Vulnerabilities in the tumor and microenvironment in follicular lymphoma

The landscape of T-cell engagers for the treatment of follicular lymphoma

Follicular lymphoma (FL), the second most common subtype of non-Hodgkin lymphoma, relies on interactions with immune elements in the tumor microenvironment, including T-follicular helper cells and follicular dendritic cells, for its survival and progression. Despite its initial responsiveness to chemoimmunotherapy, FL is generally considered incurable. Strategies to improve immune-mediated control of FL could significantly benefit this population, particularly as it includes many elderly and comorbid patients. Immune cell engagers, especially bispecific antibodies (BsAbs), are crucial in targeting FL by bridging tumor and effector cells, thereby triggering T-cell activation and cytotoxic killing. CD3 × CD20 BsAbs have shown the most promise in clinical development for B-NHL patients, with structural variations affecting their target affinity and potency. This review summarizes the current clinical trials of BsAbs for relapsed/refractory FL, highlighting the approval of some agents, their role in first-line treatment or combination therapies, their toxicity profiles, and the future of this therapeutic approach compared to other immune cell therapies.

Impact of positive CD4 cells on event-free survival in follicular lymphoma patients

OBJECTIVE

Previous results about prognostic value of CD4+ T cells in follicular lymphoma (FL) remain controversial.

METHODS

Immunohistochemistry was used to examine expression of positive CD4 cells in 103 patients with FL 1-3A. Early failure was described as failing to achieve event-free survival (EFS) at 12 or 24 months.

RESULTS

There were 49 (47.6%) male and 54 (52.4%) females, with a median age of 54 years. Compared to patients with <20% of positive CD4 cells, patients with ≥20% of positive CD4 cells exhibited a significant lower risk of early failure (2-year EFS rate: 56.7% vs 73.5%, p = 0.047). When patients were stratified based on positive CD4 cell combined with FLIPI, the median EFS (p = 0.002) and median OS (p = 0.007) were significantly different.

CONCLUSIONS

This study demonstrated that higher expression of positive CD4 cells predicts lower risk of early failure in follicular lymphoma, and combination analysis of CD4 and FLIPI could better predict disease relapse and survival outcome.

Glucose metabolism in B cell malignancies: a focus on glycolysis branching pathways

Glucose catabolism, one of the essential pathways sustaining cellular bioenergetics, has been widely studied in the context of tumors. Nevertheless, the function of various branches of glucose metabolism that stem from 'classical' glycolysis have only been partially explored. This review focuses on discussing general mechanisms and pathological implications of glycolysis and its branching pathways in the biology of B cell malignancies. We summarize here what is known regarding pentose phosphate, hexosamine, serine biosynthesis, and glycogen synthesis pathways in this group of tumors. Despite most findings have been based on malignant B cells themselves, we also discuss the role of glucose metabolism in the tumor microenvironment, with a focus on T cells. Understanding the contribution of glycolysis branching pathways and how they are hijacked in B cell malignancies will help to dissect the role they have in sustaining the dissemination and proliferation of tumor B cells and regulating immune responses within these tumors. Ultimately, this should lead to deciphering associated vulnerabilities and improve current therapeutic schedules.

Analyzing the risk factors for disease progression within 2 years and histological transformation in patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone as first-line treatment: A 15-year follow-up of patients with advanced follicular lymphoma in JCOG0203

Follicular lymphoma (FL) is an indolent lymphoma that becomes aggressive due to histological transformation (HT), leading to reduced survival. Patients with FL have different clinical courses and various treatment options. Some patients exhibit shorter survival and experience disease progression within 24 months of diagnosis/treatment (POD24); the optimal treatment remains an unmet needs. Thus, identifying factors that predict shorter survival is essential to stratify treatment and prolong the survival of patients with FL. To analyze risk factors for POD24 and HT in patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) as first-line treatment, we performed this post-hoc analysis of patients with advanced indolent B-cell lymphoma in a randomized clinical trial wherein six cycles of R-CHOP were administered every 2-3 weeks. The primary analysis showed no differences in outcomes, which enabled the analysis of 248 patients with FL, assigned to two arms. All histopathological specimens from the 300 enrolled patients were reviewed by three expert hematopathologists. Multivariable analysis implicated Follicular Lymphoma International Prognostic Index (FLIPI) intermediate (odds ratio [OR] 2.531, 95% confidence interval [CI] 0.676-9.466) and high- (OR 2.236, 95% CI 0.160-31.226) risks, B symptoms (OR 2.091, 95% CI 0.747-5.851), and grade 3A (G3A) (OR 1.833, 95% CI 0.634-5.299) as risk factors for POD24. Furthermore, multivariable analysis through a median follow-up of 15.9 years implicated G3A (OR 2.628, 95% CI 0.806-8.575) and high-risk FLIPI (OR 4.401, 95% CI 0.186-104.377) as risk factors for HT. However, an analysis limited to the first 10 years revealed that the prognostic factors elucidated from the longer-term analysis had a greater impact on HT. G3A and high-risk FLIPI may independently predict POD24 and HT, thereby informing treatment stratification of patients with untreated advanced-stage FL in future trials, particularly to address the unmet needs of patients with POD24.

Unveiling the Role of the Tumor Microenvironment in the Treatment of Follicular Lymphoma

Simple Summary

Follicular lymphoma is the most common type of indolent non-Hodgkin lymphoma and is characterized by its heterogeneity and variable course. In addition to tumor cells, the immune microenvironment plays a fundamental role in the pathogenesis of the disease. Despite advances in treatment, responses vary among patients, and outcomes are often unpredictable: a subset of high-risk patients will be refractory to standard treatments or will develop a high-grade histology. In this review, we try to understand the crosstalk between follicular lymphoma B-cells and the tumor microenvironment as well as its impact on prognosis and the risk of transformation. We also highlight recent findings related to novel therapies developed to treat this complex disease, in which genetic mutations and microenvironment cells play a key role.

Abstract

Follicular lymphomas (FL) are neoplasms that resemble normal germinal center (GC) B-cells. Normal GC and neoplastic follicles contain non-neoplastic cells such as T-cells, follicular dendritic cells, cancer associated fibroblasts, and macrophages, which define the tumor microenvironment (TME), which itself is an essential factor in tumor cell survival. The main characteristics of the TME in FL are an increased number of follicular regulatory T-cells (T_reg) and follicular helper T-cells (T_fh), M2-polarization of macrophages, and the development of a nodular network by stromal cells that creates a suitable niche for tumor growth. All of them play important roles in tumor angiogenesis, inhibition of apoptosis, and immune evasion, which are key factors in tumor progression and transformation risk. Based on these findings, novel therapies have been developed to target specific mutations present in the TME cells, restore immune suppression, and modulate TME.