Barta, Stefan K

Abstract The Bridging the Gaps (BTG) in Leukemia, Lymphoma and Multiple Myeloma Consensus Conference 2025 brought together a multidisciplinary group of oncology experts to address the complexities of lymphoma management, focusing on mantle cell lymphoma (MCL), chronic lymphocytic leukemia (CLL), and diffuse large B‐cell lymphoma (DLBCL). This article presents consensus recommendations developed through a modified Delphi process, which emphasize the need for tailored therapeutic strategies in light of recent advancements in treatment options. Key recommendations include the screening for high‐risk features in MCL, use of the BOVen regimen (zanubrutinib, obinutuzumab, and venetoclax) for TP53 ‐aberrant cases, and integration of chimeric antigen receptor T‐cell therapy for patients with mantle cell lymphoma that is refractory to covalent Bruton tyrosine kinase inhibitors. For CLL, recommendations include consideration of time‐limited therapies for younger patients and a “watch and wait” strategy for asymptomatic patients despite the improved activity and safety of current treatment regimens. For DLBCL, this article highlights the challenges in treatment sequencing and the role of circulating tumor DNA and minimal residual disease testing in monitoring disease progression. Overall, the conference describes the importance of ongoing research to refine management strategies and improve patient outcomes in lymphoma care, addressing the gaps in clinical practice where high‐level evidence is lacking.

Abstract The benefit of rituximab maintenance after first-line (1L) bendamustine-rituximab (BR) in patients with mantle cell lymphoma (MCL) remains uncertain, with inconsistent results from the phase 2 MAINTAIN trial and several retrospective studies. We conducted a large retrospective study at 27 US and Canadian academic centers to examine the benefit of rituximab maintenance after BR. A total of 911 patients received 1L BR between 2010 and 2020, and 703 had an objective response and no evidence of disease progression at the 3-month post-BR landmark. Among those, 394 (56%) received rituximab maintenance and 309 (44%) did not, with largely similar baseline patient and disease characteristics. In the landmark analysis, rituximab maintenance was associated with improved event-free survival (EFS; median, 49.9 vs 29.7 months; P< .001) as well as overall survival (OS; median, 109.5 vs 74.2 months; P< .001). The EFS and OS benefits were observed across most of the subgroups. EFS and OS differences were statistically significant in those who achieved a complete response to 1L BR (n = 590; median EFS, 62.7 vs 31.1 months [P< .001]; median OS, 136.1 vs 75.3 months [P< .001]), but the analysis among those who achieved a partial response to 1L BR was limited by the small sample size. These results provide additional evidence for the survival benefit of rituximab maintenance after BR in MCL and support its use in clinical trial design and routine practice.

Abstract Introduction: The real-world outcomes in patients (pts) with PCALCL in the era of targeted therapies like Brentuximab Vedotin (BV) is not well defined due to lack of large multicenter studies. We conducted a multicenter retrospective analysis (RWA) to assess patient and disease characteristics, treatment patterns, survival outcomes and impact of novel therapies in this rare type of cutaneous T cell lymphoma (CTCL). Methods: The analysis included 167 adult (≥18 years) patients (pts) with PCALCL across 9 academic institutions in the United States diagnosed between 01/2012 to 06/2022. The study was approved by the Institutional Review Boards at the respective sites. Demographic and disease factors were summarized using descriptive statistics. Overall survival (OS) and relapse-free survival (RFS) were estimated using Kaplan-Meier method and compared via log rank tests. Prognostic models included factors such as age, sex, race, performance status (PS), disease stage, type of initial lesion, presence of B symptoms, previous history of lymphomatoid papulosis and prior transplant. Prognostic factors for survival were assessed using both univariable and multivariable Cox proportional hazard models. Results: The median age at diagnosis was 61 (range 18-93) years. The majority of pts were male (55%) and white (82%), with good PS as indicated by an ECOG 0-1 (71%). The initial skin presentation consisted of tumors in 62% of the pts, while 34% presented with plaques or patches. Notably, no pts presented with erythroderma. Most pts underwent PET scan for staging at initial diagnosis (83%) with the majority having early-stage (IA-IIA) disease (86%). Furthermore, palpable lymph nodes (11%) and the presence of B symptoms (4%) were rare at diagnosis, and no pts had blood involvement. The most common sites of involvement were extremities (33%) followed by the head and neck (H&N) and trunk (31% each). Immunophenotyping revealed CD4 positivity in 59% of pts and CD8 positivity in 25%. The T cell receptor (TCR) rearrangement was positive in 28% of pts, though it was not completed in the majority of cases (72%). Most common initial treatments included localized radiation (61%) and surgical excision (19%). A small subset of pts received frontline systemic chemotherapy regimens such as cytotoxic chemotherapy (11%), BV (8%) and oral methotrexate (MTX) (8%). Approximately 7% of the pts had a stem cell transplant. Overall response rate (ORR) for radiation, oral MTX, BV and cytotoxic chemotherapy were 78% (CR:78% 74/100), 42% (CR:63% 6/12) and 39% (CR:67% 6/12), 89% (CR: 88% 15/18) respectively. At a median follow-up of 3.8 years (range 0.04-10.23), the median RFS and OS were 2.7 years (95% CI:1.86, 3.43) and 12 years (95% CI:10.6- NA) respectively. The estimated 3- and 5-year RFS are 46% (95% CI:0.38, 0.55) and 37% (95% CI:0.28, 0.46) respectively. The estimated 3- and 5-year OS were 89% (95% CI:0.82, 0.93) and 82% (95% CI:0.73, 0.88) respectively. At the time of the last follow-up, 79% were alive, while 21% were deceased. The cause of death (COD) was unknown in 50% of the cases and only 10% (3/of deaths were attributed to lymphoma. Other known CODs included infection (20%) and second malignancies 7%. On univariate analysis (UVA), age (p=.007), female sex (p=.04), ECOG PS 1-2 compared to 0 (p=.007) and prior transplant (p=.009) predicted for worse RFS. On multivariate analysis (MVA), only ECOG PS 1-2 (HR 2.31, 95 CI:1.06, 1.18, p=.009) and prior transplant (HR 5.38, 95 CI:2.30, 12.57, p=.0001) had a significant impact on RFS. Age and presence of B symptoms were strong predictors of OS on both UVA (age p=<.0001; B symptoms p=<.0001) and MVA (age: HR 1.12, 95 CI:1.06, 1.18, p=<.0001; B symptoms: HR 16.48, 95 CI: 3.69, 73.60, p=.0002). However, the impact of B symptoms should be interpreted with caution as only 4% of pts presented with this at baseline. On UVA, each one-year increase in age was associated with an 8.5% rise in the risk of death. ECOG PS 1-2 was associated with worse OS on univariate analysis (HR 2.62, 95% CI 0.99, 6.93, p=.05), but was not significant on MVA (HR 1.05, 95% CI 0.368, 2.974, p=.93). Conclusions: In this large RWA of PCALCL, excellent long-term survival was observed with predominantly skin directed frontline therapies. The use of systemic treatments, including BV, was infrequent as first line therapy. Older age and poor PS were significant predictors for reduced survival.

Abstract Introduction: Primary central nervous system T-cell lymphoma (PCNSTL) is a rare form of PCNSL, comprising 2–8% of cases. Prognostic factors remain undefined, and no standard treatment protocol currently exists. Prior studies have been limited by small sample sizes, incomplete molecular profiling, and poor representation of novel treatment modalities. In this study, we aimed to identify clinicopathologic factors associated with patient (pt) outcomes and delineate the spectrum of treatment regimens used to inform future clinical practice. Methods A multicenter retrospective study was conducted across 15 North American academic institutions. Pts aged ≥18 years with biopsy-confirmed PCNSTL between 2009 and 2025 with no evidence of systemic disease were included. Cases with CNS relapse of systemic T-cell lymphoma were excluded. Baseline characteristics were analyzed using independent t-tests, Fisher's exact tests, or Pearson's chi-square tests. Primary endpoints were overall survival (OS) and progression-free survival (PFS), evaluated by Kaplan–Meier, log-rank tests, and Cox regression. Results: Forty-two pts met inclusion criteria. Median age was 57 (range 19–77), 69% were male, and 79% were white. Most (69%) had ECOG 0–1. No patients had HIV, hepatitis B or C, or a history of solid organ transplant. LDH was elevated at diagnosis in 38%, and 24% had B-symptoms. Mean absolute lymphocyte count at diagnosis was 1.82/µL. The most common histologic subtypes were PTCL-NOS (76%), followed by ALK-negative ALCL (12%) and γδ T-cell lymphoma (5%). All patients had parenchymal brain lesions with 57% having multifocal disease. Additionally, CSF involvement was seen in 21%, vitreoretinal involvement in 3%, and deep brain involvement in 34%. Next-generation sequencing was performed in seven pts (17%), with disease-associated variants identified in three cases. Among these, two pts had mutations in TP53, and one had a mutation in DNMT3A. Cytogenetics were obtained in 7 pts with only one exhibiting a complex karyotype. Only one pt was EBV positive by EBER-ISH. Overall, 79% received HD-MTX-based therapy. First-line treatments were mainly HD-MTX alone (38%), HD-MTX + temozolomide (17%), or vincristine + procarbazine (12%). No patients were treated on clinical trials. Median treatment duration was 78 days and median number of treatment cycles was 4 (range 1–9 cycles). One patient received radiation alone; 5% received radiation with systemic therapy. A steroid pre-phase was used in 60%, with 44% exhibiting a clinical response. Overall response rate to first-line treatment was 63% (13 CR, 12 PR). Imaging alone was used in determining response in all patients. Repeated biopsy was not performed. Twelve patients (29%) underwent consolidative autologous transplant, most commonly with thiotepa/carmustine (TT/BCNU, 69%) or BEAM conditioning (25%). Median duration of follow-up was 10.4 months. Sixty-two percent of pts progressed during the study period, with 7% experiencing extra-CNS relapse. Median PFS was 8.2 months. Improved PFS was associated with >3 cycles of therapy (p=0.03) and transplant with TT/BCNU (p=0.0004). At last follow-up, 43% were in remission and 52% were deceased, mostly due to disease progression (77%). Median OS was 17.6 months. One- and two-year OS rates were 58% and 42%, respectively. OS was associated with Nottingham/Barcelona score <2 (p=0.02), >3 treatment cycles (p=0.0008), response to first-line therapy (p=0.0007), and TT/BCNU-based transplant (p=0.0001). IELSG, Taipei, and MSKCC risk scores were not significantly associated with survival, though IELSG approached significance (p=0.09). Discussion: This study is among the largest cohorts of PCNSTL pts compiled to date. PCNSTL remains rare and heterogenous. Treatment across centers largely mirrors management of B-cell PCNSL with high utilization of HD-MTX regimens and TT/BCNU conditioning autologous transplant. Survival outcomes within our cohort are consistent with those previously reported within the literature. Receipt of >3 cycles of therapy, TT/BCNU conditioning and Nottingham/Barcelona scores were associated with longer survival within our cohort. Limitations of our study include its retrospective design and heterogeneity within pt disease characteristics, treatments utilized and disease assessment intervals. Further exploration into pathophysiology and optimal management of this unique entity is needed.

Abstract Introduction: T-PLL is a rare, aggressive leukemia with poor prognosis and limited therapies. Previous studies on T-PLL patients receiving an allogeneic stem cell transplant (alloSCT) are limited by small numbers with limited data on disease and transplant characteristics. Further, recent data from our large national cohort of patients demonstrated significant survival difference between TCL1A+ and TCL1A- T-PLL, and CD8+ T-PLL vs CD8- T-PLL. In this large multi-center series, utilizing comprehensive disease subtype and alloSCT clinical data, we evaluated prognostic and survival therapeutic outcomes in T-PLL patients that had an alloSCT with a particular focus on T-PLL disease subtypes. Methods: We retrospectively evaluated 572 diagnosed with T-PLL at 21 academic cancer centers throughout the USA between 2000-2023, of which we performed a further evaluation on the169 that proceeded with alloSCT. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier methods and Cox proportional hazard models. Results: Among n=169 alloSCT recipients with T-PLL, the median follow-up time was 20.9 months post-alloSCT (range: 0.2-182.9), the median age at transplant was 59 years (range: 35-77) and 52% were male. In evaluated patients (n=109), TCL1A was positive by cytogenetics or FISH in 69%. As our recent analysis demonstrated significant differences in survival among specific subtypes of T-PLL, we evaluated outcomes in patients with CD4+CD8- T-PLL (n=90, 53%), CD4-CD8+ (n=17, 10%) T-PLL, and CD4+CD8+ T-PLL (n=52, 31%). 53% (87/164) had known nodal involvement at diagnosis identified by PET or CT scan and 45% (43/96) of known patients had minimal residual disease (MRD) at the time of transplant [defined as <5% T-PLL in marrow by flow, or +cytogenetics (e.g. TCL1A)] prior to alloSCT. At the time of alloSCT, 136 (80%) patients were in CR and 23 (14%) patients were in PR. Forty-nine (30%) had a myeloablative (MAC)conditioning regimen and 114 (70%) had a reduced intensity chemotherapy (RIC) conditioning regimen. Eighty (49%) patients had TBI as part of their regimen. The most common regimens were fludarabine (flu)/melphalan based regimens (n=44; 26.0%), flu/cyclophosphamide (cy) based regimens (n=33; 19.5%), flu/busulfan based regimens (n=22; 13.0%), flu/total body irradiation (TBI) (n=8; 4.7%), and cy/TBI (n=4; 2.4%). Across the whole cohort, the median OS and PFS post-alloSCT was 32.6 months (95% CI: 21.0-41.9) and 20.8 months (95% CI: 14.4-30.5) months while the 1-year cumulative incidences (CI) of NRM and relapse were 17% and 20%, respectively. The incidences of grade II-IV acute GVHD and cGVHD were 19% and 23%. There was no difference between patients with myeloablative conditioning (MAC) (n=49, 29%) when compared to patients that received reduced intensity conditioning (RIC) (n=114, 67%) in OS (33.1 vs 29.2; p=0.68) and PFS (20.2 vs 20.8; p=0.97). Patients that were MRD+ (n=31) had worse OS (22.2 vs 48.6; p=0.1) and PFS (14.1 vs 32.5; p=0.04) and higher rates of relapse (1-year relapse 20% vs 8%; p=0.08) than patients that were MRD- (n=50). PFS was improved in those who received alloSCT though only trended towards significance due to low numbers (HR 0.76, p=0.09). In subtype analysis, TCL1A+ T-PLL had significantly worse outcomes compared to TCL1A negative T-PLL. TCL1A+ disease had significantly worse OS (21.6 vs 63.1; p=0.01) and PFS (12.4 vs 50.7; p=0.01) compared to TCL1A-. Additionally, in TCL1A+ disease CI of NRM (24% vs 3%; p=0.02) and relapse (25% vs 12%; p=0.86) was higher vs TCL1A- PLL. CD4+CD8-, CD4-CD8+, and CD4+CD8+ disease had no difference in survival via either OS (28.0 vs 34.4 vs 21.0; p=0.17) or PFS (29.4 vs 23.5 vs 13.6; p=0.09) as well as no difference 1-year CI of NRM ( 11.6 vs 23.5 vs 26.2; p=0.35) and relapse (18.5 vs 23.5 vs 20.0; p=0.67).Conclusions: AlloSCT significantly improved outcomes for patients with T-PLL compared to those who did not proceed to alloSCT and remains he only curative therapy for those with T-PLL. OS, PFS, and CI relapse were significantly worse for patients with TCL1A+ subtype of T-PLL, or those with MRD positivity or PR prior to alloSCT. Novel strategies to decrease relapse such as post-alloSCT maintenance therapy to improve outcomes are urgently needed in these patients.

Introduction: Mantle cell lymphoma (MCL) is an uncommon B-cell non-Hodgkin lymphoma (NHL) Prognosis is highly variable due to underlying biological and molecular heterogeneity. The first-line (1L) treatment paradigm for MCL continues to evolve with increasing use of bruton tyrosine kinase inhibitors (BTKi) and decreasing use of autologous stem cell transplant (ASCT). TP53 alterations are associated with inferior outcomes in MCL. The aim of this retrospective study is to determine treatment strategies and clinical outcomes in MCL patients based on TP53 gene mutation status. Methods: Retrospective data were collected from 19 institutions in the United States from 1/1993 to 1/2024. We examined treatment patterns and outcomes among MCL patients >18 years of age with known TP53 mutation status by sequencing. Patients who did not receive treatment were excluded. The analysis was stratified based on presence of TP53 mutations. Systemic therapies were categorized as chemo-immunotherapy (CIT), non-chemotherapy (including monoclonal antibodies, lenalidomide, venetoclax, and novel agents on clinical trial), and regimens containing BTKi. The primary outcome was overall survival (OS) and secondary outcomes were progression free survival (PFS) and time to next treatment (TTNT). OS and PFS were estimated with the Kaplan-Meier method and log-rank tests were used to compare groups. Results: 645 patients were included in the study, with 468 men (72.6%) and median age was 64 years (range 30-89). 230/645 patients (35.7%) had a TP53 mutation, of which 182 (79%) were identified prior to 1L. While the male/female distribution was the same between the mutated and unmutated groups, median age at diagnosis and MIPI risk score was higher in the TP53 mutated group (age 65.9 vs 63.1 yrs, p= 0.015; MIPI 6.4 vs 6.1, p<0.001). TP53 unmutated patients had a median of 1 line of therapy vs. 2 for the mutated group (p<0.001, range 1-8). Blastoid histology and higher ki67 were also associated with the TP53 mutated group (p=0.045, 0.01 respectively) The median OS was 14.2 years for TP53 unmutated and 8.3 years for TP53 mutated patients (p<0.0001). PFS in 1L was 0.95 years in TP53 mutated compared to 2.02 years in TP53 unmutated group (p<0.0001). Selection of 1L therapeutic strategy was not associated with presence of TP53 mutation (Χ2 p= 0.21) although more patients in the TP53 unmutated group underwent ASCT (119/415 vs 38/230; Χ2 p=0.0006) TP53 mutation was associated with inferior survival compared to TP53 unmutated patients for CIT in 1L but the difference did not reach statistical significance when non-chemotherapy regimens and regimens containing BTKi were used. For CIT in 1L, 5 year OS was 78% [71-84%] for unmutated compared to 58% [48-67%] for the mutated group (p=0.0001 ). For non-chemotherapy regimens, 5 year OS for unmutated patients was 73% [52- 86%] compared to 52% [25-73%] for the mutated group (p=0.09). For regimens containing BTKi, 5 year OS for unmutated was 93% [81-97%] compared to 57% [28-78%] for mutated (p=0.07). Within the TP53 mutated group, there were no differences in any clinical outcomes between those receiving CIT, non-chemotherapy, or BTKi in 1L. While median OS appeared numerically longer in the BTKi group (14.4 yrs vs 8.8 yrs for CIT and 6.8 yrs for non-chemotherapy), the difference did not reach statistical significance (p=0.58). In contrast,TP53 unmutated patients who received CIT in 1L had better TTNT (p=0.0039) compared to those in non-chemotherapy and BTKi groups. There was no improvement in PFS (p=0.79) or OS (p=0.47). Conclusions To our knowledge this is the largest retrospective real world dataset of MCL treatment outcomes stratified by TP53 mutation. As in prior studies, TP53 mutation portends a worse prognosis in MCL compared to TP53 unmutated patients, but outcomes are better than historically reported. CIT in 1L was not associated with improved OS in either group. Irrespective of TP53 mutation status, incorporation of BTKi in first line was not associated with improved clinical outcomes. The gap in OS between TP53 mutated and unmutated MCL may be narrowing as treatment paradigms shift away from intensive induction chemotherapy and ASCT, and due to an increasing number of effective therapies for relapsed patients. Clinical trials of novel agents are needed to further improve the OS of TP53 mutated MCL patients.

Introduction: T-PLL is a rare, aggressive malignancy with poor prognosis and limited therapies. Outside of prospective trials utilizing alemtuzumab, data is derived primarily from small retrospective series, and limited data on survival outcomes and therapeutic efficacy, particularly beyond frontline therapy are available. In this large multi-center series, with comprehensive clinical data, we evaluated survival and therapeutic outcomes in T-PLL patients, with a focus on identification of prognostic subgroups of T-PLL, that will inform future investigations into the biology and treatment of this disease. Methods: We retrospectively evaluated all patients diagnosed with T-PLL at 15 academic cancer centers throughout the USA between 2000-2023 using the recent TPLL-ISG staging and response criteria with overall response rate (ORR) defined as CR and PR. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier methods and cox proportional hazard models. Single-cell RNA sequencing (scRNAseq) was performed using the standard 10X Genomics platform. Results: 377 patients, with a median follow-up time of 29 months (range: 0-196) were evaluated. The median age at diagnosis was 64 and 51% were male. In evaluated patients (n=223), TCL1A was positive by cytogenetics or FISH in 82%. 61% of patients had CD4+CD8- T-PLL, 11% of patients had CD4-CD8+ T-PLL, and 24% of patients had CD4+CD8+ T-PLL, with 4% unknown. 175 patients (46.4%) had known nodal involvement at diagnosis identified by PET or CT scan. Among treated patients (n=342, 91%), using TPLL-ISG criteria, the ORR to any frontline treatment was 67% (49% CR, 18% PR). Median OS and PFS was 19 months and 10 months in responding patients from the start of treatment initiation. For those treated with frontline alemtuzumab (n=250), the ORR was 74% (58% CR), with a median OS and PFS of 18 and 12 months. 20 patients (5%) were treated with a combination of alemtuzumab/pentostatin frontline with an ORR of 85% (70% CR), which was superior to alemtuzumab alone (ORR 74%, 58% CR). Patients that had frontline chemotherapy (excluding pentostatin, n=48) had a worse ORR of 35% (15% CR) (p<0.001), and a worse PFS of 4 months (p=0.002), when compared to those who received alemtuzumab. Among patients in 1st CR/PR (n=226), 44% (n=99) received an allograft and had an improved 3-year OS of 50% vs 17%, (HR=0.67, 95%CI 0.48-0.93), and 50% improvement in PFS (HR 0.48, 0.33-0.68) compared to those who did not receive an allograft. For patients that received second line treatment (n=176, 52%), re-treatment with alemtuzumab (n=33) produced a 46% ORR (21% CR). Other active second-line treatments included: pentostatin (n=23; 44% ORR, 17% CR), ruxolitinib-based regimens (n=4; 25% ORR, 0% CR), venetoclax-based regimens (n=13; 39% ORR, 8% CR), bendamustine (n=10; 30% ORR, 0% CR), and nelarabine (n=4; 75% ORR, 50% CR). In subgroup survival analysis, TCL1A+ patients had a worse OS and PFS when compared to TCL1A- patients (23 months vs 43 months; p=0.02), and (14 months vs 24 months; p=0.02) respectively, with HR 1.58 (1.08, 2.31) (p=0.02) for OS and HR 1.62 (1.09-2.40) (p=0.02) for PFS. Furthermore, CD4- T-PLL had worse OS (16 months vs 25 months) when compared to CD4+ patients [HR 1.57 (1.08, 2.27), p=0.02]. Single cell RNA seq in 13 patients, including 3 TCL1A- patients, with a total of 66,269 T-PLL cells, demonstrated a unique RNA signature between the CD4+/- and TCL1A+/- patients, suggesting these represent unique molecular subtypes of T-PLL. Conclusions: In this large, multi-center study of T-PLL, frontline treatment with a combination of alemtuzumab/pentostatin improved response rates and OS. Further, among patients who attained a CR, allograft improved OS & PFS vs no allograft. In relapsed T-PLL, retreatment with alemtuzumab had a high ORR, and we report significant activity of multiple novel/alternative agents with the largest reported numbers to date. Intriguingly, TCL1A+, and CD4- T- PLL had worse OS/PFS, and scRNAseq confirmed unique molecular signatures in these populations, suggesting these represent novel molecular subtypes of T-PLL with prognostic significance. These studies form the foundation for future, targeted, therapeutic studies in this rare, aggressive disease with few treatment options.

Abstract There are limited data assessing the risk scores for primary treatment failure (PTF) in patients with classical Hodgkin lymphoma (cHL; PTF-cHL) undergoing autologous hematopoietic cell transplantation (auto-HCT). ECLIPSE (Evaluation of Classical Hodgkin Lymphoma patients wIth Primary treatment failure and analySis of outcomEs) is a multicenter retrospective cohort of patients with PTF-cHL (aged ≥15 years) diagnosed on or after 1 January 2005, at 15 US medical centers. PTF was defined as 1 of the following patterns of failure: (1) progressive disease by imaging during or within 6 weeks of completion of frontline chemotherapy (primary progression [PP]); (2) partial response (PR) or stable disease (SD) by imaging after completion of frontline treatment (PR/SD); (3) progression of disease by imaging (and confirmed by biopsy) within 12 months of frontline therapy completion after prior documentation of complete response (CR; early relapse [ER]). A total of 478 patients were included in the analysis. Among these, 217 (45%) were PP, 86 (18%) were PR/SD, and 175 (37%) were ER. The 6-month and 1-year cumulative incidence of nonrelapse mortality after auto-HCT were 0.9% and 1.1%, respectively. The median progression-free survival (PFS) and overall survival (OS) after auto-HCT were 4.33 and 10.09 years, respectively. Although those not in CR at the time of auto-HCT were associated with inferior PFS and OS, advanced age and diagnosis before 2011 were associated with inferior OS. This study showcases the safety and long-term efficacy of auto-HCT, even in patients with high-risk disease who are traditionally considered chemotherapy refractory, and will serve as a benchmark for the ongoing transplant vs no transplant trials.

Abstract Little is known about risk factors for central nervous system (CNS) relapse in mature T-cell and natural killer cell neoplasms (MTNKNs). We aimed to describe the clinical epidemiology of CNS relapse in patients with MTNKN and developed the CNS relapse In T-cell lymphoma Index (CITI) to predict patients at the highest risk of CNS relapse. We reviewed data from 135 patients with MTNKN and CNS relapse from 19 North American institutions. After exclusion of leukemic and most cutaneous forms of MTNKNs, patients were pooled with non-CNS relapse control patients from a single institution to create a CNS relapse–enriched training set. Using a complete case analysis (n = 182), including 91 with CNS relapse, we applied a least absolute shrinkage and selection operator Cox regression model to select weighted clinicopathologic variables for the CITI score, which we validated in an external cohort from the Swedish Lymphoma Registry (n = 566). CNS relapse was most frequently observed in patients with peripheral T-cell lymphoma, not otherwise specified (25%). Median time to CNS relapse and median overall survival after CNS relapse were 8.0 and 4.7 months, respectively. We calculated unique CITI risk scores for individual training set patients and stratified them into risk terciles. Validation set patients with low-risk (n = 158) and high-risk (n = 188) CITI scores had a 10-year cumulative risk of CNS relapse of 2.2% and 13.4%, respectively (hazard ratio, 5.24; 95% confidence interval, 1.50-18.26; P = .018). We developed an open-access web-based CITI calculator (https://redcap.link/citicalc) to provide an easy tool for clinical practice. The CITI score is a validated model to predict patients with MTNKN at the highest risk of developing CNS relapse.

Introduction: The real-world outcomes in patients (pts) with PCALCL in the era of targeted therapies like Brentuximab Vedotin (BV) is not well defined due to lack of large multicenter studies. We conducted a multicenter retrospective RWA to assess patient and disease characteristics, treatment patterns, survival outcomes and impact of novel therapies in this rare type of cutaneous T cell lymphoma (CTCL). Methods: A total of 95 adult (≥18 years) pts from 8 academic institutions in the United States diagnosed from 2010-2022 were included in the analysis. The study was approved by the Institutional Review Boards at the respective sites. Demographic and disease factors were summarized by descriptive statistics. Overall survival (OS) was estimated by Kaplan-Meier method and compared using log rank method. Results: In our cohort, the median age at diagnosis was 63 (range 18-93) years. The majority of pts were male 60%, white 79%, and had good performance status (PS) ECOG 0-1 (93%). Median time from initial presentation to diagnosis was 1.8 (range 0-211) months. Most common initial skin presentation was tumor 46% (44/95), followed by plaques 27% (26/95) and patches 15% (14/95). No pt presented with erythroderma. Median size of the largest lesion was 2 (range 0.5-20) cm. 63% had early stage (IA-IIA) disease and 86% had <5 skin lesions at the time of initial diagnosis. Furthermore, palpable lymph node (LN) (10%) and elevated LDH (18%) were uncommon at diagnosis. Initial treatments include localized radiation 60%, surgical excision 21% and topical steroids 11%. A small subset of pts received systemic treatments like CHOP 13% (12/95), BV 8% (8/95) and oral methotrexate 7% (7/95) as frontline therapy. A proportion of pts received XRT with CHOP (6/12) and BV (2/8). The overall response rate (ORR) to initial therapy was 68% (65/95) with 61% achieving a CR and 17% had primary refractory disease (stable and progressive disease). Relapse rate after 1st line therapy was 52% (49/95). In our cohort a total of 22 pts received BV after frontline therapy, of which 19 were BV naïve and 3 were re-treated. At the time of last follow up, 27% of our cohort were still on treatment, 78% were alive and 21% were dead; only 3% of deaths were attributed to the lymphoma. The median OS was 128 months (95% CI: 78.4-NA) (Figure 1) with a median follow up of 42 (range 0.5-123.5) months. The 5-year OS was 77%. On univariate analysis, older age (≥65 vs <65 years) (median OS 78 vs 128 months; p=0.004) and higher number of lesions (5-10 vs <5) (mOS 34 vs 128 months; p=<0.0001) were significant associated with OS (Table 1). Type and size of the skin lesions, presence of palpable LN, elevated LDH, stage, and treatment modalities had no impact on OS. Results of multivariate analysis will be presented at the conference. Conclusion: In this large multicenter RWA of PCALCL, excellent long-term survival was observed following frontline therapies that were mostly skin directed. The use of systemic therapies including BV were infrequent even in relapsed disease. Older age and increased number of skin lesions were associated with poor OS.