Wallace, Danielle

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.

7058 Background: Follicular and marginal zone B cell lymphoma (FL; MZL) demonstrate an indolent course with heterogeneous outcomes anda potential for spontaneous remissions indicating immune system intervention. Therapeutic immunization is therefore an attractive approach but new antigens that evoke a strong immune response are needed. EO2463 expands pre-existing memory CD8+ T cells recognizing non-self protein sequences from gut bacteria which cross-react with B cell antigens and can kill HLA-A2 restricted cells (T2) loaded with target peptides. EO2463 includes 4 HLA-A2 synthetically produced epitopes which exhibit molecular mimicry with the B cell markers CD20, CD22, CD37, and CD268 (BAFF-receptor), as well as a the CD4 helper-epitope UCP2 derived from hTERT. EO2463 is being used to drive anti-tumor activity against B cell malignancies. Methods: Patients (pts) with FL and MZL, stage 1-3A, and HLA-A2, are eligible. In the safety lead-in pts with relapsed/refractory (R/R) disease were given EO2463 SC q2 weeks (w) x 4, then q4w, for a max of 12 months; at w7 lenalidomide (20 mg/day for 21/28 days up to 12 cycles) is added (EL), and if no complete remission (CR) at w19, rituximab (375 mg/m2 IV, q1w x 4, then q4w x 4) is also added (ER2). Doses evaluated: 150 μg and 300μg/peptide. Results: 3 pts received 150 μg/peptide and 6 pts 300 μg/peptide (EO2463 1 pat, EL 2 pts, ER2 6 pts): 2 MZL, 7 FL pts with median 2 lines (range 1-4) of prior systemic therapy. No related grade ≥3 adverse events were seen with EO2463 monotherapy. Most common related events were grade 1 to 2 local administration site reactions in 5/9 pts. Adverse events during combination treatment were as expected for R2. PET-CT on w6 after EO2463 monotherapy suggested clinical activity in 4/9 pts (1 PR, 1 pt size reduction 15%, 1 pt 20% reduced tracer uptake, 1 pt 5/6 target lesions reduced metabolic activity). Overall objective responses (OR) were seen in 6/9 pts (67%; 1st OR on EO2463 1 pat, EL 4 pts, ER2 1 pat), with CR in 5/9 (56%) pts; median time to response was 18w (range 8-43w), response ongoing in 5 pts, range 24-76w. Expansion of specific CD8+ T cells against mimic peptides and targeted B cell antigens were detected in all responding pts, incl. 2 pts with no measurable B cells at baseline (prior anti-CD20). Expansion of specific T cells was detected at w5 in 5/6 pts and was maintained as long as currently tested (up to w94, 43w after last EO2463 dose). No decline in expansions were seen after start rituximab. Conclusions: EO2463 (300 μg/peptide) monotherapy, EL, and ER2 are well tolerated, with encouraging clinical activity with EO2463 monotherapy and with subsequent CR in 5/9 pts on combo. Rapid and durable expansion of specific CD8+ T cells was seen in all responding pts, consistent with the preclinical hypothesis. Additional cohorts investigate EO2463 alone or in combination in newly diagnosed or R/R pts. Results will be reported at the meeting. Clinical trial information: NCT04669171 .

Background Peripheral T-cell lymphomas (PTCLs) comprise a rare, heterogeneous group of non-Hodgkin lymphomas of mature T-cell origin. Most systemic (s) PTCL subtypes typically have poor outcomes with conventional anthracycline-based chemotherapy. Biomarker-driven and subtype-specific treatments are promising but unmet needs. Few benchmark studies exist to characterize the current real-world landscape of clinical and pathologic practice. We report the patterns of care and updated outcome data for PTCL patients enrolled in the LEO-MER multi-center prospective cohort study (ClinicalTrials.gov NCT02736357). Methods Patients aged 18 years or older with newly diagnosed PTCL were prospectively enrolled in the University of Iowa/Mayo Clinic MER cohort (2002-2015) or the expanded LEO cohort (2015-2020). Clinical, pathology, treatment, and outcome data were abstracted from medical records using a standard protocol in both cohorts. Pathology underwent expert re-review based on WHO criteria. Overall survival (OS) was calculated from date of diagnosis to date of death or last follow-up. Event-free survival (EFS) was calculated from date of diagnosis to disease progression, initiation of 2 nd line therapy, or death from any cause. EFS and OS were evaluated using Cox model and Kaplan-Meier estimator. Log-rank test was used to test the significance of difference between groups. Results LEO-MER enrolled 1132 PTCL patients during the study period (462 MER and 670 LEO). Of these, 722 were sPTCLs (281 MER and 441 LEO), including PTCL-NOS (N=253, 35%), anaplastic large cell lymphoma (ALCL; N=180, 24.9% [74 ALK+, 106 ALK-]), angioimmunoblastic T-cell lymphoma (AITL, N=164, 22.7%), extranodal NK-TCL (N=50, 6.9%), adult T-cell leukemia/lymphoma (N=33, 4.6%), enteropathy-associated TCL (N=19, 2.6%), and hepatosplenic TCL (N=13, 1.8%) ( Table 1). Median age at diagnosis was 60 years. M:F ratio was 1.5. Comparing LEO to MER, African American population was 15.4% vs 0.7%, and Hispanic was 10% vs 2.2%. Clinical characteristics were comparable between MER and LEO overall: PS≥2, 20.9%; elevated LDH, 50.7%; stage III-IV, 67.6%; and IPI 2-5, 65.7%. The most common 1 st line chemotherapy regimens overall were CHOP-based (N=506, 70%), including 60% receiving CHOP-like chemotherapy in both MER and LEO cohorts (CHOP [N=268, 37%], CHOEP [N=91, 13%] or EPOCH [N=75, 10%]), and 16% with CHOP-like in combination with novel agents in LEO cohort (BV+ [N=41, 9.3%], azacitidine+ [N=11, 2.5%], pralatrexate+ [N=10, 2.3%], lenalidomide+ [N=8, 1.9%]) ( Table 1). More patients received etoposide in LEO (40.3%) than in MER (20.3%). 74 patients (10.3%) underwent consolidative SCT following induction chemotherapy (71 auto and 3 allo). 65 patients (11.2%) received frontline therapy on clinical trials. At a median follow-up of 9.4 years in MER and 4 years in LEO, 177 (MER) and 269 (LEO) events, and 150 (MER) and 206 (LEO) deaths were observed, respectively. The 3-year EFS and 4-year OS estimates for sPTCL were 46.3% and 59.1% in MER, and 40.4% and 51.3% in LEO. EFS and OS correlated with IPI scores and differed by sPTCL subtypes ( Figure 1). ALCL had superior survival, with 3-year EFS and 4-year OS of 78.2% and 90.5% for ALK+, and 65.9% and 76.9% for ALK-. Non-ALCL subtypes including PTCL-NOS and AITL had inferior outcomes, with 3-year EFS and 4-year OS of 31.4% and 42.8% for PTCL-NOS, and 33.4% and 50.7% for AITL. In subset analysis, the addition of etoposide to CHOP chemotherapy as either CHOEP or EPOCH was associated with improved OS for ALK- ALCL (p=0.038, log-rank), but not for ALK+ ALCL (p=0.75) or non-ALCL subtypes of PTCL-NOS and AITL (p=0.88). Conclusion The LEO-MER study is the largest prospective cohort study of PTCL to date. Patterns of care in the LEO cohort begin to incorporate novel agents in frontline therapy. Outcomes continue to mature with longitudinal follow-up and ongoing accrual, which poise to shape benchmarks in the contemporary era. The lack of benefit of etoposide adding to CHOP induction and poor overall survival of non-ALCL subtypes underscores the unmet need of therapeutic breakthrough for non-ALCL frontline treatment, particularly through clinical trials with biomarker-guided approaches incorporating novel agents.

TPS7586 Background: EO2463 is a therapeutic vaccine designed to activate existing commensal bacteria-specific memory T cells that cross-react with B cell markers in order to drive anti-tumor immune activity against B-cell malignancies. The four microbial-derived, synthetically produced peptides contained in EO2463 (OMP72, OMP64, OMP65, and OMP66), correspond to cytotoxic CD8 T cell HLA-A2 restricted epitopes, and exhibit molecular mimicry with the B cell markers CD20, CD22, CD37, and CD268 (BAFF-receptor), respectively. In pre-clinical models, these peptides can generate strong immune responses and specifically stimulate cross-reactive cytotoxic CD8 T cells to recognize the chosen B cell targets. EO2463 also contains a CD4 helper peptide referred to as universal cancer peptide 2, derived from the human telomerase reverse transcriptase catalytic subunit. The present study is a first-in-human clinical trial of this microbiome-derived peptide therapeutic cancer vaccine approach in patients with follicular lymphoma (FL) and marginal zone lymphoma (MZL). Methods: This four-cohort phase 1/2 trial will investigate EO2463 monotherapy, and combinations of EO2463/lenalidomide (EL), EO2463/rituximab (ER), and EO2463/lenalidomide/rituximab (ER2), for treatment of patients with FL and MZL. Cohort 1 is a safety lead-in dose-finding in patients with relapsed/refractory (RR) disease, with a 3-by-3 design to establish the recommended phase 2 dose (RP2D) for EO2463 monotherapy and to confirm the safety of the RP2D for combination schedules of EL, and ER2. After the recommended EO2463 monotherapy dose is established, cohorts 2, 3, and 4 will open to accrual. Cohort 2 will investigate EO2463 monotherapy in patients with newly diagnosed FL/MZL who are not in need of treatment; cohort 3 will investigate EO2463 monotherapy, followed by ER in patients with limited tumor burden who need treatment, and cohort 4 will further investigate EL, followed by ER2 in the RR setting. EO2463 will be administered SC 4 times at 2-week intervals, followed by continued booster administrations every 4 weeks for 9 (Cohorts 2 and 3) or 12 (Cohorts 1 and 4) months. Inclusion/exclusion criteria, and the design and schedule of the intense immune and safety monitoring will be presented. The safety lead-in dose-finding is currently ongoing, and no safety concerns have been observed thus far. Clinical trial information: NCT04669171.