High-risk Mantle Cell Lymphoma Research Articles

Upfront Management of Blastoid Variant Mantle Cell Lymphoma: Making the Case for 2nd/3rd-Generation Bruton Tyrosine Kinase Inhibitor-Based Therapies.

Blastoid variant-mantle cell lymphoma (BV-MCL) represents an aggressive subset of patients with no established standard of care treatment approach. We performed a retrospective analysis of the clinical characteristics and outcomes of 17 de novo BV-MCL patients treated at our institution between May 2009 and September 2023. In addition, we reviewed the literature supporting 2nd/3rd generation Bruton's Tyrosine-kinase (BTKi)-based therapies for upfront management. The complete response rate to frontline and salvage therapy was 66.7% and 25%, respectively. Two-year overall survival (OS) was low at 62.5% (95% CI, 34.7%-81.1%). Variables associated with higher OS included receipt of consolidative HSCT (p = 0.017), TP53-wild type (p = 0.031), intermediate- versus high-risk Mantle Cell Lymphoma Prognostic Index score (p = 0.026), and achieving complete response with induction therapy (p = 0.027). Treatment outcomes with chemo-immunotherapy in BV-MCL patients are poor, especially among TP53-mutated patients. Recent findings describing positive outcomes with novel BTKi-based therapies are encouraging and should be considered in this high-risk population.

Impact of rituximab maintenance on survival of patients with mantle cell lymphoma: A north Indian tertiary care center experience.

e19047 Background: Mantle cell lymphoma (MCL) is an aggressive variant of non-Hodgkin lymphoma. Indian data is scarce owing to its rarity in south-east Asia. Till now, studies have not shown overall survival benefit with rituximab maintenance (RM). Our study aims to assess if RM improves overall survival of MCL patients. Methods: We retrospectively analysed clinicopathological data of 90 transplant-ineligible MCL patients treated between January’2013-December’2023 at Institute Rotary Cancer Hospital - All India Institute of Medical Sciences, New Delhi, India. Rituximab-based induction chemotherapy was used in all patients as per institutional protocol. RM was used in twenty-eight (31.0%) patients due to financial constraints. Primary outcome was overall survival (OS). Secondary outcomes were event free survival (EFS) and factors affecting OS, EFS. OS was defined as time from treatment initiation to demise from any cause or last follow-up. EFS was defined as time from treatment initiation to disease progression or relapse or demise from any cause. Response was assessed by modified Cheson’s lymphoma response evaluation criteria. STATA 13.0 was used to assess survival by Kaplan-Meier analysis and log rank test. Factors affecting survival were assessed by multivariate analysis (Cox proportional hazards model) and expressed as adjusted hazard ratio (aHR). p value < 0.05 defined statistical significance. Results: Median age was sixty years; male-female ratio 3:1. Thirty-five (39.0%) had one or more co-morbidities, 79(88.0%) generalised lymphadenopathy, 72(80.0%) extra-nodal involvement, 49(54.0%) B symptoms, 84(93.0%) advanced stage (III/IV), 49(54.0%) high risk MCL international prognostic index (MIPI). Clinical and tumor characteristics, response rates after initial induction were similar in both maintenance and non-maintenance groups. Overall, 52(58.0%) patients were alive with median follow-up of 63.0 months (inter-quartile range 37.0-90.0 months). Median OS was 37.5 months in non-maintenance group and did not reach in maintenance group. Estimated 1.0-, 2.0, 3.0-year OS were 100.0%, 91.0%, 81.0% vs 75.0%, 63.0%, 55.0% respectively in maintenance vs non-maintenance group. RM was significantly associated with better OS [aHR (95% confidence interval): 0.31 (0.13-0.75), p=0.01]. Advanced stage, Eastern Co-operative Oncology Group performance status (ECOG PS) ≥2 at presentation were also significant factors for poor OS. Median EFS was significantly lower in non-maintenance group [14.0 vs 42.5 months; aHR (95% confidence interval): 0.34 (0.18-0.64), p=0.001]. Advanced stage, anemia, high risk MIPI at presentation were also significant factors for poor EFS. Conclusions: This was the first study from south-east Asia demonstrating impact of rituximab maintenance in MCL. Rituximab maintenance significantly improved OS and EFS of MCL patients.

Selective pharmacologic targeting of CTPS1 shows single-agent activity and synergizes with BCL2 inhibition in aggressive mantle cell lymphoma.

Innovative therapeutic strategies have emerged over the past decade to improve outcomes for most lymphoma patients. Nevertheless, the aggressive presentation seen in high-risk mantle cell lymphoma (MCL) patients remains an unmet medical need. The highly proliferative cells that characterize these tumors depend on nucleotide synthesis to ensure high DNA replication and RNA synthesis. To take advantage of this vulnerability, STP-B, a clinically available small molecule selectively targeting CTP synthase 1 (CTPS1) has been recently developed. CTPS1 is a key enzyme of the pyrimidine synthesis pathway mediated through its unique ability to provide enough CTP in highly proliferating cells. Herein, we demonstrated that CTPS1 was expressed in all MCL cells, and that its high expression was associated with unfavorable outcomes for patients treated with chemotherapy. Using aggressive MCL models characterized by blastoid morphology, TP53 mutation or polyresistance to targeted therapies, we showed that STP-B was highly effective at nanomolar concentrations in vitro and in vivo, irrespective of these high-risk features. Inhibition of CTPS1 rapidly leads to cell cycle arrest in early S-phase accompanied by inhibition of translation, including of the anti-apoptotic protein MCL1. Consequently, CTPS1 inhibition induced synergistic cell death in combination with the selective BCL2 inhibitor venetoclax, both in vitro and in vivo. Overall, our study identified CTPS1 as a promising target for MCL patients and provided a mechanism-based combination with the BCL2 inhibitor venetoclax for the design of future chemotherapy-free treatment regimens to overcome resistance.

Ibrutinib as first-line therapy for mantle cell lymphoma: a multicenter, real-world UK study

AbstractDuring the COVID-19 pandemic, ibrutinib with or without rituximab was approved in England for initial treatment of mantle cell lymphoma (MCL) instead of immunochemotherapy. Because limited data are available in this setting, we conducted an observational cohort study evaluating safety and efficacy. Adults receiving ibrutinib with or without rituximab for untreated MCL were evaluated for treatment toxicity, response, and survival, including outcomes in high-risk MCL (TP53 mutation/deletion/p53 overexpression, blastoid/pleomorphic, or Ki67 ≥ 30%). A total of 149 patients from 43 participating centers were enrolled: 74.1% male, median age 75 years, 75.2% Eastern Cooperative Oncology Group status of 0 to 1, 36.2% high-risk, and 8.9% autologous transplant candidates. All patients received ≥1 cycle ibrutinib (median, 8 cycles), 39.0% with rituximab. Grade ≥3 toxicity occurred in 20.3%, and 33.8% required dose reductions/delays. At 15.6-month median follow-up, 41.6% discontinued ibrutinib, 8.1% due to toxicity. Of 104 response-assessed patients, overall (ORR) and complete response (CR) rates were 71.2% and 20.2%, respectively. ORR was 77.3% (low risk) vs 59.0% (high risk) (P = .05) and 78.7% (ibrutinib-rituximab) vs 64.9% (ibrutinib; P = .13). Median progression-free survival (PFS) was 26.0 months (all patients); 13.7 months (high risk) vs not reached (NR) (low risk; hazard ratio [HR], 2.19; P = .004). Median overall survival was NR (all); 14.8 months (high risk) vs NR (low risk; HR, 2.36; P = .005). Median post-ibrutinib survival was 1.4 months, longer in 41.9% patients receiving subsequent treatment (median, 8.6 vs 0.6 months; HR, 0.36; P = .002). Ibrutinib with or without rituximab was effective and well tolerated as first-line treatment of MCL, including older and transplant-ineligible patients. PFS and OS were significantly inferior in one-third of patients with high-risk disease and those unsuitable for post-ibrutinib treatment, highlighting the need for novel approaches in these groups.

Rituximab, Bendamustine and Cytarabine Followed By Venetoclax (V-RBAC) in High-Risk Older Patients with Mantle Cell Lymphoma: A Phase 2 Study By the Fondazione Italiana Linfomi (FIL)

Introduction: The R-BAC regimen is considered among standard first-line treatments for elderly fit patients with mantle cell lymphoma (MCL). We previously reported (RBAC500 trial) a significantly inferior progression-free survival (PFS) for patients with high risk (HR) features, namely blastoid morphology and/or elevated Ki67 proliferative index, as compared to other patients, that were defined as low risk (LR). Indeed, when treated with R-BAC, LR patients had excellent outcome, albeit no maintenance therapy was delivered. Methods: We designed a phase 2 prospective multicenter study, which enrolled patients aged ≥65 years and fit according to the geriatric CGA assessment, or age ≤64 years if not eligible to high-dose chemotherapy plus transplantation. Asymptomatic patients with non-nodal disease were excluded. At presentation patients were allocated by central review as LR or HR, depending on tumor morphology (blastoid versus others), Ki67 expression (≥30% versus others), or presence of TP53 mutation and/or deletion. Patients with any of the three risk factors were classified as HR. Patients with LR disease were treated with 6 cycles of R-BAC (rituximab 375 mg/m2 d 1; bendamustine 70 mg/m2 d 1,2; cytarabine 500 mg/m2 d 1,2,3), while HR patients received abbreviated induction with 4 R-BAC followed by consolidation (4 months, 800 mg/d), and maintenance (20 months, 400 mg/d) with venetoclax. The primary endpoint was 2-years PFS for the HR patients. The sample size was calculated with the one arm non parametric survival analysis (alpha-error 0.05, power 90%), assuming that the addition of venetoclax would improve 2-years PFS from 40% (null hypothesis) to 60%. Tumor response was assessed with Lugano criteria. All patients were analyzed by real-time quantitative PCR at baseline on peripheral blood and bone marrow samples for minimal residual disease (MRD) evaluation, and HR patients were followed up at different time points. Results of this specific analysis will be subject of future reports. This trial was registered at ClinicalTrials.gov Identifier: NCT03567876. Results: Overall, 140 patients from 35 centers of the Fondazione Italiana Linfomi (FIL) were prospectively enrolled between 2018 and 2021. Of them, 54 were HR (39%). Median age was 72 (range 57-79), and 44% had elevated MIPI. LR and HR patients had similar clinical characteristics, but differed for LDH, and MIPI, both being significantly higher in the HR group. Overall, 28 (20%) patients had TP53 mutations, 19 (14%) had TP53 deletions, Ki67 was ≥30% in 34 (24%), and blastoid variant was diagnosed in 13 patients (9%, Figure 1A). Toxicity during R-BAC was in line with previous reports, while most frequent grade >=3 adverse events during venetoclax treatment consisted of neutropenia (21%), followed by skin reactions (10%). Of note, there were 5 deaths due to COVID-19 infection in patients in CR (4 LR, 1 HR). Overall response at the end of R-BAC differed between HR and LR patients (85% vs 99%, p=0.001), as was for complete response (61% vs 91%, p=0.0001). Of the 54 HR patients, 43 (80%) started venetoclax consolidation, 37 (69%) started the maintenance phase, with 26 patients (48%) completing the whole treatment per protocol. Of 10 patients that started Venetoclax in partial remission (PR) or stable disease after R-BAC, 3 converted to CR, 1 maintained PR, while 6 patients progressed during maintenance. After a median follow-up of 34 months, the 2-years PFS for the whole population was 74.9% (95% CI 66-82), and OS was 80% (95% CI 72-85). Patients with HR MCL had 2-years PFS and OS of 58% (95% CI 43-70) and 66% (95% CI 50-77), respectively, which were significantly lower than LR patients (85% and 88%, respectively, p=0.0001 for both, see Figure 1B). Predictors of PFS using Cox regression models adjusted for MIPI were blastoid morphology (Hazard Ratio 3.51), and TP53 mutation (Hazard Ratio 4.17), with Ki67, and TP53 deletions that lost their power in multivariate analysis. Conclusions: The VR-BAC trial represents the first prospective study that stratified upfront patients with MCL to different treatments according to the risk profile. In this trial the null hypothesis (2-years PFS 40%) was rejected in HR patients, suggesting that the addition of venetoclax to R-BAC improves the performance of the induction strategy. These results point to the importance of identifying HR patients since initial diagnosis.

CD19-Directed CAR T-Cells (CD19-CAR) Combined with Acalabrutinib Achieves Durable Remissions in Patients with Relapsed or Refractory (r/r) Mantle Cell Lymphoma (MCL)

Background: MCL is an aggressive non-Hodgkin lymphoma (NHL) subtype which remains incurable despite improvements in progression free survival with consolidative autologous transplant and the introduction of novel targeted therapies [Dreyling et al. Blood 2012]. CD19-directed chimeric antigen receptor (CAR) T-cell therapy (CD19-CAR) has shown durable disease control in r/r MCL, but current standard of care products are limited by high rates of grade 3+ immune-related toxicities [Wang et al. NEJM 2020]. We hypothesized that combining a naïve/stem-memory (T N/SCM) phenotype-enriched CD19-CAR T-cell product with the selective BTK inhibitor (BTKi) acalabrutinib would attenuate the rates of severe toxicities, improve durable remission rates, and obviate the need for indefinite use of acalabrutinib in r/r MCL. Methods: We conducted a phase 1 single center, prospective clinical trial (NCT04484012) evaluating a single infusion of T N/SCM-enriched CD19.28.z.EGFRt-CAR at a target dose of either 2x10 8 (DL1) or 5x10 8 (DL2) CAR+ cells (≤20% lower dose allowed) in combination with ongoing acalabrutinib 100 mg twice daily for patients with r/r MCL after at least 1 prior line of therapy. Patients were required to undergo at least 3 months but less than 7 months of treatment with a BTKi prior to enrollment without evidence of progression and with measurable disease per Lugano criteria. All patients were switched to acalabrutinib for protocol therapy prior to lymphodepletion, and planned to continue until day 180 post CD19-CAR infusion at which time all therapy would be discontinued. We report outcomes from the dose finding portion of the study. Descriptive statistics were utilized for baseline characteristics and survival analyses were calculated utilizing the Kaplan-Meier method. Investigator-assessed response rates were based on Lugano criteria. Minimal residual disease (MRD) status was determined using either multiparameter flow cytometry (FCM) or next-generation sequencing (NGS). Results: To date, 8 patients enrolled and have received CD19-CAR (n=4 at DL1; n=4 at DL2). Manufacturing was successful in 100% of patients. Median time from leukapheresis to product infusion was 53 days (range, 41-114). Treated patients were 75% male; with a median age of 63 years (range, 38-70); and median number of prior therapies of 2 (range, 2-3). All patients had bone marrow involvement, and had high risk features including progression of disease within 24 months (n=6), relapse after autologous HCT (n=2), TP53 mutations (n=6), Ki-67 ≥30% (n=4), and/or complex karyotype (n=1). Prior to enrollment, all patients had received BTKi (n=8 acalabrutinib) for a median of 6.1 months (range, 4.5-7.3). No BTK and PLC-γ mutations were detected in patients with available samples. The combination of acalabrutinib and CD19-CAR was well tolerated; 5 patients (63%; n=1 grade 2; n=4 grade 1) had cytokine release syndrome (CRS), with no severe cases. No patients (0%) had immune effector cell associated neurotoxicity syndrome (ICANS) [Figure 1A]. No patient required corticosteroids for toxicity management, and only 2 patients (n=2/5, 40%) required tocilizumab for CRS. There were no serious adverse events (SAEs), and no treatment discontinuations due to AEs observed. The best ORR was 88% [n=6 CR (75%); n=1 PR (13%)], with median time to best response of 28 days. In those 6 patients who achieved CR, 2 patients were FCM-MRD negative (<10 -4) and 2 were NGS-MRD negative (<10 -6) (n=4/6, 67%) [Figure 1B]. After a median follow-up of 18.5 months (range, 8.3-28.9), 5 of 6 patients remain in CR, while1 patient who achieved an initial CR relapsed at 9.2 months. At 1-year post-infusion, the cumulative incidence of relapse and NRM were 30% (95% CI, 3%-67%) and 0%, respectively. The 1-year PFS and OS were 70% (95% CI: 22%-92%) and 100%, respectively. Conclusion: The combination of CD19-CAR with acalabrutinib was well tolerated and effective, yielding an ORR 88% and MRD- rate 50% in a cohort of patients with high-risk MCL. Notably, CRS events were manageable and low grade, and no ICANS was observed. Enrollment is ongoing in the expansion cohort (DL2), and additional clinical and correlative analyses will be presented at the meeting.

Optical Genome Mapping Provides New Molecular Insights in High-Risk Mantle Cell Lymphoma: A Lysa Study

Introduction Around 5-10% of mantle cell lymphoma (MCL) patients are primary refractory to chemotherapy. They have an extremely dismal prognosis, as do responsive patients that relapsed within 12 months. Despite better understanding of risk factors and evolving classifications, these scores do not predict all high-risk patients and were not designed to guide treatment strategy in newly diagnosed MCL. Optical genome mapping (OGM) is a cutting-edge technology developed for genome-wide detection of structural variants (SVs) including balanced and unbalanced translocations, inversions, insertions, deletions, duplications as well as copy number variations (CNVs). Methods High-risk (HR) patients included in the prospective phase III LyMa trial (NCI NCT00921414; Le Gouill et al. NEJM 2017), were identified as patients experiencing early progression of disease (i.e. within 1 year after randomization). We performed OGM in the HR cohort using available frozen tumoral tissue. Low-risk patients (LR) were used as a control. The data were analyzed with the Bionano Solve software. Results Among 299 MCL patients included in the LyMa trial, 31 high-risk MCL patients were identified (10.4%). OGM was performed in 15 patients: 8 HR and 7 LR. OGM successfully detected the t(11;14) in all patients. We detected a median of 38 SVs (range, 16-129) and 12 CNVs (range, 1-119) per case, higher in HR patients than in LR patients (median 51 vs. 32, p=0.07 for SVs; and 14 vs. 5, p=0.11 for CNVs). Chromothripsis and chromoplexia occurred in both cohorts, but breakage-fusion-bridge (BFB) cycles was only observed in 2 HR MCL. HR MCL were characterized by frequent loss of 17p/ TP53 (63% vs. 0%, p=0.03), and rare deletions of 11q22-q23/ ATM (13% vs. 57%, p=0.12). Three HR patients had no TP53 deletions, two of whom presented a gain of BCL2. Gain of UBR5, that influence transcription and posttranscription processes, was found in 3/8 HR patients compared to 1/8 LR patients. MTAP deletion that has been recently described as biomarkers predicting refractory MCL was found in 5/8 HR MCL and is associated with CDKN2A/2B deletions, compared to 0/8 LR. MTAP deletion was associated with TP53 deletions in two HR MCL, that is supposed to confer resistance to PRMT5 targeted therapy (Sloan SL et al. Blood 2023). Deletion of the chromatin modifier MEF2B occurred in 3/8 HR MCL and 1/8 LR MCL. Two patients had deletion of SMARCA4 at diagnosis, that confers resistance to the BCL-2 inhibitor venetoclax (Agarwal et al. Nature Med 2018). Mutations in the NF-κB alternative pathway, responsible for resistance to ibrutinib, are found in both LR and HR patients. Conclusion In this small cohort of MCL patients included in a trial, complex structural alterations were identified by OGM at the time of diagnosis. OGM is a very promising technology that demonstrated its potential in the cytogenetic prognostic staging of MCL.

Ibrutinib Combined with Venetoclax in Patients with Relapsed/Refractory Mantle Cell Lymphoma: Primary Analysis Results from the Randomized Phase 3 Sympatico Study

Background: Ibrutinib (Ibr) is a once-daily Bruton tyrosine kinase (BTK) inhibitor approved in multiple regions for patients (pts) with mantle cell lymphoma (MCL) who have received ≥1 prior therapy. Venetoclax (Ven) is a BCL-2 inhibitor approved in the US for pts with chronic lymphocytic leukemia and previously untreated acute myeloid leukemia. Ibr and Ven have distinct and complementary modes of action, and the combination has shown promising clinical activity in early phase studies in MCL (Tam, N Engl J Med 2018; Wang, J Hematol Oncol 2021). Here, we report the primary analysis results from the multinational, randomized, double-blind, phase 3 SYMPATICO (NCT03112174) study comparing Ibr+Ven vs Ibr + placebo (Pbo) in pts with relapsed/refractory (R/R) MCL. Methods: Pts aged ≥18 y with R/R MCL after 1-5 prior therapies were randomly assigned 1:1 to receive oral Ibr 560 mg once daily concurrently with oral Ven (standard 5-wk ramp-up to a target dose of 400 mg once daily) or Pbo for 2 y, followed by single-agent Ibr until progressive disease (PD) or unacceptable toxicity. Randomization was stratified based on ECOG PS, prior lines of therapy, and tumor lysis syndrome (TLS) risk based on tumor burden and CrCl. The primary endpoint was progression-free survival (PFS) by investigator (INV) assessment using Lugano criteria; pts without PD or death were censored at the last non-PD assessment (per global censoring rules). Additional sensitivity analyses included PFS assessment by independent review committee (IRC) and censoring per US FDA rules (Table). Key secondary endpoints were tested hierarchically in the following order: complete response (CR) rate by INV assessment, time to next treatment (TTNT), overall survival (OS, interim analysis), and overall response rate (ORR) by INV assessment. Results: A total of 267 pts were enrolled and randomly assigned to receive Ibr+Ven (n=134) or Ibr+Pbo (n=133). Median age was 68 y; 96% of pts had an ECOG PS of 0-1, 17% had ≥3 prior lines of therapy, and 22% were at increased risk for TLS. At baseline, pts in the Ibr+Ven vs Ibr+Pbo arms had median ages 69 vs 67 y, high-risk simplified MCL International Prognostic Index score 38% vs 31%, bulky disease ≥5 cm 46% vs 40%, bone marrow involvement 46% vs 41%, splenomegaly 31% vs 25%, and TP53 mutated 30% vs 28%; other baseline characteristics were generally similar between arms. With a median time on study of 51.2 mo, median PFS by INV assessment was significantly longer with Ibr+Ven vs Ibr+Pbo (31.9 vs 22.1 mo), with a hazard ratio (HR) of 0.65 (95% CI, 0.47-0.88; stratified log-rank P=0.0052) (Figure). PFS rates at 24 mo were 57% and 45% with Ibr+Ven and Ibr+Pbo, respectively. PFS benefit with Ibr+Ven vs Ibr+Pbo was generally consistent across prespecified subgroups, including those with blastoid variant or TP53-mutated MCL. Sensitivity analyses of PFS were consistent with the primary analysis (Table). Ibr+Ven significantly improved CR rates (54% vs 32%) and TTNT (median not reached [NR] vs 35.4 mo); at the current 51.2 mo median follow-up, median OS was 44.9 mo with Ibr+Ven vs 38.6 mo with Ibr+Pbo (HR 0.85 [95% CI, 0.62-1.19]) (Table). Median duration of treatment was 22.2 mo for the Ibr+Ven arm and 17.7 mo for the Ibr+Pbo arm; at the time of analysis, 30% of pts in the Ibr+Ven arm and 20% of pts in the Ibr+Pbo arm remained on single-agent Ibr. Grade ≥3 adverse events (AEs) occurred in 84% of pts with Ibr+Ven vs 76% with Ibr+Pbo; the most frequent (occurring in ≥5% of pts) were neutropenia (31% vs 11%), pneumonia (13% vs 11%), thrombocytopenia (13% vs 8%), anemia (10% vs 3%), diarrhea (8% vs 2%), leukopenia (7% vs 0%), MCL (7% vs 12%), atrial fibrillation (5% vs 5%), COVID-19 (5% vs 1%), and hypertension (4% vs 9%). Serious AEs occurred in 60% of pts in each arm. No clinical TLS occurred; laboratory TLS occurred in 5% and 2% of pts in the Ibr+Ven and Ibr+Pbo arms, respectively. COVID-19 deaths occurred in 10 pts in each arm and had no meaningful impact on PFS or OS HRs. Conclusion: The Ibr+Ven combination demonstrated a statistically significant improvement in PFS compared with Ibr+Pbo in pts with R/R MCL; CR rates and TTNT were also significantly improved with Ibr+Ven. OS was numerically but not significantly improved at this interim analysis. The safety profile of Ibr+Ven was consistent with known AEs for each agent, with no new safety signals observed. Overall, these results demonstrate a favorable benefit-risk profile for Ibr+Ven in pts with R/R MCL.

Phase II Trial of Ibrutinib in Previously Untreated High-Risk Smoldering Mantle Cell Lymphoma

Background: Mantle cell lymphoma (MCL) patients usually require immediate therapy, however about 20% of newly diagnosed MCL patients can be initially observed. A subgroup of patients who are suitable for initial observation but exhibit high-risk features are of particular concern as they have a propensity to progress. We consider these patients as high-risk smoldering MCL (defined below). Generally, these patients are observed without systemic therapy for 18-24 months. We investigated the impact of single-agent ibrutinib on time to progression for these patients who would otherwise be observed. Methods: This is a single center, single arm, investigator-initiated phase 2 clinical trial (NCT03282396). High-risk smoldering MCL included one or more of the following criteria: non-blastoid/pleomorphic variant, Ki-67 of 15-30%, white blood cell count of 15-30 x 10^9/L, lymph nodes ≤5 cm, TP53 mutated or wild type, del17p, MYC positive, complex karyotype, presence of KMT2D, BIRC3, or ≥1 other somatic mutations, and were asymptomatic without any clinical indication to start systemic therapy. Major exclusion criteria included significant disease-related symptoms, blastoid/pleomorphic variants, Ki-67 >30%, bulky tumors >5 cm. Patients received ibrutinib 560 mg P.O. daily in 28-day cycles and continued until progression, transformation, drug intolerance, or up to 5 years. The primary endpoint was progression-free survival (PFS). Secondary endpoints were safety, response rate, and duration of response (DOR). Response was measured using the Lugano criteria. It is expected that the current trial will achieve a median PFS time of about 18 months, which would be an improvement over PFS reported on high-risk patients under a watch and wait approach. The median follow-up time was 23.4 months. Results: Twenty patients were enrolled (Table 1). The median age was 60.5 years (range 38-79). Most were male (n=15/20). At baseline, 13 patients (65%) had bone marrow involvement and 15 patients (75%) had gastrointestinal tract involvement. Seven patients (35%) had TP53 alterations. One patient was not evaluable for response due cessation of therapy after less than 1 cycle due to new onset atrial fibrillation. Among 19 evaluable patients, the best overall response rate was 94.7% (n=18/19). Of those who had a positive PET at baseline and were evaluable for PET response, 92.9% (n=13/14) achieved a PET complete response (CR). Of those with bone marrow involvement at baseline, 30.7% (n=4/13) achieved CR by flow cytometry. Of those with baseline gastrointestinal tract involvement, 33.3% (n=5/15) achieved histologically confirmed CR. The median number of cycles received was 16 (range 0-32). The median PFS and DOR were not reached. Seven patients discontinued therapy: atrial fibrillation (n=3), progressive disease (n=1), infection (n=1), lung cancer (n=1). The most frequent grade 3 toxicities were diarrhea (n=2, 10%), atrial fibrillation (n=1, 5%), infection (n=1, 5%), mucositis (n=1, 5%), and syncope (n=1, 5%). No grade 4 toxicities occurred. No deaths on study occurred. Conclusions: Ibrutinib demonstrated significant efficacy with manageable toxicities in previously untreated patients with high-risk smoldering MCL.

Fixed Duration Mosunetuzumab Plus Polatuzumab Vedotin Has Promising Efficacy and a Manageable Safety Profile in Patients with BTKi Relapsed/Refractory Mantle Cell Lymphoma: Initial Results from a Phase Ib/II Study

Background: New treatment options are needed for patients (pts) with relapsed/refractory (R/R) mantle cell lymphoma (MCL), especially for pts with progressive disease (PD) after Bruton's tyrosine kinase inhibitor (BTKi) therapy. Outcomes for R/R MCL pts with PD after the BTKi ibrutinib are very poor, demonstrated by a median overall survival of 2.9 months (Martin et al. Blood 2016). While chimeric antigen receptor (CAR) T-cell therapies are approved for pts with R/R MCL; treatment is associated with high toxicity and difficulty with accessibility. Mosunetuzumab (Mosun) is a CD20xCD3 T-cell engaging bispecific antibody that engages and redirects T cells to eliminate malignant B cells. Polatuzumab vedotin (Pola) is a CD79b-targeted antibody-drug conjugate that inhibits cell division and induces apoptosis in B cells. This ongoing Phase Ib/II study (NCT03671018) is investigating Mosun in combination with Pola (M-Pola) in pts with R/R B cell non-Hodgkin lymphoma. Here, we report initial safety and efficacy data from an ongoing Phase II expansion cohort of pts with R/R MCL who had received prior BTKi therapy. Methods: Eligiblepts had histologically confirmed R/R MCL and had received ≥2 prior regimens (including an anti-CD20 agent, BTKi, and anthracycline- or bendamustine-based therapy). Mosun was administered subcutaneously (SC) by step-up dosing on Days (D) 1 (5mg), 8 (45mg), and 15 (45mg) of Cycle (C) 1, then 45mg on D1 of every cycle from C2D1, every 3 weeks for a total of 17 cycles. Pola (1.8mg/kg intravenous [IV] infusion) was administered on D1 of C1-6. All pts received corticosteroid premedication prior to C1 of treatment. From C2, premedication was optional for pts who did not experience cytokine release syndrome (CRS) in the previous cycle. Response was assessed by investigators using Lugano 2014 criteria (Cheson et al. J Clin Oncol 2014). Results: As of October 27, 2022, 20 pts had received M-Pola (n=10 active on treatment, n=1 completed treatment, n=9 discontinued Mosun treatment). Median age of all pts was 68.0 (range: 44-82) years, 75% were male, 95% had Ann Arbor stage III/IV disease, and 40% had a MIPI score ≥6 at study entry. Median number of prior lines of therapy (LOT) was 3 (range: 2-9). All pts had received prior BTKi therapy; 7 pts (35%) had received prior CAR T-cell therapy; and 85% (17/20) of pts were refractory to their last LOT. Median time since last LOT was 1.6 (range: 0-39) months. The proportions of pts with high-risk MCL factors at baseline were: 65% of pts with Ki-67 proliferation index ≥50%; 50% with blastoid/pleomorphic variants; and 20% with TP53 mutation. The overall median time on study was 7.2 (range: 0.4-17.5) months. The most common (≥25%) Mosun and/or Pola-related adverse events (AEs) in all pts (n=20) were CRS (50%), injection site reaction (50%), fatigue (45%), dyspnea (35%), paresthesia (30%), diarrhea (30%), myalgia (30%), infusion-related reaction (25%), and nausea (25%). Two (10%) Grade (Gr) 5 AEs occurred, both of which were due to COVID-19 pneumonia; neither were deemed treatment-related by the investigator. Ten pts (50%) experienced CRS events; 9 pts experienced Gr 1 events, and 1 pt experienced a Gr 2 event, which was managed with tocilizumab and low-flow oxygen. One pt was managed with corticosteroids and no pts required pressors or ICU admission. All CRS events resolved by the data cut-off. Treatment-related neurologic AEs, potentially consistent with ICANs, occurred in 3 pts (15%; Gr 1 confusional state and Gr 2 amnesia, 1 pt; Gr 1 agitation, 1 pt; and Gr 2 memory impairment, 1 pt). Neuropathy occurred in 3 pts (15%); all events were Gr 1. Four pts (20%) had AEs leading to treatment discontinuation: 1 pt with Gr 3 uveitis (related to M-Pola); 1 pt with Gr 3 pneumonitis (related to M-Pola); and 2 pts with Gr 5 COVID-19 pneumonia (both unrelated to M-Pola). Overall response rate (ORR) and complete response (CR) rates were 75% and 70%, respectively (Figure). Best ORR and CR rates were generally consistent in high-risk MCL subgroups (Figure). Median duration of CR was not evaluable (NE; 95% confidence interval: 3.8-NE). Conclusions: Fixed-duration Mosun SC in combination with Pola IV induced high CR rates in pts with R/R MCL who had previously received BTKi therapy, including those in high-risk subgroups and those who had received prior CAR T-cell therapy. CRs were observed early and persisted during the follow up period. M-Pola had a manageable safety profile, and all CRS events were low grade.

IMMUNE‐DEPLETED TUMOR MICROENVIRONMENT IS ASSOCIATED WITH POOR OUTCOMES AND BTK INHIBITOR RESISTANCE IN MANTLE CELL LYMPHOMA

Introduction: An understanding of the tumor microenvironment (TME) and its cellular and analyte composition plays a critical role in promoting mantle cell lymphoma (MCL) cell growth, proliferation. To further understand the relevance of the tumor-immune landscape in tissue microenvironments, we performed multiomic profiling to characterize the TME in tissues from MCL patients and examined the relationship between TME subtypes and their impact on clinical outcome and the response to BTKi. Methods: This cohort study was conducted under an IRB approved protocol for MCL patients at our Center. Tissue biopsies (28 lymph nodes and 13 other tissues) were collected from 41 patients with MCL. We conducted whole exome sequencing (WES; n = 41) and RNA-seq (n = 41) from MCL tissue biopsies from patients treated with BTKi (ibrutinib, acalabrutinib or zanubrutinib) in combination with the analysis of a published MCL cohort (n = 122). Joint WES and RNA-seq mutation calling and TME molecular signatures were categorized based on response to BTKi. All WES and bulk RNA sequencing was performed with Illumina HiSeq4000 using a 76 bp paired end configuration. Results: Unsupervised clustering identified four MCL TME subtypes reflecting distinct tumor-immune cell gene signatures. Four distinct groups—normal lymph node (n = 27), immune cell-enriched (n = 46), mesenchymal (n = 44) and immune cell-depleted “D” (n = 51). “D” subtype was predominant in patients with primary BTKi resistance. A high tumor proliferation gene signature was observed exclusively in the “D” group. We further observed that Ki-67% from tissue biopsies had a linear correlation with proliferation rate signature genes and significantly overexpressed in the D group (p = 0.002). Somatic mutations such as TP53, NSD2, NOTCH1, KMT2D, SMARCA4, which were previously reported in ibrutinib-resistant MCL and/or in refractory high-risk MCL patients, were predominant in the Dsubtype. Finally, the evaluable patients (n = 39) were divided according to response to BTKi- sensitive, primary resistant and acquired resistant and MFP clusters. Patients with primary and acquired resistance had significant proportion of patients with D subtype (p = 0.004), compared to N and IE subtypes. Primary and BTKi resistant patients had a trend of inferior survival compared to sensitive patients (p = 0.07). Furthermore, we demonstrated that the D TME group had worse overall survival compared to other TME categories (p = 0.001). Keyword: microenvironment The research was funded by: Boston Gene Corp

Brexucabtagene Autoleucel for Relapsed or Refractory Mantle Cell Lymphoma in Standard-of-Care Practice: Results From the US Lymphoma CAR T Consortium.

Brexucabtagene autoleucel (brexu-cel) is an autologous CD19-directed chimeric antigen receptor (CAR) T-cell therapy approved for relapsed/refractory mantle cell lymphoma (MCL). This therapy was approved on the basis of the single-arm phase II ZUMA-2 trial, which showed best overall and complete response rates of 91% and 68%, respectively. We report clinical outcomes with brexu-cel in the standard-of-care setting for the approved indication. Patients who underwent leukapheresis between August 1, 2020 and December 31, 2021, at 16 US institutions, with an intent to manufacture commercial brexu-cel for relapsed/refractory MCL, were included. Patient data were collected for analyses of responses, outcomes, and toxicities as per standard guidelines. Of 189 patients who underwent leukapheresis, 168 (89%) received brexu-cel infusion. Of leukapheresed patients, 79% would not have met ZUMA-2 eligibility criteria. Best overall and complete response rates were 90% and 82%, respectively. At a median follow-up of 14.3 months after infusion, the estimates for 6- and 12-month progression-free survival (PFS) were 69% (95% CI, 61 to 75) and 59% (95% CI, 51 to 66), respectively. The nonrelapse mortality was 9.1% at 1 year, primarily because of infections. Grade 3 or higher cytokine release syndrome and neurotoxicity occurred in 8% and 32%, respectively. In univariable analysis, high-risk simplified MCL international prognostic index, high Ki-67, TP53 aberration, complex karyotype, and blastoid/pleomorphic variant were associated with shorter PFS after brexu-cel infusion. Patients with recent bendamustine exposure (within 24 months before leukapheresis) had shorter PFS and overall survival after leukapheresis in intention-to-treat univariable analysis. In the standard-of-care setting, the efficacy and toxicity of brexu-cel were consistent with those reported in the ZUMA-2 trial. Tumor-intrinsic features of MCL, and possibly recent bendamustine exposure, may be associated with inferior efficacy outcomes.

Overexpression of the key metabolic protein CPT1A defines mantle cell lymphoma patients with poor response to standard high-dose chemotherapy independent of MIPI and complement established highrisk factors.

The variable outcome to standard immunochemotherapy for mantle cell lymphoma (MCL) patients is a clinical challenge. Established risk factors, including high MCL International Prognostic Index (MIPI), high proliferation (Ki-67), non-classic (blastoid/pleomorphic) morphology, and mutated TP53, only partly identify patients in need of alternative treatment. Deepened understanding of biological factors that influence time to progression and relapse would allow for an improved stratification, and identification of novel targets for high-risk patients. We performed gene expression analyses to identify pathways and genes associated with outcome in a cohort of homogeneously treated patients. In addition to deregulated proliferation, we show that thermogenesis, fatty acid degradation and oxidative phosphorylation are altered in patients with poor survival, and that high expression of carnitine palmitoyltransferase 1A (CPT1A), an enzyme involved in fatty acid degradation, can specifically identify high-risk patients independent of the established high-risk factors. We suggest that complementary investigations of metabolism may increase the accuracy of patient stratification and that immunohistochemistry- based assessment of CPT1A can contribute to defining high-risk MCL.

Differential Phosphoproteomics Deciphers Physiopathology of High-Risk Mantle Cell Lymphoma

Background: Mantle cell lymphoma (MCL) is a rare adult-onset non-Hodgkin lymphoma of which genetic hallmark is CCND1 translocation with IG genes, although CCND2, CCND3 or CCNE translocations are alternatives. The median survival of patients with MCL has lately increased due to improved therapies. However, the identification of high-risk MCLs characterized by pleomorphic or blastoid appearance, high proliferation index and TP53 deletions/mutations, remains mandatory due to their highly aggressive features and dismal clinical course even with intensified regimens. Therefore, specific therapeutic approaches are still warranted for such patients, but clinical and biological data are scarce since high-risk MCLs represent only 10-20% of all MCLs. A valuable source of rare samples for clinical/translational research is archived collections of formalin-fixed paraffin-embedded (FFPE) tissue blocks which enable retrospective studies to be performed. However, FFPE samples remain challenging for omics studies, especially phosphoproteomics. Here we implemented an original process to overcome this technical roadblock and took full advantage of FFPE samples to investigate biological processes differentially involved in high-risk and classical MCL (cMCL) to highlight rationale for innovative targeted therapies for these aggressive forms. Material and methods: We employed an unbiased differential label-free phosphoproteomic approach using archived FFPE MCL samples. Briefly, archived FFPE lymph nodes conclusive for cMCL or blastoid MCL (bMCL) diagnoses were retrieved from the Biological Resource Center of Strasbourg University Hospital from 1996 to 2016. H&E slides were reevaluated, and areas enriched in tumoral cells were selected to be punched from FFPE blocks. Our original sample preparation procedure entailed 1/ xylene-based deparaffinization, 2/ protein extraction with high content SDS-based lysis buffer, 3/ sample reduction/alkylation followed by cleanup and protein digestion on carboxylate paramagnetic beads and Lys-C/trypsin proteolytic enzyme mix, 4/ phosphopeptide enrichment on the AssayMap Bravo platform (Agilent) using IMAC Fe(III)-NTA cartridges. All samples were then analyzed on a NanoElute coupled to a TimsTOF Pro mass spectrometer (Bruker). Label-free quantification was performed using MaxQuant with the human database downloaded from SwissProt in April 2022. Further bioinformatics analyses were conducted in Perseus and Prostar. Data were functionally annotated with Reactome Pathway Database and STRING for association networks. Results: For this monocentric study we retrieved 30 FFPE blocks of lymph node biopsies conclusive for MCL diagnosis, including 15 bMCL and 15 cMCL. Although FFPE samples represented a challenge to work with for phosphoproteomics, we extracted enough protein from three 2mm-punches to proceed to the phosphopeptide enrichment according to our original sample preparation procedure. Overall, we successfully identified and quantified 7,220 class I phosphosites, i.e., sites of phosphorylation for which the probability of the phosphate group localization is greater than 0.75. No significant difference was found considering neither the archived period length of FFPE blocks nor the MCL subtypes (bMCL or cMCL). Differential analysis of bMCL and cMCL identified 180 differentially phosphorylated phosphosites (p-value < 0.05) corresponding to 103 proteins. Among these phosphosites, 139 were more phosphorylated in bMCL. Functional annotation of their corresponding proteins highlighted an over-representation of proteins involved in cell cycle, DNA repair and RNA metabolism within bMCL differential phosphoproteome (Fig.1). In addition, the kinase enrichment analysis of these differentially phosphorylated proteins predicted an increased activity of cyclin-dependent kinases in bMCL compared to cMCL. Conclusion: Here we performed for the first time phosphoproteomics from archived FFPE MCL samples. Differential analysis revealed that high-risk MCLs are characterized by an increased phosphorylation of proteins involved in cell cycle and an increased activity of cyclin-dependent kinases. Further studies are mandatory to fully understand to which extent cyclin-dependent kinases could be suitable targeted therapeutic candidates for patients with high-risk MCL. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Mutation Spectrum, Characteristics and Impact of Mutation Profiling on Prognosis, Outcome and Treatment Responses in Patients (pts) with Mantle Cell Lymphoma

Background: Genomic profiles of mantle cell lymphoma (MCL) are associated with clinical outcomes. BTKi Resistance in MCL can be predicted with mutation profile. Identifying these patients (pts) early can help guide therapy decisions and predict outcomes. We describe results from a clinical NGS based assay with a customized 162-gene panel in routine work-ups of MCL pts. Materials and Methods: We reviewed data from MCL patients who underwent CLIA approved lymphoma gene panel testing at MDACC from October 2020 until the end of June 2022. Data on treatment response, outcomes, and patient characteristics were collected. Mutation panel testing was conducted on various patient samples. Genomic DNA was isolated from fresh bone marrow (BM) aspirate, formalin-fixed paraffin-embedded (FFPE) tissues, fine needle aspirate (FNA) and peripheral blood (PB) specimens. Sequencing was performed using the Illumina NextSeq platform (Illumina, San Diego, CA). Variant calling was performed using Agilent SureCall software v4.1 and post-variant call analysis and annotation were performed using an in-house bioinformatics pipeline (OncoSeek v 1.1). Analytical sensitivity of the assay was established at 2% using a per base coverage cut-off of 200x. The assay was performed in cases with >10% lymphoma cells in the sample. Results: We included 227 MCL pts in this study: 129 treatment naïve and 97 with prior therapies. The distribution of patients according to the sample type included: BM (n=107), FFPE (n=50; 24 lymph node, 20 GI tract, and 6 miscellaneous tissues), FNA from involved nodal and non-nodal tissues (n=50) and PB (n=20). Baseline pt features included a median age of 67 years (range, 38-88 years). There were 164 men and 63 women. Histomorphology was classic in 165 pts, blastoid in 31, pleomorphic in 19 and blastoid/pleomorphic in 2. Ten pts had unclear histomorphology. Ki-67% in involved tissues was evaluable in 180 pts (in 47 pts Ki-67% was not available). Ki-67% was high (>=30%) in 98 and low in 82 biopsy specimens. Among the 97 previously treated pts, 47 had BTKi refractory disease. Twenty-three pts were treated with standard of care brexucabtagene autoleucel (CART). The spectrum of gene mutations is depicted by both previously untreated and pts with prior therapy in figure-1A. The most common mutated genes were: ATM (51.5%), TP53 (29.5%), KMT2D (21.1%), CCND1 (19.3%), BIRC3 (16.2%), NSD2 (11.4%), SMARCA4 (10.1%), UBR5 (9%), NOTCH1 (8.3%), CARD11 (7%), SAMHD1 (7%), NFKB1E (6.6%), SP140 (6.6%), S1PR1 (6.6%), DNMT3A (6%), NOTCH2 (6%), IGLL5 (6%), TRAF2 (5%), TET2 (5%). Unlike chronic lymphocytic leukemia, mutations of BTK (n=5; 2%) and PLCg (n=4; 2%) were rare. BTK mutations included missense mutations: C481Y, C481R, T474I and 2 with L528W. All patients with BTK mutations were resistant to prior BTKi and 4/5 died with refractory disease. Additional mutations of prognostic interest in other lymphomas were detected at very low frequency (<3%) and included CDKN2A, CD79b, MYD88, MEF2B, MAP3K14, Rb1, PAX5, SPEN, SF3B1, DIS3. We also evaluated pt survival from the date of gene panel testing and noted that TP53 mutant MCL pts had significantly inferior survival. We further divided the pts based on >=3 mutations (n=77) vs < 3 mutations (n=150) and identified that pts with a higher number of mutations had inferior survival, P <0.0001 (Figure 1C). Pts with SMARCA4 and TRAF2 mutations also demonstrated shorter survival compared to those which were wild type (not shown). Twenty-three pts received CART therapy and 7 had progressed and 16 have not. The distribution of mutations before CART in the two groups was not significantly different. Among the 47 BTKi refractory MCL, the frequency of certain mutations was higher: TP53 (49%), ATM (55%), KMT2D (31%), CCND1 (23%), 10% each for SMARCA4, NSD2 and SP140. Currently, we are utilizing this test to evaluate and include pts with high risk MCL on our clinical trials in MCL and treat with risk stratified treatments. Conclusion: The clinical NGS-based assay for MCL pts at our institution has proven to have prognostic significance. Resistant MCL pts exhibit a preponderance of mutations involving TP53, epigenetic modifier and chromatin regulator genes. Comprehensive risk stratification of pts early on and during therapy is very useful and improves patient care, helps design next generation clinical trials and improves our understanding of the biology of resistant MCL in the BTKi and CART era. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Whole Transcriptome Sequencing Reveals Cancer-Related, Prognostically Significant Transcripts and Tumor-Infiltrating Immunocytes in Mantle Cell Lymphoma.

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma (NHL) subtype characterized by overexpression of CCND1 and SOX11 genes. It is generally associated with clinically poor outcomes despite recent improvements in therapeutic approaches. The genes associated with the development and prognosis of MCL are still largely unknown. Through whole transcriptome sequencing (WTS), we identified mRNAs, lncRNAs, and alternative transcripts differentially expressed in MCL cases compared with reactive tonsil B-cell subsets. CCND1, VCAM1, and VWF mRNAs, as well as MIR100HG and ROR1-AS1 lncRNAs, were among the top 10 most significantly overexpressed, oncogenesis-related transcripts. Survival analyses with each of the top upregulated transcripts showed that MCL cases with high expression of VWF mRNA and low expression of FTX lncRNA were associated with poor overall survival. Similarly, high expression of MSTRG.153013.3, an overexpressed alternative transcript, was associated with shortened MCL survival. Known tumor suppressor candidates (e.g., PI3KIP1, UBXN) were significantly downregulated in MCL cases. Top differentially expressed protein-coding genes were enriched in signaling pathways related to invasion and metastasis. Survival analyses based on the abundance of tumor-infiltrating immunocytes estimated with CIBERSORTx showed that high ratios of CD8+ T-cells or resting NK cells and low ratios of eosinophils are associated with poor overall survival in diagnostic MCL cases. Integrative analysis of tumor-infiltrating CD8+ T-cell abundance and overexpressed oncogene candidates showed that MCL cases with high ratio CD8+ T-cells and low expression of FTX or PCA3 can potentially predict high-risk MCL patients. WTS results were cross-validated with qRT-PCR of selected transcripts as well as linear correlation analyses. In conclusion, expression levels of oncogenesis-associated transcripts and/or the ratios of microenvironmental immunocytes in MCL tumors may be used to improve prognostication, thereby leading to better patient management and outcomes.

Is There Still a Role for Transplant for Patients with Mantle Cell Lymphoma (MCL) in the Era of CAR-T Cell Therapy?

Opinion statementFor years, upfront autologous hematopoietic cell transplant (auto-HCT) has been the standard of care for younger and physically fit mantle cell lymphoma (MCL) patients after chemoimmunotherapy (CIT) induction. Bruton’s tyrosine kinase (BTK) inhibitors have proven to be excellent salvage therapies, but their durability remains a question, especially in high-risk (HR) MCL. Allogeneic HCT (allo-HCT) was the only option for long-term remission and possibly cure for MCL relapse after auto-HCT and sometime as upfront consolidation for a young patient with HR MCL (debatable). We have seen a paradigm shift since the FDA approval in July 2020 of the brexucabtagene autoleucel chimeric antigen receptor T (CAR-T) cell therapy for relapsed and refractory (R/R) MCL with an preliminary evidence suggesting CAR-T may overcome known biological risk factors in MCL. Given its safety profile and excellent efficacy, the role of CAR-T among other approved therapies and HCT may need to be better defined. Based on the current evidence, auto-HCT remains a standard frontline consolidation therapy. CAR-T therapy is a preferred option for patients with relapsed/refractory (R/R) MCL, particularly those who failed BTK inhibitors. In certain high-risk MCL patients (such as high ki 67, TP53 alterations, complex karyotype, blastoid morphology, early relapse after initial diagnosis), CAR-T cell therapy may be considered before BTK inhibitors (preferably on a clinical trial). The role of allo-HCT is unclear in the CAR-T era, but remains a viable option for eligible patients who have no access or who have failed CAR-T therapy. Our review discusses current standards and the shifting paradigms in the indications for HCT and the role of CAR-T cell therapy for MCL. Prospective studies tailored based on risk factors are needed to better define the optimal sequences of HCT and cellular therapy and other approved novel therapies.

CT-321 Uncommon Viral Infections in Patients Treated With CAR-T Cell Therapy: Concurrent Adenovirus and BK Virus Infection in a Mantle Cell Lymphoma Patient Within 30 Days After Receiving Brexucabtagene Autoleucel

Chimeric antigen receptor-T (CAR-T) cell therapy has emerged as an immunotherapy option for several hematological malignancies. Patients treated with CAR-T cell therapy are immunocompromised and prone to infections. However, limited data exist regarding prophylaxis and management strategies, which vary among institutions. We report a single-institution experience of adenovirus (AdV) infection treatment following CAR-T cell therapy. Case report. Academic referral center. A 67-year-old man with high-risk mantle cell lymphoma previously treated with chemoimmunotherapy and ibrutinib received brexucabtagene autoleucel for refractory disease. Treatment was complicated by grade 2 immune effector cell-associated neurotoxicity syndrome (ICANS), warranting corticosteroid treatment that was tapered over 4 weeks, and cytokine release syndrome (CRS), resolved with tocilizumab. The patient was admitted within 30 days post-CAR-T cell therapy with pancytopenia and bilateral pulmonary infiltrates. His only symptoms were fatigue and malaise. A respiratory viral panel was positive for AdV. Further infectious testing revealed AdV viremia at 128,000 copies/mL and viruria at 7.10E+07 copies/mL, as well as BK viremia at 5,200 copies/mL and viruria >62,800,000 copies/mL. The patient was initially treated with intravenous immune globulin and then started on intravenous cidofovir 1 mg/kg with pre- and post-hydration. Adenovirus and BK virus levels were monitored in blood and urine weekly. Cidofovir was continued until the plasma level of AdV was <400 copies/mL on two separate occasions. AdV viremia and viruria, BK virus viremia and viruria, symptoms. Viral levels of AdV steadily decreased over 3 weeks to <190 copies/mL in plasma and 5200 copies/mL in urine. No new symptoms other than intermittent hematuria were noted. BK virus plasma levels increased temporarily, but fluoroquinolones were not given due to allergy and scarce evidence of their efficacy. Immunosuppression in patients receiving CAR-T cell therapy is multifactorial. CRS and ICANS are common acute toxicities that frequently require treatment with immunosuppressive agents. Prolonged use of corticosteroids has been identified as a predictor of infection after CAR-T cell therapy. Clinical trials addressing appropriate infection prophylaxis and treatment in this population are needed.

The EHA Research Roadmap: Malignant Lymphoid Diseases.

The EHA Research Roadmap: Malignant Lymphoid Diseases.

Long-term Outcomes With Ibrutinib Treatment for Patients With Relapsed/Refractory Mantle Cell Lymphoma: A Pooled Analysis of 3 Clinical Trials With Nearly 10 Years of Follow-up.

Long-term Outcomes With Ibrutinib Treatment for Patients With Relapsed/Refractory Mantle Cell Lymphoma: A Pooled Analysis of 3 Clinical Trials With Nearly 10 Years of Follow-up.