Dong, Ning

Introduction: CD20xCD3 bispecific antibodies (BsAbs) represent a major advance in the treatment of relapsed or refractory (r/r) large B-cell lymphoma (LBCL). In their pivotal trials, epcoritamab (Epcor) and glofitamab (Glofi) showed an overall response rate (ORR) and complete response rate (CRR) of 52-63% and 39%, respectively, in patients (pts) with r/r LBCL after 2 or more prior lines of therapy (LOT). Data on the efficacy and safety of BsAbs in standard of care (SOC) setting is limited. Here, we report our multicenter retrospective study on SOC BsAbs for the approved indication in r/r LBCL. Methods: All pts who received SOC BsAbs for r/r LBCL at four cancer centers in Florida were included. Pts who died before the first response evaluation were considered to have disease progression. Median follow up time was calculated using reverse Kaplan Meier (KM) method. Univariate analysis (UVA) and multivariate analysis (MVA) of response rates were done using logistic regression. UVA and MVA of PFS and OS were done using Cox proportional hazard model. Median PFS (mPFS) and median OS (mOS) were estimated using KM method. Results: As of June 1, 2024, a total of 69 pts received SOC BsAbs for r/r LBCL (43 epcor and 26 glofi). Forty pts (58.0%) were male; median age was 66 years (range 32-89); ECOG >= 3 in 14 (20.3%) pts; transformed indolent lymphoma in 20 (29.0%); Richter transformation in 3 (4.4%); HGBL with MYC/BCL2 rearrangements (double-hit lymphoma [DHL]) in 12 (17.4%); bulky disease>10cm in 33 (47.8%); IPI score >= 4 in 15 (21.7%). Pts received a median of 3 prior LOT (range 2-12); 46 (66.7%) had primary refractory disease; 40 (58.0%) received prior CD19 CAR-T therapy; 35 pts (50.7%) would not have met the inclusion criteria of the pivotal trials due to: ECOG>=3 (n=14), thrombocytopenia (n=11), neutropenia (n=2), CNS involvement (n=6), recent infection (n=6), prior CAR-T within 30 days (n=1), and CrCL<45 (n=2). Among the 69 pts, 65 were evaluable for response. At a median follow up of 7 months, the ORR and CRR were 52.3% and 26.2%, respectively. Median PFS was 4.2 months (m) (95%CI: 2.8-6.9). Median OS was 6.2m (95%CI: 5.9-not reached [NR]). The ORRs in pts without prior CAR-T (CART-naive), progressed after achieving CR/PR to prior CAR-T (CART-R), and not achieving CR/PR to prior CAR-T (CART-NR) were 13/25 (52.0%), 18/24 (75%), and 3/16 (18.8%), respectively, p<0.01. In the UVA of ORR, the following factors were associated with lower response: CART-NR (18.8% vs 63.3%, p<0.01) and ECOG >=3 (21.4% vs 60.8%, p=0.01). Bulky disease, IPI >=4, DHL, >=4 prior lines of therapy, DLBCL subtype or BsAb type was not associated with response. In MVA, only CART-NR was a significant predictor of lack of response to BsAb (odds ratio 5.6, 95%CI: 1.3-24). In the UVA of PFS, CART-NR and ECOG >=3 were associated with shorter mPFS (1.9m [95%CI: 0.6-3] vs 5.4m [95%CI: 4.0-NR] in CAR-T non-responders vs responders; 1.1m [95%CI: 0.4-3.2] vs 5.4m [95%CI: 3.2-NR] in ECOG>=3 vs <3). In the MVA, CART-NR and ECOG>=3 were associate with shorter PFS (HR 2.7, p<0.01 and 2.5, p<0.02, respectively). One of the 3 pts with Richter transformation had continuous PR at 5 months. Cytokine release syndrome (CRS) occurred in 21 pts (36.2%), including 4 (5.8%) grade (Gr) >= 3. Immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in 12 pts (17.4%) with 6 (8.7%) Gr >= 3. Gr3-4 neutropenia was observed in 18 pts (26.1%); Gr3-4 thrombocytopenia in 10 (14.5%). Infection all grades and Gr >= 3 occurred in 26 pts (37.7%) and 19 pts (27.5%), respectively. Among them, bacterial infection was identified in 13, COVID in 5, fungal in 2, and CMV in 1 patient. Conclusion: BsAbs had comparable efficacy in SOC setting as in the pivotal trials. CRS and ICANS were mostly low-grade; however, a high incidence of serious infection was observed. Pts with no response to prior CAR-T also had poor BsAbs response. This could reflect a common mechanism of resistance to immunotherapy, either due to tumor characteristics or host T-cell exhaustion. Longer follow-up is needed to evaluate the durability of response.

Introduction: Scant data exist on prognostic factors, survival and treatment (Tx)-related outcomes in SCNSL. We conducted a multicenter international analysis to identify prognostic factors and outcomes in SCNSL at diagnosis (de novo), or after frontline Tx (1L) either with (concomitant) or without (isolated) systemic (syst) relapse. Methods: This study collected data from patients (pts) treated between 2001-2023 at 35 centers. Overall (OS) and progression-free survival (PFS) were calculated from SCNSL diagnosis to first event (death for OS, relapse/death for PFS) or last follow-up. Uni- (UVA) and multivariable (MVA) Cox analyses were performed to assess prognostic factors; Kaplan-Meier method was used to estimate survival. Results: 1173 (US: 863, UK: 273, Canada: 37) pts with SCNSL were included. Baseline characteristics were median age: 62 years (interquartile range 52.5-69), male sex: 58.7%, elevated LDH: 71.1%, stage III/IV: 88.6%, HIV: 3%, transformed LBCL (tLBCL): 13.8%, non-germinal center B-cell like (non-GCB) subtype: 52.3%, double expressor (DE): 40%, MYC rearrangement (MYC-R): 28.3%, MYC/BCL2 double hit: 16.6%, MYC/BCL2/BCL6 triple hit (TH): 6.1%. Among 522 pts with de novo SCNSL, 84.2% had involvement of a single CNS compartment (44.7% brain parenchyma; 40.4% leptomeningeal [lepto]). 1L regimens included 36.2% R-CHOP with high-dose methotrexate (HD-MTX), 12.5% MARIETTA-type, and 9.8% R-CODOX-M/IVAC; 54.6% received intrathecal chemotherapy. Consolidation Thiotepa-based autologous stem cell transplant (TT-ASCT) occurred in 15.3%. The majority of pts who underwent TT-ASCT had previously achieved CR or PR in syst (92.5%) and CNS (72.5%) compartments. At median follow-up 25.7 months (mos), subsequent relapse was observed in 27.5% TT-ASCT recipients: 36.3% had isolated CNS, 27.4% syst, and 36.3% concomitant. 588 pts presented with SCNS after 1L (66.2% isolated, 33.8% concomitant). Brain parenchyma involvement was observed in 56.8%, lepto in 22.6%. Tx included 31.6% HD-MTX combination (eg, R-MPV, MTR); 18.4% HD-MTX +/- rituximab; 16.2% MARIETTA-type; and 9.4% platinum-based regimen. Consolidation TT-ASCT occurred in 22.4% (n=132), and 13.8% (n=81) received CAR-T cell therapy (excluding subsequent relapses in de novo group). Syst (65.1%) & CNS (69.1%) responses (CR/PR) were higher before TT-ASCT compared to CAR-T cell (49.5% & 54.5%, respectively). After TT-ASCT, 52 pts (39.3%) relapsed, mainly in the CNS (n=30, 57.7%), with only 4 (7.7%) concomitant. After CAR-T, 48 pts (59.3%) relapsed: 15 (31.2%) isolated in CNS and 15 (31.2%) concomitant. 12-month cumulative incidence of relapse (with death as competing risk) was 21.1% after TT-ASCT and 55.8% after CAR-T. In 63 pts (5.4%), the first CNS event occurred >2 lines of Tx. With median follow-up of the entire cohort of 24.6 mos, median PFS and OS were 11 and 21 mos, respectively. mPFS and mOS were significantly better in pts with de novo SCNSL (13.4 & 47.4 mos) compared to SCNSL after 1L (10.4 & 14.2 mos) and >2 lines of Tx (6.5 & 9.7 mos); P<0.0001. Factors associated with significantly shorter OS in UVA across all presentations were age >60, male sex, GCB subtype, MYC-R, tLBCL, DE, TH, elevated LDH, ECOG PS ≥2, SCNSL after 1L (vs. de novo), and failure to achieve syst/CNS response to 1L. Of these, age >60, male sex, MYC-R, ECOG PS ≥2, and failure to achieve response to 1L remained significant in MVA. In de novo cases, age >60, DE, ECOG PS≥2, and failure to achieve syst/CNS response to 1L were associated with poorer OS; for pts with SCNSL after 1L, age >60, GCB subtype, and ECOG PS ≥2 were significant. Pts treated with HD-MTX-based regimens after 1L experienced longer OS than those treated with platinum regimens or high-dose cytarabine. In de novo cases, TT-ASCT was significantly associated with longer OS (HR=0.58; P=0.025) in MVA after adjusting for significant factors, 1L type, and response. For SCNSL at relapse, TT-ASCT (HR=0.34; P<.0001) and isolated SCNSL presentation (vs. concomitant HR=0.70, P=0.007) were associated with longer OS, adjusting for significant factors, type of second-line Tx, & site of CNS relapse. Conclusions: This study represents the largest analysis of SCNSL inclusive of all modes of presentation. Concomitant SCNSL at relapse was associated with poor outcomes, while TT-ASCT consolidation was associated with improved OS in de novo & relapsed disease. Despite advances in LBCL SCNSL remains an unmet therapeutic need.

93 Background: Tumor mutational load (TML) has been proposed as a biomarker of responsiveness to novel immune checkpoint inhibitors (ICIs) due its association with increased neoantigen formation and tumor immunogenicity. Gastrointestinal cancers (GICs) are generally insensitive to ICIs; therefore the aim of this study was to evaluate the TML, clinically relevant genomic alterations (CRGAs), and PDL-1 status of GIC patients (pts). Methods: We analyzed samples of pts with GICs using a multiplatform profiling tool (Caris Life Sciences, Phoenix, AZ). TML and CRGAs were calculated based on next generation sequencing and mutational load was stratified as high (≥17 mut/Mb), intermediate (8-16 mut/Mb), and low (≤ 7 mut/Mb). PD-L1 status was determined by IHC. Descriptive statistics and simple linear regression were used for analysis. Results: A total of 85 pts with GICs were analyzed. The median pt age was 65. 53% were males and 47% were females. Tumors were colorectal 51%, pancreatic 13%, esophageal 13%, gastric 9%, hepatobiliary 11%, anal canal 4%, and small intestine 1%. 80 cases (94%) had an adequate sample for profiling and TML was available in 59 cases (74%). Cases were 5% TML-high, 56% TML-intermediate, and 39% TML-low. The median TML was 9 mut/Mb and median CRGAs was 3. The most commonly detected CRGAs were TP53 (56%), APC (44%), KRAS (40%), ATM (18%) and PTEN (6%). A positive but very weak correlation was found between TML and number of CRGAs (R2 = 0.3). PD-L1 status was available in 74 cases (93%) with 86% being PD-L1 negative and 14% PD-L1 positive. PD-L1 expression was most commonly seen in esophageal (50%) and anal canal (30%) cancers. Among 57 tumors tested for both biomarkers, no correlation was found between a high TML and PD-L1 expression. Conclusions: TML varies among GICs, and higher TML scores were not associated with PD-L1 expression, but there was a weak correlation between TML and the number of CRGAs. Further analysis by stratification of GIC type and prognostic analysis to assess the correlation between TMB and response to ICIs is warranted.