Minimal Residual Disease Status Predicts Outcome in Patients With Previously Untreated Follicular Lymphoma: A Prospective Analysis of the Phase III GALLIUM Study

Advances in the treatment of high burden Follicular lymphoma: a Comprehensive review

Follicular lymphoma (FL) represents the second most frequent type of non-Hodgkin lymphoma and the most common indolent histology. The disease course of FL is heterogeneous, likely resulting from diverse molecular and immunological features that drive a broad spectrum of clinical presentations. While some patients with low-volume and asymptomatic disease are suitable for observation, patients with high tumor burden, advanced-stage, or symptomatic disease more often necessitate treatment initiation. The decision to begin therapy is personalized and typically initiated when GELF criteria are met. The introduction of novel agents has modified the treatment landscape for FL, allowing for more personalized strategies based on the specific characteristics of patients and diseases. In this review, we discuss the indications for treatment initiation and optimization, focusing on long-term follow-up of pivotal studies and emerging non-chemotherapy regimens. We further consider effective novel combination regimens and future directions for the evolution of frontline immunotherapy for the treatment of patients with FL.

Circulating Tumor DNA as Measurable Residual Disease in Aggressive B-Cell Lymphoma: A Narrative Review

Importance

Achieving remission is the first step toward a cure in treating aggressive B-cell lymphomas. Radiographic imaging, such as fluorodeoxyglucose-positron emission tomography/computed tomography scans are the current standard to define remission at the end of therapy but lack specificity for lymphoma and cannot detect disease at the molecular level. Identifying measurable residual disease with ultrasensitive detection of circulating tumor DNA potentially offers the possibility of improving clinical outcomes.

Observations

Early studies of circulating tumor DNA in aggressive B-cell lymphomas showed a strong association with overall tumor burden, and baseline quantitative levels are associated with clinical outcomes after frontline chemotherapy. Next-generation sequencing methods that detect lymphoma-relevant genetic aberrations in circulating tumor DNA can also be used for noninvasive genotyping that strongly mirror tissue biopsies. Rapid changes in circulating tumor DNA dynamics after 1 or 2 cycles of frontline chemotherapy or within weeks of treatment with chimeric antigen receptor T-cell salvage therapy are also highly prognostic. Although serial monitoring of circulating tumor DNA can detect molecular relapse 3 to 6 months before clinical relapse, improved analytical thresholds are required to detect measurable residual disease at a singular point at the end of therapy. Modern advances in circulating tumor DNA methods now allow for the reliable detection of measurable residual disease, with an analytical detection threshold of 1 in 1 million cell-free DNA molecules.

Conclusions and Relevance

The results of this review suggest that modern ultrasensitive methods of detecting circulating tumor DNA may improve the current definition of remission in aggressive B-cell lymphomas. Incorporating circulating tumor DNA at the end of therapy assessment identifies patients who do not require surveillance monitoring and introduces paradigms of treating measurable residual disease within clinical trials. Practical barriers, including standardization of collection, availability, turnaround times, and cost, remain hurdles preventing widespread implementation into clinical practice.

Advances in Personalized Treatment and Prognostic Factors of Follicular Lymphoma

OPINION STATEMENT

Follicular lymphoma is the most prevalent form of indolent B-cell lymphoma, characterized by gradual disease progression and potential survival over several decades. Although the overall prognosis is typically favorable, some patients remain at risk for disease progression or transformation into a more aggressive variant. Recent advancements in the treatment of relapsed or refractory follicular lymphoma include cereblon modulators, kinase inhibitors, chimeric antigen receptor (CAR) T-cell therapies, and antibody-drug conjugates. Ongoing research into novel prognostic markers may improve the identification of patients at high risk for early progression, multiple relapses, or histological transformation, facilitating more precise and individualized treatment strategies.

Current treatment approach and future perspectives in B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) and follicular lymphoma (FL) represent the two major subtypes of mature B cell lymphoma. A deeper understanding of tumor biology, as well as molecular classification characterized by targetable gene alterations, and the introduction of novel treatment options, including targeted drugs (e.g., antibody-drug conjugates and small molecules [e.g., Bruton tyrosine kinase inhibitor]) and immune therapies (e.g., chimeric antigen receptor [CAR] T cell therapy and bispecific antibody [BsAb]), has changed the treatment paradigms for DLBCL and FL. In clinical practice, however, treatment regimens are determined mainly based on prior treatment history, duration of response after previous treatment, patient age, and patient frailty because there have been few randomized trials to inform treatment selection for patients with relapsed or refractory disease and because there is no single prognostic index that guides suitable treatment for each patient. In this review, we summarize the treatment options for DLBCL and FL and discuss the treatment strategies for these two subtypes. We also discuss future perspectives for the treatment of these subtypes.

Flow Cytometric MRD Detection in Selected Mature B-Cell Malignancies

The quantification of submicroscopic minimal residual disease (MRD) after therapy proved to have independent prognostic significance in many mature B-cell malignancies. With the advent of routine benchtop cytometers capable of simultaneously analyzing ≥8 colors and with improved standardization, flow cytometry has become the method of choice for MRD assessments in some lymphoma entities. Herein we describe general aspects of flow cytometric standardization. Chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are used as examples to explain the technical standardization of flow cytometry for MRD detection according to EuroFlow strategies. MRD data acquisition and detailed analysis in MM and CLL is a particular focus of this chapter.

Surrogate endpoints in mature B-cell neoplasms - meaningful or misleading?

Indolent mature B-cell neoplasms are a group of diseases in which recent therapeutic advances have led to an improved overall survival (OS) extending beyond several years. While cause of celebration for patients and caregivers, the increasingly long observation periods necessary to capture treatment effects are complicating trial design and possibly hindering swift access to more effective therapies. Surrogate endpoints are a tool with the potential of earlier study readouts, however, their validity needs to be proven in each individual disease and therapeutic setting. The validation of surrogate endpoints and available data for mature B-cell neoplasms are discussed within this perspective article, followed by an outlook on the potential of precise tools such as measurable residual disease assessment as novel surrogate candidates.

Follicular lymphoma research: an open dialogue for a collaborative roadmap

Follicular lymphoma (FL) is the second most common type of lymphoma (20% of all non-Hodgkin lymphomas), derived from germinal centre (GC) B cells, and is characterised by its significant clinical, prognostic and biological heterogeneity, leading to complexity in management. Despite significant biological investigation and indisputable clinical progress since the advent of the immunotherapy era more than 20 years ago, much remains to be done to understand and cure this lymphoma. Today, FL is metaphorically a giant puzzle on the table with patches of sky, landscape and foliage clearly appearing. However, many of the remaining pieces are held by various stakeholders (e.g. clinicians, pathologists, researchers, drug developers) without global agreement on what the gaps are, or any clear blueprint on how to solve the puzzle of understanding the heterogeneity of this disease and create curative and tailored therapies. With the advent of new investigation and drug technologies, together with recent advances in our capacity to manage big data, the time seems ripe for a change of scale. More than ever, this will require collaboration between and within all stakeholders to overcome the current bottlenecks in the field. As for every investigator, we acknowledge that this first draft is necessarily biased, incomplete and some FL expert readers might recognise some remaining gaps not addressed. We hope they will reply to make this effort a collaborative one to assemble all the pieces in the most ideal fashion. As such, this review intends to be a first step and an interactive platform to a collaborative roadmap towards better understanding and care of FL.

MRD Detection in B-Cell Non-Hodgkin Lymphomas Using Ig Gene Rearrangements and Chromosomal Translocations as Targets for Real-Time Quantitative PCR and ddPCR

Minimal residual disease (MRD) diagnostics is of high clinical relevance in patients with indolent B-cell non-Hodgkin lymphomas (B-NHL), B-cell chronic lymphocytic leukemia (CLL), and multiple myeloma and serves as a surrogate parameter to evaluate treatment effectiveness and long-term prognosis. Real-time quantitative PCR (RQ-PCR) targeting circulating lymphoma cells is still the gold standard for MRD detection in indolent B-NHL and currently the most sensitive and the most broadly applied method in follicular lymphoma (FL) and mantle cell lymphoma (MCL). Alternatively, droplet digital PCR (ddPCR) can be used for MRD monitoring in multiple myeloma, mantle cell lymphoma, CLL, and FL with comparable sensitivity, accuracy, and reproducibility.The most broadly applicable MRD target in B-NHL is the junctional regions of the rearranged immunoglobulin heavy (IGH) and light chain genes. Complete and incomplete IGH and additionally IG kappa light chain rearrangements can be used as targets for MRD. Next-generation sequencing (NGS) of IG-rearrangements (IG-NGS) as new sequencing-based technology can overcome the limitation of PCR-based approaches and has a potential for higher sensitivity. Chromosomal translocations like the t(14;18)(q32;q21) translocation associated with IGH::BCL2 fusion in FL and t(11;14)(q13;q32) translocation in MCL leading to the IGH::CCND1 fusion can be used as MRD target in selected lymphoma subtypes. In patients with CLL, both flow-cytometry and RQ-PCR are equally suited for MRD assessment as long as a sensitivity of 10-4 is achieved.MRD diagnostics targeting the IG loci is complex and requires extensive knowledge and experience because the junctional regions of each clonal rearranged gene have to be identified before the patient-specific PCR assays can be designed for MRD monitoring. In addition, the presence and load of somatic hypermutation within the rearranged IGH gene occurring during B-cell development of germinal center and post-germinal center B-cell lymphomas may hamper appropriate primer binding leading to false-negative results. The translocations mentioned above have the advantage that consensus forward primers and probes, both placed in the breakpoint regions of chromosome 18 in FL and chromosome 11 in MCL, can be used in combination with a reverse primer placed in the IGH joining region of chromosome 14. PCR-based methods using allele-specific primers can reach a high sensitivity of up to 10-5. This chapter provides all relevant background information and technical aspects for the complete laboratory process from detection of the clonal IG gene rearrangements and the chromosomal translocations at diagnosis to the actual MRD measurements in clinical follow-up samples of B-NHL. However, it should be noted that MRD diagnostics for clinical treatment protocols has to be accompanied by regular international quality control rounds to ensure the reproducibility and reliability of the MRD results. This is available by the EuroMRD network ( https://euromrd.org ), a subgroup of ESHLO ( https://eslho.org ).

In pursuit of a functional cure for follicular lymphoma

We are now a quarter of a century after the transformative impact of rituximab in improving overall survival for patients with follicular lymphoma. With a burgeoning array of effective immunochemotherapy approaches, we can now frame many patients' expectations of longevity and a "functional cure," with survival estimates for many newly diagnosed patients comparable to age- and gender-matched populations. We highlight not just heterogeneity in disease but also in patients, which influences therapeutic decision-making in an immunochemotherapy era where progression-free survival advances are associated with efficacy-toxicity trade-offs, and no clear overall survival advantage is associated with any specific regimen. We provide the metrics that assist, prognostication both at diagnosis and after initial therapy, but we also highlight the limited long-term follow-up in institutional, population, and clinical trial data sets to inform our survival estimates. Nonetheless, the data are sufficient to empower us to reframe more optimistic conversations with our patients and the lymphoma community, discussions that engender hope and planning for a life lived long, and well, after therapy for follicular lymphoma.

Measurable Residual Disease in Mantle Cell Lymphoma: The Unbearable Lightness of Being Undetectable

PURPOSE OF REVIEW

This paper evaluates the benefits and limitations of detecting measurable residual disease (MRD) in mantle cell lymphoma (MCL) and assesses its prognostic value. It also aims to highlight the importance of detecting low MRD levels post-treatment and their application in clinical practice.

RECENT FINDINGS

Recent studies show that MRD levels predict relapse and survival outcomes in hematologic neoplasms, including MCL. RT-qPCR is currently the most used method due to its high reproducibility and sensitivity. Ideal MRD detection should be highly sensitive, cost-effective, and applicable to a wide demographic of patients. This paper concludes that MRD detection has prognostic value in MCL but faces limitations in sensitivity and specificity. Further research is needed to establish the significance of low MRD levels before integrating these methods into clinical practice. Improved MRD detection technologies and understanding their impact on clinical outcomes will guide better patient management in MCL.

Liquid biopsy: Comprehensive overview of circulating tumor DNA (Review)

Traditional tumor diagnosis methods rely on tissue biopsy, which can be invasive and unsuitable for long-term monitoring of tumor dynamics. The advent of liquid biopsy has notably improved the overall management of patients with cancer. Liquid biopsy techniques primarily involve detection of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). The present review focuses on ctDNA because of its significance in tumor diagnosis, monitoring and treatment. The use of ctDNA-based liquid biopsy offers several advantages, including non-invasive or minimally invasive collection methods, the ability to conduct repeated assessment and comprehensive insights into tumor biology. It serves crucial roles in disease management by facilitating screening of high-risk patients, dynamically monitoring therapeutic responses and diagnosis. Furthermore, ctDNA can be used to demonstrate pseudo-progression, monitor postoperative tumor status and guide adaptive treatment plans. The present study provides a comprehensive review of ctDNA, exploring its origins, metabolism, detection methods, clinical role and the current challenges associated with its application.

Long-Term Follow-Up of Patients With Follicular Lymphoma Using Next Generation Sequencing to Detect Minimal Residual Disease

BACKGROUND

Follicular lymphoma (FL) is a highly treatable, indolent non-Hodgkin lymphoma. Although FL is considered incurable, a patient without progression of disease by 24 months after treatment is predicted to have a survival consistent with persons without lymphoma. Using a sensitive assessment of minimal residual disease (MRD), we tested the hypothesis that MRD monitoring can predict long term remissions.

METHODS

Unselected patients who were in a clinical remission for at least 24 months after their last treatment were enrolled and monitored prospectively for MRD detectability using a sensitive next-generation sequencing assay (clonoSEQ, Adaptive Biotechnologies, Seattle, WA).

RESULTS

Forty-seven consecutive patients were monitored. We evaluated the MRD thresholds 10-4, 10-5, and 10-6 for the ability to predict long-term remissions in this cohort and determined that undetectable disease at 10-6 was the best predictor with a specificity and negative predictive value (NPV) of 70% and 100%, respectively. While 3 patients exhibited clinical disease progression during the course of the study, none of the 31 patients with persistent MRD undetectability at 10-6 experienced relapse.

CONCLUSIONS

A significant proportion (31/47; 66.0%) of FL patients in clinical remission after ≥24 months following last therapy were undetectable at 10-6 by a sensitive assay of MRD. The threshold of sensitivity was 100%, specificity 70%, with a PPV of 19%, but a NPV of 100%. Although longer follow-up is needed for confirmation, many of these patients may continue to have durable complete remissions.

Current and future therapies for follicular lymphoma

Follicular lymphoma (FL) is an indolent, germinal center B cell-derived lymphoid neoplasm, for which recent advances in treatment have substantially improved patient survival. However, FL remains an incurable and heterogeneous disease, with groups of patients experiencing early disease progression, histologic transformation, or a high risk of treatment-related toxicity. Additionally, FL is a continually relapsing disease, and response rates and disease-control intervals decrease with each subsequent line of therapy. In this review, we explore the current treatment landscape for relapsed or refractory FL and promising therapies in development, highlighting the efficacy and potential risks of each treatment. We provide a real-world perspective on the unmet needs of patients with FL. Novel therapeutic approaches in development offer a wide array of options for clinicians when treating relapsed or refractory FL. A nuanced approach is required to address the needs of individual patients, taking into consideration both the risks and benefits of each treatment option, as well as patient preferences.

Local radiotherapy and measurable residual disease-driven immunotherapy in patients with early-stage follicular lymphoma (FIL MIRO): final results of a prospective, multicentre, phase 2 trial

BACKGROUND

The mainstay of treatment for early-stage follicular lymphoma is local radiotherapy, with a possible role for anti-CD20 monoclonal antibody (mAb). We aimed to evaluate the effect of these treatments using a measurable residual disease (MRD)-driven approach.

METHODS

This prospective, multicentre, phase 2 trial was conducted at 27 centres of the Fondazione Italiana Linfomi (FIL) in Italy. Eligible participants were adults (≥18 years) with newly diagnosed, histologically confirmed follicular lymphoma (stage I or II; grade I-IIIa). Patients were initially treated with 24 Gy involved-field radiotherapy over 12 days; those who were MRD-positive after radiotherapy or during follow-up received eight intravenous doses (1000 mg per dose; one dose per week) of the anti-CD20 mAb ofatumumab. The primary endpoint was the proportion of patients who were MRD-positive after involved-field radiotherapy and became MRD-negative after ofatumumab treatment. Patients were included in the primary endpoint analysis population if they were positive for BCL2::IGH rearrangement at enrolment in peripheral blood or bone marrow samples. MRD positivity was defined as the persistence of BCL2::IGH rearrangement in peripheral blood or bone marrow, assessed centrally by laboratories of the FIL MRD Network. The trial was registered with EudraCT, 2012-001676-11.

FINDINGS

Between May 2, 2015, and June 1, 2018, we enrolled 110 participants, of whom 106 (96%) were eligible and received involved-field radiotherapy. Of these, 105 (99%) were White, one (1%) was Black, 50 (47%) were male, and 56 (53%) were female. Of 105 participants in whom BCL2::IGH status was evaluable, 32 (30%) had a detectable BCL2::IGH rearrangement at baseline. After radiotherapy, 12 (40%) of 30 patients reached MRD-negative status, which was long-lasting (at least 36 or 42 months) in three (25%). In those who were MRD-positive after radiotherapy, ofatumumab induced MRD-negativity in 23 (92%; 95% CI 74-99) of 25 evaluable patients. After a median follow-up of 46·1 months (IQR 42·8-50·8), 14 (61%) of these 23 patients remain in complete response and are MRD-negative. The most common grade 3-4 adverse events were infusion-related reactions, observed in four patients.

INTERPRETATION

Local radiotherapy is frequently not associated with the eradication of follicular lymphoma. An MRD-driven, anti-CD20 monoclonal antibody consolidation enables molecular remission to be reached in almost all patients and is associated with a reduced incidence of relapse over time. A clinical advantage of an MRD-driven consolidation is therefore suggested.

FUNDING

AIRC Foundation for Cancer Research in Italy, Novartis International, and GlaxoSmithKline.

Progression-free survival is a weakly predictive surrogate end-point for overall survival in follicular lymphoma: A systematic review and meta-analysis

Although progression-free survival (PFS) is a commonly used surrogate end-point for clinical trials of follicular lymphoma (FL), no analyses have evaluated the strength of surrogacy for PFS with overall survival (OS). A systematic review was performed and 20 studies (total participants, 10 724) met final inclusion criteria. PFS was weakly associated with OS (correlation coefficient; 0.383, p < 0.001). The coefficient of determination was 0.15 (95% CI: 0.002-0.35) suggesting 15% of OS variance could be explained by changes in PFS. This challenges the role for PFS as a surrogate end-point for clinical trials and drug approvals.