Abstract: Age-adapted high-dose chemotherapy and autologous stem cell transplantation is safe and highly effective in elderly patients with PCNSL.

Abstract: Induktionstherapie Die weltweit größte Studie mit einem randomisierten Vergleich verschiedener Induktionstherapien zeigte, dass die Hinzunahme von Thiotepa und Rituximab zu einer hochdosierten Methotrexat- (MTX) und Cytarabin- (AraC) Therapie (sogenanntes MATRix-Protokoll) sowohl Ansprechen als auch Gesamtüberleben von Patienten mit Erstdiagnose eines primären ZNS-Lymphoms (PZNSL) verbessert. Die MATRix-Kombination gilt seither in Deutschland und international als neuer Behandlungsstandard. Aktuelle retrospektive Daten belegen die gute Wirksamkeit und Verträglichkeit nicht nur im Rahmen klinischer Studien, sondern auch im klinischen Alltag. Konsolidierungstherapie In den vergangenen Jahren spielt die Hochdosistherapie mit nachfolgender autologer Stammzelltransplantation (HDT-ASZT) als Teil der Erstlinientherapie von Patienten mit PZNSL eine immer wichtigere Rolle. Im Rahmen zweier kürzlich vorgestellter randomisierter Studien wurde bestätigt, dass die HDT-ASZT mit einem 2-Jahres-Gesamtüberleben 〉  80 % einen effektiven Therapieansatz darstellt. Ältere Patienten Aktuelle Daten aus Deutschland belegen die Effektivität einer Therapie mit hochdosiertem MTX in Kombination mit Rituximab und Procarbazin, gefolgt von Erhaltungstherapie mit Procarbazin (PRIMAIN-Protokoll). Retrospektive Daten sowie erste Ergebnisse einer prospektiven Studie zeigen außerdem, dass fitte Patienten 〉  65 Jahre von einer intensiveren Therapie inklusive HDT-ASZT profitieren können. Therapie bei Rezidiv/refraktärem Verlauf Daten einer kürzlich publizierten Studie zeigen bei Patienten bis 66 Jahre Ansprechraten von bis zu 50 % nach Konsolidierungstherapie mittels Thiotepa-basierter HDT-ASZT. Randomisierte Studien zur Rezidivtherapie beim PZNSL liegen derzeit nicht vor. Zielgerichtete Substanzen In den vergangenen Jahren wurden verschiedene Substanzen wie z. B. Lenalidomid und Pomalidomid sowie Ibrutinib mit vielversprechenden Ergebnissen in klinischen Studien untersucht. Aktuell ist in Deutschland noch keine Substanz für die zielgerichtete Therapie von Patienten mit PZNSL zugelassen. Ausblick Intensive Induktionsstrategien sowie die konsolidierende HDT-ASZT stellen zunehmend den Therapiestandard dar. Aktuell laufen weitere große klinische Studien zum Stellenwert der HDT-ASZT sowohl bei jüngeren Patienten im Vergleich zu einer konventionellen Chemotherapie als auch bei älteren Patienten als kurativer Therapieansatz. Zusätzlich werden in Kürze neue Daten zum Einsatz zielgerichteter Substanzen erwartet.

Abstract: Abstract 3089 Introduction: High-dose chemotherapy (HDT) and autologous stem-cell transplantation (ASCT) demonstrated high efficacy in the treatment of newly-diagnosed primary CNS lymphoma (PCNSL) in eligible patients (pts). Prognosis of PCNSL is associated with several clinical and histopathological risk factors (RF). Early complete response (CR) during chemotherapy (CHT) was recently reported to be an additional independent prognostic factor in pts undergoing polychemotherapy without HDT+ASCT. In this analysis, we examined the extent to which known RF determined survival in pts who were treated with HDT-ASCT. We additionally investigated the impact of HDT-ASCT specific factors (e.g. conditioning regimen) on survival. Pts. and Methods: Retrospective multicenter (N=10) analysis of 100 pts with untreated PCNSL who underwent HCT-ASCT with or without whole brain radiotherapy (WBRT). We used univariate and multivariate Cox regression analysis to investigate the prognostic impact of the following factors on overall survival (OS): early CR, age, performance status, involvement of deep brain structures, and LDH serum level and thiotepa dose. Until now data of 82 pts have been analyzed. Results: Median age at diagnosis was 53 years (range 23–69), the majority was male (67%). After a median follow-up of 58 months median OS was reached after 121 mo (range 3–149 mo). Before HDT+ASCT, 48/82 pts (58%) did not achieve CR (35 PR, 3 SD, 10 PD). After HDT+ASCT, 54/82 pts (66%) were in CR and altogether 39% of the pts were irradiated after HDT+ASCT. Of note, of those pts with PD before HDT+ASCT, 5/10 achieved CR after HDT+ASCT without WBRT. Overall, at the time of last follow-up, 24 pts have died. Of the surviving pts, 50 were in CR (86%), 2 in PR (3%), 2 in SD, and 2 developed progression /relapse. None of the established RF (age, performance status, involvement of deep brain structures, and LDH serum level) significantly distinguished outcome with regard to OS in uni and multivariate analysis. Additionally, neither CR before HDT-ASCT, nor sex nor the dose of thiotepa (10mg versu 20mg/m2) was associated with decreased OS. Conclusion: We conclude that HCT+ASCT is able to neutralize established RF in PCNSL. HDT+ASCT is a high-efficient treatment option independently of remission rate before entering HDT. New prognostic factors for pts eligible for HCT-ASCT have to be identified to guide therapy and care for PCNSL pts and to define stratification criteria for future trials. Most recent follow up will be presented. Disclosures: No relevant conflicts of interest to declare.

Abstract: Introduction: Clinical outcomes for patients with central nervous system lymphoma (CNSL) are remarkably heterogeneous, yet identification of patients at high risk for treatment failure remains challenging with existing methods. In addition, diagnosis of CNSL requires invasive neurosurgical biopsies that carry procedural risks and often cannot be performed in frail or elderly patients. Circulating tumor DNA (ctDNA) has shown great potential as a noninvasive biomarker in systemic lymphomas. Yet, previous studies revealed low ctDNA detection rates in blood plasma of CNSL patients. In this study, we utilized ultrasensitive targeted high-throughput sequencing technologies to explore the role of ctDNA for disease classification, MRD detection, and early prediction of clinical outcomes in patients with CNSL. Methods: We applied Cancer Personalized Profiling by Deep Sequencing (CAPP-Seq) and Phased Variant Enrichment and Detection Sequencing (PhasED-Seq, Kurtz et al, Nat Biotech 2021) to 85 tumor biopsies, 131 plasma samples, and 62 CSF specimens from 92 CNSL patients and 44 patients with other brain cancers or inflammatory cerebral diseases, targeting 794 distinct genetic regions. Concentrations of ctDNA were correlated with radiological measures of tumor burden and tested for associations with clinical outcomes at distinct clinical time points. We further developed a novel classifier to noninvasively distinguish CNS lymphomas from other CNS tumors based on their mutational landscapes in plasma and CSF, using supervised training of a machine learning approach from tumor whole genome sequencing data and own genotyping analyses, followed by its independent validation. Results: We identified genetic aberrations in 100% of CNSL tumor biopsies (n=63), with a median of 262 mutations per patient. Pretreatment plasma ctDNA was detectable in 78% of plasma samples and in 100% of CSF specimens (Fig. 1a), with ctDNA concentrations ranging from 0.0004 - 5.94% allele frequency (AF, median: 0.01%) in plasma and 0.0049 - 50.47% AF (median: 0.62%) in CSF (Fig. 1b). Compared to ctDNA concentrations in patients with systemic diffuse large B-cell lymphoma (DLBCL, data from Kurtz et al., J Clin Oncol, 2018), plasma ctDNA levels in CNSL were in median more than 200-fold lower (Fig. 1b). We observed a significant correlation of ctDNA concentrations with total radiographic tumor volumes (TRTV) measured by MRI (Fig. 1c,d), but no association with clinical risk scores (i.e., MSKCC score) or concurrent steroid treatment. Assessment of ctDNA at pretreatment time points predicted progression-free survival (PFS) and overall survival (OS), both as continuous and binary variable (Fig. 1e,f). Notably, patients could be stratified into risk groups with particularly favorable or poor prognoses by combining ctDNA and TRTV as pretreatment biomarkers (Fig. 1g). Furthermore, ctDNA positivity during curative-intent induction therapy was significantly associated with clinical outcomes, both PFS and OS (Fig. 1h). Finally, we applied our novel machine learning classifier to 207 specimens from an independent validation cohort of CNSL and Non-CNSL patients. We observed high specificity (100%) and positive predictive value (100%) for noninvasive diagnosis of CNSL, with a sensitivity of 57% for CSF and 21% for plasma, suggesting that a significant subset of CNSL patients might be able to forego invasive surgical biopsies. Conclusions: We demonstrate robust and ultrasensitive detection of ctDNA at various disease milestones in CNSL. Our findings suggest that ctDNA accurately mirrors tumor burden and serves as a valuable clinical biomarker for risk stratification, outcome prediction, and surgery-free lymphoma classification in CNSL. We foresee an important potential future role of ctDNA as a decision-making tool to guide treatment in patients with CNSL. Figure 1 Figure 1. Disclosures Esfahani: Foresight Diagnostics: Current holder of stock options in a privately-held company. Kurtz: Genentech: Consultancy; Roche: Consultancy; Foresight Diagnostics: Consultancy, Current holder of stock options in a privately-held company. Schorb: Riemser Pharma GmbH: Honoraria, Research Funding; Roche: Research Funding; AbbVie: Research Funding. Diehn: BioNTech: Consultancy; RefleXion: Consultancy; Roche: Consultancy; AstraZeneca: Consultancy; Foresight Diagnostics: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; CiberMed: Current holder of stock options in a privately-held company, Patents & Royalties; Illumina: Research Funding; Varian Medical Systems: Research Funding. Alizadeh: Foresight Diagnostics: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Gilead: Consultancy; Roche: Consultancy, Honoraria; Celgene: Consultancy, Research Funding; Janssen Oncology: Honoraria; CAPP Medical: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Forty Seven: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Cibermed: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Bristol Myers Squibb: Research Funding.

Abstract: Introduction: IELSG32 is an international randomized phase II trial with 2 key clinical questions in pts with PCNSL. The first question focused on optimal induction therapy, and results of the 1st randomization have demonstrated that MATRix combination (methotrexate (MTX), cytarabine (ARAC), thiotepa, rituximab (R)) is associated with significantly better outcome [Ferreri AJ, et al. Lancet Haematol 2016]. The second question addresses the efficacy and neurotolerability of ASCT, as an alternative to WBRT as consolidation. Herein, we report the results of the 2nd randomization (NCT01011920). Methods: HIV-neg pts 18-70 ys and ECOG PS ≤3 with new histology-proven PCNSL and measurable disease were randomly assigned to receive 4 courses of MTX-ARAC (arm A); or R-MTX-ARAC (arm B); or MATRix (arm C). ASC were collected after 2nd c. Pts with responsive or stable disease were further randomized between WBRT 36 ± 9 Gy (arm D) and BCNU-thiotepa conditioned/ASCT (arm E). Stratification parameters were induction arm and response . Primary endpoint of the 2ndrandomization was 2-year PFS. To demonstrate a 2-yr PFS improvement from 65% (P0) to 85% (P1), 52 pts/arm (one-sided; α 5%; β 95%) were required. Consolidation arm would be considered effective if ≥40 pts were progression-free survivors at 2 ys. Analyses were performed on an intention-to-treat (ITT) basis. Effects of consolidation treatments on neurocognitive functions and quality of life (QoL) were assessed with the IPCG tests panel and EORTC-QLQ at baseline, after treatment and every 6 months afterwards. Results: 227 pts were enrolled in 52 centers of 5 countries; 219 assessable pts were referred to 1st randomization (arm A 75; B 69; C 75). 167 pts had responsive or stable disease after induction: 49 pts were excluded from 2nd randomization (poor mobilization, poor condition or patients' refusal); 118 pts were thus randomized (59 pts/arm) and constitute the study population (median age 58 ys; range 18-70). 15 (13%) pts had high IELSG risk, 3 pts had ocular disease and 20 pts had meningeal disease; with the exception of a higher male prevalence in arm D, there were no differences in clinical presentation between two arms; There were 6 protocol violations: 4 pts randomly allocated to arm D were treated with ASCT and 2 pts randomly allocated to arm E were treated with WBRT; 5 pts (D 2; E 3) refused consolidation. Therefore, per-protocol (PP) groups consisted of 55 pts treated with WBRT and 58 with ASCT. Both consolidation therapies were well tolerated. Grade 4 toxicity was uncommon (≤5% of pts); as expected, hematological toxicity was more common in arm E (neutropenia 5% vs. 71%; p=0.00001 - thrombocytopenia 2% vs. 72%; p=0.00001). There were 2 toxic deaths (infections), both in arm E. Neuropsychological tests showed a significant impairment of attention/executive functions and a non-significant trend to impaired memory among pts treated with WBRT, whereas pts treated with ASCT exhibited improved functions. Both consolidation therapies were associated with significant improvement in language and QoL. Both WBRT and ASCT were active and resulted in significant improvement in CR rate: from 54% after induction to 95% (95%CI: 90-100) after consolidation in arm D, and from 53% to 93% (95%CI: 87-99) in arm E. After a median follow-up of 40 months (range 24-76), there were 20 events (16 relapses, 2 PDs, 2 off-therapy deaths) in arm D, and 25 events (18 relapses, 2 PDs, 2 toxic deaths, 3 off-therapy deaths) in arm E. Importantly, WBRT and ASCT were both effective, with a number of progression-free survivors at 2 ys equal to the pre-determined efficacy threshold: 40 among both the first 52 arm-D and 52 arm-E pts. There were no significant differences in PFS between WBRT and ASCT; on ITT basis, the 2-yr PFS was 80 ± 5% after WBRT and 70 ± 6% after ASCT; per protocol, the 2-yr PFS was 76 ± 6% and 75 ± 6%, respectively. In multivariate analysis, IELSG risk group, number of lesions and induction arm were independently associated with PFS; gender, CSF cytology status and consolidation arm were not. Forty-two pts randomized to arm D and 37 randomized to arm E are alive, with 2-year OS of 85 ± 5% and 71 ± 6% (p=0.12), respectively. Conclusions: WBRT and ASCT are both feasible, active and effective as consolidation therapies after high-dose-MTX-based chemoimmunotherapy in pts ≤70 ys with PCNSL. Potential impairment of specific neurocognitive functions after WBRT should be considered at the time of therapeutic decision. Disclosures Ferreri: Sandoz: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Research Funding, Speakers Bureau; Italfarmaco: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adienne: Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees. Fox:Adienne: Honoraria, Research Funding; Takeda: Honoraria, Other: travel funding; Gilead: Honoraria, Other: travel funding; Janssen: Honoraria, Other: travel funding; AbbVie: Consultancy. Röth:Alexion Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria. Johnson:Celldex Therapeutics: Research Funding. Linton:Takeda: Research Funding. Hess:Roche: Honoraria; Novartis: Honoraria; Janssen: Honoraria; Roche, CTI, Pfizer, Celgene: Research Funding; Celgene: Honoraria; Pfizer: Honoraria. Stilgenbauer:Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Genentech: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Hoffman La-Roche: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Genzyme: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau. Rummel:Roche Pharma AG: Other: Personal fees, Research Funding; Mundipharma GmbH: Other: Personal fees, Research Funding. Illerhaus:Riemser: Honoraria; Amgen: Honoraria.

Abstract: To address the role of chronic antigenic stimulation in primary central nervous system lymphoma (PCNSL), we searched for autoantigens and identified sterile α-motif domain containing protein 14 (SAMD14) and neural tissue-specific F-actin binding protein I (neurabin-I) as autoantigenic targets of the B-cell receptors (BCRs) from 8/12 PCNSLs. In the respective cases, SAMD14 and neurabin-I were atypically hyper-N-glycosylated (SAMD14 at ASN339 and neurabin-I at ASN1277), explaining their autoimmunogenicity. SAMD14 and neurabin-I induced BCR pathway activation and proliferation of aggressive lymphoma cell lines transfected with SAMD14- and neurabin-I-reactive BCRs. Moreover, the BCR binding epitope of neurabin-I conjugated to truncated Pseudomonas exotoxin-killed lymphoma cells expressing the respective BCRs. These results support the role of chronic antigenic stimulation by posttranslationally modified central nervous system (CNS) driver autoantigens in the pathogenesis of PCNSL, serve as an explanation for their CNS tropism, and provide the basis for a novel specific treatment approach.

Abstract: Purpose To investigate safety and efficacy of high-dose chemotherapy followed by autologous stem cell transplantation (HCT-ASCT) in patients with relapsed or refractory primary CNS lymphoma (PCNSL). Patients and methods We conducted a single-arm multicentre phase 2 study for immunocompetent patients ( 〈 66 years of age) with PCNSL failing prior HD-MTX based chemotherapy. Induction treatment consisted of 2 courses of rituximab (rituximab 375mg/m2), high-dose cytarabine (2 x 3g/m2) and thiotepa (40mg/m2) with collection of autologous stem cells in between. Conditioning treatment for HCT-ASCT consisted of rituximab 375mg/m2, carmustine 400mg/m2 and thiotepa (4 x 5mg/kg). Patients commenced HCT-ASCT irrespective of response status after induction. Only patients not achieving complete remission (CR) after HCT-ASCT received whole brain radiotherapy (WBRT). The primary endpoint was CR after HCT-ASCT by intention-to-treat (ITT). Secondary endpoints included safety, progression free survival (PFS, time to progression or death) and overall survival (OS, time to death due to any cause). Results Between May 2007 and July 2012, we enrolled 39 patients from 12 German centres. The median age and Karnofsky performance score was 57 years (range 37 to 65) and 90% (range 60% to 100%), respectively. 28 (71.8%) patients had relapsed and 8 (28.2%) refractory disease. 22 (56.4%) patients responded to induction (4 CR, 18 partial remissions [PR]) and 32 (82.1%) patients commenced HCT-ASCT. 22 patients (56.4%, 95% CI 39.6% to 72.2%) achieved CR after HCT-ASCT, 6 (15.4%) achieved PR, and 1 (2.6%) had stable disease. In 9 (17.8%) patients the final scan was not done, because 7 (18.0%) did not undergo HCT-ASCT and 2 died (5.1%) during HCT-ASCT procedure. After a median follow-up of 45.2 months, the respective 2-year PFS and OS rates were 46.0% (95% CI 30.3% to 61.7%, median PFS 12.4 months, Figure 1) and 56.4% (95% CI 40.8% to 72.0%); median OS not reached (Figure 2). The non-relapse mortality rate was 10.3% (95% CI 4.1% to 26.0%) at 1 year without any further increase afterwards. In the subset of 32 patients who received HCT-ASCT, 14 (56.3%) experienced progression or died translating into 1 and 2-year PFS rates (calculated from date of HCT-ASCT) of 62.5% (95% CI 45.7% to 79.3%) and 56.1% (95% CI 38.8% to 73.3%) with no further decrease afterwards. Main grade 3 or higher toxicities were hematological as expected. We recorded four (10.3%) treatment-related deaths, 2 during induction and 2 during HCT-ASCT. Conclusions In eligible PCNSL patients failing HD-MTX based chemotherapy, a short induction with high-dose cytarabine and thiotepa followed by HCT-ASCT is an effective treatment option. Our data provide a reliable benchmark for future comparative studies needed to further scrutinize the role of HCT-ASCT in the salvage setting for PCNSL. Figure 1. Progression free survival Figure 1. Progression free survival Figure 2. Overall survival Figure 2. Overall survival Disclosures Kasenda: Riemser: Other: Travel Support. Schmidt-Wolf:Janssen: Research Funding; Novartis: Research Funding. Röth:Alexion Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria. Stilgenbauer:Amgen: Consultancy, Honoraria, Other: Travel grants, Research Funding; Genentech: Consultancy, Honoraria, Other: Travel grants , Research Funding; Boehringer Ingelheim: Consultancy, Honoraria, Other: Travel grants , Research Funding; Janssen: Consultancy, Honoraria, Other: Travel grants , Research Funding; Hoffmann-La Roche: Consultancy, Honoraria, Other: Travel grants , Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: Travel grants , Research Funding; Novartis: Consultancy, Honoraria, Other: Travel grants , Research Funding; Sanofi: Consultancy, Honoraria, Other: Travel grants , Research Funding; Gilead: Consultancy, Honoraria, Other: Travel grants , Research Funding; AbbVie: Consultancy, Honoraria, Other: Travel grants, Research Funding; Mundipharma: Consultancy, Honoraria, Other: Travel grants , Research Funding; Genzyme: Consultancy, Honoraria, Other: Travel grants , Research Funding; GSK: Consultancy, Honoraria, Other: Travel grants , Research Funding; Celgene: Consultancy, Honoraria, Other: Travel grants , Research Funding. Illerhaus:Riemser: Honoraria; Amgen: Honoraria.