Current and future management of follicular lymphoma

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.

Pretreatment CT Texture Parameters as Predictive Biomarkers of Progression-Free Survival in Follicular Lymphoma Treated with Immunochemotherapy and Rituximab Maintenance

The purpose of this study was to determine whether texture analysis features present on pretreatment unenhanced computed tomography (CT) images, derived from 18F-fluorodeoxyglucose positron emission/computed tomography (18-FDG PET/CT), can predict progression-free survival (PFS), progression-free survival at 24 months (PFS 24), time to next treatment (TTNT), and overall survival in patients with high-tumor-burden follicular lymphoma treated with immunochemotherapy and rituximab maintenance. Seventy-two patients with follicular lymphoma were retrospectively included. Texture analysis was performed on unenhanced CT images extracted from 18-FDG PET/CT examinations that were obtained within one month before treatment. Skewness at a fine texture scale (SSF = 2) was an independent predictor of PFS (hazard ratio = 3.72 (95% CI: 1.15, 12.11), p = 0.028), PFS 24 (hazard ratio = 13.38; 95% CI: 1.29, 138.13; p = 0.029), and TTNT (hazard ratio = 5.11; 95% CI: 1.18, 22.13; p = 0.029). Skewness values above -0.015 at SSF = 2 were significantly associated with lower PFS, PFS 24, and TTNT. Kurtosis without filtration was an independent predictor of PFS (SSF = 0; HR = 1.22 (95% CI: 1.04, 1.44), p = 0.013), and TTNT (SSF = 0; hazard ratio = 1.23; 95% CI: 1.04, 1.46; p = 0.013). This study shows that pretreatment unenhanced CT texture analysis-derived tumor skewness and kurtosis may be used as predictive biomarkers of PFS and TTNT in patients with high-tumor-burden follicular lymphoma treated with immunochemotherapy and rituximab maintenance.

Cerebellum/liver index in pretherapeutic 18F-FDG PET/CT as a predictive marker of progression-free survival in follicular lymphoma treated by immunochemotherapy and rituximab maintenance

ABSTRACT

The purpose of this study was to investigate the value of the "cerebellum/ liver index for prognosis" (CLIP) as a new prognostic marker in pretherapeutic 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG PET) in patients with follicular lymphoma treated by immunochemotherapy and rituximab maintenance, focusing on progression-free survival (PFS).Clinicobiological and imaging data from patients with follicular lymphoma between March 2010 and September 2015 were retrospectively collected and 5-year PFS was determined. The conventional PET parameters (maximum standardized uptake value and total metabolic tumor volume) and the CLIP, corresponding to the ratio of the cerebellum maximum standardized uptake value over the liver SUVmean, were extracted from the pretherapeutic 18F-FDG PET.Forty-six patients were included. Eighteen patients (39%) progressed within the 5 years after treatment initiation. Five-year PFS was 78.6% when CLIP was >4.0 and 42.0% when CLIP was <4.0 (P = .04). CLIP was a significant predictor of PFS on univariate analysis (hazard ratio 3.1, P = .049) and was near-significant on multivariate analysis (hazard ratio 2.8, P = .07) with ECOG PS as a cofactor.The CLIP derived from pretherapeutic 18F-FDG PET seems to be an interesting predictive marker of PFS in follicular lymphoma treated by immunochemotherapy and rituximab maintenance. These results should be evaluated prospectively in a larger cohort.

Cause of Death in Follicular Lymphoma in the First Decade of the Rituximab Era: A Pooled Analysis of French and US Cohorts

PURPOSE

Although the life expectancy of patients with follicular lymphoma (FL) has increased, little is known of their causes of death (CODs) in the rituximab era.

PATIENTS AND METHODS

We pooled two cohorts of newly diagnosed patients with FL grade 1-3A. Patients were enrolled between 2001 and 2013 in two French referral institutions (N = 734; median follow-up 89 months) and 2002 and 2012 in the University of Iowa and Mayo Clinic Specialized Program of Research Excellence (SPORE; N = 920; median follow-up 84 months). COD was classified as being a result of lymphoma, other malignancy, treatment related, or all other causes.

RESULTS

Ten-year overall survival was comparable in the French (80%) and US (77%) cohorts. We were able to classify COD in 248 (88%) of 283 decedents. In the overall cohort, lymphoma was the most common COD, with a cumulative incidence of 10.3% at 10 years, followed by treatment-related mortality (3.0%), other malignancy (2.9%), other causes (2.2%), and unknown (3.0%). The 10-year cumulative incidence of death as a result of lymphoma or treatment was higher than death as a result of all other causes for each age group (including patients ≥ 70 years of age at diagnosis [25.4% v 16.6%]) Follicular Lymphoma International Prognostic Index score 3 to 5 (27.4% v 5.2%), but not Follicular Lymphoma International Prognostic Index score 0 to 1 (4.0% v 3.7%); for patients who failed to achieve event-free survival within 24 months from diagnosis (36.1% v 7.0%), but not for patients who achieved event-free survival within 24 months of diagnosis (6.7% v 5.7%); and for patients with a history of transformed FL (45.9% v 4.7%), but not among patients without (8.1% v 6.2%). Overall, 77 of 140 deaths as a result of lymphoma occurred in patients whose FL transformed after diagnosis.

CONCLUSION

Despite the improvement in overall survival in patients with FL in the rituximab era, their leading COD remains lymphoma, especially after disease transformation. Treatment-related mortality also represents a concern, which supports the need for less-toxic therapies.

Genetic landscape and deregulated pathways in B-cell lymphoid malignancies

With the introduction of next-generation sequencing, the genetic landscape of the complex group of B-cell lymphoid malignancies has rapidly been unravelled in recent years. This has provided important information about recurrent genetic events and identified key pathways deregulated in each lymphoma subtype. In parallel, there has been intense search and development of novel types of targeted therapy that 'hit' central mechanisms in lymphoma pathobiology, such as BTK, PI3K or BCL2 inhibitors. In this review, we will outline the current view of the genetic landscape of selected entities: follicular lymphoma, diffuse large B-cell lymphoma, mantle cell lymphoma, chronic lymphocytic leukaemia and marginal zone lymphoma. We will detail recurrent alterations affecting important signalling pathways, that is the B-cell receptor/NF-κB pathway, NOTCH signalling, JAK-STAT signalling, p53/DNA damage response, apoptosis and cell cycle regulation, as well as other perhaps unexpected cellular processes, such as immune regulation, cell migration, epigenetic regulation and RNA processing. Whilst many of these pathways/processes are commonly altered in different lymphoid tumors, albeit at varying frequencies, others are preferentially targeted in selected B-cell malignancies. Some of these genetic lesions are either involved in disease ontogeny or linked to the evolution of each disease and/or specific clinicobiological features, and some of them have been demonstrated to have prognostic and even predictive impact. Future work is especially needed to understand the therapy-resistant disease, particularly in patients treated with targeted therapy, and to identify novel targets and therapeutic strategies in order to realize true precision medicine in this clinically heterogeneous patient group.

Intralesional rituximab in primary conjunctival follicular lymphoma relapsed

CLINICAL CASE

A 49-year-old woman experienced a local relapse of a primary follicular lymphoma (FL) of the conjunctiva. She received 4 weekly intra-lesional injections followed by 6 monthly injections of rituximab (6mg/ml). A clinical response was achieved after first injection. No adverse ocular event or signs of lymphoma relapse were seen after 10 months of follow-up.

DISCUSSION

Intralesional administration of rituximab for treating primary FL of the conjunctiva was an effective and safe therapeutic option; therefore it could be an alternative to other conventional treatments, such as radiotherapy or chemotherapy.

Recurrent Mutations in the MTOR Regulator RRAGC in Follicular Lymphoma

PURPOSE

This study was performed to further our understanding of the biological and genetic basis of follicular lymphoma and to identify potential novel therapy targets.

EXPERIMENTAL DESIGN

We analyzed previously generated whole exome sequencing data of 23 follicular lymphoma cases and one transformed follicular lymphoma case and expanded findings to a combined total of 125 follicular lymphoma/3 transformed follicular lymphoma. We modeled the three-dimensional location of RRAGC-associated hotspot mutations. We performed functional studies on novel RRAGC mutants in stable retrovirally transduced HEK293T cells, stable lentivirally transduced lymphoma cell lines, and in Saccharomyces cerevisiae RESULTS: We report recurrent mutations, including multiple amino acid hotspots, in the small G-protein RRAGC, which is part of a protein complex that signals intracellular amino acid concentrations to MTOR, in 9.4% of follicular lymphoma cases. Mutations in RRAGC distinctly clustered on one protein surface area surrounding the GTP/GDP-binding sites. Mutated RRAGC proteins demonstrated increased binding to RPTOR (raptor) and substantially decreased interactions with the product of the tumor suppressor gene FLCN (folliculin). In stable retrovirally transfected 293T cells, cultured in the presence or absence of leucine, multiple RRAGC mutations demonstrated elevated MTOR activation as evidenced by increased RPS6KB/S6-kinase phosphorylation. Similar activation phenotypes were uncovered in yeast engineered to express mutations in the RRAGC homolog Gtr2 and in multiple lymphoma cell lines expressing HA-tagged RRAGC-mutant proteins.

CONCLUSIONS

Our discovery of activating mutations in RRAGC in approximately 10% of follicular lymphoma provides the mechanistic rationale to study mutational MTOR activation and MTOR inhibition as a potential novel actionable therapeutic target in follicular lymphoma. Clin Cancer Res; 22(21); 5383-93. ©2016 AACR.

Rituximab-induced Acute Thrombocytopenia in High Tumor Burden Follicular Lymphoma

Rituximab-induced acute thrombocytopenia (RIAT), a rare complication of rituximab administration, has not yet been described in follicular lymphoma (FL). A 65-year-old man received rituximab for the treatment of high tumor burden follicular lymphoma in the leukemic phase. The next day, his platelet count abruptly dropped from 85,000 to 5,000/μL, which spontaneously recovered in a few days without specific treatment. We speculate that the occurrence of infusion-related cytokine release syndrome in rituximab-sensitive high tumor burden FL contributed to the development of RIAT. Frequent monitoring of the platelet count is advisable for select patients considered to be at a high risk for RIAT.

Dulanermin with rituximab in patients with relapsed indolent B-cell lymphoma: an open-label phase 1b/2 randomised study

BACKGROUND

Dulanermin-a non-polyhistidine-tagged soluble recombinant human apoptosis ligand 2 (Apo2L) or tumour-necrosis-factor-related apoptosis-inducing-ligand (TRAIL)-has pro-apoptotic activity in a range of cancers and synergistic preclinical activity with rituximab against lymphoma in vivo. We aimed to assess the safety, pharmacokinetics, and efficacy of dulanermin and rituximab in patients with relapsed indolent B-cell non-Hodgkin lymphoma.

METHODS

We did an open-label phase 1b/2 randomised study. Four study centres in the USA enrolled patients into phase 1b, and 27 study centres in the USA, Italy, Australia, France, Czech Republic, New Zealand, and Poland enrolled patients into phase 2. In phase 1b, patients (age ≥18 years) with indolent B-cell non-Hodgkin lymphoma with stable disease or better lasting at least 6 months after the most recent rituximab-containing regimen were included. In phase 2, patients (age ≥18 years) with follicular lymphoma grades 1-3a were included. In phase 1b, patients received 4 mg/kg or 8 mg/kg intravenous dulanermin on days 1-5 of up to four 21-day cycles and intravenous rituximab 375 mg/m(2) weekly for up to eight doses. In phase 2, patients were randomly assigned (1:1:1) centrally by an interactive voice response system to dulanermin (8 mg/kg for a maximum of four 21-day cycles), rituximab (375 mg/m(2) weekly for up to eight doses), or both in combination, stratified by baseline follicular lymphoma International Prognostic Index (0-3 vs 4-5) and geographic site (USA vs non-USA). The primary endpoints of the phase 1b study were the safety, tolerability, and pharmacokinetics of dulanermin with rituximab. The primary endpoint of phase 2 was the proportion of patients who achieved an objective response. All patients who received any dose of study drug were included in safety analyses. Efficacy analyses were per protocol. Treatment was open label; all patients and investigators were unmasked to treatment allocation. This study is registered with ClinicalTrials.gov, NCT00400764.

FINDINGS

Between June 6, 2006, and Feb 15, 2007, 12 patients were enrolled in phase 1b, and between April 4, 2007, and April 20, 2009, 60 patients were enrolled in phase 2, of whom 59 were included in safety analyses and 58 in efficacy analyses. No dose-limiting toxic effects were noted in phase 1b. The most common grade 1-2 adverse events in phase 1b were fatigue (nine; 75%), rash (five; 42%), and chills, decreased appetite, diarrhoea, and nausea (four each; 33%). 19 grade 3 or higher adverse effects were noted in five (42%) patients, with 14 occurring in one patient. After treatment with 8 mg/kg of dulanermin, in six patients the mean serum peak concentration was 80 μg/mL, dropping below the minimum detectable concentration (2 ng/mL) within 24 h after the dose. The mean steady state peak and trough concentrations of rituximab were 461 μg/mL (SD 97.5) and 303 μg/mL (92.8), respectively. In phase 2, eight (14%) of 59 patients experienced 12 grade 3 or higher adverse events. In phase 2, objective responses were noted in 14 of 22 (63.6%, 95% CI 41.8-81.3) patients treated with rituximab only, 16 of 25 (64.0%, 43.1-81.5) treated with dulanermin and rituximab, and one of 11 (9.1%, 0.5-39.0) treated with dulanermin only. The study was terminated early, on May 5, 2010, because of an absence of efficacy in the combination group.

INTERPRETATION

The addition of dulanermin to rituximab in patients with indolent B-cell non-Hodgkin lymphoma was tolerable but did not lead to increased objective responses. This combination is not being developed further in non-Hodgkin lymphoma.

FUNDING

Genentech and Amgen.

Chemotherapy-free treatment in patients with follicular lymphoma

The outcome of patients with follicular lymphoma (FL) has improved over the last two decades through the introduction of anti-CD20 monoclonal antibodies, usually used in combination with chemotherapy. However, patients with FL still experience multiple relapses, requiring several lines of treatment. Early toxicity of chemotherapy is a significant concern and as the life expectancy of patients with FL is increasing, late toxicities become an increasingly important concern. Progress made in understanding the biology of FL, especially dysregulation of intracellular pathways and immunological antitumor responses, recently allowed for the development of innovative chemo-free therapeutic approaches. In this report, different options such as new anti-CD20 antibodies, antibodies targeting other cell surface antigens, bi-specific antibodies, immunomodulation, idiotype vaccine and other targeted therapies are presented. The article also highlights how, although promising in early phase studies, the cost-effectiveness of new agents will have to be justified in Phase III trials. Furthermore, chemo-free regimen might not mean toxicity-free treatment and monitoring of early and late toxicities is required.

Activating STAT6 mutations in follicular lymphoma

Follicular lymphoma (FL) is the second most common non-Hodgkin lymphoma in the Western world. FL cell-intrinsic and cell-extrinsic factors influence FL biology and clinical outcome. To further our understanding of the genetic basis of FL, we performed whole-exome sequencing of 23 highly purified FL cases and 1 transformed FL case and expanded findings to a combined total of 114 FLs. We report recurrent mutations in the transcription factor STAT6 in 11% of FLs and identified the STAT6 amino acid residue 419 as a novel STAT6 mutation hotspot (p.419D/G, p.419D/A, and p.419D/H). FL-associated STAT6 mutations were activating, as evidenced by increased transactivation in HEK293T cell-based transfection/luciferase reporter assays, heightened interleukin-4 (IL-4) -induced activation of target genes in stable STAT6 transfected lymphoma cell lines, and elevated baseline expression levels of STAT6 target genes in primary FL B cells harboring mutant STAT6. Mechanistically, FL-associated STAT6 mutations facilitated nuclear residency of STAT6, independent of IL-4-induced STAT6-Y641 phosphorylation. Structural modeling of STAT6 based on the structure of the STAT1-DNA complex revealed that most FL-associated STAT6 mutants locate to the STAT6-DNA interface, potentially facilitating heightened interactions. The genetic and functional data combined strengthen the recognition of the IL-4/JAK/STAT6 axis as a driver of FL pathogenesis.

Dysregulation of microRNAs and their association in the pathogenesis of T-cell lymphoma/leukemias

MicroRNAs (miRNAs) are non-coding regulatory RNAs consisting of 20-24 nucleotides. Over 4,500 miRNAs have been identified in humans, and it is known that nearly all human protein-encoding genes can be controlled by miRNAs in both healthy and malignant cells. Abnormal miRNA expression is known to occur in many cancers, including in malignant lymphomas (MLs). Detailed genome-wide miRNA expression analysis has been performed in various ML subtypes, and these analyses have led to the discovery of subtype-specific miRNA alterations. Actually, in B-cell lymphomas, several miRNAs have been used as prognostic markers, and their targets are for new agents for ML therapy. Successful studies for delineating miRNA functions in B-cell lymphomas lead us to hypothesize that miRNA dysregulation may also be deeply associated with the pathogenesis of T-cell lymphomas. Indeed, studies for delineating essential miRNAs have been conduced against comparatively well-defined T-cell lymphoma entities. In this review, we describe several key miRNAs and their targets in distinct T-cell lymphoma subsets and their roles in their pathogenesis, studies of which will lead to new therapeutic strategies against T-cell lymphomas.

Treatment approaches to asymptomatic follicular lymphoma

Follicular lymphoma is a heterogeneous disease in which some patients present an indolent evolution for decades and others, a rather aggressive form of the disease requiring immediate therapy. While immunochemotherapy has emerged as a standard of care for symptomatic patients, treatment of the asymptomatic population remains controversial. Since the disease is still considered incurable, delayed initiation of therapy is an acceptable option. However, four single injections of rituximab can result in an acceptable clinical response and can improve the duration of the interval without cytotoxic therapy. With recent therapeutic approaches that enable substantial improvements in life expectancy for follicular lymphoma patients, limiting short- or long-term treatment toxicities appears as a new concern in the asymptomatic population. Based on these options, the challenge is to preserve patient quality of life and prolong survival: from the patient's perspective, his/her opinion is therefore of significant importance.

Clinical outcomes of allogeneic stem cell transplantation for relapsed or refractory follicular lymphoma: a retrospective analysis by the Fukuoka Blood and Marrow Transplantation Group

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is considered the only curative treatment for relapsed or refractory follicular lymphoma (FL), but it has a high treatment-related mortality rate. Only a few reports, however, have described the efficacy of allo-SCT for FL in the Japanese population. We retrospectively analyzed the outcome of allo-SCT in 30 patients with FL. Seventeen (56.7 %) patients were chemorefractory, whereas 13 (43.3 %) were chemosensitive. An estimated 2-year overall survival rate (OS) and relapse rate of all patients was 46.7 and 20.0 %, respectively. There were no significant differences in the estimated 2-year OS rate between patients who received myeloablative conditioning and those who received reduced-intensity conditioning (P = 0.98), and among the recipients of related bone marrow (BM)/peripheral blood stem cell, unrelated BM and umbilical cord blood (P = 0.20). In patients who were either chemosensitive or chemorefractory at allo-SCT, the 2-year OS rate was 69.2 and 29.4 % (P = 0.06). Patients with mild-to-moderate acute GVHD had better 2-year PFS rate compared with patients who had severe acute GVHD (P = 0.01), but not better PFS compared with patients who had no acute GVHD (P = 0.12). Our results suggest that the graft-versus-lymphoma effects of allo-SCT may provide survival benefits even in patients with chemorefractory FL.

Rituximab for the treatment of follicular lymphoma

Rituximab is the first and most widely adopted anti-CD20 monoclonal antibody, and has dramatically improved outcomes for patients with B-cell malignancies. Rituximab is active as a single agent and when combined with chemotherapy improves both response rates and survival compared with chemotherapy alone. This approach has become standard of care in this setting. A number of Phase III studies using extended applications of rituximab have demonstrated that patients achieve a significantly longer progression-free survival, at the cost of an increase in infective complications. This has resulted in the widespread adoption of maintenance rituximab following the completion of primary therapy. Rituximab is useful in both previously untreated patients and at relapse, although a subset of patients develop disease that is rituximab resistant, which along with histologic transformation remains a significant management problem for patients with follicular lymphoma. The toxicities are modest and manageable, including infusion reactions, late-onset neutropenia, impaired humoral immunity, reactivation of hepatitis and possibly pulmonary toxicity.