Abhyankar, Anuja

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: NAVD has become a standard-of-care for frontline (1L) treatment (tx) of advanced stage cHL, based on the results of the S1826 study. S1826 demonstrated a 1-year progression free survival (PFS) of 94% for NAVD compared to 86% for brentuximab vedotin-AVD, which remained durable at 2 years (Herrera et al, NEJM 2024). Adverse events (AEs) and efficacy have not been reported in patients (pts) treated with NAVD outside of a clinical trial. Hence, we sought to evaluate safety profile and efficacy outcomes of pts with cHL treated with 1L NAVD in a real-world setting (RWS). Methods: In this multicenter retrospective cohort study, we included pts ≥18 years with cHL treated with 1L standard of care NAVD between 2023 and 2025 at 20 US academic sites. The safety evaluable cohort received at least 1 cycle of NAVD and included pts who have not completed tx. The efficacy evaluable cohort had completed 6 cycles of tx including end of treatment (EOT) PET-CT and included pts who intended to complete tx but died or discontinued due to progressive disease or AEs. The primary endpoint was EOT overall response rate (ORR). Secondary endpoints included EOT complete response rate (CRR), PFS and overall survival (OS). PFS and OS were calculated from the start date of tx and analyzed using the Kaplan Meier method. Results: A total of 311 pts with cHL were treated with NAVD with 26% of pts with tx ongoing (n=83) and 73% with tx completed (n=228). Baseline demographics included 55% male pts, 60% with stage IV disease (stage IIB, n=4) and 84% with nodular sclerosis subtype. Median age was 37 years (range 18-88), 29% had bulky disease (>7.5 cm), 28% were EBV positive (n=74/268), 8% had history of an autoimmune disease, and 31% had an IPS 4-7. G-CSF was given in 64% of pts. All patients were safety evaluable. Tx was interrupted (any length) in 24%, reduced in 12%, and discontinued in 14%. The most common reason for dose reduction was neuropathy in 4%. Nivolumab was discontinued in 10% and all therapy in 3.7% due to toxicity. Any AE and any grade 3 or higher AE (>G3) were observed in 92% and 62%, respectively. Neutropenia of any grade occurred in 68% (48% >G3), infection in 25% (10% >G3), and neuropathy in 30% (2.8% >G3). Hospitalization for an AE occurred in 20% (4.5% febrile neutropenia). Among pts with complete data (n=305), any immune related AE (irAE) occurred in 78 pts (25.6%) with any >G3 irAE in 23 pts (7.5%). The most common irAEs included hypothyroidism (7.9%, all grade 1-2), hepatotoxicity (1.6% G1/G2, 3.3% >G3), inflammatory arthritis (3% G1/G2, 0.6% >G3), rash (2.6%, all grade 1-2), and colitis (1% G1/G2, 1% >G3). Other notable >G3 irAEs included adrenal insufficiency (n=2), AKI/ATN (n=1), myocarditis (n=1), diabetes (n=1) and pancreatitis (n=1). Of 84 irAE events, 47 (56%) have had complete resolution. Among all pts, 14.4% (n=45) required systemic steroids at any time (intravenous in 4.1%), 3.2% (n=10) require ongoing steroids/immunosuppression and 8.3% other therapy for an irAE (n=23 levothyroxine, n=1 hemodialysis, n=1 heart failure tx, n=1 insulin). Among all pts, 265 (85%) had an interim PET-CT after 2-4 cycles. The ORR and CRR at interim PET-CT were 97% and 78%, respectively. In the efficacy evaluable population (n=228), the EOT ORR and CRR were 96% and 90%. The median follow up was 10.2 mo (range 0.27-28.52). The 1-year PFS and OS estimates were 93.8% (95% CI: 90.8-98.4%) and 99.1% (95% CI: 97.9-100%), respectively. In multivariable analysis (MVA), only IPS score (OR 0.6, 95%CI: 0.59-0.60) was associated with lower CRR. In Cox univariable analysis, EBV+ status (HR=14.8, 95% CI: 3.2-69.2), IPS score (HR=1.5, 95% CI: 1.0-2.2), and ESR (HR=1.02, 95% CI: 1.00-1.04) were associated with worse PFS. Among the 11 pts with progression/relapse, 9 were primary refractory. 10 pts were started on second line (2L) therapy, and all pts are alive (1 pt pending 2L tx initiation). There were 2 deaths: one related to infectious complications and other unknown and both occurred after the first cycle of therapy. Conclusions: Pts treated with NAVD in a large RWS showed comparable response rates and 1-year survival outcomes to those in the pivotal S1826 trial. Most AEs were similar and grade 1-2, but close monitoring of irAEs is necessary given the potential long-term toxicity of checkpoint inhibitors and potential for ≥G3 irAEs (7.5%) in this young patient population. Our data supports the use of NAVD for 1L advanced stage cHL.