Rituximab-Lenalidomide-Ibrutinib Combination for Relapsed/Refractory Primary CNS Lymphoma: A Case Series of the LOC Network

Updates of primary central nervous system lymphoma

Lymphoma occurring in the central nervous system is considered primary central nervous system lymphoma (PCNSL), usually without systematic lesions. Over the last few decades, a deep understanding of PCNSL has been lacking due to the low incidence rate, and the overall survival and progression-free survival of patients with PCNSL are lower than those with other types of non-Hodgkin lymphoma. Recently, there have been several advancements in research on PCNSL. Advances in diagnosis of the disease are primarily reflected in the promising diagnostic efficiency of novel biomarkers. Pathogenesis mainly involves abnormal activation of nuclear factor kappa-B signaling pathways, copy number variations, and DNA methylation. Novel therapies such as Bruton's tyrosine kinase inhibitors, immunomodulatory drugs, immune checkpoint inhibitors, and phosphoinositide 3-kinase/mammalian target of rapamycin inhibitors are being evaluated as possible treatment options for PCNSL, especially for relapsed/refractory (R/R) cases. Several clinical trials also indicated the promising feasibility and efficacy of chimeric antigen receptor T-cell therapy for selected R/R PCNSL patients. This review focuses on discussing recent updates, including the diagnosis, pathogenesis, and novel therapy of PCNSL.

Primary central nervous system lymphomas: EHA-ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up

This EHA-ESMO Clinical Practice Guideline provides key recommendations for managing primary DLBCL of the CNS.The guideline covers clinical, imaging and pathological diagnosis, staging and risk assessment, treatment and follow-up.Algorithms for first-line and salvage treatments are provided.The author group encompasses a multidisciplinary group of experts from different institutions and countries in Europe.Recommendations are based on available scientific data and the authors' collective expert opinion.

[New treatment strategies for primary lymphoma of the central nervous system]

Primary central nervous system lymphomas (PCNSL) are rare highly aggressive diffuse large B cell non-Hodgkin lymphomas confined to the brain, meninges, the spinal cord and the eyes. Although the implementation of high-dose methotrexate-based chemotherapy has significantly improved the prognosis of PCNSL during the last decades, about one third of patients show refractory disease and about half of the patients eventually relapse after having achieved complete response. This highlights the need for novel treatment strategies. The most promising progress has been made in the field of molecular targeted therapy that interferes with the oncogenic signaling pathways of PCNSL. These include inhibitors of Bruton tyrosine kinase and inhibitors of the PI3K/mTOR signaling pathway. In addition, the thalidomide analogues lenalidomide and pomalidomide, which belong to the class of immunomodulators, show efficacy in the treatment of PCNSL. As immune evasion appears to play a relevant pathogenetic role in PCNSL, immunotherapies in the treatment of PCNSL are the subject of intensive research. Promising initial clinical data are available for both immune checkpoint inhibitors and cellular immunotherapy with chimeric antigen receptor (CAR) T cells. Before the widespread clinical application of these novel therapies, the efficacy needs to be confirmed in larger prospective studies. Despite high response rates, targeted therapies and immunotherapy often fail to achieve lasting tumor control. Therefore, novel approaches are currently being investigated in combination protocols.

Primary central nervous system lymphoma (PCNSL) in older patients

INTRODUCTION

Primary central nervous system lymphoma (PCNSL) is a rare, chemo and radio-sensitive tumor limited to the central nervous system. The incidence of PCSNL increases notably in the elderly population which represented approximately half of the patients. The limit of 'elderly' population remained debated and nonuniform, including 60 years as a cutoff for brain radiotherapy, 65 years for autologous stem-cell transplantation, and 70 years for the last clinical trials. Current therapeutic options include first line treatment based on high-dose methotrexate based polychemotherapy, consolidation chemotherapy, and adapted autologous stem cell transplantation for highly selected patients. At relapse, single agent targeted therapies or salvage chemotherapy followed by intensive consolidation are promising therapeutic options. Nevertheless, improving management of elderly patients is an urgent medical need that currently remains unresolved.

OBJECTIVE

We will focus on elderly patients with PCNSL and their specificities including clinical presentations, available therapeutic options and adaptations to be made.

CONCLUSION

To improve survival, it will be necessary to personalized and adapt the treatments, to each patient and his comorbidities, to increase their effectiveness and limit their toxicity in this frail population. Finally, inclusion of these patients in clinical trials is one of the major challenges to significantly change PCNSL elderly patient prognosis.

New hopes in relapsed refractory primary central nervous system lymphoma

PURPOSE OF REVIEW

Patients with relapsed/refractory primary central nervous system lymphoma (rrPCNSL) have poor prognosis, with a median survival after relapse of 6.8 months. In this review, we discuss the evolving landscape and the possible future directions related to this important unmet clinical need.

RECENT FINDINGS

The modern two-phase approach for newly diagnosed PCNSL based on an induction using high-dose methotrexate (HD-MTX) combinations and a subsequent consolidation, has significantly improved the outcome in this setting. However, this strategy is able to cure more or less 50% of patients. rrPCNSL patients have a very poor prognosis with a reported 5-year overall survival of 18%. Late relapses (after third year) and use of high-dose chemotherapy and autologous stem cell transplantation (HDT-ASCT) represent important factors associated with a better outcome in this setting. On the basis of the growing acquisition of knowledge on the molecular characteristics of PCNSL, the use of non-chemotherapeutic drugs such as bruton tyrosine kinase inhibitors (BTK-is), immunomodulatory drugs (IMiDs) and immune checkpoint blockers (ICBs) is increasing in the last years along with the introduction of novel approaches (CAR-T cells and blood--brain barrier disruption). However, despite high responses in some cases, durations are often short, translating in outcome results still unsatisfactory.

SUMMARY

Treatment of rrPCNSL patients is challenging. As no standard of care exist in this setting, it is of paramount importance to acquire new knowledge related to this condition and start multidisciplinary collaboration in order to improve pts outcome.

Central nervous system lymphomas-Assessment and treatment and prevention of central nervous system relapse

In this review focused on lymphoma and the central nervous system (CNS), we summarize recent developments in the management of primary (PCNSL) and secondary CNS lymphoma (SCNSL), treatment of CNS lymphoma in the older population, the neuroradiological assessment of CNS lymphoma and finally highlight the ongoing debate on optimal CNS prophylaxis. The section on PCNSL focuses on the different approaches available for frontline treatment in Europe and the United States and discusses consolidation strategies. We then highlight available strategies to treat PCNSL in the elderly population, an area of unmet need. New therapies aiming at minimizing toxicity and prioritizing quality of life are emerging for these patients. Secondary CNS lymphoma, especially in the relapsed/refractory setting is another area of unmet need, and the efficacy of CAR-T cell therapy is being explored. We provide an overview of the imaging challenges in the neuroradiological assessment of CNS lymphoma. Finally, the section on CNS prophylaxis summarizes recent findings from large retrospective studies challenging the efficacy of present approaches to prophylaxis in higher-risk patients with lymphoma.

European Association of Neuro-Oncology (EANO) guidelines for treatment of primary central nervous system lymphoma (PCNSL)

The management of primary central nervous system (PCNSL) is one of the most controversial topics in neuro-oncology because of the complexity of the disease and the limited number of controlled studies available. In 2021, given recent advances and the publication of practice-changing randomized trials, the European Association of Neuro-Oncology (EANO) created a multidisciplinary task force to update the previously published evidence-based guidelines for immunocompetent adult patients with PCNSL and added a section on immunosuppressed patients. The guideline provides consensus considerations and recommendations for the treatment of PCNSL, including intraocular manifestations and specific management of the elderly. The main changes from the previous guideline include strengthened evidence for the consolidation with ASCT in first-line treatment, prospectively assessed chemotherapy combinations for both young and elderly patients, clarification of the role of rituximab even though the data remain inconclusive, of the role of new agents, and the incorporation of immunosuppressed patients and primary ocular lymphoma. The guideline should aid the clinicians in everyday practice and decision making and serve as a basis for future research in the field.

Radiotherapy or chemotherapy: a real-world study of the first-time relapsed and refractory primary central nervous system lymphoma

Background

Primary central nervous system lymphoma (PCNSL) is an uncommon variant of non-Hodgkin lymphoma (NHL) with high aggressiveness and poor prognosis. Although complete remission (CR) could be achieved with therapy, some patients remain refractory or recurrently with a worse response to salvage treatment and poor prognosis. No consensus on rescue therapy has been established currently. This study is aimed to evaluate the efficacy of radiotherapy or chemotherapy in first-time relapsed or refractory progressed PCNSL (R/R PCNSL) and analysis the prognostic factors, to explore differences between relapsed and refractory PCNSL.

Methods

Totally 105 R/R PCNSL patients from Huashan Hospital between 1 January 2016 and 31 December 2020 were enrolled, underwent salvage radiotherapy or chemotherapy and received response assessments after each course. PFS1 was defined as the time from diagnosis to the first time of recurrence or refractory progression. Statistical analysis was performed with SPSS version 26.0.

Results

Response and survival were analyzed over a 17.5months (median) follow-up. Compared to relapsed PCNSL (n = 42), refractory PCNSL (n = 63) had a shorter median PFS1 related to deep lesions. 82.4% of cases were discovered as the second relapse or progression. ORR and PFS were both higher in relapsed PCNSL than those in refractory PCNSL. ORR of radiotherapy in both relapsed and refractory PCNSL was higher than that of chemotherapy. Elevated CSF protein and ocular involvement were related to PFS and OS after recurrence respectively in relapsed PCNSL. Age ≥ 60y was unfavorable to OS-R (OS after recurrence or progression) in refractory PCNSL.

Conclusions

Our results indicate that relapsed PCNSL responds well to inducing and salvage therapy and has a better prognosis compared to refractory PCNSL. Radiotherapy is effective for PCNSL after the first relapse or progression. Age, CSF protein level, and ocular involvement could be potential factors to predict prognosis.

Performance status, comorbidities, and cycles of methotrexate exert the greatest influence on outcomes of primary and secondary CNS lymphomas: the Lexington experience

Primary central nervous system lymphoma (PCNSL) occurs primarily in older patients and has a worse prognosis than other extranodal lymphomas. Contemporary treatment is based on high-dose methotrexate (HD-MTX), which crosses the blood-brain barrier. Secondary CNS lymphoma (SCNSL) can occur concomitantly with systemic lymphoma or later at relapse and generally has a dismal outcome. We reviewed disease characteristics and outcomes of 103 patients (44 PCNSL and 59 SCNSL) treated at our center between 2015 and 2020. Median ages at diagnosis were 64 and 62 years, respectively. In both groups, diffuse large B cell lymphoma (DLBCL) was the major histologic type; in SCNSL, other types were also seen. SCNSL, in contrast with PCNSL, manifested with smaller tumors or cerebrospinal fluid positivity. For SCNSL the mean interval to brain involvement was 18 months (0-138). The overall survival had a trend to worse in SCNSL; median survival 11 months versus 61 months in PCNSL (p = 0.089). Progression-free survival was similar in both groups. A significant proportion of SCNSL patients with poor performance status could not obtain CNS-directed treatments. The strongest predictor of poor outcome was ECOG performance status 2 + at diagnosis for both groups. Charlson comorbidity index was predictive only for the PCNSL cohort. Tumor size was not prognostic for survival. The number of HD-MTX cycles correlated with survival, whereas the regimen itself and average cumulative dose of methotrexate did not play a role. Our study is in line with the recent literature and confirms ongoing challenges. We discuss how the outcomes of CNS lymphomas can be improved.

Primary central nervous system lymphoma: advances in its pathogenesis, molecular markers and targeted therapies

PURPOSE OF REVIEW

Primary central nervous system lymphoma (PCNSL) is a rare subtype of diffuse large B-cell lymphoma (DLBCL) located in the CNS with a less favorable prognosis. Recent information addressing the disease molecular heterogeneity is paving the way for tailored treatment strategies. This article reviews current work on the pathogenesis of the disease, potential biomarkers, and treatments.

RECENT FINDINGS

Previous molecular classifications of PCNSL, built on DLBCL heterogeneity, did not properly address its intrinsic variability. Recent evidence has shown the existence of four different molecular PCNSL subtypes with associated multiomic characteristics, including prognostic relevance. Several studies have identified the tumor microenvironment (TME) as a driving prognostic factor in PCNSL. Therapy efforts continue mainly into targeting either the NF-κβ (nuclear factor kappa-light-chain enhancer of activated B cells) pathway or modulating the TME through immunomodulatory drugs (lenalidomide) or immunotherapy (antiprogrammed cell death 1/programmed cell death 1 ligand 1).

SUMMARY

Despite the increasing understanding of PCNSL pathogenesis with recent studies, future efforts are still needed to yield diagnostic biomarkers to detect either PCNSL or its molecular subtypes and hence ease routine clinical use.

Treatment Options for Recurrent Primary CNS Lymphoma

OPINION STATEMENT

Primary CNS lymphoma (PCNSL) constitutes a rare extranodal variant of non-Hodgkin lymphoma (NHL) with an annual incidence of 0.45/100,000. Given the paucity of large prospective clinical trials, there is no consensus treatment for refractory or relapsed (r/r) PCNSL, and available strategies are largely based on retrospective analyses. Patient age, performance status, previously administered treatment, duration of response, and molecular characteristics guide selection of salvage therapy. Patients with a good performance status (KPS >70), particularly ≤65 years, and adequate organ function should be considered for salvage polychemotherapy. Based on its high overall response rate even in the relapsed setting, we choose high-dose (≥ 3.5g/m²) methotrexate (HD-MTX) based regimens, e.g., R-MPV (rituximab, HD-MTX, procarbazine, and vincristine), for remission re-induction as long as patients were sensitive to first line HD-MTX-based regimens, especially when duration of previous response was ≥ 1 year. Following successful remission induction, we choose myeloablative chemotherapy (e.g., thiotepa, busulfan, cyclophosphamide) and subsequent autologous stem cell transplant in curative intent whenever feasible. Alternatively, conventional chemotherapy regimens (for example, monthly HD-MTX) or low-dose whole-brain radiation therapy (WBRT) are selected for consolidation in non-transplant candidates in complete remission. In cases of HD-MTX refractory disease or contraindications, we use pemetrexed; temozolomide/rituximab; high-dose cytarabine; or whole brain radiation for remission induction. Clinical trial participation is considered as well. Emerging therapies for upfront or salvage therapy under ongoing investigation include bruton tyrosine kinase inhibition (e.g., ibrutinib), immunomodulatory drugs (e.g., lenalidomide), immune checkpoint inhibitors (ICI, e.g., nivolumab), and chimeric antigen receptor T (CAR-T) cell therapy.

BTK inhibitors in the treatment of hematological malignancies and inflammatory diseases: mechanisms and clinical studies

Bruton's tyrosine kinase (BTK) is an essential component of multiple signaling pathways that regulate B cell and myeloid cell proliferation, survival, and functions, making it a promising therapeutic target for various B cell malignancies and inflammatory diseases. Five small molecule inhibitors have shown remarkable efficacy and have been approved to treat different types of hematological cancers, including ibrutinib, acalabrutinib, zanubrutinib, tirabrutinib, and orelabrutinib. The first-in-class agent, ibrutinib, has created a new era of chemotherapy-free treatment of B cell malignancies. Ibrutinib is so popular and became the fourth top-selling cancer drug worldwide in 2021. To reduce the off-target effects and overcome the acquired resistance of ibrutinib, significant efforts have been made in developing highly selective second- and third-generation BTK inhibitors and various combination approaches. Over the past few years, BTK inhibitors have also been repurposed for the treatment of inflammatory diseases. Promising data have been obtained from preclinical and early-phase clinical studies. In this review, we summarized current progress in applying BTK inhibitors in the treatment of hematological malignancies and inflammatory disorders, highlighting available results from clinical studies.

Secondary Central Nervous System Lymphoma: Updates in Treatment and Prophylaxis Strategies

OPINION STATEMENT

Referring to any central nervous system (CNS) involvement with preceding or concurrent systemic disease, secondary CNS lymphoma (SCNSL) lacks a clear standard of care and historically carries a very poor prognosis. Aggressive histologies predominate, most notably diffuse large B cell lymphoma (DLBCL), with higher relative frequency in Burkitt lymphoma but lower absolute incidence. Therapeutic strategies commonly feature intensive CNS-penetrant chemotherapy, including methotrexate, cytarabine, and others. Combination regimens, novel targeted agents, and cellular therapy considerations are reviewed, noting that patients with SCNSL are often excluded from clinical trials and dedicated SCNSL studies are historically limited. Given these challenges, there has been renewed attention on CNS prophylaxis as well as strategies for early CNS detection. Prophylaxis is standard of care in Burkitt lymphoma, whereas its role in DLBCL and related histologies is increasingly unclear.

Update on Novel Therapeutics for Primary CNS Lymphoma

Simple Summary

Primary central nervous system lymphoma is a rare and aggressive form of non-Hodgkin lymphoma. While it is highly responsive to first-line chemo and radiation treatments, rates of relapse are high, demonstrating the need for improved therapeutic strategies. Recent advancements in the understanding of the pathophysiology of this disease have led to the identification of new potential treatment targets and the development of novel agents. This review aims to discuss different targeted strategies and review some of the data supporting these approaches, and discusses recently completed and ongoing clinical trials using these novel agents.

Abstract

Primary central nervous system lymphoma (PCNSL) is a rare lymphoma isolated to the central nervous system or vitreoretinal space. Standard treatment consists of cytotoxic methotrexate-based chemotherapy, with or without radiation. Despite high rates of response, relapse is common, highlighting the need for novel therapeutic approaches. Recent advances in the understanding of PCNSL have elucidated mechanisms of pathogenesis and resistance including activation of the B-cell receptor and mammalian target of rapamycin pathways. Novel treatment strategies such as the Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib, phosphatidylinositol-3 kinase (PI3K) inhibitors, and immunomodulatory drugs are promising. Increasingly, evidence suggests immune evasion plays a role in PCNSL pathogenesis and several immunotherapeutic strategies including checkpoint inhibition and targeted chimeric antigen receptor T (CAR-T) cells are under investigation. This review provides a discussion on the challenges in development of targeted therapeutic strategies, an update on recent treatment advances, and offers a look toward ongoing clinical studies.