Neoantigen Landscape Supports Feasibility of Personalized Cancer Vaccine for Follicular Lymphoma.

Personalized cancer vaccines designed to target neoantigens represent a promising new treatment paradigm in oncology. In contrast to classical idiotype vaccines, we hypothesized that 'polyvalent' vaccines could be engineered for the personalized treatment of follicular lymphoma (FL) using neoantigen discovery by combined whole exome sequencing (WES) and RNA sequencing (RNA-Seq). Fifty-eight tumor samples from 57 patients with FL underwent WES and RNA-Seq. Somatic and B-cell clonotype neoantigens were predicted and filtered to identify high-quality neoantigens. B-cell clonality was determined by alignment of B-cell receptor (BCR) CDR3 regions from RNA-Seq data, grouping at the protein level, and comparison to the BCR repertoire from healthy individuals using RNA-Seq data. An average of 52 somatic mutations per patient (range: 2-172) were identified, and two or more (median: 15) high-quality neoantigens were predicted for 56 of 58 FL samples. The predicted neoantigen peptides were composed of missense mutations (77%), indels (9%), gene fusions (3%), and BCR sequences (11%). Building off of these preclinical analyses, we initiated a pilot clinical trial using personalized neoantigen vaccination combined with PD-1 blockade in patients with relapsed or refractory FL (#NCT03121677). Synthetic long peptide (SLP) vaccines targeting predicted high-quality neoantigens were successfully synthesized for and administered to all four patients enrolled. Initial results demonstrate feasibility, safety, and potential immunologic and clinical responses. Our study suggests that a genomics-driven personalized cancer vaccine strategy is feasible for patients with FL, and this may overcome prior challenges in the field.

Myeloablative Vs. Non-Myeloablative Consolidation for Primary Central Nervous System Lymphoma: Results of Alliance 51101.

While it is evident that standard dose whole brain radiotherapy as consolidation is associated with significant neurotoxicity, the optimal consolidative strategy for primary central nervous system lymphoma (PCNSL) is not defined. We performed a randomized phase 2 clinical trial via the U.S. Alliance cancer cooperative group to compare myeloablative consolidation supported by autologous stem cell transplantation with non-myeloablative consolidation after induction therapy for PCNSL. This is the first randomized trial to be initiated that eliminates whole brain radiotherapy as a consolidative approach in newly-diagnosed PCNSL. Patients, age 18-75 years, were randomly assigned in a 1:1 manner to induction therapy (methotrexate, temozolomide, rituximab and cytarabine) followed by consolidation with either thiotepa plus carmustine and autologous stem cell rescue versus induction followed by non-myeloablative, infusional etoposide plus cytarabine (EA) The primary endpoint was progression-free survival (PFS). 113 patients were randomized and 108 (54 in each arm) were evaluable. More patients in the non-myeloablative arm experienced progressive disease or death during induction (28% versus 11%, p = 0.05). Thirty-six patients received autologous stem cell transplant and 34 received non-myeloablative consolidation. The estimated 2-year PFS was higher in the myeloablative versus non-myeloablative arm (73% versus 51%; p= 0.02). However, a planned secondary analysis, landmarked at start of consolidation, revealed that the estimated 2-year PFS in those who completed consolidation therapy was not significantly different between the arms (86% versus 71%; p = 0.21). Both consolidative strategies yielded encouraging efficacy and similar toxicity profiles. Clinicaltrials.gov (NCT01511562).

Durable Responses With Mosunetuzumab in Relapsed/Refractory Indolent and Aggressive B-Cell Non-Hodgkin Lymphomas: Extended Follow-Up of a Phase I/II Study.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Mosunetuzumab is a CD20xCD3 T-cell-engaging bispecific antibody administered as an off-the-shelf, fixed-duration treatment in an outpatient setting. We report an updated analysis of the durability of response, by investigator assessment, after an overall median follow-up of 3.5 years in patients with relapsed/refractory indolent or aggressive B-cell non-Hodgkin lymphoma (iNHL/aNHL) from the dose-escalation stage of a phase I/II study of mosunetuzumab (ClinicalTrials.gov identifier: NCT02500407). Across dose levels, 65.7% of patients with iNHL and 36.4% with aNHL achieved a complete or partial response to mosunetuzumab. Median duration of response (DoR) in patients with iNHL for all responders was 23.2 months (95% CI, 13.8 to not estimable [NE]), but was not reached in complete responders (95% CI, 21.0 to NE). After a median time on study of 38.9 months, no relapses were observed beyond 26 months in complete responders. In patients with aNHL, median DoR for all responders was 7.8 months (95% CI, 4.6 to 22.8). Among 12 complete responders who progressed postmosunetuzumab treatment and were retreated with mosunetuzumab, 83.3% had an objective response and 58.3% achieved a second complete response. Our study reports the longest follow-up using bispecific antibodies in patients with B-cell non-Hodgkin lymphoma and demonstrates that mosunetuzumab can mediate durable remissions with time-limited treatment.

Follow-up from the A041202 study shows continued efficacy of ibrutinib regimens for older adults with CLL.

ABSTRACT: A041202 (NCT01886872) is a phase 3 study comparing bendamustine plus rituximab (BR) with ibrutinib and the combination of ibrutinib plus rituximab (IR) in previously untreated older patients with chronic lymphocytic leukemia (CLL). The initial results showed that ibrutinib-containing regimens had superior progression-free survival (PFS) and rituximab did not add additional benefits. Here we present an updated analysis. With a median follow-up of 55 months, the median PFS was 44 months (95% confidence interval [CI], 38-54) for BR and not yet reached in either ibrutinib-containing arm. The 48-month PFS estimates were 47%, 76%, and 76% for BR, ibrutinib, and IR, respectively. The benefit of ibrutinib regimens over chemoimmunotherapy was consistent across subgroups of patients defined by TP53 abnormalities, del(11q), complex karyotype, and immunoglobulin heavy chain variable region (IGHV). No significant interaction effects were observed between the treatment arm and del(11q), the complex karyotype, or IGHV. However, a greater difference in PFS was observed among the patients with TP53 abnormalities. There was no difference in the overall survival. Notable adverse events with ibrutinib included atrial fibrillation (afib) and hypertension. Afib was observed in 11 patients (pts) on BR (3%) and 67 pts on ibrutinib (18%). All-grade hypertension was observed in 95 pts on BR (27%) and 263 pts on ibrutinib (55%). These data show that ibrutinib regimens prolong PFS compared with BR for older patients with treatment-naïve CLL. These benefits were observed across subgroups, including high-risk groups. Strikingly, within the ibrutinib arms, there was no inferior PFS for patients with abnormalities in TP53, the highest risk feature observed in CLL. These data continue to demonstrate the efficacy of ibrutinib in treatment-naïve CLL.

Long-term outcomes of patients with large B-cell lymphoma treated with axicabtagene ciloleucel and prophylactic corticosteroids.

ZUMA-1 safety management cohort 6 investigated the impact of prophylactic corticosteroids and earlier corticosteroids and/or tocilizumab on the incidence and severity of cytokine release syndrome (CRS) and neurologic events (NEs) following axicabtagene ciloleucel (axi-cel) in patients with relapsed/refractory large B-cell lymphoma (R/R LBCL). Prior analyses of cohort 6 with limited follow-up demonstrated no Grade ≥3 CRS, a low rate of NEs, and high response rates, without negatively impacting axi-cel pharmacokinetics. Herein, long-term outcomes of cohort 6 (N = 40) are reported (median follow-up, 26.9 months). Since the 1-year analysis (Oluwole, et al. Blood. 2022;138[suppl 1]:2832), no new CRS was reported. Two new NEs occurred in two patients (Grade 2 dementia unrelated to axi-cel; Grade 5 axi-cel-related leukoencephalopathy). Six new infections and eight deaths (five progressive disease; one leukoencephalopathy; two COVID-19) occurred. Objective and complete response rates remained at 95% and 80%, respectively. Median duration of response and progression-free survival were reached at 25.9 and 26.8 months, respectively. Median overall survival has not yet been reached. Eighteen patients (45%) remained in ongoing response at data cutoff. With ≥2 years of follow-up, prophylactic corticosteroids and earlier corticosteroids and/or tocilizumab continued to demonstrate CRS improvement without compromising efficacy outcomes, which remained high and durable.

Mosunetuzumab Safety Profile in Patients With Relapsed/Refractory B-cell Non-Hodgkin Lymphoma: Clinical Management Experience From a Pivotal Phase I/II Trial.

BACKGROUND: Mosunetuzumab is a CD20xCD3 T-cell engaging bispecific antibody approved in Europe and the United States for relapsed/refractory (R/R) follicular lymphoma (FL) after ≥ 2 prior therapies. MATERIALS AND METHODS: We present interim safety data from the mosunetuzumab GO29781 (NCT02500407) phase I/II dose-escalation study in R/R non-Hodgkin lymphoma (NHL), focusing on FL. RESULTS: Overall, 218 patients with R/R NHL, including 90 with R/R FL, received a median of eight 21-day cycles of intravenous mosunetuzumab with step-up dosing in Cycle (C) 1 (C1 Day [D] 1, 1 mg; C1D8, 2 mg; C1D15/C2D1, 60 mg; C3D1 and onwards, 30 mg). Cytokine release syndrome (CRS) was the most common adverse event (AE), occurring in 39.4% (NHL) and 44.4% (FL) of patients. Events occurred predominantly during C1 at the first loading dose; the majority were grade 1/2. CRS events were managed at the investigator's discretion with supportive care, steroids, and tocilizumab, based on protocol management guidelines. Immune effector cell-associated neurotoxicity syndrome was uncommon, reported in 0.9% (NHL) and 1.1% (FL) of patients. Neutropenia occurred in 27.5% (NHL) and 28.9% (FL) of patients (mostly grade 3/4) and could be effectively managed using granulocyte colony-stimulating factor. Tumor lysis syndrome occurred in 0.9% (NHL) and 1.1% (FL) of patients (all grade 3/4 with CRS; all resolved). CONCLUSION: Mosunetuzumab monotherapy as treatment for R/R B-cell NHL, including FL, was associated with low rates of severe AEs (including CRS) and is suitable for outpatient administration in the community setting. Adapted protocol guidance for the management of select AEs during mosunetuzumab treatment is included.

A multi-cohort phase 1b trial of rituximab in combination with immunotherapy doublets in relapsed/refractory follicular lymphoma.

Antibodies targeting PD-1 or 4-1BB achieve objective responses in follicular lymphoma (FL), but only in a minority of patients. We hypothesized that targeting multiple immune receptors could overcome immune resistance and increase response rates in patients with relapsed/refractory FL. We therefore conducted a phase 1b trial testing time-limited therapy with different immunotherapy doublets targeting 4-1BB (utomilumab), OX-40 (ivuxolimab), and PD-L1 (avelumab) in combination with rituximab among patients with relapsed/refractory grade 1-3A FL. Patients were enrolled onto 2 of 3 planned cohorts (cohort 1 - rituximab/utomilumab/avelumab; cohort 2 - rituximab/ivuxolimab/utomilumab). 3+3 dose escalation was followed by dose expansion at the recommended phase 2 dose (RP2D). Twenty-four patients were enrolled (16 in cohort 1 and 9 in cohort 2, with one treated in both cohorts). No patients discontinued treatment due to adverse events and the RP2D was the highest dose level tested in both cohorts. In cohort 1, the objective and complete response rates were 44% and 19%, respectively (50% and 30%, respectively, at RP2D). In cohort 2, no responses were observed. The median progression-free survivals in cohorts 1 and 2 were 6.9 and 3.2 months, respectively. In cohort 1, higher density of PD-1+ tumor-infiltrating T-cells on baseline biopsies and lower density of 4-1BB+ and TIGIT+ T-cells in on-treatment biopsies were associated with response. Abundance of Akkermansia in stool samples was also associated with response. Our results support a possible role for 4-1BB agonist therapy in FL and suggest that features of the tumor microenvironment and stool microbiome may be associated with clinical outcomes (NCT03636503).

Loss of CD20 expression as a mechanism of resistance to mosunetuzumab in relapsed/refractory B-cell lymphomas.

ABSTRACT: CD20 is an established therapeutic target in B-cell malignancies. The CD20 × CD3 bispecific antibody mosunetuzumab has significant efficacy in B-cell non-Hodgkin lymphomas (NHLs). Because target antigen loss is a recognized mechanism of resistance, we evaluated CD20 expression relative to clinical response in patients with relapsed and/or refractory NHL in the phase 1/2 GO29781 trial investigating mosunetuzumab monotherapy. CD20 was studied using immunohistochemistry (IHC), RNA sequencing, and whole-exome sequencing performed centrally in biopsy specimens collected before treatment at predose, during treatment, or upon progression. Before treatment, most patients exhibited a high proportion of tumor cells expressing CD20; however, in 16 of 293 patients (5.5%) the proportion was <10%. Analyses of paired biopsy specimens from patients on treatment revealed that CD20 levels were maintained in 29 of 30 patients (97%) vs at progression, where CD20 loss was observed in 11 of 32 patients (34%). Reduced transcription or acquisition of truncating mutations explained most but not all cases of CD20 loss. In vitro modeling confirmed the effects of CD20 variants identified in clinical samples on reduction of CD20 expression and missense mutations in the extracellular domain that could block mosunetuzumab binding. This study expands the knowledge about the occurrence of target antigen loss after anti-CD20 therapeutics to include CD20-targeting bispecific antibodies and elucidates mechanisms of reduced CD20 expression at disease progression that may be generalizable to other anti-CD20 targeting agents. These results also confirm the utility of readily available IHC staining for CD20 as a tool to inform clinical decisions. This trial was registered at www.ClinicalTrials.gov as #NCT02500407.

Blinatumomab consolidation post-autologous stem cell transplantation in patients with diffuse large B-cell lymphoma.

ABSTRACT: Outcomes in patients with relapsed diffuse large B-cell lymphoma (DLBCL) who undergo autologous stem cell transplant (auto-SCT) are poor. Blinatumomab is a CD3/CD19 bispecific T-cell engager that directs cytotoxic T cells to CD19+ cells. Here, we performed a pilot study of blinatumomab consolidation after auto-SCT for 14 patients with DLBCL or transformed follicular lymphoma. All patients underwent standard-of-care auto-SCT with carmustine, etoposide, cytarabine, and melphalan (BEAM) conditioning followed by 1 cycle (4 weeks continuous infusion) of blinatumomab consolidation starting at day 42 after auto-SCT. All 14 patients treated on study completed BEAM auto-SCT and 1 cycle of posttransplant blinatumomab. Five patients developed grade 1 cytokine release syndrome (CRS), with no grade 2 or higher CRS. Immune effector cell-associated neurotoxicity syndrome was not observed. Patients were followed up for 3 years after auto-SCT, with median follow-up of 37 (range, 12-65) months. One-hundred days after auto-SCT (1 month after blinatumomab consolidation), 12 patients (86%) had achieved complete remission. At 1 year after auto-SCT, 7 patients (50%) remained in CR, and 1 patient had died of progressive disease. Patients who relapsed had a lower CD8:CD4 T-cell ratio before starting blinatumomab than patients who remained in remission. This pilot study demonstrates blinatumomab consolidation after auto-SCT is safe and well tolerated. Strategies to increase the CD8:CD4 ratio and use additional cycles of consolidation in a larger randomized trial are needed to confirm the efficacy of consolidation with blinatumomab after auto-SCT. This trial was registered at www.clinicaltrials.gov as #NCT03072771.

Ultra-Deep Sequencing Reveals the Mutational Landscape of Classical Hodgkin Lymphoma.

The malignant Hodgkin and Reed Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL) are scarce in affected lymph nodes, creating a challenge to detect driver somatic mutations. As an alternative to cell purification techniques, we hypothesized that ultra-deep exome sequencing would allow genomic study of HRS cells, thereby streamlining analysis and avoiding technical pitfalls. To test this, 31 cHL tumor/normal pairs were exome sequenced to approximately 1,000× median depth of coverage. An orthogonal error-corrected sequencing approach verified >95% of the discovered mutations. We identified mutations in genes novel to cHL including: CDH5 and PCDH7, novel stop gain mutations in IL4R, and a novel pattern of recurrent mutations in pathways regulating Hippo signaling. As a further application of our exome sequencing, we attempted to identify expressed somatic single-nucleotide variants (SNV) in single-nuclei RNA sequencing (snRNA-seq) data generated from a patient in our cohort. Our snRNA analysis identified a clear cluster of cells containing a somatic SNV identified in our deep exome data. This cluster has differentially expressed genes that are consistent with genes known to be dysregulated in HRS cells (e.g., PIM1 and PIM3). The cluster also contains cells with an expanded B-cell clonotype further supporting a malignant phenotype. This study provides proof-of-principle that ultra-deep exome sequencing can be utilized to identify recurrent mutations in HRS cells and demonstrates the feasibility of snRNA-seq in the context of cHL. These studies provide the foundation for the further analysis of genomic variants in large cohorts of patients with cHL. SIGNIFICANCE: Our data demonstrate the utility of ultra-deep exome sequencing in uncovering somatic variants in Hodgkin lymphoma, creating new opportunities to define the genes that are recurrently mutated in this disease. We also show for the first time the successful application of snRNA-seq in Hodgkin lymphoma and describe the expression profile of a putative cluster of HRS cells in a single patient.

NCCN Guidelines® Insights: B-Cell Lymphomas, Version 6.2023.

Novel targeted therapies (small molecule inhibitors, antibody-drug conjugates, and CD19-directed therapies) have changed the treatment landscape of relapsed/refractory B-cell lymphomas. Bruton's tyrosine kinase (BTK) inhibitors continue to evolve in the management of mantle cell lymphoma (MCL), in both the relapsed/refractory and the frontline setting. Anti-CD19 CAR T-cell therapies are now effective and approved treatment options for relapsed/refractory follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and MCL. Bispecific T-cell engagers represent a novel immunotherapeutic approach for relapsed FL and DLBCL after multiple lines of therapies, including prior CAR T-cell therapy. These NCCN Guideline Insights highlight the significant updates to the NCCN Guidelines for B-Cell Lymphomas for the treatment of FL, DLBCL, and MCL.

Cell-of-origin effect of polatuzumab vedotin in diffuse large B-cell lymphoma: no ordinary subgroup analysis.

ABSTRACT: Subgroup analysis from the POLARIX trial of polatuzumab vedotin plus chemotherapy for untreated large B-cell lymphoma suggests greater efficacy among patients with activated B-cell subtype disease. Both preclinical and additional clinical evidence support this interaction between cell-of-origin and polatuzumab efficacy.

Outcomes of limited stage primary bone diffuse large B-cell lymphoma in the rituximab era: a multicenter, retrospective study.

Primary bone diffuse large B cell lymphoma (DLBCL) is a rare variant of extranodal non-Hodgkin lymphoma (NHL) historically treated with induction chemotherapy followed by consolidative radiation therapy (RT). It remains unknown whether RT confers additional benefit following rituximab-based chemoimmunotherapy (CIT) induction in patients with limited-stage disease. We conducted a multicenter retrospective analysis of patients treated between 2005 and 2019 using rituximab-based CIT regimens with or without consolidative RT to discern whether consolidative RT adds benefit in patients with stage I-II disease that could be encompassed in one radiation field. A total of 112 patients were included: 78 received CIT and radiation (RT group), and 34 received CIT alone (no RT group). The OS at 10 years was 77.9% in the RT group and 89.0% in the no RT group (p = 0.42). The RFS at 10 years was 73.5% in the RT group and 80.3% in the no RT group (p = 0.88). Neither improved OS nor RFS was associated with the addition of consolidative RT. Subgroup analysis of patients only achieving a partial response after CIT suggests that these patients may benefit from consolidative RT.

Mutations associated with progression in follicular lymphoma predict inferior outcomes at diagnosis: Alliance A151303.

Follicular lymphoma (FL) is clinically heterogeneous, with select patients tolerating extended watch-and-wait, whereas others require prompt treatment, suffer progression of disease within 24 months of treatment (POD24), and/or experience aggressive histologic transformation (t-FL). Because our understanding of the relationship between genetic alterations in FL and patient outcomes remains limited, we conducted a clinicogenomic analysis of 370 patients with FL or t-FL (from Cancer and Leukemia Group B/Alliance trials 50402/50701/50803, or real-world cohorts from Washington University School of Medicine, Cleveland Clinic, or University of Miami). FL subsets by grade, stage, watch-and-wait, or POD24 status did not differ by mutation burden, whereas mutation burden was significantly higher in relapsed/refractory (rel/ref) FL and t-FL than in newly diagnosed (dx) FL. Nonetheless, mutation burden in dx FL was not associated with frontline progression-free survival (PFS). CREBBP was the only gene more commonly mutated in FL than in t-FL yet mutated CREBBP was associated with shorter frontline PFS in FL. Mutations in 20 genes were more common in rel/ref FL or t-FL than in dx FL, including 6 significantly mutated genes (SMGs): STAT6, TP53, IGLL5, B2M, SOCS1, and MYD88. We defined a mutations associated with progression (MAP) signature as ≥2 mutations in these 7 genes (6 rel/ref FL or t-FL SMGs plus CREBBP). Patients with dx FL possessing a MAP signature had shorter frontline PFS, revealing a 7-gene set offering insight into FL progression risk potentially more generalizable than the m7-Follicular Lymphoma International Prognostic Index (m7-FLIPI), which had modest prognostic value in our cohort. Future studies are warranted to validate the poor prognosis associated with a MAP signature in dx FL, potentially facilitating novel trials specifically in this high-risk subset of patients.