use of venetoclax in the most frequently encountered disease scenarios: first-line, relapsed/Bruton tyrosine kinase inhibitor (BTKi)-naïve, and relapsed/BTKi-exposed. METHODS We identified patients who received venetoclax therapy for CLL (between 4/2012-4/2023) from the Mayo Clinic CLL Database. Undetectable measurable residual disease (uMRD) was defined as <1 CLL cell per 10,000 leukocytes using 8-color flow cytometry on peripheral blood (PB) or bone marrow (BM). Overall survival (OS) was defined as the time from venetoclax start until date of death or last known to be alive. Treatment-free survival (TFS) after venetoclax was defined as the time from venetoclax start until the earliest of date of next treatment, or death. Kaplan-Meier was used to display OS and TFS. Multivariable Cox proportional hazards regression models were used to estimate associations of factors with time-to-event outcomes. RESULTS A total of 155 patients received venetoclax: firstline therapy (in combination with obinutuzumab, n=55) and relapsed CLL (n=100; 17 had relapsed/BTKi-naïve CLL, and 83 had previously received BTKi [55 with progression after BTKi], relapsed/BTKi-exposed). The median follow-up for the cohorts of first-line therapy, relapsed/BTKi-naïve, and relapsed/BTKi-exposed was 12.9 months, 37.0 months, and 27.6 months, respectively. Baseline characteristics at the time of venetoclax initiation for all patients are shown in Table 1. The median TFS for the overall cohort was 39.0 months. The median OS was 54.6 months. Among patients treated with venetoclax as first-line therapy (n=55), the 2-year TFS ( Figure 1) and 2-year OS rates were both 91%. MRD testing was performed in 28 patients and was uMRD in 23 (82%) patients (only PB assessed, n=7; only BM assessed, n=2; PB and BM assessed, n=14). Detectable MRD was identified in 3 patients, and 2 patients had discordant results (PB uMRD and BM detectable disease). Among patients treated with venetoclax in the relapsed/BTKi-naïve setting (n=17), the 2-year TFS rate was 73% ( Figure 1) and the 2-year OS rate was 100%. MRD testing was performed in 7 patients and was uMRD in all 7 (100%) (only PB assessed, n=3; only BM assessed, n=2; PB and BM assessed, n=2). The median time to first uMRD result was 14.1 months. Among relapsed/BTKi-exposed venetoclax-treated patients (n=83), the median TFS was 26.9 months ( Figure 1), and the median OS was 39.4 months.In this subgroup, the median TFS for patients with (n=55) and without (n=28) prior disease progression on prior BTKi were 22.3 and 42.3 months, respectively. Median TFS with venetoclax monotherapy (n=30) was 24.0 months, venetoclax in combination with rituximab (n=37) was 26.9 months, and venetoclax in combination with obinutuzumab (n=16) was 39.0 months. BTKi-exposed patients that were chemotherapy-naïve (n=27) and chemotherapy-exposed (n=56) had median TFS of 29.1 and 24.0 months, respectively. MRD testing was performed in 28 patients and was uMRD in 16 (57%) patients (only PB assessed, n=9; only BM assessed, n=2; PB and BM assessed, n=5). Detectable MRD was identified in 11 patients, and 1 had discordant results (PB uMRD and BM detectable disease). The median time to first uMRD result was 11.5 months. TP53 disruption, unmutated IGHV genes, older age, complex karyotype (CK; defined as more than 3 chromosomal aberrations on CpG stimulated karyotype), and disease progression on prior BTKi were associated with shorter TFS in the overall cohort on univariate analysis. TP53 disruption, older age, CK, and disease progression on prior BTKi were associated with shorter OS in the overall cohort on univariate analysis. Multivariable analysis was performed by including only those patients where all variables significant in univariable analysis were available (OS model n=65, TFS model n=53). In these models, only CK was significantly associated with shorter TFS (HR 8.5; 95%CI 2.5-29.1; P<0.001) and shorter OS (HR 4.1; 95%CI 1.2-14; P=0.03). CONCLUSIONS Patients with BTKi-exposed CLL, particularly those with prior disease progression on BTKi, had worse outcomes. Our study identified CK as one of the most important baseline predictors of adverse TFS and OS in the overall cohort of patients, supporting karyotype assessment for prognostication prior to venetoclax treatment.

Background: Patients (pts) receiving FDA-approved chimeric antigen receptor T-cell (CAR-T) therapy or Bispecific antibody Teclistamab (Tec) are commonly managed in the inpatient setting given the common adverse events such as cytokine release syndrome (CRS) and immune cell-associated neurotoxicity syndrome ICANS. We have previously reported that hospital-based outpatient (HBO) management of pts receiving CAR-T is feasible and safe (Bansal et al, ASH2022). In 2023, HBO management at our institution began incorporating home health visits and management of grade 1 CRS in outpatient setting for select pts receiving standard of care (SOC) CAR-T. Here, we report outcomes of our updated practice. Methods: We retrospectively analyzed medical records and remote monitoring data of adult pts who received SOC CAR-T or Tec between 10/2020 and 7/2023 at Mayo Clinic, Rochester under an IRB approved protocol. Results: In 3/2023, pts deemed to be low risk for severe CRS (fever onset >= 3 days from infusion, CRP<100) received HBO management for grade 1 CRS, including outpatient administration of tocilizumab. If CRS improved or resolved, outpatient monitoring was continued. If CRS persisted within the observation period on HBO, pts were admitted. Recurrent CRS after the first episode were all managed inpatient. Nine pts met these criteria for HBO CRS management and their outcomes were compared to those who received initial inpatient (INPT) CRS management (INPT, n=17) during the same timeframe, as well as the outcome of 164 pts who had CRS management INPT prior to our practice change (Table 1). Two-third of the pts with initial management of CRS outpatient did not require hospitalization. Median time to hospitalization trended later than those managed inpatient at the onset of CRS. The duration of hospitalization was comparable for all pts admitted between initial HBO and INPT CRS management. However with fewer admissions in the initial CRS HBO group, the average hospitalization days (LOS) per patient treated for that group was lower compared to initial INPT CRS management. Data on additional pts will be presented at ASH. In 1/2023, pts on RPM with no ongoing CRS symptoms, no language barriers, and no compliance concerns received home health visits during weeks 3 and 4 post CAR-T infusion in place of clinic visits on HBO. Home health visit team communicated with HBO staff to review assessment and plan. Changes in HBO utilization will be presented. Finally, 24 pts received 223 Tec infusions on HBO. Median age was 66 years, 15 (61%) were males, 9 (38%) had high risk cytogenetics. The median prior lines of therapy was 5. Among these pts, 220/223 (99%) doses were performed on HBO and 204/220 (93%) infusions never required admission for management. Twenty pts enrolled in RPM (Figure 1). An average of 2 alerts were generated per patient during the 2 week period and median time from infusion to alert was 1.5 days. Majority of alerts were resolved over a phone call and only 13/114 (11%) alerts required a physician visit/hospital admission. Of the 16 Tec infusions resulting in admission, 4/16 (25%) required re-admission resulting in a total of 20 hospitalizations. Admissions mostly occurred during step-up dosing (18/20; 90%). Most common reason for first admission was fever (13/16, 85%) and median time to admission was 1 day from infusion. Median LOS was 1.5 days (range, 0-12). In terms of CRS, majority were Grade 1 (12/13, 93%) which were managed with steroids (dexamethasone/ prednisone) alone. One patient had CRS grade 4 event, in the setting of concurrent decompensation during dialysis, and was treated with steroids, tocilizumab, vasopressor, CRRT, thoracentesis, intubation and mechanical ventilation. The rate of second CRS event after management of first CRS with steroid (dexamethasone/ prednisone) was 15% (2/13). These second CRS episodes also resolved with steroid alone. Data on additional pts receiving Tec will be presented at ASH. Conclusion: Our data showed that additional advances in outpatient practice, including initial outpatient management of CRS and outpatient administration of Tec step up dosing are feasible, safe and reduce hospital resource utilization.

Background: Richter Transformation (RT) refers to the development of an aggressive lymphoma in the setting of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Small molecule inhibitors (SMI), such as the Bruton tyrosine kinase inhibitors (BTKi) and BCL2 inhibitors (BCL2i), have revolutionized the treatment of CLL/SLL. Prior studies evaluated outcomes of patients (pts) with RT in an era where chemoimmunotherapy (CIT) was typically used to treat CLL/SLL. Now that SMI are standard of care, fewer pts with CLL/SLL receive CIT, therefore we sought to determine which variables predict survival in pts who developed RT without prior CIT exposure for CLL/SLL. Methods: We conducted an international multicenter retrospective study of pts from 11 academic centers. Pts with RT occurring as large B-cell lymphoma who did not previously receive CIT (e.g., fludarabine, cyclophosphamide, bendamustine, chlorambucil) for their CLL/SLL were included. We collected pt, disease, and treatment (tx) characteristics. RT was categorized into 3 groups: “Concurrent RT,” defined as RT and CLL/SLL diagnosed simultaneously (within 3 months [mos]); “RT w/o prior CLL/SLL tx,” defined as RT and CLL/SLL diagnosed >3 mos apart with the CLL/SLL never treated; and “RT with prior non-CIT tx for CLL/SLL” defined as having received prior CLL/SLL tx. Overall survival (OS) was measured from RT diagnosis (Dx) and estimated using the Kaplan-Meier method. Cox regression model was used to identify prognostic factors associated with OS. Results: 242 pts were identified. At CLL/SLL Dx, 66% of pts had unmutated IGHV, 37% had del17p/ TP53 disruption, and 20% had trisomy 12. At RT Dx, 56% of the RT with prior non-CIT tx for CLL/SLL group had a del17p/ TP53 disruption versus 27% for the concurrent RT group and 18% for the RT w/o prior CLL/SLL tx groups. Median time from CLL/SLL Dx to RT Dx was 47 mos (range 3-394) for RT w/o prior CLL/SLL tx and 46 mos (range 4-218) for RT with prior non-CIT tx for CLL/SLL. Pts with prior non-CIT tx for CLL/SLL received a median of 1 (range 1-5) prior tx. 86% of pts previously received a BTKi or a BCL2i for tx of CLL/SLL (54% BTKi only, 5% BCL2i only, 27% both). The remaining 14% had been treated with an anti-CD20 monoclonal antibody (MoAb), steroids, lenalidomide, radiation, or alemtuzumab. 85% of pts developed RT while on active tx with SMI. Median age at RT Dx was 69 years (range 37-92). At RT Dx, 38% and 21% of pts had del17p/ TP53 disruption, and trisomy 12 in CLL/SLL tissue, respectively. At RT Dx, there was no difference in highest SUV on PET (median 16, range 2.9-65.6), LDH (median 325, range 103-8162, ULN range 180-271), largest lymph node in diameter (median 4.9 cm, range 0-17.1), Ki-67 (median 80%, range 5%-100%), rate of GCB subtype (27%), presence of MYC translocation (20%), or CLL/SLL and RT clonal relationship (81%) for those pts tested amongst the 3 groups ( Table). The most common 1 st line tx for RT was CIT with or w/o radiation and/or steroids (76%), followed by CIT plus SMI (13%), SMI single agent or combination (7%), and other (4%, which includes anti-CD20 MoAb). Median follow-up from RT Dx was 42.3 mos; the median OS for the entire cohort was 25.8 mos (95% CI: 16.8-49.1). Pts with RT after non-CIT tx for CLL/SLL had a significantly worse OS (median 8.2 mos [95% CI: 5.6-14.3]) than pts with concurrent RT (median 46.3 mos [95% CI: 23.8-96.9]) and RT w/o prior CLL/SLL tx (median 63.5 mos [95% CI: 28.3-70.3]) ( Figure). From an exploratory univariable analysis, we found RT after non-CIT tx for CLL/SLL compared to concurrent RT (HR 2.32 [95% CI: 1.55-3.46]), RT Dx age (HR for 5-year increase 1.14 [95% CI: 1.05-1.23]), del17p/ TP53 disruption (HR 2.27 [95% CI: 1.45-3.56]), and LDH (HR for 2-fold increase 1.37 [95% CI: 1.20-1.58]) were prognostic for worse OS. Conclusions: This is the largest cohort of pts who developed RT having received only SMI with no CIT for their CLL reported, thus reflecting the current treatment landscape. Despite being CIT-naïve, pts in our series who received tx for their CLL/SLL and then developed RT had a short OS, underscoring the need to develop better therapies for these pts. In contrast, as in other published analyses (Wang Haematologica 2020), pts w/o prior tx for CLL/SLL had more favorable outcomes, with a median OS of approximately 5 years. Further analysis to determine PFS and OS by tx for RT for pts who have been treated with SMI for their CLL/SLL is ongoing.