Nowakowski, Grzegorz S.

Abstract Marginal zone lymphoma (MZL) includes extranodal MZL (EMZL), splenic MZL (SMZL), and nodal MZL (NMZL) subtypes. Histologic transformation (HT) to large B-cell lymphomas is well documented but with a large variability in published cumulative incidence rates. We report results from the Molecular Epidemiology Resource (MER) cohort on the cumulative incidence of HT (with death as competing risk) and the associated risk factors and outcomes. We also conducted a meta-analysis of available studies on the cumulative incidence of HT. From 2002 to 2015, 529 patients with MZL were enrolled in the MER study (69% EMZL, 16% SMZL, and 15% NMZL). The 10-year overall survival (OS) from diagnosis was 66%. HT occurred in 21 patients with a 5-year and 10-year cumulative incidence of 2.7% (95% confidence interval [CI], 0.02-0.05) and 3.6% (95% CI, 0.02-0.06), respectively. HT was associated with an increased risk for death (subdistribution hazard ratio [HR], 3.95; 95% CI, 2.06-7.55). Predictors of HT were ≥2 extranodal sites and mucosa-associated lymphoid tissue International Prognostic Index score ≥2. The OS was 79% at 5 years and 55% at 10 years after HT. In the meta-analysis of 12 studies (6161 patients), the 5- and 10-year cumulative incidence of HT across all subtypes were 5% (95% CI, 0.05-0.06) and 8% (95% CI, 0.07-0.09), respectively. These rates were lower in EMZL (3% and 5%) than in SMZL (7% and 13%) and NMZL (9% and 13%). Although HT is relatively uncommon in the first decade after MZL diagnosis, it is associated with an inferior outcome and needs new approaches for prevention and management.

Abstract Little is known about the central nervous system (CNS) risk in high-grade B-cell lymphoma, not otherwise specified (HGBL NOS). Hence, we sought to describe the rates of baseline CNS involvement, risk of CNS recurrence after primary therapy, and management strategies in HGBL NOS. In this multicenter retrospective study, we included 160 adults with newly diagnosed HGBL NOS treated between 2016 and 2021 at 20 US institutions. Eleven patients (7%) had baseline CNS involvement at diagnosis (leptomeningeal = 6, parenchymal = 4, and both = 1). Baseline CNS involvement was significantly associated only with MYC rearrangement (OR = 3.5) and testicular (in men) or female pelvic (in women) involvement (OR = 8.1). There was no significant difference in survival outcomes between patients with HGBL NOS with (median PFS = 4 years) or without (median PFS = 2.4 years) baseline CNS involvement (P = 0.45). The cumulative incidence of CNS recurrence at 3 years was 11%. Patients with baseline CNS involvement were at the highest risk (48.5% vs 8% for those without baseline CNS involvement) and were excluded from the risk factors analysis for CNS recurrence. The risk for CNS recurrence was significantly associated with blood or bone marrow involvement, CD5 expression, non–germinal center B-cell subtype, and “dual-expresser lymphoma” phenotype, however, high CNS IPI was not. The prognosis of relapsed HGBL NOS was poor, regardless of whether recurrence was systemic or limited to the CNS, and with currently available salvage strategies, including autologous transplantation and chimeric antigen receptor T-cell modalities, almost all patients with CNS recurrence ultimately succumbed to their disease.

Strategies to bring clinical trials closer to patients gained momentum during the COVID-19 pandemic, enabling more participants to receive treatment and/or testing in their local communities. Incorporation of decentralized trial elements presents both opportunities and challenges, spanning regulatory, technical, and operational aspects. This ASCO research statement includes timely consensus-driven recommendations and a call for engagement of all research stakeholders. ASCO held multistakeholder meetings with leaders in oncology research and concluded that research-related regulatory and administrative requirements and burdens present critical barriers to decentralizing trials. One example is sponsor and contract research organization (CRO) use of US Food and Drug Administration (FDA)'s Statement of Investigator (Form 1572), which was found to exceed FDA's stated intent and used in conservative ways disproportionate to potential risks to participants and scientific integrity. As a result, research sites experience an avalanche of downstream administrative and regulatory activities that consume considerable resources. This statement recommends four key solutions to address such barriers and recalibrate regulatory and administrative expectations for decentralizing trials: (1) FDA should engage the research community in a public-private partnership to modernize standards and enable local access to trials; (2) sponsors and CROs should develop standards and protocols that accommodate flexible approaches, enable local participation, provide clarity around roles and requirements, and promote consistency; (3) research centers, networks, and sites should update policies and procedures to implement decentralized trial elements; and (4) research community should develop a streamlined, uniform mechanism to simplify regulatory data collection and documentation and use it consistently across trials. We can and must prioritize a concerted commitment to simplify and streamline regulatory requirements and practices to broaden access to and participation in cancer clinical trials.

Abstract Underrepresentation of racial and ethnic subgroups in cancer clinical trials remains a persistent challenge. Restrictive clinical trial eligibility criteria have been shown to exacerbate this problem. We previously identified that up to 24% of patients treated with standard immunochemotherapy would have been excluded from recent first-line trials in diffuse large B-cell lymphoma (DLBCL) based on 5 laboratory-based criteria. These ineligible patients had worse clinical outcomes and increased deaths related to lymphoma progression, suggesting the potential exclusion of patients who could have benefited most from the novel therapies being evaluated. Using data from the prospectively enrolled Lymphoma Epidemiology Outcomes cohort study, with demographics broadly similar to the US patients diagnosed with lymphoma, we evaluated the impact of laboratory eligibility criteria from recent first-line DLBCL trials across various racial and ethnic backgrounds. There were significant differences in the baseline laboratory values by race/ethnicity with Black/African American (AA) patients having the lowest mean hemoglobin and highest creatinine clearance. Based on recent clinical trial eligibility criteria, AA and Hispanic patients had higher rates of laboratory-based ineligibility than non-Hispanic White patients. The largest gap in the clinical outcomes between eligible and noneligible patients was noted within AA patients with an overall survival hazard ratio based on POLARIX clinical trial criteria of 4.09 (95% confidence interval, 1.83-9.14). A thoughtful approach to the utility of each criterion and cutoffs for eligibility needs to be evaluated in the context of its differential impact across various racial/ethnic groups.

TPS7100 Background: Despite the promising efficacy of CAR-T for patients with relapsed or refractory (R/R) large B-cell lymphomas (LBCL), more than 60% of patients will relapse, the majority of which occur in the first 6 months. Approximately 30% of patients with LBCL treated with CAR-T achieve a partial response (PR) on day 30 (D30) PET-CT assessment. Of patients in a D30 PR, 70% will eventually progress, yet the standard of care remains close observation. Early consolidative treatment strategies utilizing therapies with a different mechanism of action may improve outcomes, but there are currently no reliable biomarkers. Epcoritamab (Epco), a bispecific antibody directed against CD20 and CD3, has been approved by the FDA for LBCL patients who relapse after at least 2 lines of therapy. In the phase 2 study, Epco was associated with an overall response rate (ORR) of 63% and a complete response (CR) rate of 39%, including similar responses in a subset of patients who were relapsed 100 days post CAR-T. This study is a trial-in-progress that will evaluate the efficacy of epco compared to observation for patients with LBCLs achieving a PR on D30 post CAR-T PET-CT assessment. Methods: This is an investigator-initiated, randomized, phase II, multicenter, open-label study (NCT06238648) evaluating epco monotherapy for a fixed duration of 12 cycles compared to observation for LBCL patients with D30 PR after standard of care CAR-T. A maximum of 120 patients will be randomized 1:1 to epco or observation across 10 academic centers. Stratification factors include line of CAR-T (second vs third line) and costimulatory domain (CD28 vs 4-1BB). Key inclusion criteria include PET evidence of a D30 PR. non-bulky disease ( <7.5cm), ANC of >1000, hemoglobin >7 g/dL if asymptomatic or >8 if symptomatic, platelet count >50,000. G-CSF, pRBCs and platelet transfusions are allowed. Key exclusion criteria include prior anti CD20xCD3 bispecific antibody therapy, ongoing or uncontrolled CRS or ICANS, and active or symptomatic CNS disease. Epco is administered subcutaneously at a dose of 0.16mg on day 1, 0.8mg on day 8, prior to full dose of 48mg on day 15. Epco is administered weekly in 28 day cycles (C) for C1-3, on day 1 and 15 of C4-9 and on day 1 of C10-12. PET-CT response is assessed by the 2014 Lugano criteria after 2 cycles, and then every 3 months during active treatment. The primary objective is efficacy, measured as conversion from D30 PR to CR. The secondary endpoints include frequency and severity of treatment emergent adverse events, ORR, duration of response, duration of complete response, progression free survival, event free survival, and overall survival. Peripheral blood samples will be collected pre-treatment and during treatment to assess for biomarkers of response and resistance. The study was activated in January 2024 and recruitment is ongoing. Clinical trial information: NCT06238648 .

7080 Background: Primary mediastinal large B-cell lymphoma (PMBCL) is an uncommon type of aggressive B-cell non-Hodgkin lymphoma. PMBCL has distinct clinicopathologic features compared to diffuse large B-cell lymphoma but shares some clinical and biologic features with nodular sclerosis classic Hodgkin lymphoma (cHL). Central nervous system (CNS) relapse is exceedingly rare in cHL, therefore one may expect that CNS relapse in PMBCL is also uncommon. Herein, we examined the incidence of CNS relapse in patients with PMBCL. Methods: Patients with newly diagnosed PMBCL seen at Mayo Clinic between 1/2002 and 4/2023 were identified from the Mayo Clinic Lymphoma Database. Clinical features, treatment details and outcomes were abstracted from medical records. The CNS relapse rate was calculated using a competing risk model, with death considered as a competing risk. Results: A total of 154 PMBCL cases were identified. The median age at diagnosis was 38 years (range 18-77) and 60.4% were female. The distribution of CNS-IPI was low-risk in 80 (51.9%) patients, intermediate-risk in 43 (27.9%), and high-risk in 3 (1.9%), and data were missing for 28 patients (18.2%). 78 patients (50.6%) received R-CHOP and 76 patients (49.4%) received R-DA-EPOCH as frontline therapy. High-dose methotrexate (HD-MTX) for CNS prophylaxis was administered to 5 patients (all treated with R-CHOP). 20 patients received intrathecal (IT) chemotherapy (methotrexate and/or cytarabine) for CNS prophylaxis (4 with R-CHOP [1 received HD-MTX too],16 with R-DA-EPOCH). The median follow-up was 39 months (95% CI 28.2-49.8). Only 3 patients had CNS relapse, all associated with systemic relapse (1 concurrent, 1 had CNS relapse 8.8 months after systemic relapse, 1 had CNS relapse 2 months before systemic relapse). The cumulative incidence of CNS relapse for the entire cohort was 1.43% (95% CI 0.3%-4.6%) at 1 year and 2.21% (95% CI 0.6%-5.8%) at both 2 and 5 years. For those who did not receive CNS prophylaxis (n=130), the incidence was 0.86% (95% CI 0.1%-4.3%) at 1 year and 1.82% (95% CI 0.4%-5.8%) at both 2 and 5 years. All 3 patients who experienced CNS relapse had R-CHOP as frontline therapy; two patients did not receive any CNS prophylaxis, while 1 patient received IT CNS prophylaxis. Conclusions: The risk of isolated CNS relapse in PMBCL appears to be very low, even in patients who did not receive CNS prophylaxis. While some patients may experience CNS relapse associated with systemic relapse, the overall incidence was low (1.43% at 1 year and 2.21% at 2 and 5 years). The rarity of isolated CNS relapse in PMBCL suggests that routine CNS prophylaxis may not be necessary as part of initial therapy.

7067 Background: High intensity induction with regimens such asDA-EPOCH-R, CODOX-M/IVAC-R and HyperCVAD are often used for young patients with DHL/THL despite no overall survival (OS) benefit compared to R-CHOP. Reports on the application of CODOX-M/IVAC-R are subject to selection bias as only young fit patients can tolerate it. We aimed to investigate outcomes difference between CODOX-M/IVAC-R and DA-EPOCH-R in patients ≤ 60 years with DHL/THL diagnosed via FISH. Methods: Retrospective review of DHL/THL patients from the Mayo Clinic diagnosed between July15th 2010-October19th 2023 treated with CODOX-M/IVAC-R or DA-EPOCH-R at age of up to 60 years. Event free survival (EFS) was defined as time from diagnosis to progression, relapse, next line of treatment or death from any cause. Results: 113 patients were included; CODOX-M/IVAC-R (N=49) and DA-EPOCH-R (N=64). Patient and disease characteristics are in table. 80% (N=39) achieved CR on end of treatment (EOT) PET CT with CODOX-M/IVAC-R compared to only 58% (N=37) with DA-EPOCH-R. CODOX-M/IVAC-R was associated with superior EFS on univariate (HR=0.54, 95%CI=0.31-0.97) and multivariable analysis adjusted for age, BCL2 vs BCL6 translocation and receipt of consolidation ASCT (aHR=0.53, 95%CI=0.29-0.95), however, there was no significant influence on OS (aHR=0.97, 95%CI=0.50-1.91). At a median follow-up of 5.3 years and 3.3 years for the CODOX-M-IVAC and DA-R-EPOCH group respectively; EFS was superior in the CODOX-M/IVAC-R group having 1, 2 and 5 years EFS of 68.3%, 64.1 and 61.5% respectively compared to 52.4%, 48.9% and 39.5% respectively in the DA-EPOCH-R group (p=0.035). 33%(16/49) of the CODOX-M/IVAC-R patients had R/R disease (No CR on EOT PET CT or relapsed) with a median OS of 10.3 months compared to 33.7 months in the R/R DA EPOCH-R group (54%, 35/64). Number of patients who were able to receive salvage ASCT, CAR T and Allo-SCT were 5, 17 and 4 respectively in the DA EPOCH-R group compared to 1, 6 and 3 patients respectively in the CODOX-M/IVAC-R group. None died of regimen toxicity in both groups. 19% underwent ASCT consolidation after CR with initial induction (11 patients in each group); no OS was noticed however consolidation with ASCT was associated with increased EFS regardless of the induction regimen with best outcomes being in the CODOX-M/IVAC-R group (P=0.0072). Conclusions: Our study showed that young patients with DHL/THL who received CODOX-M/IVAC-R had superior EFS compared to DA-EPOCH-R with no OS benefit. CODOX-M/IVAC-R can spare patients receiving more subsequent therapies. Patients who have R/R disease following CODOX-M/IVAC-R have poor outcomes. [Table: see text]

7050 Background: The management of Richter transformation (RT) of CLL represents an unmet clinical need. We previously reported modest efficacy of pembrolizumab monotherapy in an initial cohort of patients with RT (Ding, et al, Blood 2017). Here we report updated results of this trial, including an expansion cohort and a combination therapy cohort. Methods: Patients with biopsy proven RT to diffuse large B-cell lymphoma were enrolled and treated with single agent pembrolizumab (200 mg IV Q3W). Patients with progressive disease (PD) or stable disease (SD) after 3 months of pembrolizumab monotherapy were allowed to add a B-cell receptor (BCR) kinase inhibitor. The primary end point was overall response rate (ORR). Results: A total of 26 patients with RT were enrolled (9 in initial cohort and 17 in expansion cohort). The median age was 68.5 years. Ten (38%) patients had del(17p) or TP53 mutation. The median number of prior lines of therapy was 3 (range 1-10). Fifteen (58%) patients had received ibrutinib previously (14 of whom had PD on ibrutinib). With pembrolizumab monotherapy (n=26), the ORR was 23.1%, with 2 (7.7%) complete response (CR), 4 (15.4%) partial response (PR), and 7 (26.9%) SD. Of the 6 patients with confirmed CR or PR, responses occurred after a median of 2 cycles of monotherapy. The median duration of response (DOR) was 3.2 months (95% CI 2.8-NA). The median progression-free survival (PFS) was 2.6 months (95% CI 1.6-3.6). Sixteen patients went on to receive a BCR kinase inhibitor (ibrutinib [n=15], idelalisib [n=1]) in combination with pembrolizumab, after SD or PD on pembrolizumab monotherapy. The ORR to combination therapy was 62.5%, with 4 (25.0%) CR and 6 (37.5%) PR. Of the 10 patients with confirmed CR or PR to combination therapy, responses occurred after a median of 4 cycles of therapy. The median DOR was 4.5 months (95% CI 1.6-NA). The median PFS was 7.6 months (95% CI 2.3-13.3). After a median follow-up of 50.4 (95% CI 34.0-56.0) months, the median overall survival (OS) for all 26 patients with RT was 11.6 months (95% CI 7.5-20.1), and the 2-year OS rate was 27%. Treatment-related adverse events (TRAEs) of any grade occurred in 24 (92%) patients, including anemia (54%), thrombocytopenia (58%), neutropenia (54%), leukopenia (35%), lymphopenia (23%), dyspnea (23%), diarrhea (19%), and nausea (23%). Treatment-related grade 3 or above AEs occurred in 21 (81%) patients, including neutropenia (38%), leukopenia (31%), thrombocytopenia (27%), anemia (15%), febrile neutropenia (12%), and lung infection (12%). Conclusions: This expanded analysis confirmed that pembrolizumab has modest single agent activity in RT. Combination therapy with pembrolizumab and a BCR kinase inhibitor is associated with increased efficacy (ORR >60%), similar to other reports. These results support further investigation of immune checkpoint inhibitor-based combination therapy in RT. Clinical trial information: NCT02332980 .

LBA7005 Background: Despite recent advances, there remains a need for novel therapies for pts with R/R DLBCL. BV, an anti-CD30 antibody-drug conjugate, has shown efficacy and safety when combined with lenalidomide (len) and with rituximab (R) in heavily pretreated populations (Bartlett 2022; Ward 2022). The double-blind, global phase 3 ECHELON-3 study (NCT04404283) compared BV with R+len (R2) vs R2 in pts with R/R DLBCL who are ineligible for HSCT or CAR T-cell therapy. Here, we present results from the interim analysis (IA) for overall survival (OS). Methods: Pts with R/R DLBCL received BV+R2 or placebo+R2 (randomized 1:1). Pts received BV (1.2 mg/kg) or placebo q3w, R (375 mg/m2) q3w, and len (20 mg) qd. The primary endpoint was OS in the intent-to-treat population. Secondary endpoints were investigator-assessed progression-free survival (PFS), objective response rate (ORR), and complete response (CR) rate. The preplanned IA was performed at 134 OS events with a prespecified efficacy boundary of 2-sided P=0.0232. Results: 230 pts were randomized: 112 to BV+R2 and 118 to R2; all but 2 pts (both in R2 arm) received ≥1 dose of study drug. Median age was 71 yrs (range, 21-89), 56.5% were male, and 10.9% had an ECOG of 2. Median prior lines of therapy was 3 (range, 2-8); 29% had prior CAR T-cell therapy and 68% were CD30- (<1% CD30 tumor expression). At median follow-up of 16.4 months (mos) (range, 0.1-31.5) (cut-off: January 22, 2024), median OS was 13.8 mos (95% CI: 10.3-18.8) with BV+R2 vs 8.5 mos (95% CI: 5.4-11.7) with R2 (HR 0.629; 95% CI: 0.445-0.891; P=0.0085); OS benefit was consistent across key subgroups. Median PFS was 4.2 mos (95% CI: 2.9-7.1) with BV+R2 vs 2.6 mos (95% CI: 1.4-3.1) with R2 (HR 0.527; 95% CI: 0.380-0.729; P<0.0001). ORR was 64.3% (95% CI: 54.7-73.1) with BV+R2 vs 41.5% with R2 (95% CI: 32.5-51.0; P=0.0006); CR rate was 40.2% vs 18.6%, respectively. In CD30+ vs CD30- subgroups, ORR/CR was 72.2%/38.9% vs 60.5%/40.8% with BV+R2, respectively, and 50.0%/26.3% vs 37.5%/15.0% with R2, respectively. Efficacy analysis including cell of origin will be presented. The safety profile of BV+R2 was tolerable vs R2: Grade (Gr) ≥3 treatment-emergent adverse events (TEAEs) were 88% vs 77%, serious TEAEs were 60% vs 50%, and Gr 5 TEAEs were 12% vs 8%, respectively. Most common TEAEs were neutropenia (46% vs 32%), anemia (29% vs 27%), and diarrhea (31% vs 23%). Rates of peripheral neuropathy for BV+R2 vs R2 were 31% vs 24% (all Gr) and 6% vs 2% (Gr 3). Median treatment duration was 3.6 mos with BV+R2 vs 2.0 mos with R2. Conclusions: Treatment with BV+R2 triplet, compared to R2, demonstrated statistically significant and clinically meaningful improvements in all key efficacy outcomes including OS in high-risk subgroups, with manageable safety. This triplet regimen represents a novel treatment option for pts with heavily pretreated R/R DLBCL. Clinical trial information: NCT04404283 .