Allogeneic stem cell transplantation for relapsed primary central nervous system lymphoma: Is it feasible?

Molecular characteristics of immunocytes infiltration in primary central nervous system lymphoma

Background: Primary central nervous system lymphoma (PCNSL) is a rare B-cell lymphoma of central nervous system, which is often found in immunocompromised patients. The common clinical treatment of PCNSL is methotrexate (MTX) and whole brain radiation therapy. With the development of tumour immunology research, the tumour microenvironment of PCNSL is characterised by abnormal expression of different immune signature molecules and patients with PCNSL may benefit from tumour immunotherapy.

Methods: In our research, RNA-seq data from 82 PCNSL patients were collated by mining the microarray data from the GEO database. All samples were classified into three types related to tumour immune response by the Cibersort algorithm and consistent clustering. Differential analysis of genes was used to uncover 2 sets of differential genes associated with tumour immunity. The ICI scores of each sample were obtained by PCA algorithm, and the relationship between ICI scores and immune checkpoint expression, immunotherapy and drug sensitivity was investigated. Genes associated with ICI scores and their functional characteristics were investigated by WGCNA analysis and PPI analysis, based on the ICI scores of each sample.

Results: The tumour microenvironment in PCNSL has a greater relationship with the tumour immune response. ICI scores obtained from 375 differential genes were associated with multiple immune responses in PCNSL. PCNSL patients with higher ICI scores had a better tumour microenvironment and were sensitive to immunotherapy and some small molecule drug. This study also identified 64 genes associated with ICI scores, which may serve as important therapeutic and prognostic targets for PCNSL.

Conclusion: The presence of multiple immunosuppressive responses in the tumour microenvironment of PCNSL which suggested that improving the immune function of PCNSL patients through immunotherapy and targeted therapies can be an effective treatment for PCNSL. And the ICI score and associated genes may also provide a better predictor of the clinical use of immunotherapy.

Allogeneic Blood or Marrow Transplantation with Nonmyeloablative Conditioning and High-Dose Cyclophosphamide-Based Graft-versus-Host Disease Prophylaxis for Secondary Central Nervous System Lymphoma

Secondary central nervous system (CNS) lymphoma is a rare and often fatal complication of non-Hodgkin lymphoma (NHL). Treatment options include radiation therapy, high-dose systemic chemotherapy, intrathecal chemotherapy, and high-dose chemotherapy with autologous stem cell rescue, but outcomes remain poor. Allogeneic blood or marrow transplantation (alloBMT) is widely used in patients with relapsed/refractory systemic NHL. We sought to understand whether a graft-versus-lymphoma effect could maintain remission in CNS disease. We reviewed outcomes in 20 consecutive patients with secondary CNS lymphoma who underwent alloBMT with nonmyeloablative conditioning using fludarabine, cyclophosphamide, and 200 cGy total body irradiation. For graft-versus-host disease prophylaxis, all patients received post-transplantation cyclophosphamide, mycophenolate mofetil, and a calcineurin inhibitor. With a median follow up of 4.1 years, the median overall survival for the entire cohort was not reached. Median progression-free survival was 3.8 years (95% confidence interval [CI], 5.3 months to not reached). The cumulative incidence of relapse was 25% (95% CI, 5% to 45%), and nonrelapse mortality was 30% (95% CI, 5% to 54%) at 4 years. Of the 5 patients who relapsed, 2 were CNS only, 1 was systemic only, and 2 were combined CNS/systemic. The use of alloBMT in CNS lymphoma merits further investigation.

Diagnosis, prognosis and treatment of primary central nervous system lymphoma in the elderly population (Review)

Primary central nervous system lymphoma (PCNSL) is a rare subtype of extranodal non-Hodgkin lymphoma that is unique and different from systemic diffuse large B-cell lymphomas. The median age at diagnosis of PCNSL is 65 years and its incidence is rising rapidly in the elderly population. A total of ≥20% of all patients with PCNSL are ≥80 years old. Notably, age has been identified as an independent poor prognostic factor for PCNSL. Elderly patients have an inferior prognosis to that of younger patients and are more severely affected by iatrogenic toxicity; therefore, elderly patients represent a unique and vulnerable treatment subgroup. The present review summarized the available literature to provide an improved understanding of the epidemiology, clinical characteristics, diagnosis, prognosis and management of PCNSL in the elderly population. Notably, the incidence of PCNSL in immunocompetent elderly patients, predominantly in men, is increasing. For the diagnosis of CNSL, imaging-guided stereotactic biopsy is considered the gold standard. When stereotactic biopsy is not possible or conclusive, certain biomarkers have been described that can help establish a diagnosis. PCNSL has a very poor prognosis in the elderly, even though several prognostic scoring systems exist and several prognostic markers have been reported in patients with PCNSL. Furthermore, the treatment of elderly patients remains challenging; it is unlikely that a novel agent could be used as a curative monotherapy; however, a combination of novel agents with polychemotherapy or its combination with other novel drugs may have therapeutic potential.

Systemic Approach to Recurrent Primary CNS Lymphoma: Perspective on Current and Emerging Treatment Strategies

There is no uniform standard of care for the treatment of refractory or recurrent primary central nervous lymphoma (r/r PCNSL). Many different systemic treatment regimens have been studied, but available data are based on small prospective or retrospective reports. There have been no randomized controlled trials in r/r PCNSL to date. Here, we provide an overview of published systemic regimens for the treatment of r/r PCNSL, as well as therapies that are under investigation. In addition, based on available data, we propose strategies of how to approach choice of therapy for different groups of patients in this disease setting. Patients can be mainly divided into three groups: 1) patients suitable for a re-challenge with high-dose methotrexate (HD-MTX)-based regimens and that may or may not be candidates for consolidation with high-dose chemotherapy with autologous stem cell transplant, 2) patients refractory to HD-MTX or that had early relapse, but suitable for an aggressive treatment strategy with re-induction with non-MTX-based therapy, possibly followed by high-dose chemotherapy with autologous transplant, and 3) patients not suitable for re-treatment with HD-MTX and that are not candidates for aggressive therapy. As PCNSL is a rare disease and as there is urgent need for better outcomes in r/r PCNSL, clinical trial participation is encouraged, especially in elderly or frail patients who are not candidates for high-dose chemotherapy and transplant.

CD19 and CD70 Dual-Target Chimeric Antigen Receptor T-Cell Therapy for the Treatment of Relapsed and Refractory Primary Central Nervous System Diffuse Large B-Cell Lymphoma

Background: The therapeutic efficacy of chimeric antigen receptor (CAR) T-cells targeting CD19 has been illustrated in the treatment of diffuse large B-cell lymphoma (DLBCL). However, there is a 21-35% relapse rate after anti-CD19 CAR T-cell induced remission. In addition, CAR T-cell therapy has severe adverse reactions, such as cytokine release syndrome (CRS) and CART-related encephalopathy syndrome (CRES). Because of the potential mortality associated with severe CRES, patients with primary central nervous system lymphoma (PCNSL) are usually excluded from clinical trials involving CAR T-cell therapy. Here, we report a case of refractory and relapsed primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL). Case Presentation: The patient is a 67-year-old male who was diagnosed with PCNSL in 2011. He achieved complete remission (CR) after receiving 6 cycles of temozolomide and high-dose methotrexate. In December 2016, he experienced his first relapse and was treated with surgery and multicourse chemotherapy. He achieved CR again after the treatment. However, he experienced a second relapse in August 2017. MRI revealed a residual mass of 26 mm*35 mm*30 mm on the right side of the post-operative cavity and stale hemorrhage in the left basal ganglia. After confirming the expression of CD19 and CD70 in his tumor samples, the patient was given lymphodepletion chemotherapy followed by infusion of 4th generation CD19-CAR T-cells (4SCART19) and 4th generation CD70-CAR T-cells (4SCART70). One month later, the patient had symptomatic improvement, and brain MRI showed CR. Both CART19 and CART70 cells were detected in the 10th month after CAR T-cell infusion. Notably, neither CRS nor CRES occurred during treatment and follow-up. To date, the patient has maintained disease-free survival with more than 17 months of follow-up. Conclusions: The results of this study indicate that combination of CD19- and CD70-specific CAR T-cells may effectively target PCNSL and maintain disease-free survival without inducing CRS or CRES. Therefore, central nervous system lymphoma is not an absolute contraindication for dual-target CAR T-cell therapy.

Hematopoietic stem cell transplantation in primary central nervous system lymphoma: a review of the literature

Primary central nervous system lymphoma (PCNSL) is an uncommon variant of extranodal non-Hodgkin lymphoma (NHL) with an aggressive course and worse outcomes compared with other lymphomas of similar tumor burden and histologic subtype. High-dose chemotherapy supported by autologous stem cell transplantation (HDC/ASCT) is an option for therapy for this disease in both the relapse setting and as post-remission consolidation. Data are currently limited to only several single-arm phase II trials with small sample sizes, but randomized trials are now ongoing. In this review, we discuss the efficacy, feasibility, and toxicity of HDC/ASCT for PCNSL and its role in the treatment of this aggressive malignancy, both in the first-line and relapse settings. We also bring to attention the current data on allogeneic stem cell transplantation (allo-SCT) in PCNSL.